Convert GeoJSON to PMTiles with AWS Serverless Pattern

import * as cdk from 'aws-cdk-lib'; import { Construct } from 'constructs'; import * as s3 from 'aws-cdk-lib/aws-s3'; import * as lambda from 'aws-cdk-lib/aws-lambda'; import * as s3n from 'aws-cdk-lib/aws-s3-notifications'; import * as path from 'path'; export class AutoTilerStack extends cdk.Stack { constructor(scope: Construct, id: string, props?: cdk.StackProps) { super(scope, id, props); // S3 buckets for input GeoJSON and output PMTiles const geojsonBucket = new s3.Bucket(this, 'GeojsonBucket', { removalPolicy: cdk.RemovalPolicy.DESTROY, autoDeleteObjects: true, }); const pmtilesBucket = new s3.Bucket(this, 'PmtilesBucket', { removalPolicy: cdk.RemovalPolicy.DESTROY, autoDeleteObjects: true, }); // Lambda function to run tippecanoe for conversion const tippecanoeLambda = new lambda.DockerImageFunction( this, 'TippecanoeLambda', { code: lambda.DockerImageCode.fromImageAsset( path.join(__dirname, '../lambda'), ), timeout: cdk.Duration.minutes(15), memorySize: 1770, // 2 vCPUs environment: { OUTPUT_BUCKET: pmtilesBucket.bucketName, }, architecture: lambda.Architecture.ARM_64, }, ); // Grant permissions geojsonBucket.grantRead(tippecanoeLambda); pmtilesBucket.grantReadWrite(tippecanoeLambda); // Configure S3 event notification to trigger Lambda directly geojsonBucket.addEventNotification( s3.EventType.OBJECT_CREATED, new s3n.LambdaDestination(tippecanoeLambda), { suffix: '.geojson' }, // Only trigger for .geojson files ); // Output the bucket names new cdk.CfnOutput(this, 'GeojsonBucketName', { value: geojsonBucket.bucketName, description: 'Name of the S3 bucket for GeoJSON files', }); new cdk.CfnOutput(this, 'PMTilesBucketName', { value: pmtilesBucket.bucketName, description: 'Name of the S3 bucket for PMTiles files', }); new cdk.CfnOutput(this, 'PMTilesBucketWebsiteUrl', { value: pmtilesBucket.bucketWebsiteUrl, description: 'URL of the PMTiles bucket website', }); } } 

import * as AWS from 'aws-sdk'; import { S3Event, S3EventRecord } from 'aws-lambda'; import { spawn, ChildProcess } from 'child_process'; import * as fs from 'fs'; import * as path from 'path'; import * as os from 'os'; const s3 = new AWS.S3(); export const handler = async (event: S3Event): Promise<any> => { console.log('Received event:', JSON.stringify(event, null, 2)); // Process only the first record (we expect only one per invocation) const record: S3EventRecord = event.Records[0]; // Get the S3 bucket and key from the event const srcBucket = record.s3.bucket.name; const srcKey = decodeURIComponent(record.s3.object.key.replace(/\+/g, ' ')); // Get the output bucket from environment variables const dstBucket = process.env.OUTPUT_BUCKET as string; // Create temporary directory for processing const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'geojson-')); const localGeojsonPath = path.join(tmpDir, 'input.geojson'); const outputDir = path.join(tmpDir, 'output'); try { // Create output directory fs.mkdirSync(outputDir, { recursive: true }); // Download the GeoJSON file from S3 console.log(`Downloading ${srcKey} from ${srcBucket}`); const geojsonObject = await s3 .getObject({ Bucket: srcBucket, Key: srcKey, }) .promise(); // Write the GeoJSON to a local file fs.writeFileSync(localGeojsonPath, geojsonObject.Body as Buffer); // Extract the base name without extension for the tile directory const baseName = path.basename(srcKey, path.extname(srcKey)); // Run tippecanoe to convert GeoJSON to PMTiles console.log('Running tippecanoe'); await runTippecanoe(localGeojsonPath, outputDir, baseName); // Upload the PMTiles file to S3 console.log('Uploading PMTiles to S3'); const pmtilesPath = path.join(outputDir, `${baseName}.pmtiles`); await uploadPMTiles(pmtilesPath, dstBucket, ''); return { statusCode: 200, body: JSON.stringify({ message: 'GeoJSON successfully converted to PMTiles', source: srcKey, destination: `${baseName}.pmtiles`, }), }; } catch (error) { console.error('Error:', error); throw error; } finally { // Clean up temporary files try { fs.rmSync(tmpDir, { recursive: true, force: true }); } catch (err) { console.error('Error cleaning up temporary files:', err); } } }; // Function to run tippecanoe async function runTippecanoe( inputFile: string, outputDir: string, baseName: string, ): Promise<void> { return new Promise((resolve, reject) => { const tileDir = path.join(outputDir, baseName); fs.mkdirSync(tileDir, { recursive: true }); const tippecanoe = spawn('tippecanoe', [ '-o', `${tileDir}.pmtiles`, '-z', '14', // Maximum zoom level '-M', '1000000', // max filesize of each tile '-l', baseName, // Layer name inputFile, ]); setupProcessListeners(tippecanoe, 'tippecanoe', (code) => { if (code !== 0) { reject(new Error(`tippecanoe process exited with code ${code}`)); return; } resolve(); }); }); } // Helper function to set up process listeners function setupProcessListeners( process: ChildProcess, name: string, onClose: (code: number | null) => void, ): void { process.stdout?.on('data', (data) => { console.log(`${name} stdout: ${data}`); }); process.stderr?.on('data', (data) => { console.error(`${name} stderr: ${data}`); }); process.on('close', onClose); } // Function to upload a PMTiles file to S3 async function uploadPMTiles( pmtilesPath: string, bucket: string, prefix: string, ): Promise<void> { const fileContent = fs.readFileSync(pmtilesPath); const fileName = path.basename(pmtilesPath); // Use the same path format as in the response const s3Key = prefix === '' ? fileName : `${prefix}/${fileName}`; await s3 .putObject({ Bucket: bucket, Key: s3Key, Body: fileContent, ContentType: 'application/octet-stream', }) .promise(); console.log(`Uploaded ${s3Key} to ${bucket}`); } 

FROM public.ecr.aws/lambda/nodejs:18 # Install dependencies for tippecanoe RUN yum update -y && \  yum install -y gcc-c++ make git sqlite-devel zlib-devel # Clone and build tippecanoe RUN git clone https://github.com/felt/tippecanoe.git && \  cd tippecanoe && \  make -j && \  make install # No need for mb-util since we're using PMTiles directly # Copy package.json and install dependencies COPY package.json tsconfig.json ${LAMBDA_TASK_ROOT}/ RUN npm install # Copy TypeScript source code COPY app.ts ${LAMBDA_TASK_ROOT}/ # Build TypeScript code RUN npm run build # Set the CMD to your handler CMD [ "dist/app.handler" ]