add whitelisted env as container metadata

This add Envs to container spec as a metadata source. When using prometheus exposition format, they will be merged into the list of metrics' labels. Also changed the cli flag to docker_env_metadata_whitelist, and add refenrences of whitelist envs to API Signed-off-by: Daniel Dao <dqminh@cloudflare.com>
sixeyed · Jan 13, 2016 · e5b6bfa · e5b6bfa
1 parent 544b852
commit e5b6bfa
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Showing 7 changed files with 79 additions and 68 deletions.
diff --git a/container/docker/factory.go b/container/docker/factory.go
@@ -49,7 +49,7 @@ var dockerCgroupRegexp = regexp.MustCompile(`.+-([a-z0-9]{64})\.scope$`)
 
 var noSystemd = flag.Bool("nosystemd", false, "Explicitly disable systemd support for Docker containers")
 
-var dockerMetadataEnvs = flag.String("docker_metadata_env", "", "Comma seperated list with names of env variables, which will be exported as metadata (default: empty)")
+var dockerEnvWhitelist = flag.String("docker_env_metadata_whitelist", "", "a comma-separated list of environment variable keys that needs to be collected for docker containers")
 
 // TODO(vmarmol): Export run dir too for newer Dockers.
 // Directory holding Docker container state information.
@@ -120,7 +120,7 @@ func (self *dockerFactory) NewContainerHandler(name string, inHostNamespace bool
 		return
 	}
 
-	exposedMetadata := strings.Split(*dockerMetadataEnvs, ",")
+	metadataEnvs := strings.Split(*dockerEnvWhitelist, ",")
 
 	handler, err = newDockerContainerHandler(
 		client,
@@ -130,7 +130,7 @@ func (self *dockerFactory) NewContainerHandler(name string, inHostNamespace bool
 		self.storageDriver,
 		&self.cgroupSubsystems,
 		inHostNamespace,
-		exposedMetadata,
+		metadataEnvs,
 	)
 	return
 }

diff --git a/container/docker/handler.go b/container/docker/handler.go
@@ -66,8 +66,9 @@ type dockerContainerHandler struct {
 	// Time at which this container was created.
 	creationTime time.Time
 
-	// Metadata labels associated with the container.
+	// Metadata associated with the container.
 	labels map[string]string
+	envs   map[string]string
 
 	// The container PID used to switch namespaces as required
 	pid int
@@ -93,7 +94,7 @@ func newDockerContainerHandler(
 	storageDriver storageDriver,
 	cgroupSubsystems *containerlibcontainer.CgroupSubsystems,
 	inHostNamespace bool,
-	exposedMetadata []string,
+	metadataEnvs []string,
 ) (container.ContainerHandler, error) {
 	// Create the cgroup paths.
 	cgroupPaths := make(map[string]string, len(cgroupSubsystems.MountPoints))
@@ -159,13 +160,11 @@ func newDockerContainerHandler(
 	handler.networkMode = ctnr.HostConfig.NetworkMode
 
 	// split env vars to get metadata map.
-	if len(exposedMetadata) > 0 {
+	for _, exposedEnv := range metadataEnvs {
 		for _, envVar := range ctnr.Config.Env {
 			splits := strings.SplitN(envVar, "=", 2)
-			for _, exposedVar := range exposedMetadata {
-				if splits[0] == exposedVar {
-					handler.labels[strings.ToLower(exposedVar)] = splits[1]
-				}
+			if splits[0] == exposedEnv {
+				handler.envs[strings.ToLower(exposedEnv)] = splits[1]
 			}
 		}
 	}
@@ -259,6 +258,7 @@ func (self *dockerContainerHandler) GetSpec() (info.ContainerSpec, error) {
 	}
 
 	spec.Labels = self.labels
+	spec.Envs = self.envs
 	spec.Image = self.image
 	spec.HasNetwork = hasNet(self.networkMode)
 

diff --git a/info/v1/container.go b/info/v1/container.go
@@ -45,6 +45,8 @@ type ContainerSpec struct {
 
 	// Metadata labels associated with this container.
 	Labels map[string]string `json:"labels,omitempty"`
+	// Metadata envs associated with this container. Only whitelisted envs are added.
+	Envs map[string]string `json:"envs,omitempty"`
 
 	HasCpu bool    `json:"has_cpu"`
 	Cpu    CpuSpec `json:"cpu,omitempty"`

diff --git a/info/v2/container.go b/info/v2/container.go
@@ -66,6 +66,8 @@ type ContainerSpec struct {
 
 	// Metadata labels associated with this container.
 	Labels map[string]string `json:"labels,omitempty"`
+	// Metadata envs associated with this container. Only whitelisted envs are added.
+	Envs map[string]string `json:"envs,omitempty"`
 
 	HasCpu bool    `json:"has_cpu"`
 	Cpu    CpuSpec `json:"cpu,omitempty"`

diff --git a/metrics/prometheus.go b/metrics/prometheus.go
@@ -514,9 +514,13 @@ func (c *PrometheusCollector) collectContainersInfo(ch chan<- prometheus.Metric)
 			}
 		}
 
-		for labelKey, labelValue := range container.Spec.Labels {
-			baseLabels = append(baseLabels, sanitizeLabelName(labelKey))
-			baseLabelValues = append(baseLabelValues, labelValue)
+		for k, v := range container.Spec.Labels {
+			baseLabels = append(baseLabels, sanitizeLabelName(k))
+			baseLabelValues = append(baseLabelValues, v)
+		}
+		for k, v := range container.Spec.Envs {
+			baseLabels = append(baseLabels, sanitizeLabelName(k))
+			baseLabelValues = append(baseLabelValues, v)
 		}
 
 		// Container spec

diff --git a/metrics/prometheus_test.go b/metrics/prometheus_test.go
@@ -58,7 +58,10 @@ func (p testSubcontainersInfoProvider) SubcontainersInfo(string, *info.Container
 				Image:        "test",
 				CreationTime: time.Unix(1257894000, 0),
 				Labels: map[string]string{
-					"foo.metric": "bar",
+					"foo.label": "bar",
+				},
+				Envs: map[string]string{
+					"foo+env": "prod",
 				},
 			},
 			Stats: []*info.ContainerStats{