+// If SystemLogs.RequestQueueDumpDirectory is set, monitor the
+// server's incoming HTTP request queue size. When it exceeds 90% of
+// API.MaxConcurrentRequests, write the /_inspect/requests data to a
+// JSON file in the specified directory.
+func (c *command) requestQueueDumpCheck(cluster *arvados.Cluster, prog string, reg *prometheus.Registry, srv *http.Server, logger logrus.FieldLogger) {
+ outdir := cluster.SystemLogs.RequestQueueDumpDirectory
+ if outdir == "" || cluster.ManagementToken == "" || cluster.API.MaxConcurrentRequests < 1 {
+ return
+ }
+ logger = logger.WithField("worker", "RequestQueueDump")
+ outfile := outdir + "/" + prog + "-requests.json"
+ for range time.NewTicker(requestQueueDumpCheckInterval).C {
+ mfs, err := reg.Gather()
+ if err != nil {
+ logger.WithError(err).Warn("error getting metrics")
+ continue
+ }
+ dump := false
+ for _, mf := range mfs {
+ if mf.Name != nil && *mf.Name == "arvados_concurrent_requests" && len(mf.Metric) == 1 {
+ n := int(mf.Metric[0].GetGauge().GetValue())
+ if n > 0 && n >= cluster.API.MaxConcurrentRequests*9/10 {
+ dump = true
+ break
+ }
+ }
+ }
+ if dump {
+ req, err := http.NewRequest("GET", "/_inspect/requests", nil)
+ if err != nil {
+ logger.WithError(err).Warn("error in http.NewRequest")
+ continue
+ }
+ req.Header.Set("Authorization", "Bearer "+cluster.ManagementToken)
+ resp := httptest.NewRecorder()
+ srv.Handler.ServeHTTP(resp, req)
+ if code := resp.Result().StatusCode; code != http.StatusOK {
+ logger.WithField("StatusCode", code).Warn("error getting /_inspect/requests")
+ continue
+ }
+ err = os.WriteFile(outfile, resp.Body.Bytes(), 0777)
+ if err != nil {
+ logger.WithError(err).Warn("error writing file")
+ continue
+ }
+ }
+ }
+}
+
+func (c *command) requestPriority(req *http.Request, queued time.Time) int64 {
+ switch {
+ case req.Method == http.MethodPost && strings.HasPrefix(req.URL.Path, "/arvados/v1/containers/") && strings.HasSuffix(req.URL.Path, "/lock"):
+ // Return 503 immediately instead of queueing. We want
+ // to send feedback to dispatchcloud ASAP to stop
+ // bringing up new containers.
+ return math.MinInt64
+ case req.Method == http.MethodPost && strings.HasPrefix(req.URL.Path, "/arvados/v1/logs"):
+ // "Create log entry" is the most harmless kind of
+ // request to drop.
+ return 0
+ case req.Header.Get("Origin") != "":
+ // Handle interactive requests first.
+ return 2
+ default:
+ return 1
+ }
+}
+