generic-pool-prometheus-exporter

Prometheus exporter for the generic-pool npm package that's used by knex.

API

poolExporter

Create pool exporter

Types:

• {type=min} min size of the pool
• {type=max} size of the pool
• {type=acquired} number of resources that are currently acquired
• {type=spare_capacity} number of resources the pool could create before hitting any limits
• {type=available} number of unused resources in the pool
• {type=borrowed} number of resources that are currently acquired by userland code
• {type=pending} number of callers waiting to acquire a resource

Metrics:

# HELP pool_size_total Size of the pool
# TYPE pool_size_total gauge
pool_size_total{type="min"} 2
pool_size_total{type="max"} 3
pool_size_total{type="acquired"} 1
pool_size_total{type="spare_capacity"} 2
pool_size_total{type="available"} 0
pool_size_total{type="borrowed"} 1
pool_size_total{type="pending"} 0

Parameters

• pool Pool generic-pool instance
• opts Object? options
  • opts.register String? register to use
  • opts.name Object metrics name (optional, default "pool_size_total")
  • opts.labels Object extra labels (optional, default {})
  • opts.interval Number pool info update interval, set to null to disable and call exporter.observe() manually (optional, default 10000)

Examples

With generic-pool (node-pool)

const promClient = require('prom-client');
const pool = require('generic-pool');
const poolExporter = require('generic-pool-prometheus-exporter');

const myPool = genericPool.createPool({ ... }, { min 1, max: 5 });
const exporter = poolExporter(myPool);

console.log(promClient.register.metrics())
// exporter.registry.off()

<caption>With manual observe
const promClient = require('prom-client');
const pool = require('generic-pool');
const poolExporter = require('generic-pool-prometheus-exporter');

const myPool = genericPool.createPool({ ... }, { min 1, max: 5 });
const exporter = poolExporter(myPool, { interval: null });

// exporter.observe();
console.log(promClient.register.metrics())
// exporter.observe();
console.log(promClient.register.metrics())

With knex

const promClient = require('prom-client');
const Knex = require('knex');
const poolExporter = require('generic-pool-prometheus-exporter');

const knex = Knex({
 client: 'mysql'
 ...
});
const exporter = poolExporter(knex);

console.log(promClient.register.metrics())
// =>
// # HELP pool_size_total Size of the pool
// # TYPE pool_size_total gauge
// pool_size_total{type="min"} 2
// pool_size_total{type="max"} 3
// pool_size_total{type="acquired"} 1
// pool_size_total{type="spare_capacity"} 2
// pool_size_total{type="available"} 0
// pool_size_total{type="borrowed"} 1
// pool_size_total{type="pending"} 0

Returns Function exporter { off, observe }