20475: Option to dump active requests when queue is >=90% full.

[arvados.git] / lib / service / cmd.go

diff --git a/lib/service/cmd.go b/lib/service/cmd.go
index 20441c2a6c4534eb697a85bfc4c369e64ae0aad9..cc6938cbc6e1ff3f680a4ca024fcc698e946d713 100644 (file)
--- a/lib/service/cmd.go
+++ b/lib/service/cmd.go
@@ -12,10 +12,12 @@ import (
        "io"
        "net"
        "net/http"
+       "net/http/httptest"
        _ "net/http/pprof"
        "net/url"
        "os"
        "strings"
+       "time"
 
        "git.arvados.org/arvados.git/lib/cmd"
        "git.arvados.org/arvados.git/lib/config"
@@ -45,6 +47,8 @@ type command struct {
        ctx        context.Context // enables tests to shutdown service; no public API yet
 }
 
+var requestQueueDumpCheckInterval = time.Minute
+
 // Command returns a cmd.Handler that loads site config, calls
 // newHandler with the current cluster and node configs, and brings up
 // an http server with the returned handler.
@@ -189,6 +193,7 @@ func (c *command) RunCommand(prog string, args []string, stdin io.Reader, stdout
                <-handler.Done()
                srv.Close()
        }()
+       go c.requestQueueDumpCheck(cluster, prog, reg, &srv.Server, logger)
        err = srv.Wait()
        if err != nil {
                return 1
@@ -196,6 +201,55 @@ func (c *command) RunCommand(prog string, args []string, stdin io.Reader, stdout
        return 0
 }
 
+// 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 == "" {
+               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
+                       }
+               }
+       }
+}
+
 // If an incoming request's target vhost has an embedded collection
 // UUID or PDH, handle it with hTrue, otherwise handle it with
 // hFalse.