Config Service (FastAPI + MongoDB)

A tiny HTTP service to read and write app-scoped configs stored in MongoDB.

• Read one config: GET /{app_id}/get?config_id=motd
• Read all configs for an app: GET /{app_id}/get
• Write a config (GET): GET /{app_id}/set?config_id=motd&value=hello&auth=some_secret_key
• Write a config (POST): POST /{app_id}/set with JSON body

The service enforces an API key for write operations via API_AUTH_TOKEN.

Quick start with Docker

1. Build the image:

docker build -t config-service:latest .

2. Run MongoDB (example using Docker):

docker run -d --name mongo -p 27017:27017 mongo:7

3. Run the service:

docker run --rm -p 8000:8000 \
  -e MONGO_URI="mongodb://host.docker.internal:27017" \
  -e API_AUTH_TOKEN="some_secret_key" \
  --name config-service \
  config-service:latest

• If running Mongo in another container on the same Docker network, you can set MONGO_URI=mongodb://mongo:27017 and attach both containers to the same network.

API

Health

• GET /health -> {"status":"ok"}

Read

• GET /{app_id}/get?config_id=motd
  • 200: {"app_id":"test_app","config_id":"motd","value":"hello","updated_at":"...","created_at":"..." }
  • 404 if not found.
• GET /{app_id}/get
  • 200: {"app_id":"test_app","count":2,"configs":{"motd":"hello","feature_flag":true}}

Write (requires auth)

Provide the token in one of:

• Query param: ?auth=API_AUTH_TOKEN

• Header: X-API-KEY: API_AUTH_TOKEN

• POST body field: "auth": "API_AUTH_TOKEN"

• GET style (matches your example):

  • GET /{app_id}/set?config_id=motd&value=hello&auth=some_secret_key
  • Returns:

    {
      "success": true,
      "upserted": true,
      "config": {
        "app_id": "test_app",
        "config_id": "motd",
        "value": "hello",
        "updated_at": "...",
        "created_at": "..."
      }
    }

• POST style (recommended):

  • POST /{app_id}/set
  • Body:

    {
      "config_id": "motd",
      "value": "hello",
      "auth": "some_secret_key"
    }

Notes on values

• The service will attempt to parse JSON-like strings for value. Examples that will parse as JSON:
  • {"a":1}, [1,2,3], "hello", 123, true, false, null
• If parsing fails, the value is stored as a string.

Local development (without Docker)

python -m venv .venv
source .venv/bin/activate
pip install -r requirements.txt

export MONGO_URI="mongodb://localhost:27017"
export API_AUTH_TOKEN="some_secret_key"

uvicorn app:app --reload

Open docs at: http://localhost:8000/docs

Data model

• Collection: configs
• Document:

  {
    "app_id": "test_app",
    "config_id": "motd",
    "value": "hello",
    "created_at": "2025-01-01T00:00:00Z",
    "updated_at": "2025-01-01T00:00:00Z"
  }

• Unique index on (app_id, config_id).

Security

• Set API_AUTH_TOKEN to a strong secret.
• Prefer POST with header X-API-KEY to avoid logging secrets in URLs.
• Restrict network access as appropriate for your environment.