lib/proxy: set missing ServerName in TLS config for proxy_url.

While at it, allow setting Proxy-Authorization for `proxy_url` via `basic_auth` and `bearer_token` configs.

docs/CHANGELOG.md

@@ -14,6 +14,7 @@
 * BUGFIX: vmagent: prevent from high CPU usage bug during failing scrapes with small `scrape_timeout` (less than a few seconds).
 * BUGFIX: vmagent: reduce memory usage when Kubernetes service discovery is used in big number of distinct scrape config jobs by sharing Kubernetes object cache. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1113
 * BUGFIX: vmagent: apply `sample_limit` only after `metric_relabel_configs` are applied as Prometheus does. Previously the `sample_limit` was applied before metrics relabeling.
+* BUGFIX: vmagent: properly apply `tls_config`, `basic_auth` and `bearer_token` to proxy connections if `proxy_url` option is set. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1116
 * BUGFUX: avoid `duplicate time series` error if `prometheus_buckets()` covers a time range with distinct set of buckets.
 * BUGFIX: prevent exponent overflow when processing extremely small values close to zero such as `2.964393875E-314`. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1114
 

lib/promauth/config.go

@@ -65,13 +65,16 @@ func (ac *Config) tlsCertificateString() string {
 // NewTLSConfig returns new TLS config for the given ac.
 func (ac *Config) NewTLSConfig() *tls.Config {
 	tlsCfg := &tls.Config{
-		RootCAs:            ac.TLSRootCA,
 		ClientSessionCache: tls.NewLRUClientSessionCache(0),
 	}
+	if ac == nil {
+		return tlsCfg
+	}
 	if ac.TLSCertificate != nil {
 		// Do not set tlsCfg.GetClientCertificate, since tlsCfg.Certificates should work OK.
 		tlsCfg.Certificates = []tls.Certificate{*ac.TLSCertificate}
 	}
+	tlsCfg.RootCAs = ac.TLSRootCA
 	tlsCfg.ServerName = ac.TLSServerName
 	tlsCfg.InsecureSkipVerify = ac.TLSInsecureSkipVerify
 	return tlsCfg

lib/promscrape/client.go

@@ -57,7 +57,7 @@ func newClient(sw *ScrapeWork) *client {
 	requestURI := string(u.RequestURI())
 	isTLS := string(u.Scheme()) == "https"
 	var tlsCfg *tls.Config
-	if sw.AuthConfig != nil {
+	if isTLS {
 		tlsCfg = sw.AuthConfig.NewTLSConfig()
 	}
 	if !strings.Contains(host, ":") {
@@ -67,7 +67,7 @@ func newClient(sw *ScrapeWork) *client {
 			host += ":443"
 		}
 	}
-	dialFunc, err := newStatDialFunc(sw.ProxyURL, tlsCfg)
+	dialFunc, err := newStatDialFunc(sw.ProxyURL, sw.AuthConfig)
 	if err != nil {
 		logger.Fatalf("cannot create dial func: %s", err)
 	}

lib/promscrape/discoveryutils/client.go

@@ -66,7 +66,7 @@ func NewClient(apiServer string, ac *promauth.Config, proxyURL proxy.URL) (*Clie
 
 	hostPort := string(u.Host())
 	isTLS := string(u.Scheme()) == "https"
-	if ac != nil {
+	if isTLS {
 		tlsCfg = ac.NewTLSConfig()
 	}
 	if !strings.Contains(hostPort, ":") {
@@ -77,7 +77,7 @@ func NewClient(apiServer string, ac *promauth.Config, proxyURL proxy.URL) (*Clie
 		hostPort = net.JoinHostPort(hostPort, port)
 	}
 	if dialFunc == nil {
-		dialFunc, err = proxyURL.NewDialFunc(tlsCfg)
+		dialFunc, err = proxyURL.NewDialFunc(ac)
 		if err != nil {
 			return nil, err
 		}

lib/promscrape/statconn.go

@@ -2,7 +2,6 @@ package promscrape
 
 import (
 	"context"
-	"crypto/tls"
 	"fmt"
 	"net"
 	"sync"
@@ -10,6 +9,7 @@ import (
 	"time"
 
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/netutil"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promauth"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/proxy"
 	"github.com/VictoriaMetrics/fasthttp"
 	"github.com/VictoriaMetrics/metrics"
@@ -49,8 +49,8 @@ var (
 	stdDialerOnce sync.Once
 )
 
-func newStatDialFunc(proxyURL proxy.URL, tlsConfig *tls.Config) (fasthttp.DialFunc, error) {
-	dialFunc, err := proxyURL.NewDialFunc(tlsConfig)
+func newStatDialFunc(proxyURL proxy.URL, ac *promauth.Config) (fasthttp.DialFunc, error) {
+	dialFunc, err := proxyURL.NewDialFunc(ac)
 	if err != nil {
 		return nil, err
 	}

lib/proxy/proxy.go

@@ -7,9 +7,11 @@ import (
 	"fmt"
 	"net"
 	"net/url"
+	"strings"
 	"time"
 
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/netutil"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/promauth"
 	"github.com/VictoriaMetrics/fasthttp"
 )
 
@@ -48,8 +50,8 @@ func (u *URL) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	return nil
 }
 
-// NewDialFunc returns dial func for the given pu and tlsConfig.
-func (u *URL) NewDialFunc(tlsConfig *tls.Config) (fasthttp.DialFunc, error) {
+// NewDialFunc returns dial func for the given u and ac.
+func (u *URL) NewDialFunc(ac *promauth.Config) (fasthttp.DialFunc, error) {
 	if u == nil || u.url == nil {
 		return defaultDialFunc, nil
 	}
@@ -57,18 +59,32 @@ func (u *URL) NewDialFunc(tlsConfig *tls.Config) (fasthttp.DialFunc, error) {
 	if pu.Scheme != "http" && pu.Scheme != "https" {
 		return nil, fmt.Errorf("unknown scheme=%q for proxy_url=%q, must be http or https", pu.Scheme, pu)
 	}
+	isTLS := pu.Scheme == "https"
+	proxyAddr := addMissingPort(pu.Host, isTLS)
 	var authHeader string
+	if ac != nil {
+		authHeader = ac.Authorization
+	}
 	if pu.User != nil && len(pu.User.Username()) > 0 {
 		userPasswordEncoded := base64.StdEncoding.EncodeToString([]byte(pu.User.String()))
-		authHeader = "Proxy-Authorization: Basic " + userPasswordEncoded + "\r\n"
+		authHeader = "Basic " + userPasswordEncoded
 	}
+	if authHeader != "" {
+		authHeader = "Proxy-Authorization: " + authHeader + "\r\n"
+	}
+	tlsCfg := ac.NewTLSConfig()
 	dialFunc := func(addr string) (net.Conn, error) {
-		proxyConn, err := defaultDialFunc(pu.Host)
+		proxyConn, err := defaultDialFunc(proxyAddr)
 		if err != nil {
 			return nil, fmt.Errorf("cannot connect to proxy %q: %w", pu, err)
 		}
-		if pu.Scheme == "https" {
-			proxyConn = tls.Client(proxyConn, tlsConfig)
+		if isTLS {
+			tlsCfgLocal := tlsCfg
+			if !tlsCfgLocal.InsecureSkipVerify && tlsCfgLocal.ServerName == "" {
+				tlsCfgLocal = tlsCfgLocal.Clone()
+				tlsCfgLocal.ServerName = tlsServerName(addr)
+			}
+			proxyConn = tls.Client(proxyConn, tlsCfgLocal)
 		}
 		conn, err := sendConnectRequest(proxyConn, addr, authHeader)
 		if err != nil {
@@ -80,6 +96,25 @@ func (u *URL) NewDialFunc(tlsConfig *tls.Config) (fasthttp.DialFunc, error) {
 	return dialFunc, nil
 }
 
+func addMissingPort(addr string, isTLS bool) string {
+	if strings.IndexByte(addr, ':') >= 0 {
+		return addr
+	}
+	port := "80"
+	if isTLS {
+		port = "443"
+	}
+	return addr + ":" + port
+}
+
+func tlsServerName(addr string) string {
+	host, _, err := net.SplitHostPort(addr)
+	if err != nil {
+		return addr
+	}
+	return host
+}
+
 func defaultDialFunc(addr string) (net.Conn, error) {
 	network := "tcp4"
 	if netutil.TCP6Enabled() {