ipc: give executor some time to startup

Namespace-based sandbox can take some time to setup.
In particular, lots of parallel executors block on net
namespace creation.

1 files changed, 22 insertions, 0 deletions

diff --git a/ipc/ipc.go b/ipc/ipc.go
index b7c647478..0f8cac7ee 100644
--- a/ipc/ipc.go
+++ b/ipc/ipc.go
@@ -352,6 +352,10 @@ func makeCommand(bin []string, timeout time.Duration, flags uint64, inFile *os.F
 		return nil, fmt.Errorf("failed to start executor binary: %v", err)
 	}
 	c.cmd = cmd
+	if err := c.waitServing(); err != nil {
+		return nil, err
+	}
+
 	tmp := c
 	c = nil // disable defer above
 	return tmp, nil
@@ -375,6 +379,24 @@ func (c *command) close() {
 	}
 }
 
+// Wait for executor to start serving (sandbox setup can take significant time).
+func (c *command) waitServing() error {
+	read := make(chan error, 1)
+	go func() {
+		var buf [1]byte
+		_, err := c.inrp.Read(buf[:])
+		read <- err
+	}()
+	timeout := time.NewTimer(time.Minute)
+	select {
+	case err := <-read:
+		timeout.Stop()
+		return err
+	case <-timeout.C:
+		return fmt.Errorf("executor is not serving")
+	}
+}
+
 func (c *command) kill() {
 	syscall.Kill(c.cmd.Process.Pid, syscall.SIGKILL)
 }