Add WithServiceName config option for instrumentation (#353)

* Add WithServiceName condig option for instrumentation * Update changelog * Apply suggestions from code review Co-authored-by: Tyler Yahn <[email protected]> * Add support for OTEL_RESOURCE_ATTRIBUTES and defualt service name * Apply suggestions from code review Co-authored-by: Tyler Yahn <[email protected]> * Fix compilation * Fix lint * Update instrumentation.go Co-authored-by: Tyler Yahn <[email protected]> --------- Co-authored-by: Tyler Yahn <[email protected]>
open-telemetry · Sep 29, 2023 · d239377 · d239377
1 parent f31d619
commit d239377
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Showing 4 changed files with 132 additions and 16 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -8,6 +8,10 @@ OpenTelemetry Go Automatic Instrumentation adheres to [Semantic Versioning](http
 
 ## [Unreleased]
 
+### Added
+
+- Add `WithServiceName` config option for instrumentation. ([#353](https://github.com/open-telemetry/opentelemetry-go-instrumentation/pull/353))
+
 ### Changed
 
 - Fix runtime panic if OTEL_GO_AUTO_TARGET_EXE is not set. ([#339](https://github.com/open-telemetry/opentelemetry-go-instrumentation/pull/339))

diff --git a/instConfig_test.go b/instConfig_test.go
@@ -0,0 +1,55 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package auto
+
+import (
+ "fmt"
+ "os"
+ "testing"
+
+ "github.com/stretchr/testify/assert"
+
+ semconv "go.opentelemetry.io/otel/semconv/v1.21.0"
+)
+
+func TestWithServiceName(t *testing.T) {
+ testServiceName := "test_serviceName"
+
+ // Use WithServiceName to config the service name
+ c := newInstConfig([]InstrumentationOption{WithServiceName((testServiceName))})
+ assert.Equal(t, testServiceName, c.serviceName)
+
+ // No service name provided - check for default value
+ c = newInstConfig([]InstrumentationOption{})
+ assert.Equal(t, serviceNameDefault, c.serviceName)
+
+ // OTEL_RESOURCE_ATTRIBUTES
+ resServiceName := "resValue"
+ err := os.Setenv(envResourceAttrKey, fmt.Sprintf("key1=val1,%s=%s", string(semconv.ServiceNameKey), resServiceName))
+ if err != nil {
+ t.Error(err)
+ }
+ c = newInstConfig([]InstrumentationOption{WithServiceName((testServiceName))})
+ assert.Equal(t, resServiceName, c.serviceName)
+
+ // Add env var to take precedence
+ envServiceName := "env_serviceName"
+ err = os.Setenv(envServiceNameKey, envServiceName)
+ if err != nil {
+ t.Error(err)
+ }
+ c = newInstConfig([]InstrumentationOption{WithServiceName((testServiceName))})
+ assert.Equal(t, envServiceName, c.serviceName)
+}
diff --git a/instrumentation.go b/instrumentation.go
@@ -18,16 +18,29 @@ import (
  "context"
  "fmt"
  "os"
+ "path/filepath"
+ "strings"
+
+ semconv "go.opentelemetry.io/otel/semconv/v1.21.0"
 
  "go.opentelemetry.io/auto/internal/pkg/instrumentors"
  "go.opentelemetry.io/auto/internal/pkg/log"
  "go.opentelemetry.io/auto/internal/pkg/opentelemetry"
  "go.opentelemetry.io/auto/internal/pkg/process"
 )
 
-// envTargetExeKey is the key for the environment variable value pointing to the
-// target binary to instrument.
-const envTargetExeKey = "OTEL_GO_AUTO_TARGET_EXE"
+const (
+ // envTargetExeKey is the key for the environment variable value pointing to the
+ // target binary to instrument.
+ envTargetExeKey = "OTEL_GO_AUTO_TARGET_EXE"
+ // envServiceName is the key for the envoriment variable value containing the service name.
+ envServiceNameKey = "OTEL_SERVICE_NAME"
+ // envResourceAttrKey is the key for the environment variable value containing
+ // OpenTelemetry Resource attributes.
+ envResourceAttrKey = "OTEL_RESOURCE_ATTRIBUTES"
+ // serviceNameDefault is the default service name prefix used if a user does not provide one.
+ serviceNameDefault = "unknown_service"
+)
 
 // Instrumentation manages and controls all OpenTelemetry Go
 // auto-instrumentation.
@@ -55,7 +68,7 @@ func NewInstrumentation(opts ...InstrumentationOption) (*Instrumentation, error)
  return nil, err
  }
 
- ctrl, err := opentelemetry.NewController(Version())
+ ctrl, err := opentelemetry.NewController(Version(), c.serviceName)
  if err != nil {
  return nil, err
  }
@@ -104,7 +117,8 @@ type InstrumentationOption interface {
 }
 
 type instConfig struct {
- target *process.TargetArgs
+ target *process.TargetArgs
+ serviceName string
 }
 
 func newInstConfig(opts []InstrumentationOption) instConfig {
@@ -120,6 +134,45 @@ func (c instConfig) applyEnv() instConfig {
  if v, ok := os.LookupEnv(envTargetExeKey); ok {
  c.target = &process.TargetArgs{ExePath: v}
  }
+ if v, ok := os.LookupEnv(envServiceNameKey); ok {
+ c.serviceName = v
+ } else {
+ c = c.applyResourceAtrrEnv()
+ if c.serviceName == "" {
+ c = c.setDefualtServiceName()
+ }
+ }
+ return c
+}
+
+func (c instConfig) setDefualtServiceName() instConfig {
+ if c.target != nil {
+ c.serviceName = fmt.Sprintf("%s:%s", serviceNameDefault, filepath.Base(c.target.ExePath))
+ } else {
+ c.serviceName = serviceNameDefault
+ }
+ return c
+}
+
+func (c instConfig) applyResourceAtrrEnv() instConfig {
+ attrs := strings.TrimSpace(os.Getenv(envResourceAttrKey))
+
+ if attrs == "" {
+ return c
+ }
+
+ pairs := strings.Split(attrs, ",")
+ for _, p := range pairs {
+ k, v, found := strings.Cut(p, "=")
+ if !found {
+ continue
+ }
+ key := strings.TrimSpace(k)
+ if key == string(semconv.ServiceNameKey) {
+ c.serviceName = strings.TrimSpace(v)
+ }
+ }
+
  return c
 }
 
@@ -148,3 +201,17 @@ func WithTarget(path string) InstrumentationOption {
  return c
  })
 }
+
+// WithServiceName returns an [InstrumentationOption] defining the name of the service running.
+//
+// If multiple of these options are provided to an [Instrumentation], the last
+// one will be used.
+//
+// If OTEL_SERVICE_NAME is defined it will take precedence over any value
+// passed here.
+func WithServiceName(serviceName string) InstrumentationOption {
+ return fnOpt(func(c instConfig) instConfig {
+ c.serviceName = serviceName
+ return c
+ })
+}
diff --git a/internal/pkg/opentelemetry/controller.go b/internal/pkg/opentelemetry/controller.go
@@ -17,7 +17,6 @@ package opentelemetry
 import (
  "context"
  "fmt"
- "os"
  "runtime"
  "strings"
  "time"
@@ -36,10 +35,6 @@ import (
  "go.opentelemetry.io/auto/internal/pkg/log"
 )
 
-const (
- otelServiceNameEnvVar = "OTEL_SERVICE_NAME"
-)
-
 // Information about the runtime environment for inclusion in User-Agent, e.g. "go/1.18.2 (linux/amd64)".
 var runtimeInfo = fmt.Sprintf("%s (%s/%s)", strings.Replace(runtime.Version(), "go", "go/", 1), runtime.GOOS, runtime.GOARCH)
 
@@ -90,12 +85,7 @@ func (c *Controller) convertTime(t int64) time.Time {
 }
 
 // NewController returns a new initialized [Controller].
-func NewController(version string) (*Controller, error) {
- serviceName, exists := os.LookupEnv(otelServiceNameEnvVar)
- if !exists {
- return nil, fmt.Errorf("%s env var must be set", otelServiceNameEnvVar)
- }
-
+func NewController(version string, serviceName string) (*Controller, error) {
  ctx := context.Background()
  res, err := resource.New(ctx,
  resource.WithAttributes(