feat: add WithSpan helper

otelx/withspan.go

@@ -0,0 +1,41 @@
+// Copyright © 2022 Ory Corp
+// SPDX-License-Identifier: Apache-2.0
+
+package otelx
+
+import (
+	"context"
+
+	"go.opentelemetry.io/otel/codes"
+	"go.opentelemetry.io/otel/trace"
+)
+
+// WithSpan wraps execution of f in a span identified by name.
+//
+// If f returns an error or panics, the span status will be set to the error
+// state. The error (or panic) will be propagated unmodified.
+//
+// f will be wrapped in a child span by default. To make a new root span
+// instead, pass the trace.WithNewRoot() option.
+func WithSpan(ctx context.Context, name string, f func(context.Context) error, opts ...trace.SpanStartOption) (err error) {
+	ctx, span := trace.SpanFromContext(ctx).TracerProvider().Tracer("").Start(ctx, name, opts...)
+	defer func() {
+		defer span.End()
+		if err != nil {
+			span.SetStatus(codes.Error, err.Error())
+		} else if r := recover(); r != nil {
+			switch e := r.(type) {
+			case error:
+				span.SetStatus(codes.Error, "panic: "+e.Error())
+			case interface{ String() string }:
+				span.SetStatus(codes.Error, "panic: "+e.String())
+			case string:
+				span.SetStatus(codes.Error, "panic: "+e)
+			default:
+				span.SetStatus(codes.Error, "panic")
+			}
+			panic(r)
+		}
+	}()
+	return f(ctx)
+}

otelx/withspan_test.go

@@ -0,0 +1,39 @@
+// Copyright © 2022 Ory Corp
+// SPDX-License-Identifier: Apache-2.0
+
+package otelx
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"github.com/instana/testify/assert"
+	"go.opentelemetry.io/otel/trace"
+)
+
+func TestWithSpan(t *testing.T) {
+	tracer := trace.NewNoopTracerProvider().Tracer("test")
+	ctx, span := tracer.Start(context.Background(), "parent")
+	defer span.End()
+
+	assert.NoError(t, WithSpan(ctx, "no-error", func(ctx context.Context) error { return nil }))
+	assert.Error(t, WithSpan(ctx, "error", func(ctx context.Context) error { return errors.New("some-error") }))
+	assert.PanicsWithError(t, errPanic.Error(), func() {
+		WithSpan(ctx, "panic", func(ctx context.Context) error {
+			panic(errPanic)
+		})
+	})
+	assert.PanicsWithValue(t, errPanic, func() {
+		WithSpan(ctx, "panic", func(ctx context.Context) error {
+			panic(errPanic)
+		})
+	})
+	assert.PanicsWithValue(t, "panic-string", func() {
+		WithSpan(ctx, "panic", func(ctx context.Context) error {
+			panic("panic-string")
+		})
+	})
+}
+
+var errPanic = errors.New("panic-error")