leinelissen/embedded-postgres

README

🐘 A Node package that spawns PostgresQL clusters programatically.

Installation

embedded-postgres is available from NPM:

npm i embedded-postgres

Important

Embedded Postgres requires post-install scripts to function. If you have those disabled, approve build scripts for the platform package (for example with pnpm approve-builds, npm rebuild @embedded-postgres/<platform>, or bun pm trust @embedded-postgres/<platform>).

We require a post-install script to generate symlinks that Postgres requires for operation. This is necessary since NPM doesn't support symlinks in their tarballs. If these symlinks are missing at runtime, embedded-postgres throws an error with instructions. Set autoRehydrateSymlinks: true to recreate them automatically when initialising or starting a cluster.

Usage

This package contains a simple API that allows you to create clusters, start them, create / delete database and stop any existing processes.

import EmbeddedPostgres from 'embedded-postgres';

async function main() {
    // Create the object
    const pg = new EmbeddedPostgres({
        databaseDir: './data/db',
        user: 'postgres',
        password: 'password',
        port: 5432,
        persistent: true,
    });

    // Create the cluster config files
    await pg.initialise();

    // Start the server
    await pg.start();

    // Create and/or drop database
    await pg.createDatabase('TEST');
    await pg.dropDatabase('TEST');

    // Initialize a node-postgres client
    const client = pg.getPgClient();
    await client.connect();
    const result = await client.query('SELECT datname FROM pg_database');

    // Stop the server
    await pg.stop();
}

main();

PostgresQL Versions

This package aims to track the PostgresQL support policy for supported versions. Additionally, we track the binaries that are created upstream in zonky's embedded-postgres-binaries. This leads to the following current support matrix:

Platform / Architecture	14.24.0	15.19.0	16.15.0	17.11.0	18.6.0
🍎 Darwin / x64	✅	✅	✅	✅	✅
🍎 Darwin / arm64[1]	✅	✅	✅	✅	✅
🪟 Windows / x64	✅	✅	✅	✅	✅
🐧 Linux / x64	✅	✅	✅	✅	✅
🐧 Linux / arm	✅	✅	✅	✅	✅
🐧 Linux / arm64	✅	✅	✅	✅	✅
🐧 Linux / ia32	✅	✅	✅	✅	✅
🐧 Linux / ppc64	✅	✅	✅	✅	✅

In order to install a particular version, look for the latest tag in NPM. For example, if you would like to install v10.20.0, you can currently use the following tag:

npm i embedded-postgres@10.20.0-beta.6

Installing particular versions of PostgresQL (i.e. versions not released on NPM) is currently not possible. If you would have a need for doing so, please create an issue.

API

Options in the constructor can be used to modify the behaviour of the application. The parameters that are available as part of the options can be seen here:

Property	Type	Description
databaseDir	string	The location where the data should be persisted to. Defaults to `./data/db`
port	number	The port where the Postgres database should be listening. Defaults to: `5432`
user	string	The username for logging into the Postgres database. Defaults to `postgres`
password	string	The password for logging into the Postgres database. Defaults to `password`
authMethod	'scram-sha-256' \| 'password' \| 'md5'	The authentication method to use when authenticating against Postgres. Defaults to `password`
persistent	boolean	Whether all data should be left in place when the database is shut down. Defaults to `true`.
initdbFlags	string[]	Pass any additional flags to the initdb process. You can find all available flags here: https://www.postgresql.org/docs/current/app-initdb.html. Flags should be passed as a string array, e.g. `["--debug"]` or `["--locale=en-GB"]` Defaults to `[]`
postgresFlags	string[]	Pass any additional flags to the postgres process. You can find all available flags here: https://www.postgresql.org/docs/current/app-postgres.html. Flags should be passed as a string array, e.g. `["--debug"]` or `["--locale=en-GB"]`. Defaults to `[]`.
createPostgresUser	boolean	Postgres does not allow binaries to be run by root. In case you're running in root-only enviroments, such as Docker containers, you may need to create an extra user on your system in order to be able to call the binaries. NOTE: This WILL irreversibly modify your host system. The effects are somewhat minor, but it's still recommend to only use this in Docker containers. Defaults to `false`.
autoRehydrateSymlinks	boolean	Automatically recreate missing symlinks when initialising or starting a cluster. Defaults to `false`.
onLog	(message \| string) => void	Pass in a custom logging handler. This will relay and console messages that are generated by the postgres and initdb processes. Defaults to `console.log`
onError	(messageOrError \| string \| Error \| unknown) => void	Pass in a custom error logging handler. This will catch and stderr results coming in from the postgres and initdb processes. Defaults to `console.error`

Contributing

This package is open to issues, feedback, ideas and pull requests. Create an issue on this repository to get started! In order to get started with development, you might need some extra pointers

Development

In order to get yourself situated for development, you will need to the repository up and running. In order to make this work, start with a relatively recent install of NodeJS (at least v18, v20+ recommended). You can then run this command to install all packages:

npm install --force

Note

You must include --force or else NPM will refuse to install the dependencies for all packages, including those not for the current architecture.

Then, you must pre-compile all Typescript using the following command:

npm run build

As soon as that is complete, we'll download the requisite PostgresQL binaries for your particular architecture using:

npm run download

Lastly, you can hop over to packages/embedded-postgres and do some development there:

cd packages/embedded-postgres

You can force automatic recompliation of the Typescript files by running:

npm start

Don't forget to add and run tests when you are developing new functionality. Add them to tests/index.test.ts, and run the tests by running:

npm test

Troubleshotting

Running in Docker containers

Running in Docker containers might fail, because many are setup to run with the root user as default. Either you resolve to setting up a container with a specific user yourself, or you set the createPostgresUser option to true, after which embedded-postgres will automatically set up a postgres user on the system for usage by your script.

Credits and Licensing

Embedded Postgres was created by Lei Nelissen for BMD Studio. It is currently maintained by Studio Falkland. The package is based on zonky's embedded-postgres-binaries.

The binaries are made available under the Apache License 2.0, whereas the specific code in this package is made available under the MIT license.