From 5dc33c8c084672f43917681fa648a9a92a504725 Mon Sep 17 00:00:00 2001
From: Tommie Gannert <tommie@gannert.se>
Date: Sat, 5 Dec 2015 11:58:08 +0000
Subject: [PATCH] Simplify httpChallenge code.

Solve is blocking, so no need to run initialization code in a separate
goroutine. Removes the need for s.start.

Once the listener is closed, all I/O resources have been returned. No
need to wait for http.Serve to return. Removes the need for s.end.
---
 acme/http_challenge.go | 39 +++++----------------------------------
 1 file changed, 5 insertions(+), 34 deletions(-)

diff --git a/acme/http_challenge.go b/acme/http_challenge.go
index 979ec4b3..87359049 100644
--- a/acme/http_challenge.go
+++ b/acme/http_challenge.go
@@ -10,45 +10,18 @@ import (
 type httpChallenge struct {
 	jws     *jws
 	optPort string
-	start   chan net.Listener
-	end     chan error
 }
 
 func (s *httpChallenge) Solve(chlng challenge, domain string) error {
 
 	logf("[INFO] acme: Trying to solve HTTP-01")
 
-	s.start = make(chan net.Listener)
-	s.end = make(chan error)
-
 	// Generate the Key Authorization for the challenge
 	keyAuth, err := getKeyAuthorization(chlng.Token, &s.jws.privKey.PublicKey)
 	if err != nil {
 		return err
 	}
 
-	go s.startHTTPServer(domain, chlng.Token, keyAuth)
-	var listener net.Listener
-	select {
-	case listener = <-s.start:
-		break
-	case err := <-s.end:
-		return fmt.Errorf("Could not start HTTP server for challenge -> %v", err)
-	}
-
-	// Make sure we properly close the HTTP server before we return
-	defer func() {
-		listener.Close()
-		err = <-s.end
-		close(s.start)
-		close(s.end)
-	}()
-
-	return validate(s.jws, chlng.URI, challenge{Resource: "challenge", Type: chlng.Type, Token: chlng.Token, KeyAuthorization: keyAuth})
-}
-
-func (s *httpChallenge) startHTTPServer(domain string, token string, keyAuth string) {
-
 	// Allow for CLI port override
 	port := ":80"
 	if s.optPort != "" {
@@ -60,13 +33,12 @@ func (s *httpChallenge) startHTTPServer(domain string, token string, keyAuth str
 		// if the domain:port bind failed, fall back to :port bind and try that instead.
 		listener, err = net.Listen("tcp", port)
 		if err != nil {
-			s.end <- err
+			return fmt.Errorf("Could not start HTTP server for challenge -> %v", err)
 		}
 	}
-	// Signal successfull start
-	s.start <- listener
+	defer listener.Close()
 
-	path := "/.well-known/acme-challenge/" + token
+	path := "/.well-known/acme-challenge/" + chlng.Token
 
 	// The handler validates the HOST header and request type.
 	// For validation it then writes the token the server returned with the challenge
@@ -81,8 +53,7 @@ func (s *httpChallenge) startHTTPServer(domain string, token string, keyAuth str
 		}
 	})
 
-	http.Serve(listener, nil)
+	go http.Serve(listener, nil)
 
-	// Signal that the server was shut down
-	s.end <- nil
+	return validate(s.jws, chlng.URI, challenge{Resource: "challenge", Type: chlng.Type, Token: chlng.Token, KeyAuthorization: keyAuth})
 }