Function health 

async fn health(__arg0: State<AppState>) -> Response

GET /health

status is liveness: it is "ok" whenever this process can schedule a task to answer at all, which is what a load balancer’s health check should gate traffic on — see crates/didbot-serve/src/health.rs for why that is a different claim from progress, which reports whether the deployment’s own heartbeat tick is still advancing rather than merely whether a socket accepted.

certificates is the second claim, and the one an alarm can be pointed at: the deployment’s health checks read it for certificate state, and a renewal that keeps failing reaches expiry — a total outage for every hostname in the zone — over weeks. Carried in this same response rather than on a route of its own so the check already being made says it; see crates/didbot-serve/src/health.rs.

oauthPushes is the third, and it is here because POST /oauth/par cannot say it anywhere else: that endpoint is unauthenticated, so it answers a flood aimed at one account exactly as it answers an ordinary push, and the log line it writes is sampled. These are counts since this process started, so an operator watches them move rather than reading a level; see crate::oauth::par::DroppedPushes.

foreignRecords is the fourth, and the same shape: counts since the process started, from the one reader policy evaluation reads other people’s repositories through. refusals is separated from unknowns because a refusal is this deployment’s own decision and an unknown is somebody else’s outage, and an operator watching either number climb wants to know which it is looking at. See didbot_lookup::Counts.

disk is the fifth: the data volume’s freeBytes and totalBytes, read as this request is answered, and alert, the lowest free-space watermark it is below. It is null for a run with no --data. See crate::health::HealthState::disk.

firehose is the sixth: how many subscribeRepos consumers are attached right now, and the newest sequence number assigned. A relay that has stopped reading is consumers at zero while newestSeq moves.

revision is the commit the binary was built from, or null for a build that was not told; see crate::health::REVISION. A deploy waits for it to name the commit it shipped.