Add otel_project_id flag for GCP local runs (#325)

Author: roger2hk

cmd/gcp/main.go

@@ -28,12 +28,12 @@ import (
 	"syscall"
 	"time"
 
-	"github.com/transparency-dev/tesseract"
-	"github.com/transparency-dev/tesseract/storage"
-	"github.com/transparency-dev/tesseract/storage/gcp"
 	"github.com/transparency-dev/tessera"
 	tgcp "github.com/transparency-dev/tessera/storage/gcp"
 	gcp_as "github.com/transparency-dev/tessera/storage/gcp/antispam"
+	"github.com/transparency-dev/tesseract"
+	"github.com/transparency-dev/tesseract/storage"
+	"github.com/transparency-dev/tesseract/storage/gcp"
 	"golang.org/x/mod/sumdb/note"
 	"k8s.io/klog/v2"
 )
@@ -64,6 +64,7 @@ var (
 	signerPublicKeySecretName  = flag.String("signer_public_key_secret_name", "", "Public key secret name for checkpoints and SCTs signer. Format: projects/{projectId}/secrets/{secretName}/versions/{secretVersion}.")
 	signerPrivateKeySecretName = flag.String("signer_private_key_secret_name", "", "Private key secret name for checkpoints and SCTs signer. Format: projects/{projectId}/secrets/{secretName}/versions/{secretVersion}.")
 	traceFraction              = flag.Float64("trace_fraction", 0, "Fraction of open-telemetry span traces to sample")
+	otelProjectID              = flag.String("otel_project_id", "", "GCP project ID for OpenTelemetry exporter. This is only required for local runs.")
 )
 
 // nolint:staticcheck
@@ -72,7 +73,7 @@ func main() {
 	flag.Parse()
 	ctx := context.Background()
 
-	shutdownOTel := initOTel(ctx, *traceFraction, *origin)
+	shutdownOTel := initOTel(ctx, *traceFraction, *origin, *otelProjectID)
 	defer shutdownOTel(ctx)
 
 	signer, err := NewSecretManagerSigner(ctx, *signerPublicKeySecretName, *signerPrivateKeySecretName)

cmd/gcp/otel.go

@@ -34,7 +34,7 @@ import (
 //
 // Tracing is enabled with statistical sampling, with the probability passed in.
 // Returns a shutdown function which should be called just before exiting the process.
-func initOTel(ctx context.Context, traceFraction float64, origin string) func(context.Context) {
+func initOTel(ctx context.Context, traceFraction float64, origin string, projectID string) func(context.Context) {
 	var shutdownFuncs []func(context.Context) error
 	// shutdown combines shutdown functions from multiple OpenTelemetry
 	// components into a single function.
@@ -63,7 +63,11 @@ func initOTel(ctx context.Context, traceFraction float64, origin string) func(co
 		klog.Exitf("Failed to detect resources: %v", err)
 	}
 
-	me, err := mexporter.New()
+	mopts := []mexporter.Option{}
+	if projectID != "" {
+		mopts = append(mopts, mexporter.WithProjectID(projectID))
+	}
+	me, err := mexporter.New(mopts...)
 	if err != nil {
 		klog.Exitf("Failed to create metric exporter: %v", err)
 		return nil
@@ -76,7 +80,11 @@ func initOTel(ctx context.Context, traceFraction float64, origin string) func(co
 	shutdownFuncs = append(shutdownFuncs, mp.Shutdown)
 	otel.SetMeterProvider(mp)
 
-	te, err := texporter.New()
+	topts := []texporter.Option{}
+	if projectID != "" {
+		topts = append(topts, texporter.WithProjectID(projectID))
+	}
+	te, err := texporter.New(topts...)
 	if err != nil {
 		klog.Exitf("Failed to create trace exporter: %v", err)
 		return nil