Moto. Mokaem AWS

Testing is an integral part of the development process. And sometimes developers need to run tests locally before committing changes.
If the application uses Amazon Web Services, python библиотека motorcycle perfect for this.


The full list of resource coverage can be viewed here.
There is a turnip on Github Hugo Picado — motoserver. Ready image, run and use. The only nuance is that after launch, no AWS resources have not yet been created.

Well, that's easy enough to fix.

Since you need to specify the type of service at startup (env variable MOTO_SERVICE), it remains for us to describe the creation of the resource.

Let's change a little start.sh:

Instead of

moto_server $MOTO_SERVICE -H $MOTO_HOST -p $MOTO_PORT

Insert:

if [ -f /opt/init/bootstrap.py ]; then
  moto_server $MOTO_SERVICE -H $MOTO_HOST -p $MOTO_PORT & (sleep 5 && echo "Executing bootstrap script." && python /opt/init/bootstrap.py)
else
  moto_server $MOTO_SERVICE -H $MOTO_HOST -p $MOTO_PORT
fi
wait

The resulting file is:

start.sh

#!/bin/sh

# validate required input
if [ -z "$MOTO_SERVICE" ]; then
  echo "Please define AWS service to run with Moto Server (e.g. s3, ec2, etc)"
  exit 1
fi

# setting defaults for optional input
if [ -z "$MOTO_HOST" ]; then
  MOTO_HOST="0.0.0.0"
fi

if [ -z "$MOTO_PORT" ]; then
  MOTO_PORT="5000"
fi

echo "Starting service $MOTO_SERVICE at $MOTO_HOST:$MOTO_PORT"

if [ -f /opt/init/bootstrap.py ]; then
  moto_server $MOTO_SERVICE -H $MOTO_HOST -p $MOTO_PORT & (sleep 5 && echo "Executing bootstrap script." && python /opt/init/bootstrap.py)
else
  moto_server $MOTO_SERVICE -H $MOTO_HOST -p $MOTO_PORT
fi
# Prevent container from exiting when bootstrap.py finishing
wait

We build a new image and push it to our registry.

Next, let's write a resource initialization script, for example SWF domain, using the library for working with AWS - boto3:

bootstrap_swf.py

import boto3
from botocore.exceptions import ClientError
import os

os.environ["AWS_ACCESS_KEY_ID"] = "fake"
os.environ["AWS_SECRET_ACCESS_KEY"] = "fake"

client = boto3.client('swf', region_name='us-west-2', endpoint_url='http://localhost:5000')

try:
    client.register_domain(
        name='test-swf-mock-domain',
        description="Test SWF domain",
        workflowExecutionRetentionPeriodInDays="10"
    )
except ClientError as e:
    print "Domain already exists: ", e.response.get("Error", {}).get("Code")

response = client.list_domains(
    registrationStatus='REGISTERED',
    maximumPageSize=123,
    reverseOrder=True|False
)

print 'Ready'

The logic is this:

• We mount our script at startup in /opt/init/bootstrap.py.
• If the file is mounted, it will be executed.
• If the file does not exist, the bare moto-server will simply start.

And, you can mock an entire resource by running one container:

docker run --name swf -d 
    -e MOTO_SERVICE=swf 
    -e MOTO_HOST=0.0.0.0 
    -e MOTO_PORT=5000 
    -p 5001:5000 
    -v /tmp/bootstrap_swf.py:/opt/init/bootstrap.py 
    -i awesome-repo.com/moto-server:latest

Let's try it interactively:

Works!

So we can make a docker-compose.yml which will save time on testing changes:

docker-compose.yml

version: '3'
services:
  s3:
    image: picadoh/motocker
    environment:
      - MOTO_SERVICE=s3
      - MOTO_HOST=10.0.1.2
    ports:
      - "5002:5000"
    networks:
      motonet:
        ipv4_address: 10.0.1.2
    volumes:
      - /tmp/bootstrap_s3.py:/opt/init/bootstrap.py
  swf:
    image: picadoh/motocker
    environment:
      - MOTO_SERVICE=swf
      - MOTO_HOST=10.0.1.3
    ports:
      - "5001:5000"
    networks:
      motonet:
        ipv4_address: 10.0.1.3
    volumes:
      - /tmp/bootstrap_swf.py:/opt/init/bootstrap.py
  ec2:
    image: picadoh/motocker
    environment:
      - MOTO_SERVICE=ec2
      - MOTO_HOST=10.0.1.4
    ports:
      - "5003:5000"
    networks:
      motonet:
        ipv4_address: 10.0.1.4
    volumes:
      - /tmp/bootstrap_ec2.py:/opt/init/bootstrap.py
networks:                             
  motonet:                          
    driver: bridge                
    ipam:                         
      config:                       
        - subnet: 10.0.0.0/16

Actually, not only on a developer's laptop, you can use this approach. Preliminary tests with mocks after the build will help to get rid of possible problems when running on dev* environments.

Links:

motocker repo- github.com/picadoh/motocker
Moto repos - github.com/spuec/moto
Boto3 Docs- boto3.amazonaws.com/v1/documentation/api/latest/index.html

Source: habr.com