vendor: initial vendor

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/github.com/Microsoft/hcsshim/internal/hcs/watcher.go

@@ -0,0 +1,41 @@
+package hcs
+
+import (
+	"context"
+
+	"github.com/Microsoft/hcsshim/internal/logfields"
+	"github.com/Microsoft/hcsshim/internal/timeout"
+	"github.com/sirupsen/logrus"
+)
+
+// syscallWatcher is used as a very simple goroutine around calls into
+// the platform. In some cases, we have seen HCS APIs not returning due to
+// various bugs, and the goroutine making the syscall ends up not returning,
+// prior to its async callback. By spinning up a syscallWatcher, it allows
+// us to at least log a warning if a syscall doesn't complete in a reasonable
+// amount of time.
+//
+// Usage is:
+//
+// syscallWatcher(logContext, func() {
+//    err = <syscall>(args...)
+// })
+//
+
+func syscallWatcher(logContext logrus.Fields, syscallLambda func()) {
+	ctx, cancel := context.WithTimeout(context.Background(), timeout.SyscallWatcher)
+	defer cancel()
+	go watchFunc(ctx, logContext)
+	syscallLambda()
+}
+
+func watchFunc(ctx context.Context, logContext logrus.Fields) {
+	select {
+	case <-ctx.Done():
+		if ctx.Err() != context.Canceled {
+			logrus.WithFields(logContext).
+				WithField(logfields.Timeout, timeout.SyscallWatcher).
+				Warning("Syscall did not complete within operation timeout. This may indicate a platform issue. If it appears to be making no forward progress, obtain the stacks and see if there is a syscall stuck in the platform API for a significant length of time.")
+		}
+	}
+}