feat: optional instant retry before marking a monitor down

Adds per-monitor `retries` and `retryDelayMs` options. When a check fails,
the monitor is re-checked up to `retries` extra times (waiting `retryDelayMs`
between attempts, default 5000ms) before being reported as down. This filters
out transient blips / false positives, and affects both the status page state
and downtime notifications.

Backward compatible: default `retries: 0` keeps the current behavior (no retry).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

types/config.ts

@@ -45,6 +45,11 @@ export type MonitorTarget = {
   responseForbiddenKeyword?: string
   checkProxy?: string
   checkProxyFallback?: boolean
+  // [OPTIONAL] Instant retry on failure: number of extra attempts before reporting
+  // the monitor as down (default 0 = no retry). Filters out transient blips.
+  retries?: number
+  // [OPTIONAL] Delay in ms between a failed attempt and the retry (default 5000).
+  retryDelayMs?: number
 }
 
 export type WorkerConfig<TEnv = Env> = {

uptime.config.full.ts

@@ -74,6 +74,11 @@ const workerConfig: WorkerConfig = {
       checkProxy: 'https://xxx.example.com OR worker://weur',
       // [OPTIONAL] if true, the check will fallback to local if the specified proxy is down
       checkProxyFallback: true,
+      // [OPTIONAL] instant retry on failure: number of extra attempts before reporting
+      // the monitor as down, to filter out transient blips (default 0 = no retry)
+      retries: 1,
+      // [OPTIONAL] delay in ms between a failed attempt and the retry (default 5000)
+      retryDelayMs: 5000,
     },
     // Example TCP Monitor
     {

worker/src/monitor.ts

@@ -356,7 +356,16 @@ export async function getStatus(
 
 export async function doMonitor(monitor: MonitorTarget, defaultLocation: string, env: Env) {
   let checkLocation = defaultLocation
-  let status
+  let status: { ping: number; up: boolean; err: string } = { ping: 0, up: false, err: '' }
+
+  // Instant retry: if a check fails, re-check before reporting the monitor as down,
+  // to filter out transient blips (false positives). Controlled per-monitor via
+  // `retries` / `retryDelayMs` (default 0 retries = previous behavior, no retry).
+  const maxAttempts = 1 + (monitor.retries ?? 0)
+  const retryDelayMs = monitor.retryDelayMs ?? 5000
+
+  for (let attempt = 1; attempt <= maxAttempts; attempt++) {
+    checkLocation = defaultLocation
 
     if (monitor.checkProxy) {
       // Initiate a check using proxy (Geo-specific monitoring)
@@ -404,6 +413,13 @@ export async function doMonitor(monitor: MonitorTarget, defaultLocation: string,
       status = await getStatus(monitor)
     }
 
+    if (status.up || attempt === maxAttempts) break
+    console.log(
+      `[${monitor.id}] Attempt ${attempt}/${maxAttempts} failed (${status.err}); retrying in ${retryDelayMs}ms...`
+    )
+    await new Promise((resolve) => setTimeout(resolve, retryDelayMs))
+  }
+
   console.log(`[${monitor.id}] Check result from ${checkLocation}: up=${status.up}, ping=${status.ping}, err=${status.err}`)
 
   return {