CircleCi偶尔无法连接到构建中的Postgres

Question

基本上，我有一个Nodejs项目，通过knex连接到postgres数据库，我使用CircleCI进行测试。它可以工作，但偶尔会因“错误：连接ECONNREFUSED 127.0.0.1:5432”而导致构建失败，我无法弄清楚原因;它在我的机器上没有问题，在构建中必须有所不同。

运行以创建测试数据库的文件如下：

'use strict';

require('dotenv').config();

const connectionOptions = require(`${process.cwd()}/knexfile.js`)[`${process.env.NODE_ENV}`];

const knex = require('knex')(connectionOptions);
console.log('New connection to default postgres database made');

// Remove all other connections to test database
knex.raw(`select pg_terminate_backend(pid) from pg_stat_activity where datname = '${process.env.PG_TEST_DATABASE}'`)
	.then(() => {
		console.log('Removed all other connections to the test database');
		// Drop test database if it exists
		return knex.raw(`DROP DATABASE IF EXISTS ${process.env.PG_TEST_DATABASE};`);
	})
	.then(() => {
		console.log('Dropped test database (if it existed)');
		// Create test database
		return knex.raw(`CREATE DATABASE ${process.env.PG_TEST_DATABASE};`);
	})
	.then(() => {
		console.log('Test database created');
		return process.exit();
	});

当它发生时，错误将发生在我连接后第一次尝试使用postgres做任何事情时，我是否尝试删除数据库，删除其他连接等等。目前，当我尝试执行'select pg_terminate_backend'行时会发生这种情况。

我对Postgres的设置是：

const connectionOptions = {
	client: 'pg',
	version: '7.4.1',
	connection: {
		host: '127.0.0.1',
		user: process.env.PG_USER,
		password: process.env.PG_PASSWORD,
		database: process.env.PG_DATABASE,
		port: parseInt(process.env.PG_PORT) || 5432
	},
	pool: {
		min: 2,
		max: 10
	},
	migrations: {
		tableName: '_migrations',
		directory: './migrations',
	},
	seeds: {
		directory: './seeds/development'
	}
};

我的circleci yml文件如下：

version: 2
jobs:
  build:
    working_directory: ~/project
    docker:
      - image: circleci/node:8.9.4
      # The below environemnt is where you set the .env variables used throughout node
        environment:
          NODE_ENV: test
          PG_USER: jerrodq2
          PG_DATABASE: freelancing_project
          PG_TEST_DATABASE: freelancing_project_test
          PG_PORT: 5432

      - image: postgres:10.3
        environment:
          POSTGRES_USER: jerrodq2
          POSTGRES_DB: freelancing_project

    steps:
      - checkout

      # Download and cache dependencies
      - restore_cache:
          keys:
          - v1-dependencies-{{ checksum "package.json" }}
          # fallback to using the latest cache if no exact match is found
          - v1-dependencies-

      - run:
          name: Install local dependencies
          command: npm install

      - run:
          name: Create database
          command: npm run db:reset:test



      - save_cache:
          paths:
            - node_modules
          key: v1-dependencies-{{ checksum "package.json" }}

      # run tests!
      - run:
          name: Running Tests
          command: npm run test

我有cross-posted this question to CircleCI Discourse。

Answer 1

对于任何有兴趣的人，我都能找到解决方案。按照Linas在上面的评论中的建议，我找到了适当的代码，等待postgres开始进入下一步之前，我只是添加了一个命令，等待5432端口打开，然后创建数据库，如下所示：

- run:
    name: Install local dependencies
    command: npm install

- run:
    name: Wait for Postgres to start
    command: dockerize -wait tcp://localhost:5432 -timeout 1m

- run:
    name: Create database
    command: npm run db:reset:test