Server configuration

The server is configured with environment variables, set under environment: in your docker-compose.yml. Only one is required; the Docker image takes care of the rest.

Required

Variable	What it does
`ONDU_URL`	The scheme and hostname you reach the server at, like `https://music.example.com`. Must match the address the apps will use.

General

Variable	Default	What it does
`ONDU_DATABASE_PATH`	`/data/ondu.db`	Where the SQLite database is stored.
`ONDU_DISABLE_WEB`	`false`	Set to `true` to turn off the built-in web player and only serve the API.
`ONDU_DISABLE_DOCS`	`false`	Set to `true` to turn off the server’s own API docs at `/docs` and the OpenAPI spec at `/openapi`. The API itself keeps working.
`ONDU_SECRET_KEY_BASE`		Used to sign and encrypt secrets. At least 32 characters, 64 recommended. Generate one with `openssl rand -base64 48`, and keep it the same between restarts.

Be aware. The account and library setup forms are part of the web player, so finish creating your account before turning it off.

Where your music is stored

Music is read from a folder by default. It can also come from an S3 bucket, which is experimental.

Variable	Default	What it does
`ONDU_STORAGE_DRIVER`	`file`	`file` for a folder (mounted at `/music` in the setup guide), or `s3` for an S3 bucket (experimental).
`ONDU_STORAGE_S3_BUCKET`		The bucket your music is in. Required when using `s3`.
`ONDU_STORAGE_S3_REGION`		The bucket’s AWS region. Required when using `s3`.

S3 is experimental. It gets far less use than local files, so expect rough edges. AWS credentials are picked up the usual way: the standard AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY environment variables, a shared credentials file, or an IAM role when the server runs on AWS.

Artwork

Album artwork comes from your music files: the artwork embedded in them, or an image in the album’s folder. Any artwork that is found while indexing is copied and resized into this folder.

Variable	Default	What it does
`ONDU_ARTWORK_PATH`	`/data/artwork`	Where album artwork is stored.

Transcoding

The original files are always sent as they are, unless an app asks for a transcoded stream or download, for example to save mobile data. Transcoding uses ffmpeg.

Variable	Default	What it does
`ONDU_TRANSCODE_CACHE_PATH`	`/data/transcode-cache`	Where transcoded files are kept, so the same song isn’t transcoded twice.
`ONDU_TRANSCODE_CACHE_MAX_SIZE`	`10240` (10 GB)	Maximum size of the cache in megabytes. The oldest files are removed after each library scan. To disable you can also set it to `0`.
`ONDU_TRANSCODE_MAX_CONCURRENCY`	`3`	How many transcodes can run at the same time.
`ONDU_TRANSCODE_QUEUE_SIZE`	`10`	How many transcode requests can wait in line for a free slot.

Everything in `/data`

With the Docker image’s defaults, the database, artwork and transcode cache all live under /data. Mount that one folder, like the ./data:/data line in the setup guide.

Your music folder is never written to, and it’s the most important thing to back up, but back up /data too, as it holds your account, playlists, play history and any artist photos you’ve uploaded.