Merge branch 'urlparser' into 'master'

Fix backend URL parsing

Our fancy custom flag parser broke in Go 1.7. Also, the new 'strict
TCP connection' feature was not handling backend hosts like
`localhost:3000` (it was panicking).

Fixes:

https://gitlab.com/gitlab-org/gitlab-workhorse/issues/54
https://gitlab.com/gitlab-org/gitlab-workhorse/issues/53

See merge request !61

backend.go

+package main
+
+import (
+	"fmt"
+	"net/url"
+)
+
+func parseAuthBackend(authBackend string) (*url.URL, error) {
+	backendURL, err := url.Parse(authBackend)
+	if err != nil {
+		return nil, err
+	}
+
+	if backendURL.Host == "" {
+		backendURL, err = url.Parse("http://" + authBackend)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	if backendURL.Scheme != "http" {
+		return nil, fmt.Errorf("invalid scheme, only 'http' is allowed: %q", authBackend)
+	}
+
+	if backendURL.Host == "" {
+		return nil, fmt.Errorf("missing host in %q", authBackend)
+	}
+
+	return backendURL, nil
+}

backend_test.go

+package main
+
+import (
+	"testing"
+)
+
+func TestParseAuthBackend(t *testing.T) {
+	failures := []string{
+		"",
+		"ftp://localhost",
+		"https://example.com",
+	}
+
+	for _, example := range failures {
+		if _, err := parseAuthBackend(example); err == nil {
+			t.Errorf("error expected for %q", example)
+		}
+	}
+
+	successes := []struct{ input, host, scheme string }{
+		{"http://localhost:8080", "localhost:8080", "http"},
+		{"localhost:3000", "localhost:3000", "http"},
+		{"http://localhost", "localhost", "http"},
+		{"localhost", "localhost", "http"},
+	}
+
+	for _, example := range successes {
+		result, err := parseAuthBackend(example.input)
+		if err != nil {
+			t.Errorf("parse %q: %v", example.input, err)
+			break
+		}
+
+		if result.Host != example.host {
+			t.Errorf("example %q: expected %q, got %q", example.input, example.host, result.Host)
+		}
+
+		if result.Scheme != example.scheme {
+			t.Errorf("example %q: expected %q, got %q", example.input, example.scheme, result.Scheme)
+		}
+	}
+}

internal/badgateway/roundtripper.go

@@ -64,7 +64,7 @@ func mustParseAddress(address, scheme string) string {
 		}
 	}
 
-	panic("could not parse host:port from address and scheme")
+	panic(fmt.Errorf("could not parse host:port from address %q and scheme %q", address, scheme))
 }
 
 func (t *RoundTripper) RoundTrip(r *http.Request) (res *http.Response, err error) {

main.go

@@ -34,7 +34,7 @@ var printVersion = flag.Bool("version", false, "Print version and exit")
 var listenAddr = flag.String("listenAddr", "localhost:8181", "Listen address for HTTP server")
 var listenNetwork = flag.String("listenNetwork", "tcp", "Listen 'network' (tcp, tcp4, tcp6, unix)")
 var listenUmask = flag.Int("listenUmask", 0, "Umask for Unix socket")
-var authBackend = URLFlag("authBackend", upstream.DefaultBackend, "Authentication/authorization backend")
+var authBackend = flag.String("authBackend", upstream.DefaultBackend.String(), "Authentication/authorization backend")
 var authSocket = flag.String("authSocket", "", "Optional: Unix domain socket to dial authBackend at")
 var pprofListenAddr = flag.String("pprofListenAddr", "", "pprof listening address, e.g. 'localhost:6060'")
 var documentRoot = flag.String("documentRoot", "public", "Path to static files content")
@@ -55,6 +55,12 @@ func main() {
 		os.Exit(0)
 	}
 
+	backendURL, err := parseAuthBackend(*authBackend)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "invalid authBackend: %v\n", err)
+		os.Exit(1)
+	}
+
 	log.Printf("Starting %s", version)
 
 	// Good housekeeping for Unix sockets: unlink before binding
@@ -83,7 +89,7 @@ func main() {
 	}
 
 	up := upstream.NewUpstream(
-		*authBackend,
+		backendURL,
 		*authSocket,
 		Version,
 		*documentRoot,

urlflag.go

-package main
-
-import (
-	"flag"
-	"net/url"
-)
-
-type urlFlag struct {
-	*url.URL
-}
-
-func (u *urlFlag) Set(s string) error {
-	myURL, err := url.Parse(s)
-	if err != nil {
-		return err
-	}
-	u.URL = myURL
-	return nil
-}
-
-func URLFlag(name string, value *url.URL, usage string) **url.URL {
-	f := &urlFlag{value}
-	flag.CommandLine.Var(f, name, usage)
-	return &f.URL
-}