otero is a sample application that has logs, traces and metrics integrated together.

This app was built mainly as part of my blogpost; The complete guide to OpenTelemetry in Golang, you should check out that blogpost for more details.

start;

bash certs.sh
docker-compose up --build

Make some requests;
curl -vkL http://127.0.0.1:8081/serviceA
Access jaeger to check on traces:
http://localhost:16686/jaeger/ui/search
Notice that, not only do logs have traceId and spanID

{
    "app":"my_demo_app",
    "message":"serviceA called",
    "severity":"info",
    "spanId":"d15e62868fccb2bf",
    "traceId":"65dfaa69df19a385095e7e31a812091e",
    "timestamp":"2023-01-21T16:34:05.104073453Z"}

But also the traces have logs;

Access prometheus to check on metrics:
localhost:9090/graph

We also added integration of tracing and logs for both https://github.com/sirupsen/logrus, https://github.com/rs/zerolog & https://pkg.go.dev/log/slog;

{
    "time":"2023-01-27T07:09:58.444782364Z",
    "level":"info",
    "app":"my_demo_app",
    "caller":"/src/service.go:155",
    "message":"zerolog: add called."
    "traceId":"034456796123896d2b132c932b197dea",
    "spanId":"025f0abd50248e15",
}

{
    "timestamp":"2023-01-27T07:09:59.153752332Z",
    "severity":"info",
    "app":"my_demo_app",
    "file":"/src/service.go:152",
    "func":"main.add",
    "message":"logrus: add called.",
    "traceId":"6280224dcd81df78ca9a262370c730eb",
    "spanId":"674e48ff133273fa"
}

{
    "time":"2023-01-27T08:34:42.805542202Z",
    "level":"INFO",
    "app":"my_demo_app",
    "source":"/src/service.go:158",
    "msg":"slog: add called.",
    "app":"my_demo_app",
    "traceId":"1cdc62f79dc4b25065f872a95047ab37",
    "spanId":"ea1c18556211039c"
}