Highlights is a simple but flexible highlighting bot for Discord. Add a keyword to get notified in direct messages when your keyword appears in that server.

You can add highlights to your server directly with this link. If you run into any problems, please make an issue here or let me know on The Coding Den, @ThatsNoMoon#0175.

• Add keywords to be notified about, per-server or per-channel
• Ignore phrases to make your keywords more specific
• Mute channels to filter out noise
• Block obnoxious users

For self-hosters, highlights includes:

• Automatic backups and backup pruning
• Error reporting via Discord webhook
• Performance monitoring with Prometheus

You can find downloads for 64 bit Windows and Linux, as well as 64 bit Linux ARM (for e.g. Raspberry Pi) on the releases page.

Highlights requires cargo to be built. rustup is the recommended installation method for most use-cases.

Once you have cargo installed, run cargo build --release (or cargo build for an unoptimized build) to produce an executable at target/release/highlights (or target/debug/highlights).

Highlights is configured by environment variables, and also supports dotenv. To use dotenv, create a file .env in the directory you run highlights in, and put key-value pairs in it, like the below:

HIGHLIGHTS_DISCORD_TOKEN="your bot token goes here"
HIGHLIGHTS_DATA_DIR="highlights_data"

The only required environment variable is HIGHLIGHTS_DISCORD_TOKEN, which must be a valid Discord bot token. You can use the following environment variables to configure highlights' other behavior:

• HIGHLIGHTS_DATA_DIR: Configures where highlights stores its database and backup files. Default is ./data.
• HIGHLIGHTS_WEBHOOK_URL: Should be a Discord webhook url (https://discord.com/api/webhooks/<webhook ID>/<webhook token>) to send error messages to. If not set, errors will only be logged to the console. (Highlights uses a webhook instead of the bot account so that it can report panic messages and not just errors.)
• HIGHLIGHTS_MAX_KEYWORDS: Sets the limit of how many keywords users can have.
• HIGHLIGHTS_PATIENCE_SECONDS: Sets how long to wait for activity before sending a notification.
• HIGHLIGHTS_LOG_FILTER: Controls env_logger output; set this to debug to enable all console logging or error to only log errors. Default is highlights=info.
• HIGHLIGHTS_LOG_STYLE: Controls env_logger style; set this to never to disable colored console output, or always to force colored output. See env_logger's documentation for more information.
• HIGHLIGHTS_PROMETHEUS_ADDR: Sets the address to listen for Prometheus monitoring requests.
• HIGHLIGHTS_DONT_BACKUP: Disables automatic database backups.
• HIGHLIGHTS_PRIVATE: Disables sharing the bot invite link.

Unless the HIGHLIGHTS_DONT_BACKUP environment variable exists, highlights automatically backs up its database every time it starts, and every 24hrs after that. These backups are saved to $HIGHLIGHTS_DATA_DIR/backup. These backups are a full snapshot of the database, so to restore one you can just move it back to $HIGHLIGHTS_DATA_DIR and rename it to data.db. Highlights doesn't delete any backups from the last 24hrs, but it does clean up older backups automatically:

• Roughly one backup per day is kept for the past week
• Roughly one backup per week is kept for the past month
• Roughly one backup per month is kept for the past year
• Backups older than a year are deleted

Highlights uses the timestamp embedded in the backup name to determine how old it is, so don't mess with the file names (it'll log a warning about any files it doesn't recognize).

If you set the HIGHLIGHTS_PROMETHEUS_ADDR environment variable, highlights will track command and database query execution times to be reported by Prometheus. The address should be in the form address:port, e.g. 127.0.0.1:9000.

Example prometheus config to scrape 127.0.0.1:9000:

global:
  scrape_interval: 15s
  evaluation_interval: 15s

scrape_configs:
  - job_name: 'highlights'
    static_configs:
      - targets: ['127.0.0.1:9000']

Highlights reports the metrics highlights_command_time and highlights_query_time.

Highlights is licensed under the OSL 3.0. Derivatives must be licensed under OSL 3.0, but this does not include any linking restrictions; you may link this code to closed-source code.