heartbeat: setup default ports in http monitors

Default http to 80 and https to 443

Resolves #3915

Author: Giuseppe Valente

heartbeat/monitors/active/http/simple_transp.go

@@ -14,6 +14,13 @@ import (
 	"github.com/elastic/beats/libbeat/outputs/transport"
 )
 
+const (
+	gzipEncoding   = "gzip"
+	urlSchemaHTTP  = "http"
+	urlSchemaHTTPS = "https"
+)
+
+// SimpleTransport contains the dialer and read/write callbacks
 type SimpleTransport struct {
 	Dialer             transport.Dialer
 	DisableCompression bool
@@ -32,7 +39,7 @@ func (t *SimpleTransport) checkRequest(req *http.Request) error {
 	}
 
 	scheme := req.URL.Scheme
-	isHTTP := scheme == "http" || scheme == "https"
+	isHTTP := scheme == urlSchemaHTTP || scheme == urlSchemaHTTPS
 	if !isHTTP {
 		return fmt.Errorf("http: unsupported scheme %v", scheme)
 	}
@@ -43,6 +50,7 @@ func (t *SimpleTransport) checkRequest(req *http.Request) error {
 	return nil
 }
 
+// RoundTrip sets up goroutines to write the request and read the responses
 func (t *SimpleTransport) RoundTrip(req *http.Request) (*http.Response, error) {
 	type readReturn struct {
 		resp *http.Response
@@ -68,7 +76,7 @@ func (t *SimpleTransport) RoundTrip(req *http.Request) (*http.Response, error) {
 		req.Method != "HEAD" {
 
 		requestedGzip = true
-		req.Header.Add("Accept-Encoding", "gzip")
+		req.Header.Add("Accept-Encoding", gzipEncoding)
 		defer req.Header.Del("Accept-Encoding")
 	}
 
@@ -132,7 +140,7 @@ func (t *SimpleTransport) readResponse(
 	}
 	t.sigStartRead()
 
-	if requestedGzip && resp.Header.Get("Content-Encoding") == "gzip" {
+	if requestedGzip && resp.Header.Get("Content-Encoding") == gzipEncoding {
 		resp.Header.Del("Content-Encoding")
 		resp.Header.Del("Content-Length")
 		resp.ContentLength = -1

heartbeat/monitors/active/http/task.go

@@ -217,10 +217,19 @@ func splitHostnamePort(requ *http.Request) (string, uint16, error) {
 	if err != nil {
 		return "", 0, err
 	}
-
-	p, err := strconv.ParseUint(port, 10, 16)
-	if err != nil {
-		return "", 0, fmt.Errorf("'%v' is no valid port number in '%v'", port, requ.URL.Host)
+	var p uint64
+	if port == "" {
+		switch requ.URL.Scheme {
+		case urlSchemaHTTP:
+			p = 80
+		case urlSchemaHTTPS:
+			p = 443
+		}
+	} else {
+		p, err = strconv.ParseUint(port, 10, 16)
+		if err != nil {
+			return "", 0, fmt.Errorf("'%v' is no valid port number in '%v'", port, requ.URL.Host)
+		}
 	}
 
 	return host, uint16(p), nil