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

…nfluxdata#2580 (influxdata#2581)

CHANGELOG.md

@@ -4,6 +4,7 @@
 ### Features
 
 - [#2773](https://github.com/influxdata/telegraf/pull/2773): Add support for self-signed certs to InfluxDB input plugin
+- [#2581](https://github.com/influxdata/telegraf/pull/2581): Add Docker container environment variables as tags. Only whitelisted
 
 ### Bugfixes
 

plugins/inputs/docker/README.md

@@ -36,6 +36,8 @@ for the stat structure can be found
   docker_label_include = []
   docker_label_exclude = []
   
+  ## Which environment variables should we use as a tag
+  tag_env = ["JAVA_HOME", "HEAP_SIZE"]
 ```
 
 ### Measurements & Fields:

plugins/inputs/docker/docker.go

@@ -31,6 +31,7 @@ type Docker struct {
 	Timeout        internal.Duration
 	PerDevice      bool     `toml:"perdevice"`
 	Total          bool     `toml:"total"`
+	TagEnvironment []string `toml:"tag_env"`
 	LabelInclude   []string `toml:"docker_label_include"`
 	LabelExclude   []string `toml:"docker_label_exclude"`
 
@@ -79,6 +80,18 @@ 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
@@ -107,6 +120,8 @@ 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
+  ##tag_env = ["JAVA_HOME", "HEAP_SIZE"]
 
   ## docker labels to include and exclude as tags.  Globs accepted.
   ## Note that an empty array for both will include all labels as tags
@@ -321,6 +336,23 @@ func (d *Docker) gatherContainer(
 		}
 	}
 
+	// Add whitelisted environment variables to tags
+	if len(d.TagEnvironment) > 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 _, configvar := range d.TagEnvironment {
+				dock_env := strings.SplitN(envvar, "=", 2)
+				//check for presence of tag in whitelist
+				if len(dock_env) == 2 && len(strings.TrimSpace(dock_env[1])) != 0 && configvar == dock_env[0] {
+					tags[dock_env[0]] = dock_env[1]
+				}
+			}
+		}
+	}
+
 	gatherContainerStats(v, acc, tags, container.ID, d.PerDevice, d.Total)
 
 	return nil

plugins/inputs/docker/docker_test.go

@@ -300,6 +300,8 @@ func TestDockerGatherInfo(t *testing.T) {
 	d := Docker{
 		client:  nil,
 		testing: true,
+		TagEnvironment: []string{"ENVVAR1", "ENVVAR2", "ENVVAR3", "ENVVAR5",
+			"ENVVAR6", "ENVVAR7", "ENVVAR8", "ENVVAR9"},
 	}
 
 	err := acc.GatherError(d.Gather)
@@ -345,6 +347,10 @@ func TestDockerGatherInfo(t *testing.T) {
 			"cpu":               "cpu3",
 			"container_version": "v2.2.2",
 			"engine_host":       "absol",
+			"ENVVAR1":           "loremipsum",
+			"ENVVAR2":           "dolorsitamet",
+			"ENVVAR3":           "=ubuntu:10.04",
+			"ENVVAR7":           "ENVVAR8=ENVVAR9",
 			"label1":            "test_value_1",
 			"label2":            "test_value_2",
 		},
@@ -393,6 +399,10 @@ func TestDockerGatherInfo(t *testing.T) {
 			"container_name":    "etcd2",
 			"container_image":   "quay.io:4443/coreos/etcd",
 			"container_version": "v2.2.2",
+			"ENVVAR1":           "loremipsum",
+			"ENVVAR2":           "dolorsitamet",
+			"ENVVAR3":           "=ubuntu:10.04",
+			"ENVVAR7":           "ENVVAR8=ENVVAR9",
 			"label1":            "test_value_1",
 			"label2":            "test_value_2",
 		},

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"
 )
 
@@ -149,3 +150,23 @@ 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",
+				"ENVVAR1FOO=loremipsum",
+				"ENVVAR2=dolorsitamet",
+				"ENVVAR3==ubuntu:10.04",
+				"ENVVAR4",
+				"ENVVAR5=",
+				"ENVVAR6= ",
+				"ENVVAR7=ENVVAR8=ENVVAR9",
+				"PATH=/bin:/sbin",
+			},
+		},
+	}
+
+	return json, nil
+}