alerts_dispatcher: Fix bad tree selection logic.

go/src/infra/monitoring/dispatcher/dispatcher.go

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Dispatcher usage:
 // go run infra/monitoring/dispatcher
 // Expects gatekeeper.json to be in the current directory.
 
 package main
 
@@ skipping 138 matching lines @@
 func (a bySeverity) Len() int      { return len(a) }
 func (a bySeverity) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
 func (a bySeverity) Less(i, j int) bool {
         return a[i].Severity < a[j].Severity
 }
 
 func mainLoop(ctx context.Context, a *analyzer.Analyzer, trees map[string]bool, transport http.RoundTripper) error {
         done := make(chan interface{})
         errs := make(chan error)
         for treeName := range trees {
-                go func(tree string) {
+                tree := treeName

[seanmccullough1, 2016/05/20 18:40:29]

ha!

+                go func() {
                         expvars.Add(fmt.Sprintf("Tree-%s", tree), 1)
                         defer expvars.Add(fmt.Sprintf("Tree-%s", tree), -1)
                         infoLog.Printf("Checking tree: %s", tree)
                         masters := []*messages.MasterLocation{}
 
-                        for treeToUse, shouldUse := range trees {
-                                if !shouldUse {
-                                        continue
-                                }
-
-                                for _, t := range gkts[treeToUse] {
-                                        for _, url := range t.Masters {
-                                                masters = append(masters, url)
-                                        }
+                        for _, t := range gkts[tree] {
+                                for _, url := range t.Masters {
+                                        masters = append(masters, url)
                                 }
                         }
 
                         // TODO(seanmccullough): Plumb ctx through the rest of these calls.
                         bes := fetchBuildExtracts(ctx, a.Reader, masters)
                         infoLog.Printf("Build Extracts read: %d", len(bes))
 
                         alerts := &messages.Alerts{
                                 RevisionSummaries: map[string]messages.RevisionSummary{},
                         }
@@ skipping 42 matching lines @@
                                 err := w.PostAlerts(alerts)
                                 if err != nil {
                                         errLog.Printf("Couldn't post alerts: %v", err)
                                         errs <- err
                                         return
                                 }
                         }
 
                         infoLog.Printf("Filtered failures: %v", filteredFailures)
                         done <- nil
-                }(treeName)
+                }()
         }
 
         for range trees {
                 select {
                 case err := <-errs:
                         return err
                 case <-done:
                 }
         }
 
@@ skipping 168 matching lines @@
         ctx, cancel := context.WithTimeout(ctx, duration)
         defer cancel()
 
         loopResults := looper.Run(ctx, f, cycle, *maxErrs, clock.GetSystemClock())
 
         if !loopResults.Success {
                 errLog.Printf("Failed to run loop, %v errors", loopResults.Errs)
                 os.Exit(1)
         }
 }