Serverless dengan AWS Lambda

AWS Lambda menjalankan kode tanpa mengelola server. Bayar hanya saat fungsi berjalan — tidak ada idle cost.

Anatomy of a Lambda Function

// handler.mjs
export const handler = async (event, context) => {
  const { httpMethod, body, pathParameters } = event;

  if (httpMethod === "POST") {
    const data = JSON.parse(body);
    // proses data...
    return {
      statusCode: 200,
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify({ success: true }),
    };
  }

  return { statusCode: 405, body: "Method Not Allowed" };
};

Triggers

• API Gateway — HTTP endpoint → Lambda
• S3 Event — File upload → Lambda (resize gambar, generate thumbnail)
• SQS/SNS — Message queue → Lambda
• CloudWatch Events — Cron schedule → Lambda
• DynamoDB Streams — Data change → Lambda

Cold Start

Lambda instance yang idle dihapus. Request pertama setelah idle = cold start (inisialisasi runtime). Mitigasi:

• Provisioned Concurrency — Keep instances warm (biaya tambahan)
• Minimize package size — Bundle kecil = init cepat
• Use lightweight runtime — Node.js/Python lebih cepat dari Java/.NET

Limits

• Timeout: max 15 menit
• Memory: 128 MB – 10 GB
• Package size: 50 MB (zip) / 250 MB (unzipped)
• Concurrent executions: 1000 default (bisa request increase)