TypeScript SDK

Installation

npm install atrion

The package includes pre-built WASM binaries. No Rust toolchain required.

Basic Usage

import { Atrion } from 'atrion'

// Initialize the engine
const atrion = new Atrion()
await atrion.connect()

// In your request handler:
app.post('/api/checkout', async (req, res) => {
  // Collect telemetry from your monitoring
  const telemetry = {
    latencyMs: getP99Latency(),
    errorRate: getErrorRate(),
    saturation: getCPUSaturation(),
  }

  // Make routing decision
  const decision = atrion.route('api/checkout', telemetry)

  if (!decision.allow) {
    return res.status(503).json({
      error: decision.reason,
      retryAfter: decision.retryAfterMs
    })
  }

  // Process the request normally
  await processCheckout(req, res)
})

Response Object

The route() method returns a decision object:

Property	Type	Description
allow	boolean	Whether the request should proceed
resistance	number	Current resistance in Ohms (Ω)
mode	string	BOOTSTRAP \| OPERATIONAL \| CIRCUIT_BREAKER
reason	string?	If rejected, explains why
retryAfterMs	number?	Suggested retry delay in milliseconds

Framework Integration

Express.js Middleware

import { Atrion } from 'atrion'

const atrion = new Atrion()

export const atrionMiddleware = async (req, res, next) => {
  const decision = atrion.route(req.path, {
    latencyMs: res.locals.latency,
    errorRate: res.locals.errorRate,
    saturation: res.locals.saturation,
  })

  if (!decision.allow) {
    res.set('Retry-After', Math.ceil(decision.retryAfterMs / 1000))
    return res.status(503).json({ error: decision.reason })
  }

  next()
}

Fastify Plugin

import fp from 'fastify-plugin'
import { Atrion } from 'atrion'

export const atrionPlugin = fp(async (fastify) => {
  const atrion = new Atrion()
  await atrion.connect()

  fastify.decorate('atrion', atrion)

  fastify.addHook('preHandler', async (request, reply) => {
    const decision = atrion.route(request.url, request.telemetry)
    if (!decision.allow) {
      reply.code(503).send({ error: decision.reason })
    }
  })
})

./guides ./configuration