Allow desktop runner Interrupt to be called multiple times

ee/desktop/runner/runner.go

@@ -107,6 +107,7 @@ type DesktopUsersProcessesRunner struct {
 	// menuRefreshInterval is the interval on which the desktop menu will be refreshed
 	menuRefreshInterval time.Duration
 	interrupt           chan struct{}
+	interrupted         bool
 	// uidProcs is a map of uid to desktop process
 	uidProcs map[string]processRecord
 	// procsWg is a WaitGroup to wait for all desktop processes to finish during an interrupt
@@ -222,6 +223,13 @@ func (r *DesktopUsersProcessesRunner) Execute() error {
 // Interrupt stops creating launcher desktop processes and kills any existing ones.
 // It also signals the execute loop to exit, so new desktop processes cease to spawn.
 func (r *DesktopUsersProcessesRunner) Interrupt(_ error) {
+	// Only perform shutdown tasks on first call to interrupt -- no need to repeat on potential extra calls.
+	if r.interrupted {
+		return
+	}
+
+	r.interrupted = true
+
 	// Tell the execute loop to stop checking, and exit
 	r.interrupt <- struct{}{}
 

ee/desktop/runner/runner_test.go

@@ -145,7 +145,7 @@ func TestDesktopUserProcessRunner_Execute(t *testing.T) {
 				assert.NoError(t, r.Execute())
 			}()
 
-			// let is run a few interval
+			// let it run a few intervals
 			time.Sleep(r.updateInterval * 3)
 			r.Interrupt(nil)
 
@@ -185,6 +185,34 @@ func TestDesktopUserProcessRunner_Execute(t *testing.T) {
 					p.Process.Wait()
 				}
 			})
+
+			// Confirm we can call Interrupt multiple times without blocking
+			interruptComplete := make(chan struct{})
+			expectedInterrupts := 3
+			for i := 0; i < expectedInterrupts; i += 1 {
+				go func() {
+					r.Interrupt(nil)
+					interruptComplete <- struct{}{}
+				}()
+			}
+
+			receivedInterrupts := 0
+			for {
+				if receivedInterrupts >= expectedInterrupts {
+					break
+				}
+
+				select {
+				case <-interruptComplete:
+					receivedInterrupts += 1
+					continue
+				case <-time.After(5 * time.Second):
+					t.Errorf("could not call interrupt multiple times and return within 5 seconds -- received %d interrupts before timeout", receivedInterrupts)
+					t.FailNow()
+				}
+			}
+
+			require.Equal(t, expectedInterrupts, receivedInterrupts)
 		})
 	}
 }