8000 feat(lib): always use pg-pool, support pool.end() · wasabigeek/postgres-meta@116fa98 · GitHub
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feat(lib): always use pg-pool, support pool.end()
* Always use `Pool` from node-postgres. Originally the library allows using the `Client` class from node-postgres (by setting `pooled: false`) which is allegedly for when we only need one DB connection that we manage manually, however it turns out that using it directly is not the "happy path", and it's simpler to just use a `Pool` with max size 1 (`pool.end()` ends connections gracefully, among other things--`client.end()` ends ongoing queries abruptly). * Support `pool.end()` from the client. Since we're dynamically creating pools in the server, we want the library to be able to end unneeded pools. Note that in the typical use case of one DB connection this isn't necessary--pools are closed when the server stops.
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2 files changed

+44
-16
lines changed

2 files changed

+44
-16
lines changed

‎src/lib/PostgresMeta.ts

Lines changed: 6 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,4 @@
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import { ClientConfig } from 'pg'
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import { PoolConfig } from 'pg'
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import PostgresMetaColumns from './PostgresMetaColumns'
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import PostgresMetaConfig from './PostgresMetaConfig'
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import PostgresMetaExtensions from './PostgresMetaExtensions'
@@ -15,6 +15,7 @@ import { PostgresMetaResult } from './types'
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export default class PostgresMeta {
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query: (sql: string) => Promise<PostgresMetaResult<any>>
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end: () => Promise<void>
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columns: PostgresMetaColumns
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config: PostgresMetaConfig
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extensions: PostgresMetaExtensions
@@ -27,8 +28,10 @@ export default class PostgresMeta {
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types: PostgresMetaTypes
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version: PostgresMetaVersion
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constructor(config: ClientConfig) {
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this.query = init(config)
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constructor(config: PoolConfig) {
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const { query, end } = init(config)
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this.query = query
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this.end = end
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this.columns = new PostgresMetaColumns(this.query)
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this.config = new PostgresMetaConfig(this.query)
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this.extensions = new PostgresMetaExtensions(this.query)

‎src/lib/db.ts

Lines changed: 38 additions & 13 deletions
Original file line numberDiff line numberDiff line change
@@ -1,19 +1,44 @@
1-
import { types, Client, ClientConfig, Pool } from 'pg'
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import { types, Pool, PoolConfig } from 'pg'
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import { PostgresMetaResult } from './types'
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types.setTypeParser(20, parseInt)
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export const init = (
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config: ClientConfig,
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{ pooled = true } = {}
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): ((sql: string) => Promise<PostgresMetaResult<any>>) => {
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const client = pooled ? new Pool(config) : new Client(config)
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return async (sql: string) => {
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try {
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const { rows } = await client.query(sql)
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return { data: rows, error: null }
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} catch (e) {
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return { data: null, error: { message: e.message } }
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}
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export const init: (
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config: PoolConfig
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) => {
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query: (sql: string) => Promise<PostgresMetaResult<any>>
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end: () => Promise<void>
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} = (config) => {
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// XXX: Race condition could happen here: one async task may be doing
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// `pool.end()` which invalidates the pool and subsequently all existing
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// handles to `query`. Normally you might only deal with one DB so you don't
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// need to call `pool.end()`, but since the server needs this, we make a
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// compromise: if we run `query` after `pool.end()` is called (i.e. pool is
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// `null`), we temporarily create a pool and close is right after.
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let pool: Pool | null = new Pool(config)
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return {
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async query(sql) {
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try {
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if (!pool) {
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const pool = new Pool(config)
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const { rows } = await pool.query(sql)
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await pool.end()
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return { data: rows, error: null }
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}
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const { rows } = await pool.query(sql)
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return { data: rows, error: null }
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} catch (e) {
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return { data: null, error: { message: e.message } }
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}
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},
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async end() {
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const _pool = pool
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pool = null
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// Gracefully wait for active connections to be idle, then close all
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// connections in the pool.
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if (_pool) await _pool.end()
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},
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}
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}

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