> For the complete documentation index, see [llms.txt](https://preen.gitbook.io/preen-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://preen.gitbook.io/preen-docs/getting-started/hello-world/configuring-sources.md).

# Configuring Sources

Define the data sources your Preen session can connect to

Preen maintains a configuration file in `$HOME/.preen/sources.yml` by default. This is can be overridden via the `PREEN_CONFIG_PATH` environment variable.

A config file might look like this:

```yaml
sources:
  - name: s3-model
    engine: s3
    connection:
      bucket_name: users
      region: us-east-1
  - name: postgres-model
    engine: postgres
    connection:
      host: localhost
      port: 33061
      database: postgres
      username: root
      password: myp@assword
  - name: mongo-model
    engine: mongodb
    connection:
      host: ${MONGO_HOST}
      port: ${MONGO_PORT}
      database: mongo
```

In a nutshell, your configuration is primarily a list of data sources, credentials, and their engine classification (see [Config](/preen-docs/documentation/config.md)for list of supported engines). **Be sure to add this file to your `.gitignore` if you are keeping it somewhere version controlled.**