From 21e830e275e7f3f9731057425f493609510601c8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan-Otto=20Kr=C3=B6pke?= <mail@jkroepke.de>
Date: Wed, 16 Jul 2025 13:29:59 +0200
Subject: [PATCH] feat: exclude OTEL instrumentation via build tag (#770)

* feat: exclude OTEL instrumentation via build tag

* add readme
---
 README.md             |  9 +++++++++
 internal/otel/otel.go | 12 ++++++++++++
 internal/otel/shim.go | 22 ++++++++++++++++++++++
 pkg/client/client.go  |  2 +-
 pkg/op/op.go          |  4 ++--
 5 files changed, 46 insertions(+), 3 deletions(-)
 create mode 100644 internal/otel/otel.go
 create mode 100644 internal/otel/shim.go

diff --git a/README.md b/README.md
index bc346f5..b7ac81c 100644
--- a/README.md
+++ b/README.md
@@ -73,6 +73,15 @@ CLIENT_ID=web CLIENT_SECRET=secret ISSUER=http://oidc.local:9998/ SCOPES="openid
 
 > Note: Usernames are suffixed with the hostname (`test-user@localhost` or `test-user@oidc.local`)
 
+
+### Build Tags
+
+The library uses build tags to enable or disable features. The following build tags are available:
+
+| Build Tag | Description                                                                                                                                                              |
+|-----------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| `no_otel`  | Disables the OTel instrumentation, which is enabled by default. This is useful if you do not want to use OTel or if you want to use a different instrumentation library. |
+
 ### Server configuration
 
 Example server allows extra configuration using environment variables and could be used for end to
diff --git a/internal/otel/otel.go b/internal/otel/otel.go
new file mode 100644
index 0000000..21f734a
--- /dev/null
+++ b/internal/otel/otel.go
@@ -0,0 +1,12 @@
+//go:build !no_otel
+
+package otel
+
+import (
+	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/trace"
+)
+
+func Tracer(name string) trace.Tracer {
+	return otel.Tracer(name)
+}
diff --git a/internal/otel/shim.go b/internal/otel/shim.go
new file mode 100644
index 0000000..62d3b0c
--- /dev/null
+++ b/internal/otel/shim.go
@@ -0,0 +1,22 @@
+//go:build no_otel
+
+package otel
+
+import (
+	"context"
+)
+
+type FakeTracer struct{}
+type FakeSpan struct{}
+
+func Tracer(name string) FakeTracer {
+	return FakeTracer{}
+}
+
+func (t FakeTracer) Start(ctx context.Context, _ string) (context.Context, FakeSpan) {
+	return ctx, FakeSpan{}
+}
+
+func (s FakeSpan) End() {
+
+}
diff --git a/pkg/client/client.go b/pkg/client/client.go
index 56417b5..c9707f3 100644
--- a/pkg/client/client.go
+++ b/pkg/client/client.go
@@ -12,7 +12,7 @@ import (
 
 	"github.com/go-jose/go-jose/v4"
 	"github.com/zitadel/logging"
-	"go.opentelemetry.io/otel"
+	"github.com/zitadel/oidc/v3/internal/otel"
 	"golang.org/x/oauth2"
 
 	"github.com/zitadel/oidc/v3/pkg/crypto"
diff --git a/pkg/op/op.go b/pkg/op/op.go
index 58ae838..b761151 100644
--- a/pkg/op/op.go
+++ b/pkg/op/op.go
@@ -8,10 +8,10 @@ import (
 	"time"
 
 	"github.com/go-chi/chi/v5"
-	jose "github.com/go-jose/go-jose/v4"
+	"github.com/go-jose/go-jose/v4"
 	"github.com/rs/cors"
+	"github.com/zitadel/oidc/v3/internal/otel"
 	"github.com/zitadel/schema"
-	"go.opentelemetry.io/otel"
 	"golang.org/x/text/language"
 
 	httphelper "github.com/zitadel/oidc/v3/pkg/http"