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

…2580

plugins/inputs/docker/README.md

@@ -30,6 +30,8 @@ for the stat structure can be found
   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 = ["JAVA_HOME", "HEAP_SIZE"]
 ```
 
 ### Measurements & Fields:

plugins/inputs/docker/docker.go

@@ -22,11 +22,12 @@ import (
 
 // Docker object
 type Docker struct {
-	Endpoint       string
-	ContainerNames []string
-	Timeout        internal.Duration
-	PerDevice      bool `toml:"perdevice"`
-	Total          bool `toml:"total"`
+	Endpoint          string
+	ContainerNames    []string
+	Timeout           internal.Duration
+	PerDevice         bool     `toml:"perdevice"`
+	Total             bool     `toml:"total"`
+	GatherEnvironment []string `toml:"gather_environment"`
 
 	client      *client.Client
 	engine_host string
@@ -70,6 +71,18 @@ 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 +111,8 @@ 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 = ["JAVA_HOME", "HEAP_SIZE"]
 
 `
 
@@ -296,6 +311,27 @@ func (d *Docker) gatherContainer(
 		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 inspecting docker container: %s", err.Error())
+		}
+		for _, envvar := range info.Config.Env {
+			for _, prefix := range d.GatherEnvironment {
+				if strings.Count(envvar, "=") > 1 {
+					continue
+				}
+				if strings.HasPrefix(envvar, prefix) {
+					kvs := strings.SplitN(envvar, "=", 2)
+					if len(kvs) == 2 && len(kvs[1]) > 0 {
+						tags[kvs[0]] = kvs[1]
+					}
+				}
+			}
+		}
+	}
+
 	gatherContainerStats(v, acc, tags, container.ID, d.PerDevice, d.Total)
 
 	return nil

plugins/inputs/docker/docker_test.go

@@ -247,8 +247,9 @@ func testStats() *types.StatsJSON {
 func TestDockerGatherInfo(t *testing.T) {
 	var acc testutil.Accumulator
 	d := Docker{
-		client:  nil,
-		testing: true,
+		client:            nil,
+		testing:           true,
+		GatherEnvironment: []string{"ENVVAR1", "ENVVAR2", "ENVVAR3", "ENVVAR4", "ENVVAR5", "ENVVAR6"},
 	}
 
 	err := d.Gather(&acc)
@@ -294,6 +295,9 @@ func TestDockerGatherInfo(t *testing.T) {
 			"cpu":               "cpu3",
 			"container_version": "v2.2.2",
 			"engine_host":       "absol",
+			"ENVVAR1":           "loremipsum",
+			"ENVVAR2":           "dolorsitamet",
+			"ENVVAR6":           " ",
 		},
 	)
 	acc.AssertContainsTaggedFields(t,
@@ -340,6 +344,9 @@ func TestDockerGatherInfo(t *testing.T) {
 			"container_name":    "etcd2",
 			"container_image":   "quay.io:4443/coreos/etcd",
 			"container_version": "v2.2.2",
+			"ENVVAR1":           "loremipsum",
+			"ENVVAR2":           "dolorsitamet",
+			"ENVVAR6":           " ",
 		},
 	)
 

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 +142,21 @@ 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",
+				"ENVVAR3==ubuntu:10.04",
+				"ENVVAR4",
+				"ENVVAR5=",
+				"ENVVAR6= ",
+				"PATH=/bin:/sbin",
+			},
+		},
+	}
+
+	return json, nil
+}