embedded-postgres/README.md

A package to run an embedded Postgresql database right from NodeJS

![Embedded
Postgres](https://github.com/leinelissen/embedded-postgres/raw/main/docs/images/embedded-postgres-header.svg)

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<h3 align="center">
    🐘 A Node package that spawns PostgresQL clusters programatically.
</h3>

## Installation
`embedded-postgres` is available from NPM:

```sh
npm i embedded-postgres
```

<br />

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

```ts
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();
```

<br />

## PostgresQL Versions
This package aims to track the [PostgresQL support
policy](https://www.postgresql.org/support/versioning/) for supported versions.
Additionally, we track the binaries that are created upstream in [zonky's
embedded-postgres-binaries](https://github.com/zonkyio/embedded-postgres). This
leads to the following current support matrix:

| Platform / Architecture   | 12.20.0 | 13.16.0 | 14.13.0 | 15.8.0 | 16.4.0 | 17.0.0 |
|---------------------------|---------|---------|---------|--------|--------|--------|
| 🍎 Darwin / x64           | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
| 🍎 Darwin / arm64[[1]](https://github.com/zonkyio/embedded-postgres/issues/86#issuecomment-1120425822) | 🚫 | 🚫 | 🚫 | ✅ | ✅ | ✅ |
| 🪟 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](https://www.npmjs.com/package/embedded-postgres). For example, if you
would like to install `v10.20.0`, you can currently use the following tag:
```sh
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.

<br />

## 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. <br />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`. |
| 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` |

<br />

## 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
```

<br />

## 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.

<br />

## Credits and Licensing
Embedded Postgres was created by Lei Nelissen for [BMD
Studio](https://bmd.studio). It is based on [zonky's
embedded-postgres-binaries](https://github.com/zonkyio/embedded-postgres). 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.

<a href="https://bmd.studio">
    <img src="https://github.com/leinelissen/embedded-postgres/raw/main/docs/images/logo-bmd.svg" alt="BMD Studio" width="150" height="150" />
</a>

<br />