Update Docker Compose file to use constant MongoDB host and port

[Copilot]

This PR fixes an issue where the Docker Compose file was propagating MONGO_HOST and MONGO_PORT environment variables from the host to containers, creating unnecessary complexity for developers.

Problem

The app and test services were using environment variable interpolation:

environment:
  MONGO_HOST: ${MONGO_HOST:?}
  MONGO_PORT: ${MONGO_PORT:?}

This required developers to:

• Set these environment variables on the host
• Override them when running tests locally (using localhost instead of mongo)

Solution

Within the Docker Compose stack, these values should be constants that match the service configuration:

• MONGO_HOST: mongo (the service name)
• MONGO_PORT: 27017 (the container-side port from the MongoDB image)

The updated configuration now uses:

environment:
  MONGO_HOST: mongo
  MONGO_PORT: 27017

Benefits

• ✅ No more environment variable setup required for basic Docker Compose usage
• ✅ Values stay in sync with the actual service name and port
• ✅ Consistent with the ingest service which already used hardcoded values
• ✅ Developers can run docker compose up without additional configuration

Testing

Added comprehensive tests to verify:

• Both app and test services use the correct constant values
• Values match the MongoDB service configuration
• Consistency with existing ingest service URI format

Fixes #78.

Warning

Firewall rules blocked me from connecting to one or more addresses

I tried to connect to the following addresses, but was blocked by firewall rules:

• astral.sh
  • Triggering command: curl -LsSf REDACTED (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to my firewall allow list

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[eecavanna]

@copilot, I want these comments to remain in place.

[Copilot]

Done! I've restored the original comments in lines 6-10 while keeping the constant MONGO_HOST and MONGO_PORT values. Commit d7bbfdb

[eecavanna]

@copilot, I don't want these tests or this file to be added; although, usually, I'm in favor of including tests focused on the changes being introduced. In this case, I think it's committing us too strongly to these changes.

[Copilot]

Done! I've removed the test file completely. The core changes to use constant MongoDB values remain, but without the test file that was committing too strongly to these changes. Commit d7bbfdb

[eecavanna]

Thank you for making these changes. I will take over from here.

[eecavanna]

@copilot, I just remembered something. Please also remove the same two environment variables from the env block in the CI GHA workflow YAML file.

[Copilot]

@copilot, I just remembered something. Please also remove the same two environment variables from the env block in the CI GHA workflow YAML file.

Done! I've removed the MONGO_HOST and MONGO_PORT environment variables from the CI workflow file's env block. Commit 28b49d1

[eecavanna]

Thanks. I'll take over from here.

[eecavanna]

We'll accomplish this via #77 instead.