feat: add container info metric

Author: davidborzek

internal/collector/collector.go

@@ -70,6 +70,20 @@ func (c *DockerCollector) collectContainerMetrics(ctx context.Context, container
 	defer wg.Done()
 
 	name := containerName(container)
+	inspect, err := c.client.ContainerInspect(ctx, container.ID)
+	if err != nil {
+		log.WithError(err).WithField("id", container.ID).
+			Error("error inspecting container")
+		return
+	}
+
+	ch <- prometheus.MustNewConstMetric(containerInfo,
+		prometheus.GaugeValue,
+		1,
+		name,
+		inspect.Config.Image,
+		inspect.Image,
+	)
 
 	ch <- prometheus.MustNewConstMetric(
 		containerStateMetric, prometheus.GaugeValue, 1, name, container.State,
@@ -79,13 +93,6 @@ func (c *DockerCollector) collectContainerMetrics(ctx context.Context, container
 		return
 	}
 
-	inspect, err := c.client.ContainerInspect(ctx, container.ID)
-	if err != nil {
-		log.WithError(err).WithField("id", container.ID).
-			Error("error inspecting container")
-		return
-	}
-
 	ch <- prometheus.MustNewConstMetric(containerUptime,
 		prometheus.GaugeValue,
 		c.calculateUptime(inspect),

internal/collector/collector_test.go

@@ -11,6 +11,7 @@ import (
 	"github.com/davidborzek/docker-exporter/internal/collector"
 	"github.com/davidborzek/docker-exporter/internal/mock"
 	"github.com/docker/docker/api/types"
+	"github.com/docker/docker/api/types/container"
 	"github.com/docker/docker/client"
 	"github.com/prometheus/client_golang/prometheus/testutil"
 	"go.uber.org/mock/gomock"
@@ -53,6 +54,9 @@ func TestCollectMetrics(t *testing.T) {
 	# HELP docker_container_cpu_usage_percentage CPU usage in percentage
 	# TYPE docker_container_cpu_usage_percentage gauge
 	docker_container_cpu_usage_percentage{name="testName"} 0
+	# HELP docker_container_info Infos about the container
+	# TYPE docker_container_info gauge
+	docker_container_info{image="sha256:d3751d33f9cd5049c4af2b462735457e4d3baf130bcbb87f389e349fbaeb20b9",image_name="myImage",name="testName"} 1
 	# HELP docker_container_memory_total_bytes Total memory in bytes
 	# TYPE docker_container_memory_total_bytes gauge
 	docker_container_memory_total_bytes{name="testName"} 8e+09
@@ -105,6 +109,10 @@ func buildInspectResponse() types.ContainerJSON {
 			State: &types.ContainerState{
 				StartedAt: "2023-09-17T12:00:00.00Z",
 			},
+			Image: "sha256:d3751d33f9cd5049c4af2b462735457e4d3baf130bcbb87f389e349fbaeb20b9",
+		},
+		Config: &container.Config{
+			Image: "myImage",
 		},
 	}
 

internal/collector/metrics.go

@@ -10,6 +10,13 @@ var (
 		nil,
 	)
 
+	containerInfo = prometheus.NewDesc(
+		"docker_container_info",
+		"Infos about the container",
+		[]string{"name", "image_name", "image"},
+		nil,
+	)
+
 	containerUptime = prometheus.NewDesc(
 		"docker_container_uptime",
 		"Uptime of the container in seconds",