chore: instrument controlplane and cas with OpenTelemetry tracing

app/artifact-cas/cmd/main.go

@@ -37,6 +37,7 @@ import (
 	"github.com/go-kratos/kratos/v2/log"
 	"github.com/go-kratos/kratos/v2/transport/grpc"
 	"github.com/go-kratos/kratos/v2/transport/http"
+	"go.opentelemetry.io/otel/trace"
 
 	_ "go.uber.org/automaxprocs"
 )
@@ -63,7 +64,7 @@ type app struct {
 	backend.Providers
 }
 
-func newApp(logger log.Logger, gs *grpc.Server, hs *http.Server, ms *server.HTTPMetricsServer, providers backend.Providers) *app {
+func newApp(logger log.Logger, gs *grpc.Server, hs *http.Server, ms *server.HTTPMetricsServer, providers backend.Providers, _ trace.TracerProvider) *app {
 	return &app{
 		kratos.New(
 			kratos.ID(id),
@@ -131,7 +132,7 @@ func main() {
 		panic(err)
 	}
 
-	app, cleanup, err := wireApp(bc.Server, bc.Auth, credentialsReader, logger)
+	app, cleanup, err := wireApp(&bc, bc.Server, bc.Auth, credentialsReader, logger)
 	if err != nil {
 		panic(err)
 	}

app/artifact-cas/cmd/wire.go

@@ -1,5 +1,5 @@
 //
-// Copyright 2023 The Chainloop Authors.
+// Copyright 2023-2026 The Chainloop Authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -31,7 +31,7 @@ import (
 )
 
 // wireApp init kratos application.
-func wireApp(*conf.Server, *conf.Auth, credentials.Reader, log.Logger) (*app, func(), error) {
+func wireApp(*conf.Bootstrap, *conf.Server, *conf.Auth, credentials.Reader, log.Logger) (*app, func(), error) {
 	panic(
 		wire.Build(
 			server.ProviderSet,

app/artifact-cas/configs/config.devel.yaml

@@ -30,5 +30,12 @@ credentials_service:
     address: ${VAULT_ADDRESS:http://0.0.0.0:8200}
     token: ${VAULT_TOKEN:notasecret}
 
+observability:
+  tracing:
+    enabled: false
+    endpoint: "localhost:4317"
+    insecure: true
+    sampling_ratio: 1.0
+
 auth:
   public_key_path: ${PUBLIC_KEY_PATH:../../devel/devkeys/cas.pub}

app/artifact-cas/internal/conf/conf.proto

@@ -28,12 +28,24 @@ message Bootstrap {
 
   message Observability {
     Sentry sentry = 1;
+    Tracing tracing = 2;
 
     // Sentry notification support
     message Sentry {
       string dsn = 1;
       string environment = 2;
     }
+    // OpenTelemetry tracing configuration
+    message Tracing {
+      // Whether tracing is enabled. Disabled by default for backward compatibility.
+      bool enabled = 1;
+      // OTLP gRPC exporter endpoint (e.g. "localhost:4317")
+      string endpoint = 2;
+      // Whether to use insecure connection (no TLS). Useful for local development.
+      bool insecure = 3;
+      // Sampling ratio between 0.0 and 1.0. Defaults to 1.0 (sample everything) when unset.
+      optional double sampling_ratio = 4;
+    }
   }
 }