docs(contrib/aws/datadog-lambda-go): docs(contrib/aws/datadog-lambda-…

contrib/aws/datadog-lambda-go/README.md

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+# Datadog Lambda Library for Go (dd-trace-go)
+
+![build](https://github.com/DataDog/dd-trace-go/actions/workflows/main-branch-tests.yml/badge.svg)
+[![Slack](https://chat.datadoghq.com/badge.svg?bg=632CA6)](https://chat.datadoghq.com/)
+[![Go Reference](https://pkg.go.dev/badge/github.com/DataDog/dd-trace-go/contrib/aws/datadog-lambda-go/v2.svg)](https://pkg.go.dev/github.com/DataDog/dd-trace-go/contrib/aws/datadog-lambda-go/v2)
+[![License](https://img.shields.io/badge/license-Apache--2.0-blue)](https://github.com/DataDog/dd-trace-go/blob/main/LICENSE)
+
+
+> **IMPORTANT NOTICE**: This package replaces the deprecated https://github.com/DataDog/datadog-lambda-go repository.
+
+Datadog Lambda Library for Go enables enhanced Lambda metrics, distributed tracing, and custom metric submission from AWS Lambda functions.
+
+## Migration Guide: Upgrading from datadog-lambda-go v1 to v2
+
+If you are upgrading from the legacy [`github.com/DataDog/datadog-lambda-go`](https://github.com/DataDog/datadog-lambda-go) repository, this guide will walk you through the migration process with code examples.
+
+### Step 1: Update Dependencies
+
+Update your `go.mod` file by replacing the old package with the new one:
+
+```bash
+# Remove the old package
+go get github.com/DataDog/datadog-lambda-go@none
+
+# Install the new v2 package
+go get github.com/DataDog/dd-trace-go/contrib/aws/datadog-lambda-go/v2
+```
+
+### Step 2: Update Import Statements
+
+The import paths have changed. Update your imports as follows:
+
+**Before (v1):**
+```go
+import (
+    ddlambda "github.com/DataDog/datadog-lambda-go"
+    "gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"
+    httptrace "gopkg.in/DataDog/dd-trace-go.v1/contrib/net/http"
+)
+```
+
+**After (v2):**
+```go
+import (
+    ddlambda "github.com/DataDog/dd-trace-go/contrib/aws/datadog-lambda-go/v2"
+    "github.com/DataDog/dd-trace-go/v2/ddtrace/tracer"
+    httptrace "github.com/DataDog/dd-trace-go/contrib/net/http/v2"
+)
+```
+
+### Step 3: Update Handler Code (API remains the same)
+
+The API is compatible, so your handler code remains largely unchanged. Here's the actual integration test code from both repositories showing the migration:
+
+**Before (v1):**
+```go
+// Source: datadog-lambda-go/tests/integration_tests/hello/main.go
+package main
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/aws/aws-lambda-go/lambda"
+
+	ddlambda "github.com/DataDog/datadog-lambda-go"
+	"github.com/aws/aws-lambda-go/events"
+	httptrace "gopkg.in/DataDog/dd-trace-go.v1/contrib/net/http"
+	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"
+)
+
+func handleRequest(ctx context.Context, ev events.APIGatewayProxyRequest) (events.APIGatewayProxyResponse, error) {
+	currentSpan, _ := tracer.SpanFromContext(ctx)
+	currentSpanContext := currentSpan.Context()
+	fmt.Println("Current span ID: " + strconv.FormatUint(currentSpanContext.SpanID(), 10))
+	fmt.Println("Current trace ID: " + strconv.FormatUint(currentSpanContext.TraceID(), 10))
+
+	// HTTP request
+	req, _ := http.NewRequestWithContext(ctx, "GET", "https://www.datadoghq.com", nil)
+	client := http.Client{}
+	client = *httptrace.WrapClient(&client)
+	client.Do(req)
+
+	// Metric
+	ddlambda.Distribution("hello-go.dog", 1)
+
+	// User-defined span
+	for i := 0; i < 10; i++ {
+		s, _ := tracer.StartSpanFromContext(ctx, "child.span")
+		time.Sleep(100 * time.Millisecond)
+		s.Finish()
+	}
+
+	return events.APIGatewayProxyResponse{
+		StatusCode: 200,
+		Body:       "hello, dog!",
+	}, nil
+}
+
+func main() {
+	lambda.Start(ddlambda.WrapHandler(handleRequest, nil))
+}
+```
+
+**After (v2):**
+```go
+// Source: dd-trace-go/contrib/aws/datadog-lambda-go/test/integration_tests/hello/main.go
+package main
+
+import (
+	"context"
+	"log/slog"
+	"net/http"
+	"time"
+
+	"github.com/aws/aws-lambda-go/lambda"
+
+	ddlambda "github.com/DataDog/dd-trace-go/contrib/aws/datadog-lambda-go/v2"
+	httptrace "github.com/DataDog/dd-trace-go/contrib/net/http/v2"
+	"github.com/DataDog/dd-trace-go/v2/ddtrace/tracer"
+	"github.com/aws/aws-lambda-go/events"
+)
+
+func handleRequest(ctx context.Context, ev events.APIGatewayProxyRequest) (events.APIGatewayProxyResponse, error) {
+	currentSpan, _ := tracer.SpanFromContext(ctx)
+	currentSpanContext := currentSpan.Context()
+	slog.Info("Current span", "span_id", currentSpanContext.SpanID())
+	slog.Info("Current trace", "trace_id", currentSpanContext.TraceID())
+
+	// HTTP request
+	req, _ := http.NewRequestWithContext(ctx, "GET", "https://www.datadoghq.com", nil)
+	client := http.Client{}
+	client = *httptrace.WrapClient(&client)
+	client.Do(req)
+
+	// Metric
+	ddlambda.Distribution("hello-go.dog", 1)
+
+	// User-defined span
+	for i := 0; i < 10; i++ {
+		s, _ := tracer.StartSpanFromContext(ctx, "child.span")
+		time.Sleep(100 * time.Millisecond)
+		s.Finish()
+	}
+
+	return events.APIGatewayProxyResponse{
+		StatusCode: 200,
+		Body:       "hello, dog!",
+	}, nil
+}
+
+func main() {
+	lambda.Start(ddlambda.WrapHandler(handleRequest, nil))
+}
+```
+
+### What Changed?
+
+- **Import paths**: All imports now use the new module paths
+- **API compatibility**: The `ddlambda` API remains the same (`WrapHandler`, `Metric`, `Distribution`, etc.)
+- **Tracer API**: The tracer API is compatible between v1 and v2
+
+### Step 4: Deploy and Configure
+
+After updating your code, follow the [Datadog AWS Lambda Instrumentation for Go](https://docs.datadoghq.com/serverless/aws_lambda/instrumentation/go/?tab=datadogui) guide to configure the Datadog Lambda Extension and environment variables for your Lambda function.
+
+### Additional Resources
+
+- [General dd-trace-go v1 to v2 Migration Guide](https://docs.datadoghq.com/tracing/trace_collection/custom_instrumentation/go/migration/)
+
+## Installation
+
+Follow the [installation instructions](https://docs.datadoghq.com/serverless/installation/go/), and view your function's enhanced metrics, traces and logs in Datadog.
+
+## Configurations
+
+See the [advanced configuration options](https://docs.datadoghq.com/serverless/configuration) to tag your telemetry, capture request/response payloads, filter or scrub sensitive information from logs or traces, and more.
+
+## Opening Issues
+
+If you encounter a bug with this package, we want to hear about it. Before opening a new issue, search the existing issues to avoid duplicates.
+
+When opening an issue, include the datadog-lambda-go version, `go version`, and stack trace if available. In addition, include the steps to reproduce when appropriate.
+
+You can also open an issue for a feature request.
+
+## Contributing
+
+If you find an issue with this package and have a fix, please feel free to open a pull request following the [procedures](https://github.com/DataDog/dd-trace-go/blob/main/CONTRIBUTING.md).
+
+## Community
+
+For product feedback and questions, join the `#serverless` channel in the [Datadog community on Slack](https://chat.datadoghq.com/).
+
+## License
+
+Unless explicitly stated otherwise all files in this package are licensed under the Apache License Version 2.0.
+
+This product includes software developed at Datadog (https://www.datadoghq.com/). Copyright 2021 Datadog, Inc.
+
+