Getting Started with SimpleIPC Express — A Lightweight IPC LibraryInter-process communication (IPC) is a fundamental building block when designing modular, efficient, and scalable applications. Whether you’re splitting work across multiple processes to utilize multi-core CPUs, isolating untrusted code, or architecting microservices on a single machine, choosing the right IPC approach can dramatically affect performance, reliability, and developer experience. This guide introduces SimpleIPC Express — a lightweight IPC library designed for simplicity, speed, and predictable behavior — and walks you through installation, core concepts, practical examples, patterns, troubleshooting, and best practices.
What is SimpleIPC Express?
SimpleIPC Express is a minimal, focused IPC library for Node.js and similar JavaScript runtimes that emphasizes:
- Simplicity: minimal API surface so you can get up and running quickly.
- Performance: lightweight message serialization and low-overhead transport.
- Flexibility: supports multiple transport backends (Unix sockets, TCP, and in-process channels) with the same API.
- Reliability: built-in request/response patterns with timeouts, automatic reconnection, and message acknowledgment.
SimpleIPC Express is intentionally small: it provides essential primitives for sending messages, handling requests and responses, and managing connections without the complexity of large frameworks.
Core concepts and terminology
- Node: an endpoint that can send and receive messages (a process or logical actor).
- Transport: the underlying channel used to carry messages (e.g., Unix socket, TCP, in-process).
- Message: a unit of data exchanged between nodes. Messages can be notifications (fire-and-forget) or requests that expect responses.
- Handler: function registered to handle incoming requests for a specific route or action.
- Broker: optional central coordinator for routing messages between nodes (useful in complex topologies).
Installation
Install via npm:
npm install simpleipc-express Or using yarn:
yarn add simpleipc-express Quick start — a basic request/response example
This example shows two processes: a server process exposing a simple handler and a client process calling it.
server.js
const { createServer } = require('simpleipc-express'); const server = createServer({ transport: 'unix', path: '/tmp/simpleipc.sock' }); server.register('math.add', async ({ a, b }) => { return a + b; }); server.listen().then(() => { console.log('SimpleIPC Express server listening'); }); client.js
const { createClient } = require('simpleipc-express'); (async () => { const client = createClient({ transport: 'unix', path: '/tmp/simpleipc.sock' }); await client.connect(); const result = await client.request('math.add', { a: 5, b: 7 }, { timeout: 2000 }); console.log('5 + 7 =', result); client.close(); })(); This shows the core flow: register handlers on the server, connect and send requests from the client, and await responses.
Message types and patterns
SimpleIPC Express supports several patterns:
- Request/Response: the client sends a request and waits for a response (promised-based). Includes timeouts and error propagation.
- Notification: one-way messages that don’t expect a reply, useful for events.
- Streams: simple streaming support for larger payloads (chunked messages), useful for file transfers or continuous data.
- Pub/Sub (optional): simple publish/subscribe mechanism for broadcasting events to multiple subscribers.
Error handling and timeouts
When making requests, always specify a timeout to avoid hanging promises:
await client.request('task.run', { id: 1 }, { timeout: 5000 }); Handlers can throw errors; errors propagate back to the requester with a structured error object:
{ "name": "ValidationError", "message": "Missing field 'id'", "code": 400 } On the client side, handle errors with try/catch:
try { await client.request(...); } catch (err) { console.error('Request failed:', err); } Transport options
- Unix domain sockets (recommended for local single-machine IPC on Unix-like systems): fast and secure.
- TCP (useful across machines or when sockets aren’t available): specify host and port.
- In-process channels (for multiple logical nodes inside one process): no OS sockets, lowest overhead.
Example: TCP server
const server = createServer({ transport: 'tcp', port: 9000 }); Example: in-process
const server = createServer({ transport: 'inproc' }); const client = createClient({ transport: 'inproc', server }); Authentication and security
For local IPC, Unix sockets provide filesystem-level permissions. For TCP transports, SimpleIPC Express supports optional token-based authentication and TLS. Typically you’ll:
- Use Unix sockets for local services where possible.
- Enable TLS and require tokens for any network-exposed endpoints.
- Validate and sanitize message payloads on handlers.
Example: enabling token auth
const server = createServer({ transport: 'tcp', port: 9000, authToken: 's3cr3t' }); const client = createClient({ transport: 'tcp', port: 9000, authToken: 's3cr3t' }); Scaling patterns
- Worker pool: spawn multiple worker processes (or threads) that connect to a central broker or to the main process. Use round-robin or least-loaded routing.
- Brokered topology: run a lightweight broker that maintains connections and forwards requests to available workers.
- Direct peer connections: for small clusters, connect nodes directly to each other.
Example: simple worker pool
// master: routes work to workers via request('worker.process', payload) Testing and development tips
- Use the in-process transport for unit tests to avoid flakiness and OS socket permissions.
- Simulate network conditions (latency, dropped packets) using tools like tc/netem when testing TCP.
- Use structured logging for message traceability (include request IDs).
Troubleshooting
- “Connection refused”: ensure server is listening and correct transport/path/port used.
- “Timeout”: increase request timeout, verify the handler registered the route, or check for errors thrown in handler.
- Permission errors with Unix sockets: check file permissions and ownership.
Example: building a simple task queue
- Start a broker that accepts task submissions.
- Start several worker processes that register a handler ‘task.execute’.
- Clients submit tasks via request(‘task.submit’, { payload }).
- Broker routes tasks to idle workers; workers reply with results or errors.
This pattern decouples task producers and consumers and lets you scale workers independently.
Best practices
- Prefer Unix sockets for local IPC when available.
- Keep handlers small and non-blocking; offload CPU-bound work to separate worker processes.
- Use timeouts and circuit-breakers in clients to avoid cascading failures.
- Validate inputs at the edge (handler entry) and normalize error responses.
- Monitor connection counts and message latency; add health-check endpoints if needed.
API reference (concise)
- createServer(options) → server
- server.register(route, handler)
- server.listen()
- server.close()
- createClient(options) → client
- client.connect()
- client.request(route, payload, opts)
- client.notify(route, payload)
- client.close()
Options common fields: transport (‘unix’|‘tcp’|‘inproc’), path, host, port, authToken, tls, timeout defaults.
Conclusion
SimpleIPC Express gives you the essentials for reliable, low-overhead inter-process communication with a small API surface. It’s ideal for applications needing fast local IPC, worker pools, or lightweight microservice patterns without bringing heavy frameworks. Start with the in-process transport for tests, use Unix sockets for local production, and add TLS/token auth when exposing services across machines.
If you want, I can: provide a full example project structure, a Docker Compose setup for TCP transport, or unit-test examples using the in-process transport. Which would you like next?
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