Add Docker container environment variables as tags. Only whitelisted i…

…nfluxdata#2580

plugins/inputs/docker/docker.go

@@ -27,6 +27,7 @@ type Docker struct {
 	Timeout        internal.Duration
 	PerDevice      bool `toml:"perdevice"`
 	Total          bool `toml:"total"`
+	GatherEnvironment []string `toml:"gather_environment"`
 
 	client      *client.Client
 	engine_host string
@@ -70,6 +71,20 @@ func statsWrapper(
 	return fc.ContainerStats(ctx, containerID, stream)
 }
 
+func inspectWrapper(
+        c *client.Client,
+        ctx context.Context,
+        containerID string,
+) (types.ContainerJSON, error) {
+        if c != nil {
+                return c.ContainerInspect(ctx, containerID)
+        }
+        fc := FakeDockerClient{}
+        return fc.ContainerInspect(ctx, containerID)
+}
+
+
+
 // KB, MB, GB, TB, PB...human friendly
 const (
 	KB = 1000
@@ -98,6 +113,8 @@ var sampleConfig = `
   perdevice = true
   ## Whether to report for each container total blkio and network stats or not
   total = false
+  ## Which environment variables should we use as a tag
+  gather_environment = ["ENV", "DC"]
 
 `
 
@@ -295,7 +312,23 @@ func (d *Docker) gatherContainer(
 	for k, label := range container.Labels {
 		tags[k] = label
 	}
+
+        // Add whitelisted environment variables to tags
+	if len(d.GatherEnvironment) > 0 {
+		info, err := inspectWrapper(d.client, ctx, container.ID)
+		if err != nil {
+			return fmt.Errorf("Error getting docker container inspect: %s", err.Error())
+		}
 
+		for _, envvar := range info.Config.Env {
+			kvs := strings.SplitN(envvar, "=", 2)
+			if !sliceContains(kvs[0], d.GatherEnvironment) {
+				continue
+			}
+			tags[kvs[0]] = kvs[1]
+		}
+	}
+
 	gatherContainerStats(v, acc, tags, container.ID, d.PerDevice, d.Total)
 
 	return nil

plugins/inputs/docker/docker_test.go

@@ -249,6 +249,7 @@ func TestDockerGatherInfo(t *testing.T) {
 	d := Docker{
 		client:  nil,
 		testing: true,
+		GatherEnvironment: []string{"ENVVAR1", "ENVVAR2"},
 	}
 
 	err := d.Gather(&acc)
@@ -294,6 +295,8 @@ func TestDockerGatherInfo(t *testing.T) {
 			"cpu":               "cpu3",
 			"container_version": "v2.2.2",
 			"engine_host":       "absol",
+			"ENVVAR1":           "loremipsum",
+			"ENVVAR2":           "dolorsitamet",
 		},
 	)
 	acc.AssertContainsTaggedFields(t,
@@ -340,6 +343,8 @@ func TestDockerGatherInfo(t *testing.T) {
 			"container_name":    "etcd2",
 			"container_image":   "quay.io:4443/coreos/etcd",
 			"container_version": "v2.2.2",
+			"ENVVAR1":           "loremipsum",
+                        "ENVVAR2":           "dolorsitamet",
 		},
 	)
 

plugins/inputs/docker/fake_client.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 
 	"github.com/docker/docker/api/types"
+	"github.com/docker/docker/api/types/container"
 	"github.com/docker/docker/api/types/registry"
 )
 
@@ -141,3 +142,17 @@ func (d FakeDockerClient) ContainerStats(ctx context.Context, containerID string
 	stat.Body = ioutil.NopCloser(strings.NewReader(jsonStat))
 	return stat, nil
 }
+
+func (d FakeDockerClient) ContainerInspect(ctx context.Context, containerID string) (types.ContainerJSON, error) {
+	json := types.ContainerJSON{
+		Config: &container.Config{
+			Env: []string{
+				"ENVVAR1=loremipsum",
+				"ENVVAR2=dolorsitamet",
+				"PATH=/bin:/sbin",
+			},
+		},
+	}
+
+	return json, nil
+}