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Aspire dashboard

The standalone Aspire dashboard can receive LeanCorpus OpenTelemetry traces, metrics, and logs without an Aspire AppHost.

Run with Docker

docker run --rm -it `
  -p 18888:18888 `
  -p 4317:18889 `
  --name aspire-dashboard `
  mcr.microsoft.com/dotnet/aspire-dashboard:latest

The container listens for its web interface on port 18888. Container port 18889 is the OTLP/gRPC receiver and is mapped to the conventional host port 4317.

The dashboard prints a login URL containing a token. Open that URL rather than assuming the root page is unauthenticated.

Run the telemetry example

In another terminal:

$env:OTEL_EXPORTER_OTLP_ENDPOINT = "http://localhost:4317"
$env:OTEL_EXPORTER_OTLP_PROTOCOL = "grpc"
dotnet run --project src/examples/Rowles.LeanCorpus.Example.Telemetry

For Bash:

OTEL_EXPORTER_OTLP_ENDPOINT=http://localhost:4317 \
OTEL_EXPORTER_OTLP_PROTOCOL=grpc \
dotnet run --project src/examples/Rowles.LeanCorpus.Example.Telemetry

If using the locally installed Aspire dashboard command instead, its insecure HTTP option must agree with the example's plain HTTP OTLP endpoint:

aspire-dashboard -s false

Expected views

View LeanCorpus signals
Traces Search, commit, flush, merge, and instrumented application operations
Metrics Search latency, query cache, commits, merges, indexing, and HNSW traversal
Structured logs Application and slow-query records when their providers are configured
Resources The service name and resource attributes supplied by the example

Select a trace to inspect spans and duration. Use metric charts to correlate search latency with merge or indexing activity. The standalone dashboard retains telemetry for development inspection, not long-term production monitoring.

Troubleshooting

Console output exists but the dashboard is empty

The application is producing telemetry, but OTLP export is not reaching the receiver. Check:

  • endpoint is http://localhost:4317 from a host process;
  • protocol is grpc;
  • container port mapping includes 4317:18889;
  • no proxy or firewall is intercepting localhost gRPC;
  • the application has the OTLP exporter enabled, not only the console exporter.

Connection refused

Confirm the container is running:

docker ps --filter name=aspire-dashboard
docker logs aspire-dashboard

If the application itself runs in a container, localhost refers to that container. Put both containers on a shared network and use the dashboard container name and internal port 18889.

Dashboard opens but no service appears

Generate activity after the exporter starts and set a stable service name. Check the browser time range and ensure the machine clock is correct.

Production security

Telemetry can contain query terms, field names, paths, and application identifiers. Do not expose the standalone web or OTLP ports publicly without authentication and network controls. Follow the Aspire dashboard security guidance.

See OpenTelemetry for LeanCorpus configuration and Production deployment for monitoring guidance.

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