add tracing and refactor some api pkgs

internal/api/grpc/client/middleware/tracing.go

@@ -0,0 +1,38 @@
+package middleware
+
+import (
+	"context"
+	"strings"
+
+	"go.opencensus.io/plugin/ocgrpc"
+	"go.opencensus.io/trace"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/stats"
+
+	"github.com/caos/zitadel/internal/api"
+	"github.com/caos/zitadel/internal/tracing"
+)
+
+type GRPCMethod string
+
+func TracingStatsClient(ignoredMethods ...GRPCMethod) grpc.DialOption {
+	return grpc.WithStatsHandler(&tracingClientHandler{ignoredMethods, ocgrpc.ClientHandler{StartOptions: trace.StartOptions{Sampler: tracing.Sampler(), SpanKind: trace.SpanKindClient}}})
+}
+
+func DefaultTracingStatsClient() grpc.DialOption {
+	return TracingStatsClient(api.Healthz, api.Readiness, api.Validation)
+}
+
+type tracingClientHandler struct {
+	IgnoredMethods []GRPCMethod
+	ocgrpc.ClientHandler
+}
+
+func (s *tracingClientHandler) TagRPC(ctx context.Context, tagInfo *stats.RPCTagInfo) context.Context {
+	for _, method := range s.IgnoredMethods {
+		if strings.HasSuffix(tagInfo.FullMethodName, string(method)) {
+			return ctx
+		}
+	}
+	return s.ClientHandler.TagRPC(ctx, tagInfo)
+}