Add example lambda build script (#24)

Author: azhong-git

README.md

@@ -30,7 +30,8 @@ Perfect for AWS Lambda and other serverless environments. Uses [@sparticuz/chrom
 
 > [!IMPORTANT]
 > This project uses Playwright, which ships with a specific version of Chromium. You need to install the matching version of `@sparticuz/chromium`. For example, we are using [Playwright 1.48](https://playwright.dev/docs/release-notes#version-148) (which supports to Chromium 130), you should install `@sparticuz/chromium@130`.
-> For running on AWS Lambda, lambda layer with ARM64 architecture is preferred. You will also need to install dependencies of canvas.
+>
+> For running on AWS Lambda, lambda layer with ARM64 architecture is preferred. You will also need to install dependencies of canvas. Here is an example of [Lambda Layer Build Script](./lambda-layer-build.sh).
 
 ```typescript
 import { BrowserAgent } from "@lightfeed/browser-agent";

lambda-layer-build.sh

@@ -0,0 +1,65 @@
+#!/bin/bash
+
+# Lambda Layer Build Script for Serverless Browser Agent
+# This script builds a lambda layer with all necessary dependencies for running
+# browser-agent in AWS Lambda environment (ARM64)
+
+# Navigate to the layer directory
+cd lambda-layers/serverless-browser
+
+# Clean up existing files
+rm -rf lib
+rm -rf nodejs/node_modules
+rm -rf nodejs/package-lock.json
+rm -rf chromium
+rm -rf tmp
+
+# Create lib directory if it doesn't exist
+mkdir -p lib
+
+# Build using Amazon Linux 2023 ARM64 Docker image with all canvas dependencies
+# Reference: https://github.com/charoitel/lambda-layer-canvas-nodejs/blob/ac16c9af8eee82fd64e29f8f178debfe78a32026/build-layer.sh
+docker run --rm -v $(pwd):/var/task --platform linux/arm64 amazonlinux:2023 bash -c "\
+    yum update -y && \
+    yum groupinstall 'Development Tools' -y && \
+    yum install gcc-c++ cairo-devel pango-devel libjpeg-turbo-devel giflib-devel librsvg2-devel pango-devel bzip2-devel python3 -y && \
+    # Install Node.js 20
+    curl -fsSL https://rpm.nodesource.com/setup_20.x | bash - && \
+    yum install -y nodejs && \
+    node --version && npm --version && \
+    cd /var/task/nodejs && \
+    npm init -y && \
+    npm install canvas@3.1.0 --build-from-source && \
+    echo '=== Copying shared libraries ===' && \
+    mkdir -p /var/task/lib && \
+    echo 'Copying direct dependencies...' && \
+    ldd node_modules/canvas/build/Release/canvas.node | grep '=>' | awk '{print \$3}' | xargs -I{} cp -L {} /var/task/lib/ && \
+    echo '=== Testing canvas in container ===' && \
+    LD_LIBRARY_PATH=/var/task/lib node -e \"try { const canvas = require('canvas'); console.log('Canvas loaded successfully'); } catch(e) { console.error('Error:', e); }\" && \
+    echo '=== Installing Chromium ===' && \
+    mkdir -p /tmp/assets && \
+    mkdir -p /var/task/tmp/bin && \
+    echo 'Downloading Chromium pack...' && \
+    curl -SL --retry 5 --retry-delay 10 -o /tmp/assets/chromium-pack.tar https://github.com/Sparticuz/chromium/releases/download/v137.0.0/chromium-v137.0.0-pack.arm64.tar && \
+    echo 'Extracting Chromium pack...' && \
+    tar -xf /tmp/assets/chromium-pack.tar -C /var/task/tmp/bin/ && \
+    if [ -d /var/task/tmp/bin/bin ]; then mv /var/task/tmp/bin/bin/* /var/task/tmp/bin/; rmdir /var/task/tmp/bin/bin; fi && \
+    chmod -R a+r /var/task/tmp/bin/* && \
+    chmod a+x /var/task/tmp/bin && \
+    echo '=== Verifying Chromium setup ===' && \
+    ls -lR /var/task/tmp/bin && \
+    rm -rf /tmp/assets"
+
+# Set correct permissions
+chmod -R 755 nodejs/node_modules
+chmod -R 755 lib
+chmod -R 755 tmp
+
+echo "=== Layer Build Complete ==="
+echo "The layer has been built for AWS Lambda (ARM64) environment."
+echo "Do not attempt to test the libraries locally as they are built for Lambda's environment."
+echo ""
+echo "Next steps:"
+echo "1. Zip the contents of this directory to create your Lambda layer"
+echo "2. Upload the layer to AWS Lambda"
+echo "3. Reference the layer in your Lambda function configuration"