prefetcharr

Let Sonarr fetch the next season of a show you are watching on Jellyfin/Emby/Plex.

Details

prefetcharr periodically polls your media server for active playback sessions. For TV shows, it checks whether the pilot is playing or if the end of a season is almost reached.
If this is the case and the next/first season has not been downloaded yet, prefetcharr asks Sonarr to monitor it and initiate a season search. If there are no more seasons left, the series gets monitored for new seasons instead.

Build and install

To install, first ensure Rust is installed on your system by following the instructions at Install Rust, then run:

cargo install --git https://github.com/p-hueber/prefetcharr

Or with docker compose:

version: '3.5'
services:
  prefetcharr:
    image: phueber/prefetcharr:latest
    container_name: prefetcharr
    environment:
      # `jellyfin`, `emby` or `plex`
      - MEDIA_SERVER_TYPE=jellyfin
      # Jellyfin/Emby/Plex baseurl
      - MEDIA_SERVER_URL=http://example.com/jellyfin
      # Jellyfin/Emby API key or plex server token
      - MEDIA_SERVER_API_KEY=<YOUR KEY HERE>
      # Sonarr baseurl
      - SONARR_URL=http://example.com/sonarr
      # Sonarr API key
      - SONARR_API_KEY=<YOUR KEY HERE>
      # Logging directory
      - LOG_DIR=/log
      # Log level
      - RUST_LOG=prefetcharr=debug
      # Polling interval in seconds
      - INTERVAL=900
      # The last <NUM> episodes trigger a search
      - REMAINING_EPISODES=2
    volumes:
      - /path/to/log/dir:/log

Configuration

API keys

prefetcharr needs two different API keys to do its job.

SONARR_API_KEY

Go to Settings -> General -> Security and copy the API key.

MEDIA_SERVER_API_KEY

The key to use and how to obtain it differs on the type of media server you use:

Jellyfin

Log in as an administrator and go to Administration -> Dashboard -> Advanced -> Api Keys. Add a new key or use an existing one.

Emby

Log in as an administrator, click on the gear on the top right and go to Advanced -> Api Keys. Add a new key or use an existing one.

Plex

You need to extract the server token from a configuration file and use it as the API key.

Upgrading pilots

If you want to store pilot episodes only, prefetcharr can fetch the first season for you on demand.
This method works well for individual episodes but may encounter issues with season packs.
For this to function in Sonarr, grabbing the season pack must be considered an upgrade of the pilot episode. This can be achieved through a custom format. Import the custom format and configure a quality profile to prefer it.

How to use

Host installation

If you installed prefetcharr through cargo, you can get a description of the command-line interface by running prefetcharr --help.

Docker installation

Users utilizing Docker only need to start the container, e.g. using docker compose up -d prefetcharr. Once the container is running, you may want to check the logs for errors. You can do so by either calling docker logs prefetcharr or by checking the logging directory you configured.