docker – Chris Kelly's Ramblings

Docker for Developers Part 2

January 17, 2016January 18, 2016 ckelly Leave a comment

The Saga continues

This is a continuation of my previous post which was an introduction to docker geared for developers. In the previous post, we got somewhat familiar with the docker ecosystem and built a very simple hello world application. In this part we are going to get dynamodb running locally, run a one off script to preload data, build a sample api service that reads from dynamo, and finally a sample website that reads from that api service. As with the first part, you can retrieve a copy of the completed code base off github or directly download the assets for part 2 here.

Running DynamoDB

Before we can really start building our API server, we need a place to store data. As we learned in the previous part, we can use docker-compose files to orchestrate the various services that make up our application. This could be a postgres or mysql instance, however in this case the application is going to leverage DynamoDB for storage. When developing the application it doesn’t make sense to create an actual dynamo table on AWS as you would incur some costs for something that is only going to be used for development. There are some caveats and limitations to this however which you can read about here. Since we would never want a local dynamodb container running in any environment other than development, we want to go ahead and edit docker-compose.override.yml with the following:

$ cat docker-compose.override.yml
movie-api:
 build: ./movie-api
 ports:
 - "8080:5000"
 volumes:
 - ./movie-api:/code
dynamodb:
 image: kcyeu/dynamodb-local
 ports:
 - 8000

$ cat docker-compose.override.yml

movie-api:

build: ./movie-api

ports:

- "8080:5000"

volumes:

- ./movie-api:/code

dynamodb:

image: kcyeu/dynamodb-local

ports:

- 8000

Save that file, and run docker-compose up -d and you should see output that the dynamodb container is running alongside our movie-api instance

→ docker ps
CONTAINER ID        IMAGE                         COMMAND                  CREATED             STATUS              PORTS                                             NAMES
3ce66d3f8e7e        kcyeu/dynamodb-local          "java -Djava.library."   2 minutes ago       Up 2 minutes        0.0.0.0:32775-&gt;8000/tcp                           dockermoviedbdemo_dynamodb_1
f34099a7531d        dockermoviedbdemo_movie-api   "/bin/sh -c 'python a"   6 days ago          Up 5 minutes        0.0.0.0:8080-&gt;5000/tcp, 0.0.0.0:32774-&gt;5000/tcp   dockermoviedbdemo_movie-api_1

→ docker ps

CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES

3ce66d3f8e7e kcyeu/dynamodb-local "java -Djava.library." 2 minutes ago Up 2 minutes 0.0.0.0:32775->8000/tcp dockermoviedbdemo_dynamodb_1

f34099a7531d dockermoviedbdemo_movie-api "/bin/sh -c 'python a" 6 days ago Up 5 minutes 0.0.0.0:8080->5000/tcp, 0.0.0.0:32774->5000/tcp dockermoviedbdemo_movie-api_1

Now that DynamoDB is running we need to be able to link our API container to it so that they can communicate. Our Compose file needs one small change..

movie-api:
  build: ./movie-api
  links:
    - dynamodb
  ports:
    - "8080:5000"
  volumes:
    - ./movie-api:/code
dynamodb:
  image: kcyeu/dynamodb-local
  ports:
    - 8000

movie-api:

build: ./movie-api

links:

- dynamodb

ports:

- "8080:5000"

volumes:

- ./movie-api:/code

dynamodb:

image: kcyeu/dynamodb-local

ports:

- 8000

Rerun docker-compose up -d which will recreate the movie-api-1 container.

Loading data into DynamoDB

Now that we have dynamodb running, we can show how to run a one off command to invoke a script that will seed data into dynamo. First, we can create the directory structure for storing our sample data and a place for our seed scripts. Within the movie-api directory create two new directors. One called scripts and the other data. We can use an amazon published sample data set for building this application. You can retrieve it here and extract this to the data directory.

The application directory structure should now look like this:

→ tree docker-movie-db-demo
docker-movie-db-demo
├── README.md
├── docker-compose.override.yml
├── docker-compose.yml
├── movie-api
│   ├── Dockerfile
│   ├── app.py
│   ├── data
│   │   └── moviedata.json
│   ├── demo
│   │   ├── __init__.py
│   │   ├── __init__.pyc
│   │   └── services
│   │       ├── __init__.py
│   │       ├── __init__.pyc
│   │       ├── api.py
│   │       └── api.pyc
│   ├── requirements.txt
│   └── scripts
└── movie-web

6 directories, 13 files

→ tree docker-movie-db-demo

docker-movie-db-demo

├── README.md

├── docker-compose.override.yml

├── docker-compose.yml

├── movie-api

│ ├── Dockerfile

│ ├── app.py

│ ├── data

│ │ └── moviedata.json

│ ├── demo

│ │ ├── __init__.py

│ │ ├── __init__.pyc

│ │ └── services

│ │ ├── __init__.py

│ │ ├── __init__.pyc

│ │ ├── api.py

│ │ └── api.pyc

│ ├── requirements.txt

│ └── scripts

└── movie-web

6 directories, 13 files

Now within the scripts directory lets write a simple script for seeding this data to our local dynamodb instance. Within the movie-api/scripts directory create a file called seed_movie_data.py and open it for editing.

from __future__ import print_function # Python 2/3 compatibility
import boto3
import json
import decimal
import sys, os
from boto3.dynamodb.conditions import Key, Attr

def main():
  dynamodb_endpoint_url = os.environ.get('DYNAMODB_ENDPOINT_URL', None)

  if dynamodb_endpoint_url:
    dynamodb = boto3.resource('dynamodb', endpoint_url=dynamodb_endpoint_url)
  else:
    dynamodb = boto3.resource('dynamodb')

  table = os.environ.get('DYNAMODB_TABLE_NAME', 'Movies')

  if table in (t.name for t in dynamodb.tables.all()):
    table = dynamodb.Table(table)
  else:
    table = dynamodb.create_table(
      TableName='Movies',
      KeySchema=[
          {
              'AttributeName': 'year',
              'KeyType': 'HASH'  #Partition key
          },
          {
              'AttributeName': 'title',
              'KeyType': 'RANGE'  #Sort key
          }
      ],
      AttributeDefinitions=[
          {
              'AttributeName': 'year',
              'AttributeType': 'N'
          },
          {
              'AttributeName': 'title',
              'AttributeType': 'S'
          },

      ],
      ProvisionedThroughput={
          'ReadCapacityUnits': 10,
          'WriteCapacityUnits': 10
      }
    )

  print("Table status:", table.table_status)

  with open(os.path.dirname(os.path.realpath(__file__)) + "/../data/moviedata.json") as json_file:
      movies = json.load(json_file, parse_float = decimal.Decimal)
      count = 0
      for movie in movies:
          year = int(movie['year'])
          title = movie['title']
          info = movie['info']

          print("Adding movie:", year, title)

          table.put_item(
             Item={
                 'year': year,
                 'title': title,
                 'info': info,
              }
          )
          count += 1
          
  print("Number of seeded items:", count)

if __name__ == '__main__':
  main()

from __future__ import print_function # Python 2/3 compatibility

import boto3

import json

import decimal

import sys, os

from boto3.dynamodb.conditions import Key, Attr

def main():

dynamodb_endpoint_url = os.environ.get('DYNAMODB_ENDPOINT_URL', None)

if dynamodb_endpoint_url:

dynamodb = boto3.resource('dynamodb', endpoint_url=dynamodb_endpoint_url)

else:

dynamodb = boto3.resource('dynamodb')

table = os.environ.get('DYNAMODB_TABLE_NAME', 'Movies')

if table in (t.name for t in dynamodb.tables.all()):

table = dynamodb.Table(table)

else:

table = dynamodb.create_table(

TableName='Movies',

KeySchema=[

{

'AttributeName': 'year',

'KeyType': 'HASH' #Partition key

{

'AttributeName': 'title',

'KeyType': 'RANGE' #Sort key

}

AttributeDefinitions=[

{

'AttributeName': 'year',

'AttributeType': 'N'

{

'AttributeName': 'title',

'AttributeType': 'S'

ProvisionedThroughput={

'ReadCapacityUnits': 10,

'WriteCapacityUnits': 10

}

)

print("Table status:", table.table_status)

with open(os.path.dirname(os.path.realpath(__file__)) + "/../data/moviedata.json") as json_file:

movies = json.load(json_file, parse_float = decimal.Decimal)

count = 0

for movie in movies:

year = int(movie['year'])

title = movie['title']

info = movie['info']

print("Adding movie:", year, title)

table.put_item(

Item={

'year': year,

'title': title,

'info': info,

}

)

count += 1

print("Number of seeded items:", count)

if __name__ == '__main__':

main()

This script is pretty straightforward, this script will create the table within dynamodb if it doesnt exist, and then seed it with a little over 4,000 movies from the json file in our data directory.

Before we can run our script, we need to set a few environment variables on our movie-api instance. Go ahead and open up docker-compose.override.yml and adjust it to reflect the following:

movie-api:
  build: ./movie-api
  environment:
    AWS_ACCESS_KEY_ID: 'foo'
    AWS_SECRET_ACCESS_KEY: 'bar'
    AWS_DEFAULT_REGION: 'us-east-1'
    DYNAMODB_TABLE_NAME: 'Movies'
    DYNAMODB_ENDPOINT_URL: 'http://dynamodb:8000'
  links:
    - dynamodb
  ports:
    - "8080:5000"
  volumes:
    - ./movie-api:/code
dynamodb:
  image: kcyeu/dynamodb-local
  ports:
    - 8000

movie-api:

build: ./movie-api

environment:

AWS_ACCESS_KEY_ID: 'foo'

AWS_SECRET_ACCESS_KEY: 'bar'

AWS_DEFAULT_REGION: 'us-east-1'

DYNAMODB_TABLE_NAME: 'Movies'

DYNAMODB_ENDPOINT_URL: 'http://dynamodb:8000'

links:

- dynamodb

ports:

- "8080:5000"

volumes:

- ./movie-api:/code

dynamodb:

image: kcyeu/dynamodb-local

ports:

- 8000

The AWS credentials do not need to be anything real, in fact, leave them as above (foo, and bar). They just need to be set to prevent boto from barfing when connecting to the local dynamodb instance. In a production setting, we would leverage IAM roles on the instance to connect which is far more secure than setting credentials via an environment variable.

Once you have created the script, and also set the environment variables we can run the following to recreate the container with the new environment variables and then run the script.

$ docker-compose up -d
dockermoviedbdemo_dynamodb_1 is up-to-date
Recreating dockermoviedbdemo_movie-api_1

$ docker ps
CONTAINER ID        IMAGE                         COMMAND                  CREATED             STATUS              PORTS                                             NAMES
22a530df6eef        dockermoviedbdemo_movie-api   "/bin/sh -c 'python a"   6 minutes ago       Up 6 minutes        0.0.0.0:8080-&gt;5000/tcp, 0.0.0.0:32778-&gt;5000/tcp   dockermoviedbdemo_movie-api_1
3ce66d3f8e7e        kcyeu/dynamodb-local          "java -Djava.library."   3 days ago          Up About an hour    0.0.0.0:32775-&gt;8000/tcp                           dockermoviedbdemo_dynamodb_1

$ docker exec -it 22a python scripts/seed_movie_data.py
Table status: ACTIVE
Adding movie: 2013 Rush
Adding movie: 2013 Prisoners
Adding movie: 2013 The Hunger Games: Catching Fire
Adding movie: 2013 Thor: The Dark World
Adding movie: 2013 This Is the End
Adding movie: 2013 Insidious: Chapter 2
Adding movie: 2013 World War Z
Adding movie: 2014 X-Men: Days of Future Past
Adding movie: 2014 Transformers: Age of Extinction
...
Adding movie: 2012 Renoir
Adding movie: 2006 The Contract
Adding movie: 2010 The Clinic
Adding movie: 2004 Little Black Book
Number of seeded items: 4609

$ docker-compose up -d

dockermoviedbdemo_dynamodb_1 is up-to-date

Recreating dockermoviedbdemo_movie-api_1

$ docker ps

CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES

22a530df6eef dockermoviedbdemo_movie-api "/bin/sh -c 'python a" 6 minutes ago Up 6 minutes 0.0.0.0:8080->5000/tcp, 0.0.0.0:32778->5000/tcp dockermoviedbdemo_movie-api_1

3ce66d3f8e7e kcyeu/dynamodb-local "java -Djava.library." 3 days ago Up About an hour 0.0.0.0:32775->8000/tcp dockermoviedbdemo_dynamodb_1

$ docker exec -it 22a python scripts/seed_movie_data.py

Table status: ACTIVE

Adding movie: 2013 Rush

Adding movie: 2013 Prisoners

Adding movie: 2013 The Hunger Games: Catching Fire

Adding movie: 2013 Thor: The Dark World

Adding movie: 2013 This Is the End

Adding movie: 2013 Insidious: Chapter 2

Adding movie: 2013 World War Z

Adding movie: 2014 X-Men: Days of Future Past

Adding movie: 2014 Transformers: Age of Extinction

...

Adding movie: 2012 Renoir

Adding movie: 2006 The Contract

Adding movie: 2010 The Clinic

Adding movie: 2004 Little Black Book

Number of seeded items: 4609

As you can see, we ran the script that we created within the container. We do not need to have our python environment setup locally. This is great, because the containers environment is isolated from every other application we may be developing (and even other services within this application). This provides a high degree of certainty that if we deploy this image, that it will function as we expect. Furthermore, we also know that if another developer pulls this code down and runs the project it will work.

Building our API

Now that we have the data in our datastore we can build a simple lightweight API to expose this information to a client. To keep things simple, we are going to create a simple endpoint which will return all the movies that were released in a specified year. Lets go ahead and open up movie-api/demo/services/api.py in our IDE and add a bit of code to make this happen.

import os
import json
import flask
import boto3
import decimal
from boto3.dynamodb.conditions import Key, Attr
from flask import request

app = flask.Flask(__name__)

dynamodb_endpoint_url = os.environ.get('DYNAMODB_ENDPOINT_URL', None)

if dynamodb_endpoint_url:
  DYNAMODB = boto3.resource('dynamodb', endpoint_url=dynamodb_endpoint_url)
else:
  DYNAMODB = boto3.resource('dynamodb')

table = os.environ.get('DYNAMODB_TABLE_NAME', 'Movies')

TABLE=DYNAMODB.Table(table)

@app.route('/')
def index():
  return 'Hello World! This is a test of the instance editing ability.'

@app.route('/movies/by/year', methods=['POST'])
def movies_by_year():
  request_data = request.get_json()
  year = int(request_data['year'])

  response = TABLE.query(
    KeyConditionExpression=Key('year').eq(year)
  )
  
  data = []
  for i in response['Items']:

    # convert decimals from dynamo
    i['info']['rating'] = float(i['info']['rating'])
    i['info']['rank'] = int(i['info']['rank'])
    i['info']['running_time_secs'] = int(i['info']['running_time_secs'])
    i['year'] = int(i['year'])

    data.append(i)

  return json.dumps(data)

import os

import json

import flask

import boto3

import decimal

from boto3.dynamodb.conditions import Key, Attr

from flask import request

app = flask.Flask(__name__)

dynamodb_endpoint_url = os.environ.get('DYNAMODB_ENDPOINT_URL', None)

if dynamodb_endpoint_url:

DYNAMODB = boto3.resource('dynamodb', endpoint_url=dynamodb_endpoint_url)

else:

DYNAMODB = boto3.resource('dynamodb')

table = os.environ.get('DYNAMODB_TABLE_NAME', 'Movies')

TABLE=DYNAMODB.Table(table)

@app.route('/')

def index():

return 'Hello World! This is a test of the instance editing ability.'

@app.route('/movies/by/year', methods=['POST'])

def movies_by_year():

request_data = request.get_json()

year = int(request_data['year'])

response = TABLE.query(

KeyConditionExpression=Key('year').eq(year)

)

data = []

for i in response['Items']:

# convert decimals from dynamo

i['info']['rating'] = float(i['info']['rating'])

i['info']['rank'] = int(i['info']['rank'])

i['info']['running_time_secs'] = int(i['info']['running_time_secs'])

i['year'] = int(i['year'])

data.append(i)

return json.dumps(data)

Save this and then we can try querying our service with a simple curl command:

$ curl -X POST -H "Content-Type: application/json" -d '{"year":1960}' http://192.168.99.100:8080/movies/by/year
[{"info": {"rating": 7.9, "genres": ["Crime", "Drama"], "plot": "A young car thief kills a policeman and tries to persuade a girl to hide in Italy with him.", "release_date": "1960-03-16T00:00:00Z", "rank": 3521, "running_time_secs": 5400, "directors": ["Jean-Luc Godard"], "actors": ["Jean-Paul Belmondo", "Jean Seberg", "Daniel Boulanger"], "image_url": "http://ia.media-imdb.com/images/M/MV5BMTI4MDUwMDEzNl5BMl5BanBnXkFtZTcwMjYxNzM1MQ@@._V1_SX400_.jpg"}, "title": "A bout de souffle", "year": 1960}, {"info": {"rating": 8.0, "genres": ["Comedy", "Drama"], "plot": "A series of stories following a week in the life of a philandering paparazzo journalist living in Rome.", "release_date": "1960-02-03T00:00:00Z", "rank": 3641, "running_time_secs": 10440, "directors": ["Federico Fellini"], "actors": ["Marcello Mastroianni", "Anita Ekberg", "Anouk Aimee"], "image_url": "http://ia.media-imdb.com/images/M/MV5BMTcwNzM0NTkxMV5BMl5BanBnXkFtZTcwOTExNDEyNQ@@._V1_SX400_.jpg"}, "title": "La dolce vita", "year": 1960}, {"info": {"rating": 6.5, "genres": ["Comedy", "Crime", "Music"], "plot": "Danny Ocean gathers a group of his World War II compatriots to pull off the ultimate Las Vegas heist. Together the eleven friends plan to rob five Las Vegas casinos in one night.", "release_date": "1960-08-10T00:00:00Z", "rank": 3686, "running_time_secs": 7620, "directors": ["Lewis Milestone"], "actors": ["Frank Sinatra", "Dean Martin", "Sammy Davis Jr."], "image_url": "http://ia.media-imdb.com/images/M/MV5BMTIxNTEzNTY1N15BMl5BanBnXkFtZTcwMzg0NTkxMQ@@._V1_SX400_.jpg"}, "title": "Ocean's Eleven", "year": 1960}, {"info": {"rating": 7.7, "genres": ["Crime", "Thriller"], "plot": "Tom Ripley is a talented mimic, moocher, forger and all-around criminal improviser; but there's more to Tom Ripley than even he can guess.", "release_date": "1960-03-10T00:00:00Z", "rank": 3623, "running_time_secs": 7080, "directors": ["Rene Clement"], "actors": ["Alain Delon", "Maurice Ronet", "Marie Laforet"], "image_url": "http://ia.media-imdb.com/images/M/MV5BMTIwNjE5ODA0OV5BMl5BanBnXkFtZTcwNDk4NzAyMQ@@._V1_SX400_.jpg"}, "title": "Plein soleil", "year": 1960}, {"info": {"rating": 8.0, "genres": ["Action", "Adventure", "Biography", "Drama", "History", "Romance", "Thriller"], "plot": "The slave Spartacus leads a violent revolt against the decadent Roman Republic.", "release_date": "1960-10-06T00:00:00Z", "rank": 1311, "running_time_secs": 11820, "directors": ["Stanley Kubrick"], "actors": ["Kirk Douglas", "Laurence Olivier", "Jean Simmons"], "image_url": "http://ia.media-imdb.com/images/M/MV5BMTAzNDcwODQ1MjJeQTJeQWpwZ15BbWU4MDY3NTAzMTAx._V1_SX400_.jpg"}, "title": "Spartacus", "year": 1960}, {"info": {"rating": 8.4, "genres": ["Comedy", "Drama", "Romance"], "plot": "A man tries to rise in his company by letting its executives use his apartment for trysts, but complications and a romance of his own ensue.", "release_date": "1960-06-15T00:00:00Z", "rank": 2646, "running_time_secs": 7500, "directors": ["Billy Wilder"], "actors": ["Jack Lemmon", "Shirley MacLaine", "Fred MacMurray"], "image_url": "http://ia.media-imdb.com/images/M/MV5BMTM1OTc4MzgzNl5BMl5BanBnXkFtZTcwNTE2NjgyMw@@._V1_SX400_.jpg"}, "title": "The Apartment", "year": 1960}, {"info": {"rating": 7.8, "genres": ["Action", "Adventure", "Drama", "Thriller", "Western"], "plot": "An oppressed Mexican peasant village assembles seven gunfighters to help defend their homes.", "release_date": "1960-10-23T00:00:00Z", "rank": 2485, "running_time_secs": 7680, "directors": ["John Sturges"], "actors": ["Yul Brynner", "Steve McQueen", "Charles Bronson"], "image_url": "http://ia.media-imdb.com/images/M/MV5BMzYyNzU0MTM1OF5BMl5BanBnXkFtZTcwMzE1ODE1NA@@._V1_SX400_.jpg"}, "title": "The Magnificent Seven", "year": 1960}, {"info": {"rating": 7.5, "genres": ["Adventure", "Fantasy", "Romance", "Sci-Fi", "Thriller"], "plot": "A Victorian Englishman travels to the far future and finds that humanity has divided into two hostile species.", "release_date": "1960-08-17T00:00:00Z", "rank": 1417, "running_time_secs": 6180, "directors": ["George Pal"], "actors": ["Rod Taylor", "Alan Young", "Yvette Mimieux"], "image_url": "http://ia.media-imdb.com/images/M/MV5BMTQ4MzMyNTc2MV5BMl5BanBnXkFtZTYwMjc0NDc5._V1_SX400_.jpg"}, "title": "The Time Machine", "year": 1960}]

$ curl -X POST -H "Content-Type: application/json" -d '{"year":1960}' http://192.168.99.100:8080/movies/by/year

[{"info": {"rating": 7.9, "genres": ["Crime", "Drama"], "plot": "A young car thief kills a policeman and tries to persuade a girl to hide in Italy with him.", "release_date": "1960-03-16T00:00:00Z", "rank": 3521, "running_time_secs": 5400, "directors": ["Jean-Luc Godard"], "actors": ["Jean-Paul Belmondo", "Jean Seberg", "Daniel Boulanger"], "image_url": "http://ia.media-imdb.com/images/M/MV5BMTI4MDUwMDEzNl5BMl5BanBnXkFtZTcwMjYxNzM1MQ@@._V1_SX400_.jpg"}, "title": "A bout de souffle", "year": 1960}, {"info": {"rating": 8.0, "genres": ["Comedy", "Drama"], "plot": "A series of stories following a week in the life of a philandering paparazzo journalist living in Rome.", "release_date": "1960-02-03T00:00:00Z", "rank": 3641, "running_time_secs": 10440, "directors": ["Federico Fellini"], "actors": ["Marcello Mastroianni", "Anita Ekberg", "Anouk Aimee"], "image_url": "http://ia.media-imdb.com/images/M/MV5BMTcwNzM0NTkxMV5BMl5BanBnXkFtZTcwOTExNDEyNQ@@._V1_SX400_.jpg"}, "title": "La dolce vita", "year": 1960}, {"info": {"rating": 6.5, "genres": ["Comedy", "Crime", "Music"], "plot": "Danny Ocean gathers a group of his World War II compatriots to pull off the ultimate Las Vegas heist. Together the eleven friends plan to rob five Las Vegas casinos in one night.", "release_date": "1960-08-10T00:00:00Z", "rank": 3686, "running_time_secs": 7620, "directors": ["Lewis Milestone"], "actors": ["Frank Sinatra", "Dean Martin", "Sammy Davis Jr."], "image_url": "http://ia.media-imdb.com/images/M/MV5BMTIxNTEzNTY1N15BMl5BanBnXkFtZTcwMzg0NTkxMQ@@._V1_SX400_.jpg"}, "title": "Ocean's Eleven", "year": 1960}, {"info": {"rating": 7.7, "genres": ["Crime", "Thriller"], "plot": "Tom Ripley is a talented mimic, moocher, forger and all-around criminal improviser; but there's more to Tom Ripley than even he can guess.", "release_date": "1960-03-10T00:00:00Z", "rank": 3623, "running_time_secs": 7080, "directors": ["Rene Clement"], "actors": ["Alain Delon", "Maurice Ronet", "Marie Laforet"], "image_url": "http://ia.media-imdb.com/images/M/MV5BMTIwNjE5ODA0OV5BMl5BanBnXkFtZTcwNDk4NzAyMQ@@._V1_SX400_.jpg"}, "title": "Plein soleil", "year": 1960}, {"info": {"rating": 8.0, "genres": ["Action", "Adventure", "Biography", "Drama", "History", "Romance", "Thriller"], "plot": "The slave Spartacus leads a violent revolt against the decadent Roman Republic.", "release_date": "1960-10-06T00:00:00Z", "rank": 1311, "running_time_secs": 11820, "directors": ["Stanley Kubrick"], "actors": ["Kirk Douglas", "Laurence Olivier", "Jean Simmons"], "image_url": "http://ia.media-imdb.com/images/M/MV5BMTAzNDcwODQ1MjJeQTJeQWpwZ15BbWU4MDY3NTAzMTAx._V1_SX400_.jpg"}, "title": "Spartacus", "year": 1960}, {"info": {"rating": 8.4, "genres": ["Comedy", "Drama", "Romance"], "plot": "A man tries to rise in his company by letting its executives use his apartment for trysts, but complications and a romance of his own ensue.", "release_date": "1960-06-15T00:00:00Z", "rank": 2646, "running_time_secs": 7500, "directors": ["Billy Wilder"], "actors": ["Jack Lemmon", "Shirley MacLaine", "Fred MacMurray"], "image_url": "http://ia.media-imdb.com/images/M/MV5BMTM1OTc4MzgzNl5BMl5BanBnXkFtZTcwNTE2NjgyMw@@._V1_SX400_.jpg"}, "title": "The Apartment", "year": 1960}, {"info": {"rating": 7.8, "genres": ["Action", "Adventure", "Drama", "Thriller", "Western"], "plot": "An oppressed Mexican peasant village assembles seven gunfighters to help defend their homes.", "release_date": "1960-10-23T00:00:00Z", "rank": 2485, "running_time_secs": 7680, "directors": ["John Sturges"], "actors": ["Yul Brynner", "Steve McQueen", "Charles Bronson"], "image_url": "http://ia.media-imdb.com/images/M/MV5BMzYyNzU0MTM1OF5BMl5BanBnXkFtZTcwMzE1ODE1NA@@._V1_SX400_.jpg"}, "title": "The Magnificent Seven", "year": 1960}, {"info": {"rating": 7.5, "genres": ["Adventure", "Fantasy", "Romance", "Sci-Fi", "Thriller"], "plot": "A Victorian Englishman travels to the far future and finds that humanity has divided into two hostile species.", "release_date": "1960-08-17T00:00:00Z", "rank": 1417, "running_time_secs": 6180, "directors": ["George Pal"], "actors": ["Rod Taylor", "Alan Young", "Yvette Mimieux"], "image_url": "http://ia.media-imdb.com/images/M/MV5BMTQ4MzMyNTc2MV5BMl5BanBnXkFtZTYwMjc0NDc5._V1_SX400_.jpg"}, "title": "The Time Machine", "year": 1960}]

Building our Website

Now that we have an API that returns the data we need, we can create a simple web interface with a form that will present this data in a nice fashion. There are a few ways to make this happen, normally i’d recommend using something like angular however to further demonstrate container linking and such I will use a seperate flask app.

Within the movie-web directory we need to create our app skeleton. To simplify things, copy the Dockerfile, app.py and requirements.txt files from movie-api to movie-web. Besides the copying of those 3 files, go ahead and create the following directory structure and empty files so that the output of tree matches the below.

tree movie-web
movie-web
├── Dockerfile
├── app.py
├── demo
│   ├── __init__.py
│   └── services
│       ├──__init__.py
│       ├── site.py
│       └── templates
│           ├── index.html
|           └── results.html
└── requirements.txt

2 directories, 5 files

tree movie-web

movie-web

├── Dockerfile

├── app.py

├── demo

│ ├── __init__.py

│ └── services

│ ├──__init__.py

│ ├── site.py

│ └── templates

│ ├── index.html

| └── results.html

└── requirements.txt

2 directories, 5 files

In requirements.txt remove the boto reference and add in requests.

$ cat requirements.txt
Flask==0.10.1
requests==2.9.1

$ cat requirements.txt

Flask==0.10.1

requests==2.9.1

Open up app.py and edit the third line to reflect the below

#!/usr/bin/env python
import sys
from demo.services.site import app

if __name__ == '__main__':
    port = int(sys.argv[1])
    app.run('0.0.0.0',debug=True,port=port)

#!/usr/bin/env python

import sys

from demo.services.site import app

if __name__ == '__main__':

port = int(sys.argv[1])

app.run('0.0.0.0',debug=True,port=port)

Go ahead and create demo/services/site.py and open it up within your IDE.

import os
import json
import flask

app = flask.Flask(__name__)

@app.route('/')
def index():
    return 'Hello World!'

import os

import json

import flask

app = flask.Flask(__name__)

@app.route('/')

def index():

return 'Hello World!'

Now to get things running we just need to edit our docker-compose.yml and docker-compose.override.yml files.

docker-compose.yml:

movie-api:
  image: TBD
  restart: always
  stdin_open: true
  ports:
   - 5000
movie-web:
  image: TBD
  restart: always
  stdin_open: true
  links:
    - movie-api
  ports:
    - 5000

movie-api:

image: TBD

restart: always

stdin_open: true

ports:

- 5000

movie-web:

image: TBD

restart: always

stdin_open: true

links:

- movie-api

ports:

- 5000

docker-compose.override.yml:

movie-api:
  build: ./movie-api
  environment:
    AWS_ACCESS_KEY_ID: 'foo'
    AWS_SECRET_ACCESS_KEY: 'bar'
    AWS_DEFAULT_REGION: 'us-east-1'
    DYNAMODB_TABLE_NAME: 'Movies'
    DYNAMODB_ENDPOINT_URL: 'http://dynamodb:8000'
  links:
    - dynamodb
  ports:
    - "8080:5000"
  volumes:
    - ./movie-api:/code
movie-web:
  build: ./movie-web
  environment:
    MOVIE_API_URL: 'http://movie-api:5000'
  ports:
    - "8081:5000"
  volumes:
    - ./movie-web:/code
dynamodb:
  image: kcyeu/dynamodb-local
  ports:
    - 8000

movie-api:

build: ./movie-api

environment:

AWS_ACCESS_KEY_ID: 'foo'

AWS_SECRET_ACCESS_KEY: 'bar'

AWS_DEFAULT_REGION: 'us-east-1'

DYNAMODB_TABLE_NAME: 'Movies'

DYNAMODB_ENDPOINT_URL: 'http://dynamodb:8000'

links:

- dynamodb

ports:

- "8080:5000"

volumes:

- ./movie-api:/code

movie-web:

build: ./movie-web

environment:

MOVIE_API_URL: 'http://movie-api:5000'

ports:

- "8081:5000"

volumes:

- ./movie-web:/code

dynamodb:

image: kcyeu/dynamodb-local

ports:

- 8000

With those changes saved. We can run docker-compose up -d which should launch our container. We can verify connectivity with curl.

→ docker-compose up -d
dockermoviedbdemo_dynamodb_1 is up-to-date
dockermoviedbdemo_movie-api_1 is up-to-date
Building movie-web
Step 1 : FROM python:2.7
 ---&gt; 10b7e9592569
Step 2 : ADD . /code
 ---&gt; 3d56f4523b5f
Removing intermediate container 43dfc12038cf
Step 3 : WORKDIR /code
 ---&gt; Running in 13eb0bdf12c9
 ---&gt; 31e595a240b4
Removing intermediate container 13eb0bdf12c9
Step 4 : RUN apt-get update
 ---&gt; Running in 9526d5db48d4
Get:1 http://security.debian.org jessie/updates InRelease [63.1 kB]
Ign http://httpredir.debian.org jessie InRelease
Get:2 http://httpredir.debian.org jessie-updates InRelease [136 kB]
Get:3 http://security.debian.org jessie/updates/main amd64 Packages [241 kB]
Get:4 http://httpredir.debian.org jessie Release.gpg [2373 B]
Get:5 http://httpredir.debian.org jessie Release [148 kB]
Get:6 http://httpredir.debian.org jessie-updates/main amd64 Packages [3619 B]
Get:7 http://httpredir.debian.org jessie/main amd64 Packages [9035 kB]
Fetched 9630 kB in 11s (859 kB/s)
Reading package lists...
 ---&gt; 78beb0ab18c5
Removing intermediate container 9526d5db48d4
Step 5 : RUN pip install -r requirements.txt
 ---&gt; Running in 208bc635ae1b
Collecting Flask==0.10.1 (from -r requirements.txt (line 1))
  Downloading Flask-0.10.1.tar.gz (544kB)
Collecting Werkzeug&gt;=0.7 (from Flask==0.10.1-&gt;-r requirements.txt (line 1))
  Downloading Werkzeug-0.11.3-py2.py3-none-any.whl (305kB)
Collecting Jinja2&gt;=2.4 (from Flask==0.10.1-&gt;-r requirements.txt (line 1))
  Downloading Jinja2-2.8-py2.py3-none-any.whl (263kB)
Collecting itsdangerous&gt;=0.21 (from Flask==0.10.1-&gt;-r requirements.txt (line 1))
  Downloading itsdangerous-0.24.tar.gz (46kB)
Collecting MarkupSafe (from Jinja2&gt;=2.4-&gt;Flask==0.10.1-&gt;-r requirements.txt (line 1))
  Downloading MarkupSafe-0.23.tar.gz
Building wheels for collected packages: Flask, itsdangerous, MarkupSafe
  Running setup.py bdist_wheel for Flask
  Stored in directory: /root/.cache/pip/wheels/d2/db/61/cb9b80526b8f3ba89248ec0a29d6da1bb6013681c930fca987
  Running setup.py bdist_wheel for itsdangerous
  Stored in directory: /root/.cache/pip/wheels/97/c0/b8/b37c320ff57e15f993ba0ac98013eee778920b4a7b3ebae3cf
  Running setup.py bdist_wheel for MarkupSafe
  Stored in directory: /root/.cache/pip/wheels/94/a7/79/f79a998b64c1281cb99fa9bbd33cfc9b8b5775f438218d17a7
Successfully built Flask itsdangerous MarkupSafe
Installing collected packages: Werkzeug, MarkupSafe, Jinja2, itsdangerous, Flask
Successfully installed Flask-0.10.1 Jinja2-2.8 MarkupSafe-0.23 Werkzeug-0.11.3 itsdangerous-0.24
 ---&gt; 69bad3a7a0a5
Removing intermediate container 208bc635ae1b
Step 6 : CMD python app.py 5000
 ---&gt; Running in 3095d4dc7d76
 ---&gt; 4b1ac1fb8a06
Removing intermediate container 3095d4dc7d76
Successfully built 4b1ac1fb8a06
Creating dockermoviedbdemo_movie-web_1

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo on git:master ✖︎ [18:04:18]
→ docker ps
CONTAINER ID        IMAGE                         COMMAND                  CREATED             STATUS              PORTS                                             NAMES
386e52df4a56        dockermoviedbdemo_movie-web   "/bin/sh -c 'python a"   6 seconds ago       Up 5 seconds        0.0.0.0:8081-&gt;5000/tcp, 0.0.0.0:32780-&gt;5000/tcp   dockermoviedbdemo_movie-web_1
bf24c23b68cd        kcyeu/dynamodb-local          "java -Djava.library."   40 minutes ago      Up 40 minutes       0.0.0.0:32779-&gt;8000/tcp                           dockermoviedbdemo_dynamodb_1
22a530df6eef        dockermoviedbdemo_movie-api   "/bin/sh -c 'python a"   About an hour ago   Up 58 minutes       0.0.0.0:8080-&gt;5000/tcp, 0.0.0.0:32778-&gt;5000/tcp   dockermoviedbdemo_movie-api_1

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo on git:master ✖︎ [18:04:20]
→ curl http://192.168.99.100:8081
Hello World!%

→ docker-compose up -d

dockermoviedbdemo_dynamodb_1 is up-to-date

dockermoviedbdemo_movie-api_1 is up-to-date

Building movie-web

Step 1 : FROM python:2.7

---> 10b7e9592569

Step 2 : ADD . /code

---> 3d56f4523b5f

Removing intermediate container 43dfc12038cf

Step 3 : WORKDIR /code

---> Running in 13eb0bdf12c9

---> 31e595a240b4

Removing intermediate container 13eb0bdf12c9

Step 4 : RUN apt-get update

---> Running in 9526d5db48d4

Get:1 http://security.debian.org jessie/updates InRelease [63.1 kB]

Ign http://httpredir.debian.org jessie InRelease

Get:2 http://httpredir.debian.org jessie-updates InRelease [136 kB]

Get:3 http://security.debian.org jessie/updates/main amd64 Packages [241 kB]

Get:4 http://httpredir.debian.org jessie Release.gpg [2373 B]

Get:5 http://httpredir.debian.org jessie Release [148 kB]

Get:6 http://httpredir.debian.org jessie-updates/main amd64 Packages [3619 B]

Get:7 http://httpredir.debian.org jessie/main amd64 Packages [9035 kB]

Fetched 9630 kB in 11s (859 kB/s)

Reading package lists...

---> 78beb0ab18c5

Removing intermediate container 9526d5db48d4

Step 5 : RUN pip install -r requirements.txt

---> Running in 208bc635ae1b

Collecting Flask==0.10.1 (from -r requirements.txt (line 1))

Downloading Flask-0.10.1.tar.gz (544kB)

Collecting Werkzeug>=0.7 (from Flask==0.10.1->-r requirements.txt (line 1))

Downloading Werkzeug-0.11.3-py2.py3-none-any.whl (305kB)

Collecting Jinja2>=2.4 (from Flask==0.10.1->-r requirements.txt (line 1))

Downloading Jinja2-2.8-py2.py3-none-any.whl (263kB)

Collecting itsdangerous>=0.21 (from Flask==0.10.1->-r requirements.txt (line 1))

Downloading itsdangerous-0.24.tar.gz (46kB)

Collecting MarkupSafe (from Jinja2>=2.4->Flask==0.10.1->-r requirements.txt (line 1))

Downloading MarkupSafe-0.23.tar.gz

Building wheels for collected packages: Flask, itsdangerous, MarkupSafe

Running setup.py bdist_wheel for Flask

Stored in directory: /root/.cache/pip/wheels/d2/db/61/cb9b80526b8f3ba89248ec0a29d6da1bb6013681c930fca987

Running setup.py bdist_wheel for itsdangerous

Stored in directory: /root/.cache/pip/wheels/97/c0/b8/b37c320ff57e15f993ba0ac98013eee778920b4a7b3ebae3cf

Running setup.py bdist_wheel for MarkupSafe

Stored in directory: /root/.cache/pip/wheels/94/a7/79/f79a998b64c1281cb99fa9bbd33cfc9b8b5775f438218d17a7

Successfully built Flask itsdangerous MarkupSafe

Installing collected packages: Werkzeug, MarkupSafe, Jinja2, itsdangerous, Flask

Successfully installed Flask-0.10.1 Jinja2-2.8 MarkupSafe-0.23 Werkzeug-0.11.3 itsdangerous-0.24

---> 69bad3a7a0a5

Removing intermediate container 208bc635ae1b

Step 6 : CMD python app.py 5000

---> Running in 3095d4dc7d76

---> 4b1ac1fb8a06

Removing intermediate container 3095d4dc7d76

Successfully built 4b1ac1fb8a06

Creating dockermoviedbdemo_movie-web_1

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo on git:master ✖︎ [18:04:18]

→ docker ps

CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES

386e52df4a56 dockermoviedbdemo_movie-web "/bin/sh -c 'python a" 6 seconds ago Up 5 seconds 0.0.0.0:8081->5000/tcp, 0.0.0.0:32780->5000/tcp dockermoviedbdemo_movie-web_1

bf24c23b68cd kcyeu/dynamodb-local "java -Djava.library." 40 minutes ago Up 40 minutes 0.0.0.0:32779->8000/tcp dockermoviedbdemo_dynamodb_1

22a530df6eef dockermoviedbdemo_movie-api "/bin/sh -c 'python a" About an hour ago Up 58 minutes 0.0.0.0:8080->5000/tcp, 0.0.0.0:32778->5000/tcp dockermoviedbdemo_movie-api_1

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo on git:master ✖︎ [18:04:20]

→ curl http://192.168.99.100:8081

Hello World!%

Now lets create a couple templates, and a build out the endpoints on our webapp so that we can perform a simple search.

Open up demo/services/templates/index.html:

<html>
  <head>
    <title>Movie Database</title>
  </head>
  <body>
    <h1>Search Movie Database</h1>
    <form action='search' method='get'>
      Enter 4 digit year: <input type='text' name='year'> <input type='submit' value='Search'>
    </form>  
  </body>
</html>

<html>

<head>

<title>Movie Database</title>

</head>

<body>

<h1>Search Movie Database</h1>

Enter 4 digit year: <input type='text' name='year'> <input type='submit' value='Search'>

</form>

</body>

</html>

Open up demo/services/templates/results.html:

<!DOCTYPE html>
<html>
  <head>
    <title>Search Results</title>
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <!-- Bootstrap -->
    <link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" rel="stylesheet" media="screen">
  </head>
  <body>
    <div class="container">
      <table class="table table-striped">
      <thead>
        <tr>
          <th>Movie Title</th>
          <th>Release Date</th>
          <th>Rating</th>
          <th>Rank</th>
          
        </tr>
      <thead>
      <tbody>
      {% for movie in movies %}
        {% if movie.info %}
          <tr>
            <td>{{movie.title}}</td>
            <td>{{movie.info.release_date}}</td>
            <td>{{movie.info.rating}}</td>
            <td>{{movie.info.rank}}</td>
          </tr>
        {% endif %}
      {% else %}
        <p>No movies found. Try a different year</p>
      {% endfor %}
      </tbody>
      </table>
    </div>
    <script src="http://code.jquery.com/jquery.js"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>
  </body>
</html>

<!DOCTYPE html>

<html>

<head>

<title>Search Results</title>

</head>

<body>

<thead>

<tr>

<th>Movie Title</th>

<th>Release Date</th>

<th>Rating</th>

</tr>

<thead>

<tbody>

{% for movie in movies %}

{% if movie.info %}

<tr>

<td>{{movie.title}}</td>

<td>{{movie.info.release_date}}</td>

<td>{{movie.info.rating}}</td>

<td>{{movie.info.rank}}</td>

</tr>

{% endif %}

{% else %}

<p>No movies found. Try a different year</p>

{% endfor %}

</tbody>

</table>

</div>

</body>

</html>

And finally edit demo/services/site.py:

import os
import json
import flask
import requests
from flask import render_template, url_for, request

app = flask.Flask(__name__)

MOVIE_API_URL = os.environ.get('MOVIE_API_URL', None)

@app.route('/')
def index():
  return render_template('index.html')

@app.route('/search')
def search():
  year = request.args.get('year')
  request_data = {'year':year}

  response = requests.post(MOVIE_API_URL + '/movies/by/year', json = request_data)

  data = response.json()
  return render_template('results.html', movies=data)

import os

import json

import flask

import requests

from flask import render_template, url_for, request

app = flask.Flask(__name__)

MOVIE_API_URL = os.environ.get('MOVIE_API_URL', None)

@app.route('/')

def index():

return render_template('index.html')

@app.route('/search')

def search():

year = request.args.get('year')

request_data = {'year':year}

response = requests.post(MOVIE_API_URL + '/movies/by/year', json = request_data)

data = response.json()

return render_template('results.html', movies=data)

If you visit your web browser at http://192.168.99.100:8081/ which should show the following:

Enter in 1993 and you should see the following results:

At this point that completes our application and this tutorial on docker for developers. To Recap, we installed and setup the docker toolbox on your machine. We then demonstrated how to use docker-machine, docker, and docker-compose to build a sample application that uses dynamodb, an api service, and finally a web application to view a sample dataset. You should be familiar now with creating a Dockerfile to build an image, and using compose to orchestrate and run your application. You have defined environment variables, container links, ports, and even leveraged the ability to map a volume coupled with flasks ability to reload on file changes to rapidly speed up development.

One thing you may have noticed is that we spent most of the time dealing with application code, and not a whole lot of time spent working with docker itself. Thats kind of the point. One of the greatest strengths of docker is that it simply gets out of your way. It mays it incredibly easy to rapidly iterate and start working on your application code.

While this wraps up my 2 part series on docker for developers, ill be writing additional posts centered around docker for QA and Operations Engineers. This will focus on testing, CI/CD, production deployments, service discovery, and more.

Docker for Developers Part 1

January 7, 2016January 17, 2017 ckelly Leave a comment

Summary

Recently I started working on a few projects where docker seemed like a great fit to rapidly speed up development of the project. In one case we wanted to build a prototype service that contained an API endpoint that utilized 4 micro services. The docker landscape is still green with a lot of toolsets not even existing for a year. While I feel the development side of things is great, the production deployment, auto scaling, and release management is still lacking. One of the projects I have been following closely is Rancher which seems to be on track to solve all of these things. This will be a series of posts initially focusing on development and the building of a fully featured sample application demonstrating the power of docker running locally. I will add posts documenting CI with Jenkins, through to a production deploy and management on AWS.

What will we do?

This tutorial is going to walk through the creation of a sample web application that utilizes a sample API service backed by dynamodb. Specifically we will:

Layout the structure of our application and explain why things are laid out like they are.
Build a sample hello world flask app that shows the initial power of docker and docker-compose.
Run a local dynamodb container locally for development.
Load some data into that local dynamodb install.
Build a sample flask API that reads from that local dynamodb instance.
Build a sample flask website that reads from the API and returns some basic data.

Setup

1. So to dive right into it, you will need two things installed on your machine to work through this tutorial. Currently everything below assumes you are running on OSX however it should work just fine under Linux as well.

Install Virtualbox: https://www.virtualbox.org/wiki/Downloads
Install the docker toolbox: https://docs.docker.com/installation/mac/

2. Assuming that you have never used boot2docker before (and if you did, you should be prompted with instructions on how to convert to docker machine), run the following command to setup a default docker machine. This will be a virtual machine that will be where all the various containers run that you launch. More on that in a minute.

$ docker-machine create --driver virtualbox default

1	$ docker-machine create --driver virtualbox default

3. You can now run $ eval “$(docker-machine env default)” to set the required environment variables. If you will be launching docker containers often, you might even elect to put this in your bashrc or zshrc file.

4. You should be able to run docker ps and see the following:

$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES

1 2	$ docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES

Helpful Commands

This area serves as a quick reference for various commands that may be helpful as a developer working with Docker. A lot of these may not make sense just yet, and thats fine. You will learn more about them below and can always come back to this one spot for reference.

docker build -t some-image (This will create an image from the Dockerfile in the CWD)
docker tag   (Helpful if you need to add a tag)
docker run -d -p 8080:80 some-image (This will run the previously built image on the docker machine and map port 8080 on the docker-machine to port 80 on the container)
docker-machine ip default (this will return the IP of the docker-machine instance that your container was deployed on)
docker-compose up -d (this will start all services using compose on the docker machine -d is important, as this will detach)
docker-compose stop (this will stop all services using compose)
docker-compose rm (this will rm all containers associated with the services using compose)
docker images (List out the current images)
docker ps (List out the currently running containers on the current docker machine)
docker logs -f &lt;container_id&gt; (tail output of application on container)
docker stop $(docker ps -a -q) (stop all docker containers)
docker rm $(docker ps -a -q) (delete all docker containers)
docker rmi $(docker images -q) (remove all docker images)
docker push name/repo:tag (Push an image to a remote docker registry. Dont forget to create the repository first at docker.com)

docker build -t some-image (This will create an image from the Dockerfile in the CWD)

docker tag (Helpful if you need to add a tag)

docker run -d -p 8080:80 some-image (This will run the previously built image on the docker machine and map port 8080 on the docker-machine to port 80 on the container)

docker-machine ip default (this will return the IP of the docker-machine instance that your container was deployed on)

docker-compose up -d (this will start all services using compose on the docker machine -d is important, as this will detach)

docker-compose stop (this will stop all services using compose)

docker-compose rm (this will rm all containers associated with the services using compose)

docker images (List out the current images)

docker ps (List out the currently running containers on the current docker machine)

docker logs -f <container_id> (tail output of application on container)

docker stop $(docker ps -a -q) (stop all docker containers)

docker rm $(docker ps -a -q) (delete all docker containers)

docker rmi $(docker images -q) (remove all docker images)

docker push name/repo:tag (Push an image to a remote docker registry. Dont forget to create the repository first at docker.com)

Building our application

So now that the tooling is setup we can discuss what our project structure will look like. You can see a completely functional and done copy of the below project on github and you can grab just the files we create here in part 1.

Initial Skeleton

First create a directory called docker-movie-db-demo somewhere.
Within that directory create two directories. One called movie-api and the other movie-web

It should look like this

$ tree docker-movie-db-demo
docker-movie-db-demo
├── movie-api
└── movie-web

2 directories, 0 files

$ tree docker-movie-db-demo

docker-movie-db-demo

├── movie-api

└── movie-web

2 directories, 0 files

We created two directories however, that are going to house two separate applications. The first of which, movie-api is going to be a simple flask API server that is backed by data in dynamodb. The second application called movie-www is going to have a simple web interface with a form, and allow the user to list movies from a certain year.

Our first Flask App

Within movie-api go ahead and create a few empty files and directories so that your structure matches the below. We will go through and touch these files one by one.

$ tree movie-api
movie-api
├── Dockerfile
├── app.py
├── demo
│   ├── __init__.py
│   └── services
│       ├── __init__.py
│       └── api.py
└── requirements.txt

2 directories, 6 files

$ tree movie-api

movie-api

├── Dockerfile

├── app.py

├── demo

│ ├── __init__.py

│ └── services

│ ├── __init__.py

│ └── api.py

└── requirements.txt

2 directories, 6 files

app.py

Open app.py up and lets toss a few lines in.

$ cat app.py
#!/usr/bin/env python
import sys
from demo.services.api import app

if __name__ == '__main__':
    port = int(sys.argv[1])
    app.run('0.0.0.0',debug=True,port=port)

$ cat app.py

#!/usr/bin/env python

import sys

from demo.services.api import app

if __name__ == '__main__':

port = int(sys.argv[1])

app.run('0.0.0.0',debug=True,port=port)

This is pretty basic, but it will initialize a basic flask app from demo/services/api.py and listen on a port that is specified as the first argument when running python app.py 5000.

requirements.txt

Open requirements.txt and add in the following

Flask==0.10.1
boto3==1.2.3

1 2	Flask==0.10.1 boto3==1.2.3

This is also pretty straightforward, but we are ensuring we install flask. Boto is installed for interfacing with dynamodb. I’ll have to write a separate article on why its important to pin versions and the headaches that can solve down the line.

demo/services/api.py

For now lets just add in the following:

import os
import json
import flask

app = flask.Flask(__name__)

@app.route('/')
def index():
  return 'Hello World!'

import os

import json

import flask

app = flask.Flask(__name__)

@app.route('/')

def index():

return 'Hello World!'

We are adding a simple route for the index page of the api service that for now just returns the text “Hello World!”

Dockerfile

The dockerfile is where the magic happens. Depending on how you are used to doing development, you might create a virtual env somewhere, or possible a vagrant image. This certainly works however you often end up with a bunch of files scattered everywhere, mismatches between your virtual env and someone elses (if you arent careful) and/or multiple vagrant images floating around that slow down your machine.

Open the Dockerfile (Note that the Dockerfile should have a capital D) up and paste in the following:

FROM python:2.7
ADD . /code
WORKDIR /code
RUN apt-get update
RUN pip install -r requirements.txt
CMD python app.py 5000

FROM python:2.7

ADD . /code

WORKDIR /code

RUN apt-get update

RUN pip install -r requirements.txt

CMD python app.py 5000

When running the build command, this tells the system how to build an image. In this case it will use a python 2.7 base image, copy the CWD (movie-api) to /code in the container, set the CWD to /code, run an apt-get update, pip install our requirements and then finally run our application. If you want more details you can read the dockerfile reference here which explains whats going on in detail and whats possible.

At this point we have enough of a skeleton to actually build a container, run it if we wanted to.

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo/movie-api [14:59:14]
→ docker build -t movie-api .
Sending build context to Docker daemon 7.168 kB
Step 1 : FROM python:2.7
 ---&gt; 10b7e9592569
Step 2 : ADD . /code
 ---&gt; 59f5bb49b433
Removing intermediate container 54f7052c6032
Step 3 : WORKDIR /code
 ---&gt; Running in c5605b48a4dd
 ---&gt; fab34805ae60
Removing intermediate container c5605b48a4dd
Step 4 : RUN apt-get update
 ---&gt; Running in ed1c221b2461
Get:1 http://security.debian.org jessie/updates InRelease [63.1 kB]
Ign http://httpredir.debian.org jessie InRelease
Get:2 http://httpredir.debian.org jessie-updates InRelease [136 kB]
Get:3 http://httpredir.debian.org jessie Release.gpg [2373 B]
Get:4 http://security.debian.org jessie/updates/main amd64 Packages [230 kB]
Get:5 http://httpredir.debian.org jessie Release [148 kB]
Get:6 http://httpredir.debian.org jessie-updates/main amd64 Packages [3619 B]
Get:7 http://httpredir.debian.org jessie/main amd64 Packages [9035 kB]
Fetched 9619 kB in 9s (1027 kB/s)
Reading package lists...
 ---&gt; 12f42e160185
Removing intermediate container ed1c221b2461
Step 5 : RUN pip install -r requirements.txt
 ---&gt; Running in e8e9ec3724ce
Collecting Flask==0.10.1 (from -r requirements.txt (line 1))
  Downloading Flask-0.10.1.tar.gz (544kB)
Collecting boto3==1.2.3 (from -r requirements.txt (line 2))
  Downloading boto3-1.2.3-py2.py3-none-any.whl (108kB)
Collecting Werkzeug&gt;=0.7 (from Flask==0.10.1-&gt;-r requirements.txt (line 1))
  Downloading Werkzeug-0.11.3-py2.py3-none-any.whl (305kB)
Collecting Jinja2&gt;=2.4 (from Flask==0.10.1-&gt;-r requirements.txt (line 1))
  Downloading Jinja2-2.8-py2.py3-none-any.whl (263kB)
Collecting itsdangerous&gt;=0.21 (from Flask==0.10.1-&gt;-r requirements.txt (line 1))
  Downloading itsdangerous-0.24.tar.gz (46kB)
Collecting jmespath&lt;1.0.0,&gt;=0.7.1 (from boto3==1.2.3-&gt;-r requirements.txt (line 2))
  Downloading jmespath-0.9.0-py2.py3-none-any.whl
Collecting futures&lt;4.0.0,&gt;=2.2.0 (from boto3==1.2.3-&gt;-r requirements.txt (line 2))
  Downloading futures-3.0.3-py2-none-any.whl
Collecting botocore&lt;1.4.0,&gt;=1.3.0 (from boto3==1.2.3-&gt;-r requirements.txt (line 2))
  Downloading botocore-1.3.17-py2.py3-none-any.whl (2.1MB)
Collecting MarkupSafe (from Jinja2&gt;=2.4-&gt;Flask==0.10.1-&gt;-r requirements.txt (line 1))
  Downloading MarkupSafe-0.23.tar.gz
Collecting python-dateutil&lt;3.0.0,&gt;=2.1 (from botocore&lt;1.4.0,&gt;=1.3.0-&gt;boto3==1.2.3-&gt;-r requirements.txt (line 2))
  Downloading python_dateutil-2.4.2-py2.py3-none-any.whl (188kB)
Collecting docutils&gt;=0.10 (from botocore&lt;1.4.0,&gt;=1.3.0-&gt;boto3==1.2.3-&gt;-r requirements.txt (line 2))
  Downloading docutils-0.12.tar.gz (1.6MB)
Collecting six&gt;=1.5 (from python-dateutil&lt;3.0.0,&gt;=2.1-&gt;botocore&lt;1.4.0,&gt;=1.3.0-&gt;boto3==1.2.3-&gt;-r requirements.txt (line 2))
  Downloading six-1.10.0-py2.py3-none-any.whl
Building wheels for collected packages: Flask, itsdangerous, MarkupSafe, docutils
  Running setup.py bdist_wheel for Flask
  Stored in directory: /root/.cache/pip/wheels/d2/db/61/cb9b80526b8f3ba89248ec0a29d6da1bb6013681c930fca987
  Running setup.py bdist_wheel for itsdangerous
  Stored in directory: /root/.cache/pip/wheels/97/c0/b8/b37c320ff57e15f993ba0ac98013eee778920b4a7b3ebae3cf
  Running setup.py bdist_wheel for MarkupSafe
  Stored in directory: /root/.cache/pip/wheels/94/a7/79/f79a998b64c1281cb99fa9bbd33cfc9b8b5775f438218d17a7
  Running setup.py bdist_wheel for docutils
  Stored in directory: /root/.cache/pip/wheels/d5/32/4f/1347e8ac67071e8150a5dc69354a51a04ac065d0b48334f608
Successfully built Flask itsdangerous MarkupSafe docutils
Installing collected packages: Werkzeug, MarkupSafe, Jinja2, itsdangerous, Flask, jmespath, futures, six, python-dateutil, docutils, botocore, boto3
Successfully installed Flask-0.10.1 Jinja2-2.8 MarkupSafe-0.23 Werkzeug-0.11.3 boto3-1.2.3 botocore-1.3.17 docutils-0.12 futures-3.0.3 itsdangerous-0.24 jmespath-0.9.0 python-dateutil-2.4.2 six-1.10.0
 ---&gt; 4e5aaebeada8
Removing intermediate container e8e9ec3724ce
Step 6 : CMD python app.py 5000
 ---&gt; Running in 70d274952e94
 ---&gt; 0ab971a5eaf1
Removing intermediate container 70d274952e94
Successfully built 0ab971a5eaf1

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo/movie-api [14:59:40]
→ docker run -d -p 5000:5000 movie-api
bad3d80e96430c7650a7ebb95011d509401dc45206116044e63145436ad65a52

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo/movie-api [14:59:56]
→ docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                    NAMES
bad3d80e9643        movie-api           "/bin/sh -c 'python a"   2 seconds ago       Up 1 seconds        0.0.0.0:5000-&gt;5000/tcp   prickly_goldberg

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo/movie-api [14:59:58]
→ docker-machine ip default
192.168.99.100

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo/movie-api [15:00:07]
→ curl 192.168.99.100:5000
Hello World!%

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo [15:20:24]
→ docker stop ba
ba

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo [15:21:12]
→ docker rm ba
ba

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo/movie-api [14:59:14]

→ docker build -t movie-api .

Sending build context to Docker daemon 7.168 kB

Step 1 : FROM python:2.7

---> 10b7e9592569

Step 2 : ADD . /code

---> 59f5bb49b433

Removing intermediate container 54f7052c6032

Step 3 : WORKDIR /code

---> Running in c5605b48a4dd

---> fab34805ae60

Removing intermediate container c5605b48a4dd

Step 4 : RUN apt-get update

---> Running in ed1c221b2461

Get:1 http://security.debian.org jessie/updates InRelease [63.1 kB]

Ign http://httpredir.debian.org jessie InRelease

Get:2 http://httpredir.debian.org jessie-updates InRelease [136 kB]

Get:3 http://httpredir.debian.org jessie Release.gpg [2373 B]

Get:4 http://security.debian.org jessie/updates/main amd64 Packages [230 kB]

Get:5 http://httpredir.debian.org jessie Release [148 kB]

Get:6 http://httpredir.debian.org jessie-updates/main amd64 Packages [3619 B]

Get:7 http://httpredir.debian.org jessie/main amd64 Packages [9035 kB]

Fetched 9619 kB in 9s (1027 kB/s)

Reading package lists...

---> 12f42e160185

Removing intermediate container ed1c221b2461

Step 5 : RUN pip install -r requirements.txt

---> Running in e8e9ec3724ce

Collecting Flask==0.10.1 (from -r requirements.txt (line 1))

Downloading Flask-0.10.1.tar.gz (544kB)

Collecting boto3==1.2.3 (from -r requirements.txt (line 2))

Downloading boto3-1.2.3-py2.py3-none-any.whl (108kB)

Collecting Werkzeug>=0.7 (from Flask==0.10.1->-r requirements.txt (line 1))

Downloading Werkzeug-0.11.3-py2.py3-none-any.whl (305kB)

Collecting Jinja2>=2.4 (from Flask==0.10.1->-r requirements.txt (line 1))

Downloading Jinja2-2.8-py2.py3-none-any.whl (263kB)

Collecting itsdangerous>=0.21 (from Flask==0.10.1->-r requirements.txt (line 1))

Downloading itsdangerous-0.24.tar.gz (46kB)

Collecting jmespath<1.0.0,>=0.7.1 (from boto3==1.2.3->-r requirements.txt (line 2))

Downloading jmespath-0.9.0-py2.py3-none-any.whl

Collecting futures<4.0.0,>=2.2.0 (from boto3==1.2.3->-r requirements.txt (line 2))

Downloading futures-3.0.3-py2-none-any.whl

Collecting botocore<1.4.0,>=1.3.0 (from boto3==1.2.3->-r requirements.txt (line 2))

Downloading botocore-1.3.17-py2.py3-none-any.whl (2.1MB)

Collecting MarkupSafe (from Jinja2>=2.4->Flask==0.10.1->-r requirements.txt (line 1))

Downloading MarkupSafe-0.23.tar.gz

Collecting python-dateutil<3.0.0,>=2.1 (from botocore<1.4.0,>=1.3.0->boto3==1.2.3->-r requirements.txt (line 2))

Downloading python_dateutil-2.4.2-py2.py3-none-any.whl (188kB)

Collecting docutils>=0.10 (from botocore<1.4.0,>=1.3.0->boto3==1.2.3->-r requirements.txt (line 2))

Downloading docutils-0.12.tar.gz (1.6MB)

Collecting six>=1.5 (from python-dateutil<3.0.0,>=2.1->botocore<1.4.0,>=1.3.0->boto3==1.2.3->-r requirements.txt (line 2))

Downloading six-1.10.0-py2.py3-none-any.whl

Building wheels for collected packages: Flask, itsdangerous, MarkupSafe, docutils

Running setup.py bdist_wheel for Flask

Stored in directory: /root/.cache/pip/wheels/d2/db/61/cb9b80526b8f3ba89248ec0a29d6da1bb6013681c930fca987

Running setup.py bdist_wheel for itsdangerous

Stored in directory: /root/.cache/pip/wheels/97/c0/b8/b37c320ff57e15f993ba0ac98013eee778920b4a7b3ebae3cf

Running setup.py bdist_wheel for MarkupSafe

Stored in directory: /root/.cache/pip/wheels/94/a7/79/f79a998b64c1281cb99fa9bbd33cfc9b8b5775f438218d17a7

Running setup.py bdist_wheel for docutils

Stored in directory: /root/.cache/pip/wheels/d5/32/4f/1347e8ac67071e8150a5dc69354a51a04ac065d0b48334f608

Successfully built Flask itsdangerous MarkupSafe docutils

Installing collected packages: Werkzeug, MarkupSafe, Jinja2, itsdangerous, Flask, jmespath, futures, six, python-dateutil, docutils, botocore, boto3

Successfully installed Flask-0.10.1 Jinja2-2.8 MarkupSafe-0.23 Werkzeug-0.11.3 boto3-1.2.3 botocore-1.3.17 docutils-0.12 futures-3.0.3 itsdangerous-0.24 jmespath-0.9.0 python-dateutil-2.4.2 six-1.10.0

---> 4e5aaebeada8

Removing intermediate container e8e9ec3724ce

Step 6 : CMD python app.py 5000

---> Running in 70d274952e94

---> 0ab971a5eaf1

Removing intermediate container 70d274952e94

Successfully built 0ab971a5eaf1

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo/movie-api [14:59:40]

→ docker run -d -p 5000:5000 movie-api

bad3d80e96430c7650a7ebb95011d509401dc45206116044e63145436ad65a52

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo/movie-api [14:59:56]

→ docker ps

CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES

bad3d80e9643 movie-api "/bin/sh -c 'python a" 2 seconds ago Up 1 seconds 0.0.0.0:5000->5000/tcp prickly_goldberg

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo/movie-api [14:59:58]

→ docker-machine ip default

192.168.99.100

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo/movie-api [15:00:07]

→ curl 192.168.99.100:5000

Hello World!%

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo [15:20:24]

→ docker stop ba

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo [15:21:12]

→ docker rm ba

We just built an image, spun up a container based off that image, queried the service and got a response, stopped the service, and deleted the container. However, every time you make a code change your going to have to rerun the build command, and then relaunch your container. If your doing quick iterative development this can get annoying quickly. There is a better way.

Introducing docker-compose

The docker-compose files are how we orchestrate the the building and running of our containers in an easier fashion. We can leverage how these files work with flasks built in reload system on file change to enable rapid iterative development

docker-compose.override.yml is special. When you run the docker-compose command, it will look for docker-compose.yml and docker-compose.override.yml. If present, it will go ahead and merge them and then perform actions based on that merged data.

We leverage this behavior to build our development environment. If we wanted a test environment for example, we would add a docker-compose.test.yml file, and when running docker-compose target that environment with docker-compose -f docker-compose.yml -f docker-compose.test.yml. However, this is generally only done by build systems, and so we use the override file for development as it keeps the command for developers simpler as they don’t need to specify -f.

docker-compose.yml

Within the root of our project directory (docker-movie-db-demo) lets create a file called docker-compose.yml and make it look like so:

movie-api:
  image: TBD
  restart: always
  stdin_open: true
  ports:
   - 5000

movie-api:

image: TBD

restart: always

stdin_open: true

ports:

- 5000

We have just defined a movie-api service that for now has no image, will always restart on failure, and exposes the container port 5000. You can see the full docker-compose file reference here

As mentioned above, the override file will allow us to override some things in the movie-api base compose definition to make development a little bit faster.

Create and edit a file called docker-compose.override.yml and make it look like so:

movie-api:
  build: ./movie-api
  ports:
    - "8080:5000"
  volumes:
    - ./movie-api:/code

movie-api:

build: ./movie-api

ports:

- "8080:5000"

volumes:

- ./movie-api:/code

If you remember, in our dockerfile, we copy up the movie-api files into the image during its build. This is great when you want to make a container that you start shipping around to various environments such as test, staging, and production. However when you just want to do local development, building that same container every time is time consuming and annoying. With our override file, we have made it so that we will mount our code base within the running container. This allows us to use our favorite IDE locally to do development but immediately see those changes reflected. We also have exposed port 5000 on the container and mapped that to port 8080 on our docker-machine. This makes it a little bit easier to debug and test. In production you generally wouldn’t do this and i’ll detail more in a seperate article focusing around production deployment of this workflow.

Starting our movie-api app.

Now, from the root of our project directory (docker-movie-db-demo) run the following command:

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo [15:15:41]
→ docker-compose up -d
Building movie-api
Step 1 : FROM python:2.7
 ---&gt; 10b7e9592569
Step 2 : ADD . /code
 ---&gt; 8181c43291b9
Removing intermediate container 15ba05dc5a89
Step 3 : WORKDIR /code
 ---&gt; Running in 605ac00f14ce
 ---&gt; 70b6a0370df3
Removing intermediate container 605ac00f14ce
Step 4 : RUN apt-get update
 ---&gt; Running in f8a51693d807
Get:1 http://security.debian.org jessie/updates InRelease [63.1 kB]
Get:2 http://security.debian.org jessie/updates/main amd64 Packages [230 kB]
Get:3 http://httpredir.debian.org jessie-updates InRelease [136 kB]
Ign http://httpredir.debian.org jessie InRelease
Get:4 http://httpredir.debian.org jessie Release.gpg [2373 B]
Get:5 http://httpredir.debian.org jessie Release [148 kB]
Get:6 http://httpredir.debian.org jessie-updates/main amd64 Packages [3619 B]
Get:7 http://httpredir.debian.org jessie/main amd64 Packages [9035 kB]
Fetched 9619 kB in 4s (1959 kB/s)
Reading package lists...
 ---&gt; e8268b320a1a
Removing intermediate container f8a51693d807
Step 5 : RUN pip install -r requirements.txt
 ---&gt; Running in 34fd8a7da9da
Collecting Flask==0.10.1 (from -r requirements.txt (line 1))
  Downloading Flask-0.10.1.tar.gz (544kB)
Collecting boto3==1.2.3 (from -r requirements.txt (line 2))
  Downloading boto3-1.2.3-py2.py3-none-any.whl (108kB)
Collecting Werkzeug&gt;=0.7 (from Flask==0.10.1-&gt;-r requirements.txt (line 1))
  Downloading Werkzeug-0.11.3-py2.py3-none-any.whl (305kB)
Collecting Jinja2&gt;=2.4 (from Flask==0.10.1-&gt;-r requirements.txt (line 1))
  Downloading Jinja2-2.8-py2.py3-none-any.whl (263kB)
Collecting itsdangerous&gt;=0.21 (from Flask==0.10.1-&gt;-r requirements.txt (line 1))
  Downloading itsdangerous-0.24.tar.gz (46kB)
Collecting jmespath&lt;1.0.0,&gt;=0.7.1 (from boto3==1.2.3-&gt;-r requirements.txt (line 2))
  Downloading jmespath-0.9.0-py2.py3-none-any.whl
Collecting futures&lt;4.0.0,&gt;=2.2.0 (from boto3==1.2.3-&gt;-r requirements.txt (line 2))
  Downloading futures-3.0.3-py2-none-any.whl
Collecting botocore&lt;1.4.0,&gt;=1.3.0 (from boto3==1.2.3-&gt;-r requirements.txt (line 2))
  Downloading botocore-1.3.17-py2.py3-none-any.whl (2.1MB)
Collecting MarkupSafe (from Jinja2&gt;=2.4-&gt;Flask==0.10.1-&gt;-r requirements.txt (line 1))
  Downloading MarkupSafe-0.23.tar.gz
Collecting python-dateutil&lt;3.0.0,&gt;=2.1 (from botocore&lt;1.4.0,&gt;=1.3.0-&gt;boto3==1.2.3-&gt;-r requirements.txt (line 2))
  Downloading python_dateutil-2.4.2-py2.py3-none-any.whl (188kB)
Collecting docutils&gt;=0.10 (from botocore&lt;1.4.0,&gt;=1.3.0-&gt;boto3==1.2.3-&gt;-r requirements.txt (line 2))
  Downloading docutils-0.12.tar.gz (1.6MB)
Collecting six&gt;=1.5 (from python-dateutil&lt;3.0.0,&gt;=2.1-&gt;botocore&lt;1.4.0,&gt;=1.3.0-&gt;boto3==1.2.3-&gt;-r requirements.txt (line 2))
  Downloading six-1.10.0-py2.py3-none-any.whl
Building wheels for collected packages: Flask, itsdangerous, MarkupSafe, docutils
  Running setup.py bdist_wheel for Flask
  Stored in directory: /root/.cache/pip/wheels/d2/db/61/cb9b80526b8f3ba89248ec0a29d6da1bb6013681c930fca987
  Running setup.py bdist_wheel for itsdangerous
  Stored in directory: /root/.cache/pip/wheels/97/c0/b8/b37c320ff57e15f993ba0ac98013eee778920b4a7b3ebae3cf
  Running setup.py bdist_wheel for MarkupSafe
  Stored in directory: /root/.cache/pip/wheels/94/a7/79/f79a998b64c1281cb99fa9bbd33cfc9b8b5775f438218d17a7
  Running setup.py bdist_wheel for docutils
  Stored in directory: /root/.cache/pip/wheels/d5/32/4f/1347e8ac67071e8150a5dc69354a51a04ac065d0b48334f608
Successfully built Flask itsdangerous MarkupSafe docutils
Installing collected packages: Werkzeug, MarkupSafe, Jinja2, itsdangerous, Flask, jmespath, futures, six, python-dateutil, docutils, botocore, boto3
Successfully installed Flask-0.10.1 Jinja2-2.8 MarkupSafe-0.23 Werkzeug-0.11.3 boto3-1.2.3 botocore-1.3.17 docutils-0.12 futures-3.0.3 itsdangerous-0.24 jmespath-0.9.0 python-dateutil-2.4.2 six-1.10.0
 ---&gt; d7a9425b50fd
Removing intermediate container 34fd8a7da9da
Step 6 : CMD python app.py 5000
 ---&gt; Running in 96896671d8db
 ---&gt; a02f38122e57
Removing intermediate container 96896671d8db
Successfully built a02f38122e57
Creating dockermoviedbdemo_movie-api_1

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo [15:21:14]
→ docker ps
CONTAINER ID        IMAGE                         COMMAND                  CREATED             STATUS              PORTS                                             NAMES
3d5ee6e7c2c6        dockermoviedbdemo_movie-api   "/bin/sh -c 'python a"   3 minutes ago       Up 3 minutes        0.0.0.0:8080-&gt;5000/tcp, 0.0.0.0:32802-&gt;5000/tcp   dockermoviedbdemo_movie-api_1

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo [15:24:29]
→ docker-machine ip default
192.168.99.100

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo [15:23:31]
→ curl 192.168.99.100:8080
Hello World!%

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo [15:15:41]

→ docker-compose up -d

Building movie-api

Step 1 : FROM python:2.7

---> 10b7e9592569

Step 2 : ADD . /code

---> 8181c43291b9

Removing intermediate container 15ba05dc5a89

Step 3 : WORKDIR /code

---> Running in 605ac00f14ce

---> 70b6a0370df3

Removing intermediate container 605ac00f14ce

Step 4 : RUN apt-get update

---> Running in f8a51693d807

Get:1 http://security.debian.org jessie/updates InRelease [63.1 kB]

Get:2 http://security.debian.org jessie/updates/main amd64 Packages [230 kB]

Get:3 http://httpredir.debian.org jessie-updates InRelease [136 kB]

Ign http://httpredir.debian.org jessie InRelease

Get:4 http://httpredir.debian.org jessie Release.gpg [2373 B]

Get:5 http://httpredir.debian.org jessie Release [148 kB]

Get:6 http://httpredir.debian.org jessie-updates/main amd64 Packages [3619 B]

Get:7 http://httpredir.debian.org jessie/main amd64 Packages [9035 kB]

Fetched 9619 kB in 4s (1959 kB/s)

Reading package lists...

---> e8268b320a1a

Removing intermediate container f8a51693d807

Step 5 : RUN pip install -r requirements.txt

---> Running in 34fd8a7da9da

Collecting Flask==0.10.1 (from -r requirements.txt (line 1))

Downloading Flask-0.10.1.tar.gz (544kB)

Collecting boto3==1.2.3 (from -r requirements.txt (line 2))

Downloading boto3-1.2.3-py2.py3-none-any.whl (108kB)

Collecting Werkzeug>=0.7 (from Flask==0.10.1->-r requirements.txt (line 1))

Downloading Werkzeug-0.11.3-py2.py3-none-any.whl (305kB)

Collecting Jinja2>=2.4 (from Flask==0.10.1->-r requirements.txt (line 1))

Downloading Jinja2-2.8-py2.py3-none-any.whl (263kB)

Collecting itsdangerous>=0.21 (from Flask==0.10.1->-r requirements.txt (line 1))

Downloading itsdangerous-0.24.tar.gz (46kB)

Collecting jmespath<1.0.0,>=0.7.1 (from boto3==1.2.3->-r requirements.txt (line 2))

Downloading jmespath-0.9.0-py2.py3-none-any.whl

Collecting futures<4.0.0,>=2.2.0 (from boto3==1.2.3->-r requirements.txt (line 2))

Downloading futures-3.0.3-py2-none-any.whl

Collecting botocore<1.4.0,>=1.3.0 (from boto3==1.2.3->-r requirements.txt (line 2))

Downloading botocore-1.3.17-py2.py3-none-any.whl (2.1MB)

Collecting MarkupSafe (from Jinja2>=2.4->Flask==0.10.1->-r requirements.txt (line 1))

Downloading MarkupSafe-0.23.tar.gz

Collecting python-dateutil<3.0.0,>=2.1 (from botocore<1.4.0,>=1.3.0->boto3==1.2.3->-r requirements.txt (line 2))

Downloading python_dateutil-2.4.2-py2.py3-none-any.whl (188kB)

Collecting docutils>=0.10 (from botocore<1.4.0,>=1.3.0->boto3==1.2.3->-r requirements.txt (line 2))

Downloading docutils-0.12.tar.gz (1.6MB)

Collecting six>=1.5 (from python-dateutil<3.0.0,>=2.1->botocore<1.4.0,>=1.3.0->boto3==1.2.3->-r requirements.txt (line 2))

Downloading six-1.10.0-py2.py3-none-any.whl

Building wheels for collected packages: Flask, itsdangerous, MarkupSafe, docutils

Running setup.py bdist_wheel for Flask

Stored in directory: /root/.cache/pip/wheels/d2/db/61/cb9b80526b8f3ba89248ec0a29d6da1bb6013681c930fca987

Running setup.py bdist_wheel for itsdangerous

Stored in directory: /root/.cache/pip/wheels/97/c0/b8/b37c320ff57e15f993ba0ac98013eee778920b4a7b3ebae3cf

Running setup.py bdist_wheel for MarkupSafe

Stored in directory: /root/.cache/pip/wheels/94/a7/79/f79a998b64c1281cb99fa9bbd33cfc9b8b5775f438218d17a7

Running setup.py bdist_wheel for docutils

Stored in directory: /root/.cache/pip/wheels/d5/32/4f/1347e8ac67071e8150a5dc69354a51a04ac065d0b48334f608

Successfully built Flask itsdangerous MarkupSafe docutils

Installing collected packages: Werkzeug, MarkupSafe, Jinja2, itsdangerous, Flask, jmespath, futures, six, python-dateutil, docutils, botocore, boto3

---> d7a9425b50fd

Removing intermediate container 34fd8a7da9da

Step 6 : CMD python app.py 5000

---> Running in 96896671d8db

---> a02f38122e57

Removing intermediate container 96896671d8db

Successfully built a02f38122e57

Creating dockermoviedbdemo_movie-api_1

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo [15:21:14]

→ docker ps

CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES

3d5ee6e7c2c6 dockermoviedbdemo_movie-api "/bin/sh -c 'python a" 3 minutes ago Up 3 minutes 0.0.0.0:8080->5000/tcp, 0.0.0.0:32802->5000/tcp dockermoviedbdemo_movie-api_1

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo [15:24:29]

→ docker-machine ip default

192.168.99.100

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo [15:23:31]

→ curl 192.168.99.100:8080

Hello World!%

You can tail the logs of the container by running:

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo [15:27:08]
→ docker logs -f 3d5
 * Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)
 * Restarting with stat
 * Debugger is active!
 * Debugger pin code: 105-865-067

# ckelly at Helios in ~/Code/personal/docker-movie-db-demo [15:27:08]

→ docker logs -f 3d5

* Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)

* Restarting with stat

* Debugger is active!

* Debugger pin code: 105-865-067

So already you can see that starting up the container is simpler. However things really shine when you start editing code. Fire vim or your favorite IDE and edit movie-api/demo/services/api.py:

import os
import json
import flask

app = flask.Flask(__name__)

@app.route('/')
def index():
  return 'Hello World! This is a test of the instance editing ability.'

import os

import json

import flask

app = flask.Flask(__name__)

@app.route('/')

def index():

return 'Hello World! This is a test of the instance editing ability.'

If you kept tailing the logs you will see that it instantly reloaded, and if you run curl 192.168.99.100:8080 again you will see that the output changes.

Wrapping it up

This concludes part 1 of the tutorial. In summary we laid out the structure for our project, went through how to setup a machine for docker, built a sample flask application that returns a hello world message. We also walked through how to make changes to the application and test those changes in realtime without having to build an image and redeploy the container.

In the next post, i’ll focus on adding a local dynamodb instance, how to run one off data scripts to do things like load data and build a sample web interface that interacts with the API.

Part 2 Here