add custom_tags to metrics

README.md

@@ -59,12 +59,18 @@ credentials:
   client_id: <secret>
   client_secret: <secret>
   tenant_id: <secret>
+custom_labels:
+  - name: cost_center
+    value: 12345s
 
 targets:
   - resource: "azure_resource_id"
     metrics:
     - name: "BytesReceived"
     - name: "BytesSent"
+    custom_labels:
+    - name: experimental
+      value: true
   - resource: "azure_resource_id"
     aggregations:
     - Minimum
@@ -106,6 +112,8 @@ When the metric namespace is specified, it will be added as a prefix of the metr
 It can be used to target [custom metrics](https://docs.microsoft.com/en-us/azure/azure-monitor/platform/metrics-custom-overview), such as [guest OS performance counters](https://docs.microsoft.com/en-us/azure/azure-monitor/platform/collect-custom-metrics-guestos-vm-classic).
 If not specified, the default metric namespace of the resource will apply.
 
+`custom_tags` specify labels that will be present in all metrics
+
 ### Resource group filtering
 
 Resources in a resource group can be filtered using the the following keys:

config/config.go

@@ -15,6 +15,7 @@ type Config struct {
 	ActiveDirectoryAuthorityURL string          `yaml:"active_directory_authority_url"`
 	ResourceManagerURL          string          `yaml:"resource_manager_url"`
 	Credentials                 Credentials     `yaml:"credentials"`
+	CustomLabels                []Label         `yaml:"custom_labels"`
 	Targets                     []Target        `yaml:"targets"`
 	ResourceGroups              []ResourceGroup `yaml:"resource_groups"`
 	ResourceTags                []ResourceTag   `yaml:"resource_tags"`
@@ -148,6 +149,7 @@ type Target struct {
 	Resource        string   `yaml:"resource"`
 	MetricNamespace string   `yaml:"metric_namespace"`
 	Metrics         []Metric `yaml:"metrics"`
+	CustomLabels    []Label  `yaml:"custom_labels"`
 	Aggregations    []string `yaml:"aggregations"`
 
 	XXX map[string]interface{} `yaml:",inline"`
@@ -161,6 +163,7 @@ type ResourceGroup struct {
 	ResourceNameIncludeRe []Regexp `yaml:"resource_name_include_re"`
 	ResourceNameExcludeRe []Regexp `yaml:"resource_name_exclude_re"`
 	Metrics               []Metric `yaml:"metrics"`
+	CustomLabels          []Label  `yaml:"custom_labels"`
 	Aggregations          []string `yaml:"aggregations"`
 
 	XXX map[string]interface{} `yaml:",inline"`
@@ -173,11 +176,20 @@ type ResourceTag struct {
 	MetricNamespace  string   `yaml:"metric_namespace"`
 	ResourceTypes    []string `yaml:"resource_types"`
 	Metrics          []Metric `yaml:"metrics"`
+	CustomLabels     []Label  `yaml:"custom_labels"`
 	Aggregations     []string `yaml:"aggregations"`
 
 	XXX map[string]interface{} `yaml:",inline"`
 }
 
+// Label is a tuple that defines a preometheus label
+type Label struct {
+	Name  string `yaml:"name"`
+	Value string `yaml:"value"`
+
+	XXX map[string]interface{} `yaml:",inline"`
+}
+
 // Metric defines metric name
 type Metric struct {
 	Name string `yaml:"name"`

main.go

@@ -50,6 +50,7 @@ type resourceMeta struct {
 	metricNamespace string
 	metrics         string
 	aggregations    []string
+	labels          []config.Label
 	resource        AzureResource
 }
 
@@ -80,7 +81,7 @@ func (c *Collector) extractMetrics(ch chan<- prometheus.Metric, rm resourceMeta,
 
 		if len(value.Timeseries) > 0 {
 			metricValue := value.Timeseries[0].Data[len(value.Timeseries[0].Data)-1]
-			labels := CreateResourceLabels(rm.resourceURL)
+			labels := CreateResourceLabels(rm)
 
 			if hasAggregation(rm.aggregations, "Total") {
 				ch <- prometheus.MustNewConstMetric(
@@ -235,6 +236,7 @@ func (c *Collector) Collect(ch chan<- prometheus.Metric) {
 		rm.metrics = strings.Join(metrics, ",")
 		rm.aggregations = filterAggregations(target.Aggregations)
 		rm.resourceURL = resourceURLFrom(target.Resource, rm.metricNamespace, rm.metrics, rm.aggregations)
+		rm.labels = append(sc.C.CustomLabels, target.CustomLabels...)
 		incompleteResources = append(incompleteResources, rm)
 	}
 

utils.go

@@ -42,15 +42,21 @@ func GetTimes() (string, string) {
 }
 
 // CreateResourceLabels - Returns resource labels for a given resource URL.
-func CreateResourceLabels(resourceURL string) map[string]string {
+func CreateResourceLabels(rm resourceMeta) map[string]string {
 	labels := make(map[string]string)
-	resource := strings.Split(resourceURL, "/")
+	resource := strings.Split(rm.resourceURL, "/")
 
 	labels["resource_group"] = resource[resourceGroupPosition]
 	labels["resource_name"] = resource[resourceNamePosition]
 	if len(resource) > 13 {
 		labels["sub_resource_name"] = resource[subResourceNamePosition]
 	}
+
+	for _, label := range rm.labels {
+		labelName := "custom_tag_" + cleanLabel(label.Name)
+		labels[labelName] = label.Value
+	}
+
 	return labels
 }
 
@@ -73,9 +79,7 @@ func CreateAllResourceLabelsFrom(rm resourceMeta) map[string]string {
 	labels := make(map[string]string)
 
 	for k, v := range rm.resource.Tags {
-		k = strings.ToLower(k)
-		k = "tag_" + k
-		k = invalidLabelChars.ReplaceAllString(k, "_")
+		k = "tag_" + cleanLabel(k)
 		labels[k] = v
 	}
 
@@ -93,13 +97,20 @@ func CreateAllResourceLabelsFrom(rm resourceMeta) map[string]string {
 	// Their tag values are used as label keys.
 	// To keep coherence with the metric labels, we create "resource_group",  "resource_name"
 	// and "sub_resource_name" by invoking CreateResourceLabels.
-	resourceLabels := CreateResourceLabels(rm.resourceURL)
+	resourceLabels := CreateResourceLabels(rm)
 	for k, v := range resourceLabels {
 		labels[k] = v
 	}
 	return labels
 }
 
+func cleanLabel(label string) string {
+	label = strings.ToLower(label)
+	label = invalidLabelChars.ReplaceAllString(label, "_")
+	label = strings.Trim(label, "_")
+	return label
+}
+
 func hasAggregation(aggregations []string, aggregation string) bool {
 	if len(aggregations) == 0 {
 		return true

utils_test.go

@@ -7,21 +7,25 @@ import (
 
 func TestCreateResourceLabels(t *testing.T) {
 	var cases = []struct {
-		url  string
+		rm   resourceMeta
 		want map[string]string
 	}{
 		{
-			"/subscriptions/abc123d4-e5f6-g7h8-i9j10-a1b2c3d4e5f6/resourceGroups/prod-rg-001/providers/Microsoft.Compute/virtualMachines/prod-vm-01/providers/microsoft.insights/metrics",
+			resourceMeta{
+				resourceURL: "/subscriptions/abc123d4-e5f6-g7h8-i9j10-a1b2c3d4e5f6/resourceGroups/prod-rg-001/providers/Microsoft.Compute/virtualMachines/prod-vm-01/providers/microsoft.insights/metrics",
+			},
 			map[string]string{"resource_group": "prod-rg-001", "resource_name": "prod-vm-01"},
 		},
 		{
-			"/subscriptions/abc123d4-e5f6-g7h8-i9j10-a1b2c3d4e5f6/resourceGroups/prod-rg-002/providers/Microsoft.Sql/servers/sqlprod/databases/prod-db-01/providers/microsoft.insights/metrics",
+			resourceMeta{
+				resourceURL: "/subscriptions/abc123d4-e5f6-g7h8-i9j10-a1b2c3d4e5f6/resourceGroups/prod-rg-002/providers/Microsoft.Sql/servers/sqlprod/databases/prod-db-01/providers/microsoft.insights/metrics",
+			},
 			map[string]string{"resource_group": "prod-rg-002", "resource_name": "sqlprod", "sub_resource_name": "prod-db-01"},
 		},
 	}
 
 	for _, c := range cases {
-		got := CreateResourceLabels(c.url)
+		got := CreateResourceLabels(c.rm)
 
 		if !reflect.DeepEqual(got, c.want) {
 			t.Errorf("doesn't create expected resource labels\ngot: %v\nwant: %v", got, c.want)