cephfs admin: poll mgr to see if mirroring module is enabled

When testing the mirroing workflow, we will not explicitly check
on the mgr for the presence of the mirroring module before proceeding
with the tests. The plan is to have this cut down on test flakes.

The previous workaround also had a bug in that the 2nd sleep was in the
wrong location. Perhaps, fixing this alone would resolve the test
flakes, but this is more proper anyway.

Signed-off-by: John Mulligan <jmulligan@redhat.com>

cephfs/admin/mirror_workflow_test.go

@@ -25,6 +25,20 @@ const (
 	mirrorClient = "client.mirror_remote"
 )
 
+func waitForMirroring(t *testing.T, fsa *FSAdmin) {
+	for i := 0; i < 20; i++ {
+		modinfo, err := fsa.listModules()
+		require.NoError(t, err)
+		for _, emod := range modinfo.EnabledModules {
+			if emod == "mirroring" {
+				return
+			}
+		}
+		time.Sleep(100 * time.Millisecond)
+	}
+	t.Fatalf("timed out waiting for mirroring module")
+}
+
 func TestMirroring(t *testing.T) {
 	if mirrorConfig() == "" {
 		t.Skip("no mirror config available")
@@ -41,7 +55,7 @@ func TestMirroring(t *testing.T) {
 		assert.NoError(t, err)
 	}()
 	require.NoError(t, err)
-	time.Sleep(500 * time.Millisecond) // TODO: improve this
+	waitForMirroring(t, fsa1)
 
 	smadmin1 := fsa1.SnapshotMirror()
 	err = smadmin1.Enable(fsname)
@@ -50,7 +64,6 @@ func TestMirroring(t *testing.T) {
 		err := smadmin1.Disable(fsname)
 		require.NoError(t, err)
 	}()
-	time.Sleep(500 * time.Millisecond) // TODO: improve this
 
 	fsa2 := newFSAdmin(t, mirrorConfig())
 	err = fsa2.EnableMirroringModule(noForce)
@@ -59,6 +72,7 @@ func TestMirroring(t *testing.T) {
 		err := fsa2.DisableMirroringModule()
 		assert.NoError(t, err)
 	}()
+	waitForMirroring(t, fsa2)
 
 	smadmin2 := fsa2.SnapshotMirror()
 	err = smadmin2.Enable(fsname)