Add container status tag to docker input (#4259)

plugins/inputs/docker/docker.go

@@ -435,6 +435,23 @@ func (d *Docker) gatherContainer(
 			}
 		}
 	}
+	if info.State != nil {
+		tags["container_status"] = info.State.Status
+		statefields := map[string]interface{}{
+			"oomkilled": info.State.OOMKilled,
+			"pid":       info.State.Pid,
+			"exitcode":  info.State.ExitCode,
+		}
+		container_time, err := time.Parse(time.RFC3339, info.State.StartedAt)
+		if err == nil && !container_time.IsZero() {
+			statefields["started_at"] = container_time.UnixNano()
+		}
+		container_time, err = time.Parse(time.RFC3339, info.State.FinishedAt)
+		if err == nil && !container_time.IsZero() {
+			statefields["finished_at"] = container_time.UnixNano()
+		}
+		acc.AddFields("docker_container_status", statefields, tags, time.Now())
+	}
 
 	if info.State.Health != nil {
 		healthfields := map[string]interface{}{

plugins/inputs/docker/docker_test.go

@@ -653,6 +653,7 @@ func TestDockerGatherInfo(t *testing.T) {
 			"label1":            "test_value_1",
 			"label2":            "test_value_2",
 			"server_version":    "17.09.0-ce",
+			"container_status":  "running",
 		},
 	)
 	acc.AssertContainsTaggedFields(t,
@@ -676,6 +677,7 @@ func TestDockerGatherInfo(t *testing.T) {
 			"label1":            "test_value_1",
 			"label2":            "test_value_2",
 			"server_version":    "17.09.0-ce",
+			"container_status":  "running",
 		},
 	)
 }

plugins/inputs/docker/docker_testdata.go

@@ -484,6 +484,12 @@ var containerInspect = types.ContainerJSON{
 				FailingStreak: 1,
 				Status:        "Unhealthy",
 			},
+			Status:     "running",
+			OOMKilled:  false,
+			Pid:        1234,
+			ExitCode:   0,
+			StartedAt:  "2018-06-14T05:48:53.266176036Z",
+			FinishedAt: "0001-01-01T00:00:00Z",
 		},
 	},
 }