Your first Go Lambda¶

Start with structured logs. This handler accepts a name, returns a greeting and writes one searchable JSON record.

Install¶

Use Go 1.27 or newer and initialize your application:

go mod init example.com/hello
CGO_ENABLED=0 go get github.com/rambow-cloud/powertools-lambda-go/logger@v1.2.0 github.com/aws/aws-lambda-go@v1.55.0

Write the handler¶

Save this as main.go:

package main

import (
    "context"
    "fmt"

    "github.com/aws/aws-lambda-go/lambda"
    "github.com/rambow-cloud/powertools-lambda-go/logger"
)

type Event struct {
    Name string `json:"name"`
}

type Response struct {
    Message string `json:"message"`
}

func main() {
    appLog := logger.New(logger.WithServiceName("hello"))
    handler := func(ctx context.Context, event Event) (Response, error) {
        if event.Name == "" {
            return Response{}, fmt.Errorf("name is required")
        }
        requestLog := appLog.WithContext(ctx)
        if err := requestLog.Info("Handling request", logger.Fields{"name": event.Name}); err != nil {
            return Response{}, fmt.Errorf("write request log: %w", err)
        }
        return Response{Message: "Hello, " + event.Name}, nil
    }
    lambda.Start(logger.WrapHandler(appLog, handler))
}

Create the logger once; obtain a request-bound logger inside the wrapped handler.

Invoke it¶

Input

{"name":"Ada"}

Response

{"message":"Hello, Ada"}

Log fields (excerpt; timestamp and Lambda request fields vary)

{"level":"INFO","message":"Handling request","service":"hello","name":"Ada"}

An empty name returns name is required. The logger does not turn a business error into a successful handler response.

Build for Lambda¶

CGO_ENABLED=0 GOOS=linux GOARCH=arm64 go build -trimpath -tags lambda.norpc -o bootstrap .

$env:CGO_ENABLED = '0'
$env:GOOS = 'linux'
$env:GOARCH = 'arm64'
go build -trimpath -tags lambda.norpc -o bootstrap .

Use amd64 for Lambda x86_64. Package the executable as bootstrap with executable permissions and configure the function for provided.al2023 and the matching architecture. See packaging notes for repository helpers.

Add the utilities you need¶

Tracing is optional. Configure a reachable OpenTelemetry collector before enabling export; use its awsxray exporter for X-Ray. The legacy X-Ray SDK adapter is deprecated and frozen.

Things to know¶

• Keep CGO_ENABLED=0 for builds and tests.
• Use explicit json tags on event/response structs. The project uses JSON v2 behavior; see JSON notes.
• Follow usage patterns when composing wrappers and sharing clients across invocations.