25c2f09eef
Add new email-server-worker project implementing a self-scheduling background worker pattern with HTTP monitoring. Removed all business-specific code from copied source, creating a clean, reusable template. Key features: - Self-scheduling worker loop with configurable interval - Graceful shutdown support (Docker-compatible) - Prometheus metrics collection - Health check endpoints (/healthcheck, /metrics, /ping) - Example worker template for easy customization - Comprehensive architecture documentation in CLAUDE.md The worker is now ready for email server implementation with no external dependencies on Evolution/MSSQL/ElasticSearch. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
116 lines
3.2 KiB
Markdown
116 lines
3.2 KiB
Markdown
# Email Server Worker
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Background worker service with HTTP health monitoring and metrics collection.
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## Overview
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This is a TypeScript-based background worker service that combines periodic task execution with HTTP health monitoring and metrics collection. It implements a self-scheduling worker pattern with graceful shutdown support.
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## Features
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- **Periodic Task Execution**: Self-scheduling worker loop with configurable interval
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- **Graceful Shutdown**: Ensures in-flight work completes before shutdown (Docker-compatible)
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- **Health Monitoring**: HTTP health check endpoint to verify worker status
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- **Metrics Collection**: Prometheus metrics with PRTG adapter
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- **Error Isolation**: Worker errors don't crash the process
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## Getting Started
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### Installation
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```bash
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npm install
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```
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### Development
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```bash
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npm run start # Start with nodemon (auto-reload)
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```
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### Build & Run
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```bash
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npm run build # Compile TypeScript
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npm run run-server # Run compiled version
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```
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### Testing
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```bash
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npm run test # Run Jest in watch mode
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```
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## Environment Variables
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### Required
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- `PULL_INTERVAL` - Milliseconds between work cycles (default: `"10000"`)
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### Optional
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- `PORT` - HTTP server port (default: `"3000"`)
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- `PROMETHEUS_APP_LABEL` - App label for Prometheus metrics (default: `"email-server-worker"`)
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- `PROMETHEUS_HISTOGRAM_BUCKETS` - Histogram bucket sizes (default: `"0.1, 0.5, 1, 5, 10"`)
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- `DEBUG` - Debug namespaces for console logging (e.g., `"server:server"`)
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- `ENV` - Environment mode: `"dev"`, `"jest"` (affects logging)
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## HTTP Endpoints
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- `GET /healthcheck` - Health check endpoint (verifies worker is running)
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- `GET /metrics` - Prometheus metrics
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- `GET /prtg` - PRTG-compatible metrics (XML format)
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- `GET /ping` - Simple ping/pong endpoint
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## Creating a Worker
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See `src/exampleWorker.ts` for the worker template. The worker must export a `doWork` function:
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```typescript
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export const doWork = async () => {
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// Your periodic task logic here
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logger.info("Task Completed", "Work done successfully");
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// Throw errors to mark as failed:
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// throw new Error("Something went wrong");
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};
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```
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Update `src/workRunner.ts` line 6 to import your worker:
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```typescript
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import { doWork } from "./yourWorker";
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```
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## Architecture
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- **entry.ts** - HTTP server setup, signal handling, worker lifecycle
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- **workRunner.ts** - Self-scheduling loop, metrics, graceful shutdown
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- **app.ts** - Express app configuration, routes
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- **src/lib/** - Shared utilities (logger, metrics, etc.)
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- **src/routes/** - HTTP route handlers
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## Deployment
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The service uses the `stoppable` library for graceful shutdown with a 10-second timeout before force-closing connections. Docker containers will receive SIGTERM signals and shut down gracefully.
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## Logging
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The service supports two logging mechanisms:
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1. **Console Logging**: Uses the `debug` package, controlled by `DEBUG` env variable
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## Metrics
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Prometheus metrics are automatically collected:
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- `request_operations_total` - Total work cycles executed
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- `request_operations_ok` - Successful work cycles
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- `request_operations_failed` - Failed work cycles
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- `request_duration_seconds` - Duration histogram of work cycles
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## Documentation
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See `CLAUDE.md` in the repository root for complete architecture documentation and guidance.
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