proxy: added 'health_check_port' to upstream (#1666)

* proxy: added 'health_check_port' to upstream

* proxy: `net.JoinHostPort` instead of `fmt.Printf` for upstream checks

* proxy: changing health_check_port type (int->string)

adding tests for invalid port config

caddyhttp/proxy/upstream.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
+	"net"
 	"net/http"
 	"net/url"
 	"path"
@@ -42,6 +43,7 @@ type staticUpstream struct {
 		Interval time.Duration
 		Timeout  time.Duration
 		Host     string
+		Port     string
 	}
 	WithoutPathPrefix  string
 	IgnoredSubPaths    []string
@@ -321,6 +323,20 @@ func parseBlock(c *caddyfile.Dispenser, u *staticUpstream) error {
 			return err
 		}
 		u.HealthCheck.Timeout = dur
+	case "health_check_port":
+		if !c.NextArg() {
+			return c.ArgErr()
+		}
+		port := c.Val()
+		n, err := strconv.Atoi(port)
+		if err != nil {
+			return err
+		}
+
+		if n < 0 {
+			return c.Errf("invalid health_check_port '%s'", port)
+		}
+		u.HealthCheck.Port = c.Val()
 	case "header_upstream":
 		var header, value string
 		if !c.Args(&header, &value) {
@@ -380,7 +396,12 @@ func parseBlock(c *caddyfile.Dispenser, u *staticUpstream) error {
 
 func (u *staticUpstream) healthCheck() {
 	for _, host := range u.Hosts {
-		hostURL := host.Name + u.HealthCheck.Path
+		hostURL := host.Name
+		if u.HealthCheck.Port != "" {
+			hostURL = replacePort(host.Name, u.HealthCheck.Port)
+		}
+		hostURL += u.HealthCheck.Path
+
 		var unhealthy bool
 
 		// set up request, needed to be able to modify headers
@@ -483,3 +504,19 @@ func (u *staticUpstream) Stop() error {
 func RegisterPolicy(name string, policy func() Policy) {
 	supportedPolicies[name] = policy
 }
+
+func replacePort(originalURL string, newPort string) string {
+	parsedURL, err := url.Parse(originalURL)
+	if err != nil {
+		return originalURL
+	}
+
+	// handles 'localhost' and 'localhost:8080'
+	parsedHost, _, err := net.SplitHostPort(parsedURL.Host)
+	if err != nil {
+		parsedHost = parsedURL.Host
+	}
+
+	parsedURL.Host = net.JoinHostPort(parsedHost, newPort)
+	return parsedURL.String()
+}

caddyhttp/proxy/upstream_test.go

@@ -2,6 +2,7 @@ package proxy
 
 import (
 	"fmt"
+	"net"
 	"net/http"
 	"net/http/httptest"
 	"strings"
@@ -375,3 +376,75 @@ func TestHealthCheckHost(t *testing.T) {
 		}
 	}
 }
+
+func TestHealthCheckPort(t *testing.T) {
+	var counter int64
+
+	healthCounter := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		r.Body.Close()
+		atomic.AddInt64(&counter, 1)
+	}))
+
+	_, healthPort, err := net.SplitHostPort(healthCounter.Listener.Addr().String())
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	defer healthCounter.Close()
+
+	tests := []struct {
+		config string
+	}{
+		// Test #1: upstream with port
+		{"proxy / localhost:8080 {\n health_check / health_check_port " + healthPort + "\n}"},
+
+		// Test #2: upstream without port (default to 80)
+		{"proxy / localhost {\n health_check / health_check_port " + healthPort + "\n}"},
+	}
+
+	for i, test := range tests {
+		counterValueAtStart := atomic.LoadInt64(&counter)
+		upstreams, err := NewStaticUpstreams(caddyfile.NewDispenser("Testfile", strings.NewReader(test.config)), "")
+		if err != nil {
+			t.Error("Expected no error. Got:", err.Error())
+		}
+
+		// Give some time for healthchecks to hit the server.
+		time.Sleep(500 * time.Millisecond)
+
+		for _, upstream := range upstreams {
+			if err := upstream.Stop(); err != nil {
+				t.Errorf("Test %d: Expected no error stopping upstream. Got: %v", i, err.Error())
+			}
+		}
+
+		counterValueAfterShutdown := atomic.LoadInt64(&counter)
+
+		if counterValueAfterShutdown == counterValueAtStart {
+			t.Errorf("Test %d: Expected healthchecks to hit test server. Got no healthchecks.", i)
+		}
+	}
+
+	t.Run("valid_port", func(t *testing.T) {
+		tests := []struct {
+			config string
+		}{
+			// Test #1: invalid port (nil)
+			{"proxy / localhost {\n health_check / health_check_port\n}"},
+
+			// Test #2: invalid port (string)
+			{"proxy / localhost {\n health_check / health_check_port abc\n}"},
+
+			// Test #3: invalid port (negative)
+			{"proxy / localhost {\n health_check / health_check_port -1\n}"},
+		}
+
+		for i, test := range tests {
+			_, err := NewStaticUpstreams(caddyfile.NewDispenser("Testfile", strings.NewReader(test.config)), "")
+			if err == nil {
+				t.Errorf("Test %d accepted invalid config", i)
+			}
+		}
+	})
+
+}