Add central database service with InfluxDB for time series data storage

[Copilot]

Ground stations need persistent time series data storage for telemetry and mission data. This adds a configurable database service based on InfluxDB v2.

Implementation

Database Writer Service (backend-deno/samples/database/)

• Subscribes to NATS subjects, writes JSON messages to InfluxDB
• Measurement names derived from subject hierarchy (e.g., data.telemetry.temperature → telemetry.temperature)
• Auto-extracts timestamps, tags, and typed fields (float/string/boolean)

Database Query Service (backend-deno/samples/database-query/)

• Request/reply pattern over NATS for querying
• Parameter-based queries (measurement, range, fields, filters) or custom Flux queries
• Queue-grouped for horizontal scaling
• Uses simple NATS subject (e.g., query.database) - no wildcard pattern needed

Configuration

• INFLUXDB_URL, INFLUXDB_TOKEN, INFLUXDB_ORG, INFLUXDB_BUCKET
• DATA_SUBJECT - NATS subject pattern with wildcard for data (e.g., data.>)
• QUERY_SUBJECT - NATS subject for queries (e.g., query.database)

Usage

// Write data
messageBus.publish("data.telemetry.temperature", JSON.stringify({
  time: new Date().toISOString(),
  value: 23.5,
  tags: { sensor: "temp-01" }
}));

// Query data
const response = await messageBus.request("query.database", JSON.stringify({
  measurement: "telemetry.temperature",
  range: "-1h",
  fields: ["value"]
}));

Deployment

Pre-built Docker Images (recommended)

• ghcr.io/wuespace/telestion-database:latest - Database Writer Service
• ghcr.io/wuespace/telestion-database-query:latest - Database Query Service
• Published automatically on releases via GitHub Actions

Also Includes

• Docker Compose configuration with InfluxDB 2.7
• Kubernetes Deployment examples with published images
• Production security guidelines (token management, TLS, retention policies)
• Test client for validation (database-test-client/)
• Build-from-source option for customization

Full deployment guide at docs/docs/Deployment/database-service.md.

• Fixes wuespace/telestion#440

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Central Database Service</issue_title>
<issue_description>Every ground station needs some database to store (mostly time series) data surrounding the mission.

Please

1. implement a central DB service based on the Telestion framework to handle these requirements
2. make it configurable such that it can be used in a multitude of projects
3. add documentation around deploying it in a typical Telestion deployment</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes wuespace/telestion#440

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[pklaschka]

@copilot So far, so good. Two points I'd like changed:

1. Currently, the address for the query service uses a wildcard. However, it doesn't look like this gets used. Please either specify how it could be used or remove it, since this is confusing.
2. Make it so that the service Docker containers get published in the package registry and reflect that publication in the deployment docs (using the published containers), to make it easy to deploy

[Copilot]

@copilot So far, so good. Two points I'd like changed:

1. Currently, the address for the query service uses a wildcard. However, it doesn't look like this gets used. Please either specify how it co...

Both issues addressed in commit 20ed43c:

1. QUERY_SUBJECT wildcard removed: The wildcard wasn't used - the query service doesn't extract information from the subject hierarchy like the database writer does. Changed to simple subject (e.g., query.database instead of query.>).

2. Docker images published:

   • Created individual Dockerfiles for both services
   • Added GitHub Actions workflow (.github/workflows/database-services.yml) to publish to ghcr.io on releases
   • Updated deployment docs to use published images: ghcr.io/wuespace/telestion-database:latest and ghcr.io/wuespace/telestion-database-query:latest
   • Added complete Kubernetes deployment examples with published images