/pglock-v2

postgres 諮詢鎖功能

Primary LanguageTypeScript

PG Lock

Description

參考 colonist4/pg-mutex-lock 完善 postgres 諮詢鎖功能，並使用 pg pool 解決斷線自動重連

Refer to colonist4/pg-mutex-lock to improve postgres advisory lock function, and use pg pool to solve disconnection and automatic reconnection

Feature

  • Support multi-process mutex lock
  • Support single-process mutex lock
  • Support retry, timeout configuration
  • Full typescript support
  • Support pg pool

API

class PGLock

This class is entry point of features. All functions are located under this class instance.

Options

Name Type Required Default Description
pool Pool no undefined use other pg pool (Create if empty)
poolConfig PoolConfig yes undefined refer to PoolConfig
timeout number no 10 * 1000 acquire lock timeout
retryCount number no 3 acquire lock retry count

Method acquireLock (client: PoolClient, key: string) : Promise<boolean>

Try to acquire lock for given key. If success, will be resolved with true. If failed, will be rejected.


Method releaseLock (client: PoolClient, key: string) : Promise<boolean>

Try to release lock for given key. It directly return results of pg_advisory_unlock.


Method lock (key: string, func: () => Promise<any>) : Promise<any>

Mutex lock by async function.

Example

import { PGLock } from 'pglock-v2'

const pgLock = new PGLock({
  poolConfig: {
    host: 'localhost',
    port: 5432,
    user: 'postgres',
    password: 'password',
    database: 'database',
  },
})

setTimeout(async () => {
  console.log('start A')
  await pgLock.lock('test', async () => {
    console.log('locked A')
    await wait(1000)
    console.log('unlocked A')
  })
}, 100)

setTimeout(async () => {
  console.log('start B')
  await pgLock.lock('test', async () => {
    console.log('locked B')
    await wait(100)
    console.log('unlocked B')
  })
}, 300)

Dependencies