Add internal/tracing: env-gated OTel setup, span/log helpers, decorators

Co-Authored-By: Claude <noreply@anthropic.com>

internal/tracing/tracing_test.go

@@ -0,0 +1,129 @@
+package tracing
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"github.com/go-logr/logr"
+	"go.opentelemetry.io/otel"
+	sdktrace "go.opentelemetry.io/otel/sdk/trace"
+	"go.opentelemetry.io/otel/trace/noop"
+)
+
+// clearOTelEnv pins every env var Setup reads, so developer shells with
+// OTEL_* set can't change test outcomes. Not parallel-safe by design
+// (t.Setenv forbids t.Parallel).
+func clearOTelEnv(t *testing.T) {
+	t.Helper()
+	for _, k := range []string{
+		"OTEL_SDK_DISABLED",
+		"OTEL_TRACES_EXPORTER",
+		"OTEL_EXPORTER_OTLP_ENDPOINT",
+		"OTEL_EXPORTER_OTLP_TRACES_ENDPOINT",
+		"OTEL_EXPORTER_OTLP_PROTOCOL",
+		"OTEL_EXPORTER_OTLP_TRACES_PROTOCOL",
+	} {
+		t.Setenv(k, "")
+	}
+}
+
+func TestSetup_envGating(t *testing.T) {
+	tests := []struct {
+		name        string
+		env         map[string]string
+		wantEnabled bool
+		wantErr     bool
+	}{
+		{name: "no env means disabled", env: nil, wantEnabled: false},
+		{
+			name:        "endpoint enables otlp",
+			env:         map[string]string{"OTEL_EXPORTER_OTLP_ENDPOINT": "http://localhost:4318"},
+			wantEnabled: true,
+		},
+		{
+			name:        "traces endpoint enables otlp",
+			env:         map[string]string{"OTEL_EXPORTER_OTLP_TRACES_ENDPOINT": "http://localhost:4318"},
+			wantEnabled: true,
+		},
+		{
+			name:        "explicit console exporter",
+			env:         map[string]string{"OTEL_TRACES_EXPORTER": "console"},
+			wantEnabled: true,
+		},
+		{
+			name:        "grpc protocol",
+			env:         map[string]string{"OTEL_TRACES_EXPORTER": "otlp", "OTEL_EXPORTER_OTLP_PROTOCOL": "grpc"},
+			wantEnabled: true,
+		},
+		{
+			name: "exporter none wins over endpoint",
+			env: map[string]string{
+				"OTEL_TRACES_EXPORTER":        "none",
+				"OTEL_EXPORTER_OTLP_ENDPOINT": "http://localhost:4318",
+			},
+			wantEnabled: false,
+		},
+		{
+			name: "OTEL_SDK_DISABLED wins over everything",
+			env: map[string]string{
+				"OTEL_SDK_DISABLED":           "true",
+				"OTEL_EXPORTER_OTLP_ENDPOINT": "http://localhost:4318",
+			},
+			wantEnabled: false,
+		},
+		{
+			name:    "unsupported exporter errors",
+			env:     map[string]string{"OTEL_TRACES_EXPORTER": "jaeger"},
+			wantErr: true,
+		},
+		{
+			name: "unsupported protocol errors",
+			env: map[string]string{
+				"OTEL_TRACES_EXPORTER":         "otlp",
+				"OTEL_EXPORTER_OTLP_PROTOCOL": "http/json",
+			},
+			wantErr: true,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			clearOTelEnv(t)
+			for k, v := range tc.env {
+				t.Setenv(k, v)
+			}
+			// Fresh noop global per case: disabled paths must leave it
+			// untouched, and resetting avoids leaking one case's SDK
+			// provider into the next (or warning-prone restores of the
+			// process-default delegate).
+			before := noop.NewTracerProvider()
+			otel.SetTracerProvider(before)
+
+			shutdown, err := Setup(context.Background(), logr.Discard(), "test-svc", "abc123")
+			if tc.wantErr {
+				if err == nil {
+					t.Fatal("want error, got nil")
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("Setup: %v", err)
+			}
+
+			_, isSDK := otel.GetTracerProvider().(*sdktrace.TracerProvider)
+			if isSDK != tc.wantEnabled {
+				t.Errorf("global provider is SDK = %v, want %v", isSDK, tc.wantEnabled)
+			}
+			if tc.wantEnabled && otel.GetTracerProvider() == before {
+				t.Error("enabled Setup must install a new global provider")
+			}
+
+			ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+			defer cancel()
+			if err := shutdown(ctx); err != nil {
+				t.Errorf("shutdown: %v", err)
+			}
+		})
+	}
+}