Use docker log timestamp as metric time (#7434)

plugins/inputs/docker_log/docker_log_test.go

@@ -53,6 +53,14 @@ func (r *Response) Close() error {
 	return nil
 }
 
+func MustParse(layout, value string) time.Time {
+	tm, err := time.Parse(layout, value)
+	if err != nil {
+		panic(err)
+	}
+	return tm
+}
+
 func Test(t *testing.T) {
 	tests := []struct {
 		name     string
@@ -87,7 +95,7 @@ func Test(t *testing.T) {
 					}, nil
 				},
 				ContainerLogsF: func(ctx context.Context, containerID string, options types.ContainerLogsOptions) (io.ReadCloser, error) {
-					return &Response{Reader: bytes.NewBuffer([]byte("hello\n"))}, nil
+					return &Response{Reader: bytes.NewBuffer([]byte("2020-04-28T18:43:16.432691200Z hello\n"))}, nil
 				},
 			},
 			expected: []telegraf.Metric{
@@ -104,7 +112,7 @@ func Test(t *testing.T) {
 						"container_id": "deadbeef",
 						"message":      "hello",
 					},
-					time.Now(),
+					MustParse(time.RFC3339Nano, "2020-04-28T18:43:16.432691200Z"),
 				),
 			},
 		},
@@ -130,7 +138,7 @@ func Test(t *testing.T) {
 				ContainerLogsF: func(ctx context.Context, containerID string, options types.ContainerLogsOptions) (io.ReadCloser, error) {
 					var buf bytes.Buffer
 					w := stdcopy.NewStdWriter(&buf, stdcopy.Stdout)
-					w.Write([]byte("hello from stdout"))
+					w.Write([]byte("2020-04-28T18:42:16.432691200Z hello from stdout"))
 					return &Response{Reader: &buf}, nil
 				},
 			},
@@ -148,7 +156,7 @@ func Test(t *testing.T) {
 						"container_id": "deadbeef",
 						"message":      "hello from stdout",
 					},
-					time.Now(),
+					MustParse(time.RFC3339Nano, "2020-04-28T18:42:16.432691200Z"),
 				),
 			},
 		},
@@ -172,7 +180,9 @@ func Test(t *testing.T) {
 			acc.Wait(len(tt.expected))
 			plugin.Stop()
 
-			testutil.RequireMetricsEqual(t, tt.expected, acc.GetTelegrafMetrics(), testutil.IgnoreTime())
+			require.Nil(t, acc.Errors) // no errors during gathering
+
+			testutil.RequireMetricsEqual(t, tt.expected, acc.GetTelegrafMetrics())
 		})
 	}
 }