lib/promscrape/discovery/kubernetes: hide role switch logic behind GetLabels function

lib/promscrape/config.go

@@ -311,46 +311,12 @@ func (sdc *KubernetesSDConfig) appendScrapeWork(dst []ScrapeWork, baseDir string
 		Namespaces: sdc.Namespaces.Names,
 		Selectors:  sdc.Selectors,
 	}
-	switch sdc.Role {
+	targetLabels, err := kubernetes.GetLabels(cfg, sdc.Role)
-	case "node":
+	if err != nil {
-		targetLabels, err := kubernetes.GetNodesLabels(cfg)
+		logger.Errorf("error when discovering kubernetes nodes for `job_name` %q: %s; skipping it", swc.jobName, err)
-		if err != nil {
-			logger.Errorf("error when discovering kubernetes nodes for `job_name` %q: %s; skipping it", swc.jobName, err)
-			return dst
-		}
-		return appendKubernetesScrapeWork(dst, swc, targetLabels, sdc.Role)
-	case "service":
-		targetLabels, err := kubernetes.GetServicesLabels(cfg)
-		if err != nil {
-			logger.Errorf("error when discovering kubernetes services for `job_name` %q: %s; skipping it", swc.jobName, err)
-			return dst
-		}
-		return appendKubernetesScrapeWork(dst, swc, targetLabels, sdc.Role)
-	case "pod":
-		targetLabels, err := kubernetes.GetPodsLabels(cfg)
-		if err != nil {
-			logger.Errorf("error when discovering kubernetes pods for `job_name` %q: %s; skipping it", swc.jobName, err)
-			return dst
-		}
-		return appendKubernetesScrapeWork(dst, swc, targetLabels, sdc.Role)
-	case "endpoints":
-		targetLabels, err := kubernetes.GetEndpointsLabels(cfg)
-		if err != nil {
-			logger.Errorf("error when discovering kubernetes endpoints for `job_name` %q: %s; skipping it", swc.jobName, err)
-			return dst
-		}
-		return appendKubernetesScrapeWork(dst, swc, targetLabels, sdc.Role)
-	case "ingress":
-		targetLabels, err := kubernetes.GetIngressesLabels(cfg)
-		if err != nil {
-			logger.Errorf("error when discovering kubernetes ingresses for `job_name` %q: %s; skipping it", swc.jobName, err)
-			return dst
-		}
-		return appendKubernetesScrapeWork(dst, swc, targetLabels, sdc.Role)
-	default:
-		logger.Errorf("unexpected `role`: %q; must be one of `node`, `service`, `pod`, `endpoints` or `ingress`; skipping it", sdc.Role)
 		return dst
 	}
+	return appendKubernetesScrapeWork(dst, swc, targetLabels, sdc.Role)
 }
 
 func appendKubernetesScrapeWork(dst []ScrapeWork, swc *scrapeWorkConfig, targetLabels []map[string]string, role string) []ScrapeWork {

lib/promscrape/discovery/kubernetes/endpoints.go

@@ -5,8 +5,8 @@ import (
 	"fmt"
 )
 
-// GetEndpointsLabels returns labels for k8s endpoints obtained from the given cfg.
+// getEndpointsLabels returns labels for k8s endpoints obtained from the given cfg.
-func GetEndpointsLabels(cfg *APIConfig) ([]map[string]string, error) {
+func getEndpointsLabels(cfg *APIConfig) ([]map[string]string, error) {
 	data, err := getAPIResponse(cfg, "endpoints", "/api/v1/endpoints")
 	if err != nil {
 		return nil, fmt.Errorf("cannot obtain endpoints data from API server: %s", err)

lib/promscrape/discovery/kubernetes/ingress.go

@@ -5,8 +5,8 @@ import (
 	"fmt"
 )
 
-// GetIngressesLabels returns labels for k8s ingresses obtained from the given cfg.
+// getIngressesLabels returns labels for k8s ingresses obtained from the given cfg.
-func GetIngressesLabels(cfg *APIConfig) ([]map[string]string, error) {
+func getIngressesLabels(cfg *APIConfig) ([]map[string]string, error) {
 	data, err := getAPIResponse(cfg, "ingress", "/apis/extensions/v1beta1/ingresses")
 	if err != nil {
 		return nil, fmt.Errorf("cannot obtain ingresses data from API server: %s", err)

lib/promscrape/discovery/kubernetes/kubernetes.go

@@ -0,0 +1,23 @@
+package kubernetes
+
+import (
+	"fmt"
+)
+
+// GetLabels returns labels for the given k8s role and the given cfg.
+func GetLabels(cfg *APIConfig, role string) ([]map[string]string, error) {
+	switch role {
+	case "node":
+		return getNodesLabels(cfg)
+	case "service":
+		return getServicesLabels(cfg)
+	case "pod":
+		return getPodsLabels(cfg)
+	case "endpoints":
+		return getEndpointsLabels(cfg)
+	case "ingress":
+		return getIngressesLabels(cfg)
+	default:
+		return nil, fmt.Errorf("unexpected `role`: %q; must be one of `node`, `service`, `pod`, `endpoints` or `ingress`; skipping it", role)
+	}
+}

lib/promscrape/discovery/kubernetes/node.go

@@ -5,8 +5,8 @@ import (
 	"fmt"
 )
 
-// GetNodesLabels returns labels for k8s nodes obtained from the given cfg.
+// getNodesLabels returns labels for k8s nodes obtained from the given cfg.
-func GetNodesLabels(cfg *APIConfig) ([]map[string]string, error) {
+func getNodesLabels(cfg *APIConfig) ([]map[string]string, error) {
 	data, err := getAPIResponse(cfg, "node", "/api/v1/nodes")
 	if err != nil {
 		return nil, fmt.Errorf("cannot obtain nodes data from API server: %s", err)

lib/promscrape/discovery/kubernetes/pod.go

@@ -7,8 +7,8 @@ import (
 	"strings"
 )
 
-// GetPodsLabels returns labels for k8s pods obtained from the given cfg
+// getPodsLabels returns labels for k8s pods obtained from the given cfg
-func GetPodsLabels(cfg *APIConfig) ([]map[string]string, error) {
+func getPodsLabels(cfg *APIConfig) ([]map[string]string, error) {
 	pods, err := getPods(cfg)
 	if err != nil {
 		return nil, err

lib/promscrape/discovery/kubernetes/service.go

@@ -5,8 +5,8 @@ import (
 	"fmt"
 )
 
-// GetServicesLabels returns labels for k8s services obtained from the given cfg.
+// getServicesLabels returns labels for k8s services obtained from the given cfg.
-func GetServicesLabels(cfg *APIConfig) ([]map[string]string, error) {
+func getServicesLabels(cfg *APIConfig) ([]map[string]string, error) {
 	svcs, err := getServices(cfg)
 	if err != nil {
 		return nil, err