Slack — Alert Notifications

The CritterWatch.Slack package posts CritterWatch's alert lifecycle to Slack as rich Block Kit messages: raised, elevated, reduced, resolved, cleared, acknowledged, and snoozed. Lifecycle updates reply in-thread to the original alert message, so one alert is one conversation.

dotnet add package CritterWatch.Slack

Configuration

Register it on the CritterWatch host (the application that runs AddCritterWatchServices — not the monitored services):

opts.AddCritterWatchSlack(slack =>
{
    // A Slack Bot OAuth token with chat:write scope (required).
    slack.BotToken = Environment.GetEnvironmentVariable("SLACK_BOT_TOKEN")!;

    // Where alert notifications land by default.
    slack.DefaultChannel = "#critterwatch-alerts";

    // Critical-severity alerts can route to a dedicated channel.
    slack.CriticalChannel = "#ops-critical";
});

The bot token is required and validated at startup — create a Slack app with the chat:write scope, install it to your workspace, and invite the bot to the target channels.

Routing and filtering

SlackConfiguration routes and filters notifications:

• DefaultChannel — where alerts land unless something more specific matches.
• CriticalChannel — critical-severity alerts route here when set.
• AlertTypeChannels — pin specific alert types (e.g. "ProjectionLag") to specific channels; takes precedence over both channels above.
• MinimumSeverity — notifications below this are skipped (default "Warning", i.e. Warning + Critical notify, Info doesn't).
• UseThreads — lifecycle updates (elevated / resolved / …) reply in the original message's thread (default true); disable to post each event standalone.

Behavior notes

• Posting is best-effort: a Slack API failure is logged as a warning and never disturbs alert evaluation or the console itself.
• Slack handlers are ordinary Wolverine handlers on the CritterWatch host, discovered automatically when the package is registered — no extra wiring.
• Alerts themselves are evaluated (and license-gated) upstream; this package only renders and delivers what the alerting pipeline produces. For generic HTTP delivery instead of Slack, see the built-in webhook notifications.