vmagent:support follow_redirects on SD level (#4286)

* vmagent:support follow_redirects on SD level

* fix follow_redirects on sd level

https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4282
(cherry picked from commit b3d0ff463a)

lib/promauth/config.go

@@ -123,6 +123,9 @@ type HTTPClientConfig struct {
 
 	// Headers contains optional HTTP headers, which must be sent in the request to the server
 	Headers []string `yaml:"headers,omitempty"`
+
+	// FollowRedirects specifies whether the client should follow HTTP 3xx redirects.
+	FollowRedirects *bool `yaml:"follow_redirects,omitempty"`
 }
 
 // ProxyClientConfig represents proxy client config.

lib/promscrape/config.go

@@ -245,7 +245,6 @@ type ScrapeConfig struct {
 	MetricsPath          string                      `yaml:"metrics_path,omitempty"`
 	HonorLabels          bool                        `yaml:"honor_labels,omitempty"`
 	HonorTimestamps      *bool                       `yaml:"honor_timestamps,omitempty"`
-	FollowRedirects      *bool                       `yaml:"follow_redirects,omitempty"`
 	Scheme               string                      `yaml:"scheme,omitempty"`
 	Params               map[string][]string         `yaml:"params,omitempty"`
 	HTTPClientConfig     promauth.HTTPClientConfig   `yaml:",inline"`
@@ -990,8 +989,8 @@ func getScrapeWorkConfig(sc *ScrapeConfig, baseDir string, globalCfg *GlobalConf
 		honorTimestamps = *sc.HonorTimestamps
 	}
 	denyRedirects := false
-	if sc.FollowRedirects != nil {
+	if sc.HTTPClientConfig.FollowRedirects != nil {
-		denyRedirects = !*sc.FollowRedirects
+		denyRedirects = !*sc.HTTPClientConfig.FollowRedirects
 	}
 	metricsPath := sc.MetricsPath
 	if metricsPath == "" {

lib/promscrape/discovery/azure/api.go

@@ -110,7 +110,7 @@ func newAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
 	if err != nil {
 		return nil, err
 	}
-	c, err := discoveryutils.NewClient(env.ResourceManagerEndpoint, ac, sdc.ProxyURL, proxyAC)
+	c, err := discoveryutils.NewClient(env.ResourceManagerEndpoint, ac, sdc.ProxyURL, proxyAC, sdc.HTTPClientConfig.FollowRedirects)
 	if err != nil {
 		return nil, fmt.Errorf("cannot create client for %q: %w", env.ResourceManagerEndpoint, err)
 	}
@@ -230,7 +230,7 @@ func getRefreshTokenFunc(sdc *SDConfig, ac, proxyAC *promauth.Config, env *cloud
 		return nil, fmt.Errorf("unsupported `authentication_method: %q` only `OAuth` and `ManagedIdentity` are supported", authenticationMethod)
 	}
 
-	authClient, err := discoveryutils.NewClient(tokenEndpoint, ac, sdc.ProxyURL, proxyAC)
+	authClient, err := discoveryutils.NewClient(tokenEndpoint, ac, sdc.ProxyURL, proxyAC, sdc.HTTPClientConfig.FollowRedirects)
 	if err != nil {
 		return nil, fmt.Errorf("cannot build auth client: %w", err)
 	}

lib/promscrape/discovery/azure/machine_test.go

@@ -66,7 +66,7 @@ func TestGetVirtualMachinesSuccess(t *testing.T) {
 				}
 			}))
 			defer testServer.Close()
-			c, err := discoveryutils.NewClient(testServer.URL, nil, nil, nil)
+			c, err := discoveryutils.NewClient(testServer.URL, nil, nil, nil, nil)
 			if err != nil {
 				t.Fatalf("unexpected error at client create: %s", err)
 			}

lib/promscrape/discovery/consul/api.go

@@ -80,7 +80,7 @@ func newAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
 	if err != nil {
 		return nil, fmt.Errorf("cannot parse proxy auth config: %w", err)
 	}
-	client, err := discoveryutils.NewClient(apiServer, ac, sdc.ProxyURL, proxyAC)
+	client, err := discoveryutils.NewClient(apiServer, ac, sdc.ProxyURL, proxyAC, sdc.HTTPClientConfig.FollowRedirects)
 	if err != nil {
 		return nil, fmt.Errorf("cannot create HTTP client for %q: %w", apiServer, err)
 	}

lib/promscrape/discovery/consulagent/api.go

@@ -74,7 +74,7 @@ func newAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
 	if err != nil {
 		return nil, fmt.Errorf("cannot parse proxy auth config: %w", err)
 	}
-	client, err := discoveryutils.NewClient(apiServer, ac, sdc.ProxyURL, proxyAC)
+	client, err := discoveryutils.NewClient(apiServer, ac, sdc.ProxyURL, proxyAC, sdc.HTTPClientConfig.FollowRedirects)
 	if err != nil {
 		return nil, fmt.Errorf("cannot create HTTP client for %q: %w", apiServer, err)
 	}

lib/promscrape/discovery/digitalocean/api.go

@@ -36,7 +36,7 @@ func newAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
 	if err != nil {
 		return nil, fmt.Errorf("cannot parse proxy auth config: %w", err)
 	}
-	client, err := discoveryutils.NewClient(apiServer, ac, sdc.ProxyURL, proxyAC)
+	client, err := discoveryutils.NewClient(apiServer, ac, sdc.ProxyURL, proxyAC, sdc.HTTPClientConfig.FollowRedirects)
 	if err != nil {
 		return nil, fmt.Errorf("cannot create HTTP client for %q: %w", apiServer, err)
 	}
@@ -56,7 +56,6 @@ func getAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
 		return nil, err
 	}
 	return v.(*apiConfig), nil
-
 }
 
 const dropletsAPIPath = "/v2/droplets"

lib/promscrape/discovery/docker/api.go

@@ -50,7 +50,7 @@ func newAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
 	if err != nil {
 		return nil, fmt.Errorf("cannot parse proxy auth config: %w", err)
 	}
-	client, err := discoveryutils.NewClient(sdc.Host, ac, sdc.ProxyURL, proxyAC)
+	client, err := discoveryutils.NewClient(sdc.Host, ac, sdc.ProxyURL, proxyAC, sdc.HTTPClientConfig.FollowRedirects)
 	if err != nil {
 		return nil, fmt.Errorf("cannot create HTTP client for %q: %w", sdc.Host, err)
 	}

lib/promscrape/discovery/dockerswarm/api.go

@@ -49,7 +49,7 @@ func newAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
 	if err != nil {
 		return nil, fmt.Errorf("cannot parse proxy auth config: %w", err)
 	}
-	client, err := discoveryutils.NewClient(sdc.Host, ac, sdc.ProxyURL, proxyAC)
+	client, err := discoveryutils.NewClient(sdc.Host, ac, sdc.ProxyURL, proxyAC, sdc.HTTPClientConfig.FollowRedirects)
 	if err != nil {
 		return nil, fmt.Errorf("cannot create HTTP client for %q: %w", sdc.Host, err)
 	}

lib/promscrape/discovery/eureka/api.go

@@ -34,7 +34,7 @@ func newAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
 	if err != nil {
 		return nil, fmt.Errorf("cannot parse proxy auth config: %w", err)
 	}
-	client, err := discoveryutils.NewClient(apiServer, ac, sdc.ProxyURL, proxyAC)
+	client, err := discoveryutils.NewClient(apiServer, ac, sdc.ProxyURL, proxyAC, sdc.HTTPClientConfig.FollowRedirects)
 	if err != nil {
 		return nil, fmt.Errorf("cannot create HTTP client for %q: %w", apiServer, err)
 	}
@@ -50,7 +50,6 @@ func getAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
 		return nil, err
 	}
 	return v.(*apiConfig), nil
-
 }
 
 func getAPIResponse(cfg *apiConfig, path string) ([]byte, error) {

lib/promscrape/discovery/http/api.go

@@ -44,7 +44,7 @@ func newAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
 	if err != nil {
 		return nil, fmt.Errorf("cannot parse proxy auth config: %w", err)
 	}
-	client, err := discoveryutils.NewClient(apiServer, ac, sdc.ProxyURL, proxyAC)
+	client, err := discoveryutils.NewClient(apiServer, ac, sdc.ProxyURL, proxyAC, sdc.HTTPClientConfig.FollowRedirects)
 	if err != nil {
 		return nil, fmt.Errorf("cannot create HTTP client for %q: %w", apiServer, err)
 	}

lib/promscrape/discovery/kuma/api.go

@@ -60,7 +60,7 @@ func newAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
 	if err != nil {
 		return nil, fmt.Errorf("cannot parse proxy auth config: %w", err)
 	}
-	client, err := discoveryutils.NewClient(apiServer, ac, sdc.ProxyURL, proxyAC)
+	client, err := discoveryutils.NewClient(apiServer, ac, sdc.ProxyURL, proxyAC, sdc.HTTPClientConfig.FollowRedirects)
 	if err != nil {
 		return nil, fmt.Errorf("cannot create HTTP client for %q: %w", apiServer, err)
 	}

lib/promscrape/discovery/nomad/api.go

@@ -68,7 +68,7 @@ func newAPIConfig(sdc *SDConfig, baseDir string) (*apiConfig, error) {
 	if err != nil {
 		return nil, fmt.Errorf("cannot parse proxy auth config: %w", err)
 	}
-	client, err := discoveryutils.NewClient(apiServer, ac, sdc.ProxyURL, proxyAC)
+	client, err := discoveryutils.NewClient(apiServer, ac, sdc.ProxyURL, proxyAC, sdc.HTTPClientConfig.FollowRedirects)
 	if err != nil {
 		return nil, fmt.Errorf("cannot create HTTP client for %q: %w", apiServer, err)
 	}

lib/promscrape/discoveryutils/client.go

@@ -83,7 +83,7 @@ type HTTPClient struct {
 var defaultDialer = &net.Dialer{}
 
 // NewClient returns new Client for the given args.
-func NewClient(apiServer string, ac *promauth.Config, proxyURL *proxy.URL, proxyAC *promauth.Config) (*Client, error) {
+func NewClient(apiServer string, ac *promauth.Config, proxyURL *proxy.URL, proxyAC *promauth.Config, followRedirects *bool) (*Client, error) {
 	u, err := url.Parse(apiServer)
 	if err != nil {
 		return nil, fmt.Errorf("cannot parse apiServer=%q: %w", apiServer, err)
@@ -139,6 +139,14 @@ func NewClient(apiServer string, ac *promauth.Config, proxyURL *proxy.URL, proxy
 			ac.SetHeaders(req, true)
 		}
 	}
+	if followRedirects != nil && !*followRedirects {
+		client.CheckRedirect = func(req *http.Request, via []*http.Request) error {
+			return http.ErrUseLastResponse
+		}
+		blockingClient.CheckRedirect = func(req *http.Request, via []*http.Request) error {
+			return http.ErrUseLastResponse
+		}
+	}
 	setHTTPProxyHeaders := func(req *http.Request) {}
 	if proxyAC != nil {
 		setHTTPProxyHeaders = func(req *http.Request) {
@@ -186,7 +194,8 @@ func (c *Client) GetAPIResponse(path string) ([]byte, error) {
 }
 
 func (c *Client) getAPIResponseWithConcurrencyLimit(ctx context.Context, client *HTTPClient, path string,
-	modifyRequest RequestCallback, inspectResponse ResponseCallback) ([]byte, error) {
+	modifyRequest RequestCallback, inspectResponse ResponseCallback,
+) ([]byte, error) {
 	// Limit the number of concurrent API requests.
 	concurrencyLimitChOnce.Do(concurrencyLimitChInit)
 	t := timerpool.Get(*maxWaitTime)

lib/promscrape/testdata/prometheus.yml

@@ -1,5 +1,29 @@
 scrape_configs:
-- job_name: foo
+  - job_name: foo
+    scrape_interval: 54s
+    scrape_timeout: 12s
+    metrics_path: /foo/bar
+    scheme: https
+    honor_labels: true
+    honor_timestamps: false
+    follow_redirects: false
+    static_configs:
+      - targets: ["foo.bar", "aaa"]
+        labels:
+          x: y
+          __scrape_timeout__: "5s"
+  - job_name: file-job
     file_sd_configs:
       - files: ["file_sd_*.yml"]
       - files: ["file_sd.json"]
+  - job_name: service-kubernetes
+    kubernetes_sd_configs:
+      - role: endpoints
+        api_server: "https://localhost:1234"
+        follow_redirects: true
+        tls_config:
+          cert_file: valid_cert_file
+          key_file: valid_key_file
+        basic_auth:
+          username: "myusername"
+          password: "mysecret"