An egress spell masked a service on the surviving network going down: with
`peerResponded` set only by the DNS and gRPC providers, every other failure fell
back to the HTTP-status heuristic, which answers "nothing replied" for anything
that is not speaking HTTP. A refused connection on the local network was read as
the instance's own loss of egress, so the check was recorded as degraded and the
monitor stayed up.
`peerAnsweredFromError` holds the errno codes that require the target's own stack
to have replied — a refusal, a reset, a TLS handshake that got as far as a
certificate. Http, Port, WebSocket and Docker use it; Http also treats any status
code as an answer, and Docker any status from the daemon. Hardware and PageSpeed
go through Http and inherit it.
`true` is the claim that costs something, since it blames the target, so it is
only set on evidence. Two cases stay conservative and are commented as such: a
ping that draws no echo reply, and a gamedig query that fails, neither of which
can be told apart from the instance losing its egress. Nor can a proxied HTTP
request that fails with no response, where the refusal may be the proxy's.
🔧
Checkmate backend
The backend service for Checkmate, an open source uptime and infrastructure monitoring application
This directory contains the backend of Checkmate, which handles data processing, storage, and API services for the Checkmate monitoring tool. The backend is responsible for managing uptime checks, handling real-time alerts, and storing historical monitoring data.
Checkmate's backend is designed to be lightweight and scalable, ensuring reliable performance even with a high number of active monitors.
Installation & documentation
For setup instructions, configuration details, and deployment guidelines, please visit our official documentation at docs.checkmate.so.
Related repositories
- Capture Agent (Optional, provides additional server insights)