+# rococo-service-host A Docker-based host for services that process messages from a queue

Processing

The docker image's main process is process.py which handles all message processing.

set up the env file

• Copy .env.example to .env at project root
• Copy .env.secrets.example to .env.secrets at project root

Building and publishing

When you merge code to main branch, the image will be built and published automatically to the dockerhub repository.

Creating a child image - custom processors

Use the example in "service_example" folder. What you need to do is:

• create a processor.py file with the Class for the processor
• create the __init__.py file importing it
• have a pyproject.toml for it
• copy all 3 files into /app/src/services/ in the target image
• have an env var in your Dockerfile with PROCESSOR_TYPE that specifies the Class, and PROCESSOR_MODULE which specifies the module to import, which is usually services.processor if you named your file processor.py
• after you named your processor class, you must create the env var < processor_class_name >_QUEUE_NAME = < your_rabbit_mq_queue_name >
• QUEUE_NAME_PREFIX value is optional but the var needs to be provided
• The queue name that is formed is queue_name_prefix+processor_class_name+_QUEUE_NAME

In this case you can test the service_example child image

From project root do:

cd service_example
docker network create rabbitmq-network
docker run -d --net=rabbitmq-network --name some-rabbit -p 5672:5672 -p 15672:15672 -e RABBITMQ_DEFAULT_USER=user -e RABBITMQ_DEFAULT_PASS=password rabbitmq:3-management
docker build -t custom-service-processor .
docker run --net=rabbitmq-network --env-file ./.env --env-file ./.env.secrets --name custom-service-processor custom-service-processor

Tests for child

docker exec -it custom-service-processor poetry run pytest -vv

For a child of a cron processor:

cd cron_service_example
docker build -t cron-service-processor .
docker run --env-file ./.env --name cron-service-processor cron-service-processor

No tests are setup for cron processor thus far.

Development

These are instructions for building the dev environment of the service host.

RabitMQ image

docker network create rabbitmq-network
docker run -d --net=rabbitmq-network --name some-rabbit -p 5672:5672 -p 15672:15672 -e RABBITMQ_DEFAULT_USER=user -e RABBITMQ_DEFAULT_PASS=password rabbitmq:3-management

Service host image

docker network create rabbitmq-network
docker build -t rococo-service-host .
docker run --net=rabbitmq-network --env-file ./.env --env-file ./.env.secrets --name rococo-service-host rococo-service-host

Test

docker exec -it rococo-service-host poetry run pytest -vv

Cron processor

If you are making a processor based on cron execution, these are the only env vars needed at Dockerfile level

• PROCESSOR_MODULE=your.processor.module
• EXECUTION_TYPE=CRON
• CRON_TIME_AMOUNT=time_in_int_or_float (example : CRON_TIME_AMOUNT=30 or CRON_TIME_AMOUNT=0.5 )
• CRON_TIME_UNIT=time_in_units (one of [SECONDS,MINUTES,HOURS,DAYS,WEEKS] , example = CRON_TIME_UNIT=SECONDS)

An example setup of a cron processor image is at "/cron_service_example"

Naturally, you wont need a RabbitMQ server nor listener for a cron processor, so the processor doesn't need a class that extends BaseServiceProcessor from rococo messaging.