Lambda Web Adapter で FastAPI を AWS Lambda にデプロイする

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from typing import Union
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from fastapi import FastAPI
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app = FastAPI()
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@app.get("/")
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def read_root():
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    return {"Hello": "World"}
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@app.get("/items/{item_id}")
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def read_item(item_id: int, q: Union[str, None] = None):
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    return {"item_id": item_id, "q": q}

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# Base image: Python 3.12 Alpine
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FROM public.ecr.aws/docker/library/python:3.12-alpine AS base
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ENV APP_ROOT=/code
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# Copy requirements and install dependencies
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COPY ./src/requirements.txt $APP_ROOT/
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RUN pip install --no-cache-dir --upgrade -r $APP_ROOT/requirements.txt
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# Development stage
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FROM base AS dev
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ENV ENV=dev
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EXPOSE 8000
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CMD ["sh", "-c", "fastapi run $APP_ROOT/main.py --port 8000"]
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# Production stage
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FROM base
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ENV ENV=prod
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EXPOSE 8080
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COPY ./src $APP_ROOT
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# Copy Lambda Web Adapter
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COPY --from=public.ecr.aws/awsguru/aws-lambda-adapter:0.8.4 /lambda-adapter /opt/extensions/lambda-adapter
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# Run FastAPI backend on port 8080 for Lambda Web Adapter
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CMD ["sh", "-c", "fastapi run $APP_ROOT/main.py --port 8080"]

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services:
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  api:
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    build:
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      context: ../
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      dockerfile: ./docker/Dockerfile
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      target: dev
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    ports:
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      - "8000:8000"
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    volumes:
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      - ../src:/code

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#!/usr/bin/env node
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import 'source-map-support/register';
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import * as cdk from 'aws-cdk-lib';
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import { CdkStack } from '../lib/cdk-stack';
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const app = new cdk.App();
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new CdkStack(app, 'App');

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import * as cdk from 'aws-cdk-lib';
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import type { Construct } from 'constructs';
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import { LambdaRestApi } from 'aws-cdk-lib/aws-apigateway';
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import {
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  DockerImageCode,
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  DockerImageFunction,
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  LoggingFormat,
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} from 'aws-cdk-lib/aws-lambda';
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import * as path from 'node:path';
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import { Platform } from 'aws-cdk-lib/aws-ecr-assets';
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export class CdkStack extends cdk.Stack {
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  constructor(scope: Construct, id: string, props?: cdk.StackProps) {
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    super(scope, id, props);
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    // Dockerized Lambda Function
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    const lambda = new DockerImageFunction(this, 'function', {
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      functionName: 'fast-api-app-function',
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      loggingFormat: LoggingFormat.JSON,
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      memorySize: 512, // Tune after measuring the workload
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      code: DockerImageCode.fromImageAsset(path.join(__dirname, '..', '..'), {
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        file: path.join('docker', 'Dockerfile'),
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        platform: Platform.LINUX_AMD64, // Match Lambda's default x86_64 architecture
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        exclude: ['*', '!src', '!docker'],
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      }),
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    });
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    // API Gateway REST API
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    new LambdaRestApi(this, 'api', {
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      handler: lambda,
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      deploy: true,
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    });
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  }
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}