Add ECS wake/sleep infra with detailed comments

Author: rusets

.gitignore

@@ -1,13 +1,17 @@
-# macOS
-.DS_Store
-
 # Terraform
-**/.terraform/
-**/terraform.tfstate
-**/terraform.tfstate.*
+*.tfstate
+*.tfstate.*
+.terraform/
+.terraform.lock.hcl
+
+# Lambda zips
+infra/wake.zip
+infra/sleep.zip
 
 # Node
-app/node_modules
-app/npm-debug.log*
-# Zip
-wake.zip
+node_modules/
+npm-debug.log
+
+# Python
+__pycache__/
+*.pyc

app/Dockerfile

@@ -1,22 +1,39 @@
-# app/Dockerfile
+# Use a small official Node.js 20 image from AWS Public ECR (Alpine-based for minimal size)
 FROM public.ecr.aws/docker/library/node:20-alpine
 
+# Set working directory inside the container
 WORKDIR /app
 
-# Copy only manifests first to leverage layer cache
+# Copy only dependency manifests first (package.json, package-lock.json)
+# This allows Docker to cache dependency installation layers
+# unless package files have changed (faster builds).
 COPY package*.json ./
 
-# Install production dependencies
+# Install production dependencies only
+# "npm ci" ensures clean, reproducible installs
+# "--omit=dev" excludes devDependencies → smaller image, faster runtime
 RUN npm ci --omit=dev
 
-# Copy source
+# Copy the application source code
+# Here we assume all source is inside "src/" directory
 COPY src ./src
 
+# Set environment variables for production
 ENV NODE_ENV=production
 ENV PORT=80
 
-# Lightweight healthcheck (no curl/wget needed)
-HEALTHCHECK --interval=30s --timeout=3s --start-period=10s   CMD node -e "fetch('http://127.0.0.1:'+process.env.PORT+'/health').then(r=>process.exit(r.ok?0:1)).catch(()=>process.exit(1))"
+# Define container health check
+# - Interval: every 30s
+# - Timeout: fail after 3s
+# - Start period: allow 10s before first check
+# - Command: Run a Node one-liner that makes HTTP request to /health endpoint
+#   → exits 0 if OK, exits 1 if failure
+# Using Node's fetch avoids installing curl or wget, keeping the image slim.
+HEALTHCHECK --interval=30s --timeout=3s --start-period=10s \
+    CMD node -e "fetch('http://127.0.0.1:'+process.env.PORT+'/health').then(r=>process.exit(r.ok?0:1)).catch(()=>process.exit(1))"
 
+# Expose application port (for ECS, Kubernetes, etc.)
 EXPOSE 80
-CMD ["npm", "start"]
+
+# Default container startup command → "npm start" defined in package.json
+CMD ["npm", "start"]