fix: decode Prometheus scrape path from Kuberentes labels (#9662)

plugins/inputs/prometheus/kubernetes.go

@@ -5,7 +5,6 @@ import (
 	"crypto/tls"
 	"encoding/json"
 	"fmt"
-	"log"
 	"net"
 	"net/http"
 	"net/url"
@@ -295,12 +294,15 @@ func registerPod(pod *corev1.Pod, p *Prometheus) {
 	if p.kubernetesPods == nil {
 		p.kubernetesPods = map[string]URLAndAddress{}
 	}
-	targetURL := getScrapeURL(pod)
-	if targetURL == nil {
+	targetURL, err := getScrapeURL(pod)
+	if err != nil {
+		p.Log.Errorf("could not parse URL: %s", err)
+		return
+	} else if targetURL == nil {
 		return
 	}
 
-	log.Printf("D! [inputs.prometheus] will scrape metrics from %q", *targetURL)
+	p.Log.Debugf("will scrape metrics from %q", targetURL.String())
 	// add annotation as metrics tags
 	tags := pod.Annotations
 	if tags == nil {
@@ -312,12 +314,7 @@ func registerPod(pod *corev1.Pod, p *Prometheus) {
 	for k, v := range pod.Labels {
 		tags[k] = v
 	}
-	URL, err := url.Parse(*targetURL)
-	if err != nil {
-		log.Printf("E! [inputs.prometheus] could not parse URL %q: %s", *targetURL, err.Error())
-		return
-	}
-	podURL := p.AddressToURL(URL, URL.Hostname())
+	podURL := p.AddressToURL(targetURL, targetURL.Hostname())
 
 	// Locks earlier if using cAdvisor calls - makes a new list each time
 	// rather than updating and removing from the same list
@@ -327,22 +324,22 @@ func registerPod(pod *corev1.Pod, p *Prometheus) {
 	}
 	p.kubernetesPods[podURL.String()] = URLAndAddress{
 		URL:         podURL,
-		Address:     URL.Hostname(),
-		OriginalURL: URL,
+		Address:     targetURL.Hostname(),
+		OriginalURL: targetURL,
 		Tags:        tags,
 	}
 }
 
-func getScrapeURL(pod *corev1.Pod) *string {
+func getScrapeURL(pod *corev1.Pod) (*url.URL, error) {
 	ip := pod.Status.PodIP
 	if ip == "" {
 		// return as if scrape was disabled, we will be notified again once the pod
 		// has an IP
-		return nil
+		return nil, nil
 	}
 
 	scheme := pod.Annotations["prometheus.io/scheme"]
-	path := pod.Annotations["prometheus.io/path"]
+	pathAndQuery := pod.Annotations["prometheus.io/path"]
 	port := pod.Annotations["prometheus.io/port"]
 
 	if scheme == "" {
@@ -351,34 +348,36 @@ func getScrapeURL(pod *corev1.Pod) *string {
 	if port == "" {
 		port = "9102"
 	}
-	if path == "" {
-		path = "/metrics"
+	if pathAndQuery == "" {
+		pathAndQuery = "/metrics"
 	}
 
-	u := &url.URL{
-		Scheme: scheme,
-		Host:   net.JoinHostPort(ip, port),
-		Path:   path,
+	base, err := url.Parse(pathAndQuery)
+	if err != nil {
+		return nil, err
 	}
 
-	x := u.String()
+	base.Scheme = scheme
+	base.Host = net.JoinHostPort(ip, port)
 
-	return &x
+	return base, nil
 }
 
 func unregisterPod(pod *corev1.Pod, p *Prometheus) {
-	url := getScrapeURL(pod)
-	if url == nil {
+	targetURL, err := getScrapeURL(pod)
+	if err != nil {
+		p.Log.Errorf("failed to parse url: %s", err)
+		return
+	} else if targetURL == nil {
 		return
 	}
 
-	log.Printf("D! [inputs.prometheus] registered a delete request for %q in namespace %q",
-		pod.Name, pod.Namespace)
+	p.Log.Debugf("registered a delete request for %q in namespace %q", pod.Name, pod.Namespace)
 
 	p.lock.Lock()
 	defer p.lock.Unlock()
-	if _, ok := p.kubernetesPods[*url]; ok {
-		delete(p.kubernetesPods, *url)
-		log.Printf("D! [inputs.prometheus] will stop scraping for %q", *url)
+	if _, ok := p.kubernetesPods[targetURL.String()]; ok {
+		delete(p.kubernetesPods, targetURL.String())
+		p.Log.Debugf("will stop scraping for %q", targetURL.String())
 	}
 }

plugins/inputs/prometheus/kubernetes_test.go

@@ -15,7 +15,8 @@ import (
 func TestScrapeURLNoAnnotations(t *testing.T) {
 	p := &corev1.Pod{ObjectMeta: metav1.ObjectMeta{}}
 	p.Annotations = map[string]string{}
-	url := getScrapeURL(p)
+	url, err := getScrapeURL(p)
+	assert.NoError(t, err)
 	assert.Nil(t, url)
 }
 
@@ -23,36 +24,57 @@ func TestScrapeURLAnnotationsNoScrape(t *testing.T) {
 	p := &corev1.Pod{ObjectMeta: metav1.ObjectMeta{}}
 	p.Name = "myPod"
 	p.Annotations = map[string]string{"prometheus.io/scrape": "false"}
-	url := getScrapeURL(p)
+	url, err := getScrapeURL(p)
+	assert.NoError(t, err)
 	assert.Nil(t, url)
 }
 
 func TestScrapeURLAnnotations(t *testing.T) {
 	p := pod()
 	p.Annotations = map[string]string{"prometheus.io/scrape": "true"}
-	url := getScrapeURL(p)
-	assert.Equal(t, "http://127.0.0.1:9102/metrics", *url)
+	url, err := getScrapeURL(p)
+	assert.NoError(t, err)
+	assert.Equal(t, "http://127.0.0.1:9102/metrics", url.String())
 }
 
 func TestScrapeURLAnnotationsCustomPort(t *testing.T) {
 	p := pod()
 	p.Annotations = map[string]string{"prometheus.io/scrape": "true", "prometheus.io/port": "9000"}
-	url := getScrapeURL(p)
-	assert.Equal(t, "http://127.0.0.1:9000/metrics", *url)
+	url, err := getScrapeURL(p)
+	assert.NoError(t, err)
+	assert.Equal(t, "http://127.0.0.1:9000/metrics", url.String())
 }
 
 func TestScrapeURLAnnotationsCustomPath(t *testing.T) {
 	p := pod()
 	p.Annotations = map[string]string{"prometheus.io/scrape": "true", "prometheus.io/path": "mymetrics"}
-	url := getScrapeURL(p)
-	assert.Equal(t, "http://127.0.0.1:9102/mymetrics", *url)
+	url, err := getScrapeURL(p)
+	assert.NoError(t, err)
+	assert.Equal(t, "http://127.0.0.1:9102/mymetrics", url.String())
 }
 
 func TestScrapeURLAnnotationsCustomPathWithSep(t *testing.T) {
 	p := pod()
 	p.Annotations = map[string]string{"prometheus.io/scrape": "true", "prometheus.io/path": "/mymetrics"}
-	url := getScrapeURL(p)
-	assert.Equal(t, "http://127.0.0.1:9102/mymetrics", *url)
+	url, err := getScrapeURL(p)
+	assert.NoError(t, err)
+	assert.Equal(t, "http://127.0.0.1:9102/mymetrics", url.String())
+}
+
+func TestScrapeURLAnnotationsCustomPathWithQueryParameters(t *testing.T) {
+	p := pod()
+	p.Annotations = map[string]string{"prometheus.io/scrape": "true", "prometheus.io/path": "/v1/agent/metrics?format=prometheus"}
+	url, err := getScrapeURL(p)
+	assert.NoError(t, err)
+	assert.Equal(t, "http://127.0.0.1:9102/v1/agent/metrics?format=prometheus", url.String())
+}
+
+func TestScrapeURLAnnotationsCustomPathWithFragment(t *testing.T) {
+	p := pod()
+	p.Annotations = map[string]string{"prometheus.io/scrape": "true", "prometheus.io/path": "/v1/agent/metrics#prometheus"}
+	url, err := getScrapeURL(p)
+	assert.NoError(t, err)
+	assert.Equal(t, "http://127.0.0.1:9102/v1/agent/metrics#prometheus", url.String())
 }
 
 func TestAddPod(t *testing.T) {