[medium/bug] fixed couple issues in agent proxy support

src/mig/agent/agent.go

@@ -160,6 +160,7 @@ func runAgent(foreground bool) (err error) {
 		ctx.Channels.Log <- mig.Log{Desc: fmt.Sprintf("Init failed: '%v'", err)}.Err()
 		if foreground {
 			// if in foreground mode, don't retry, just panic
+			time.Sleep(1 * time.Second)
 			panic(err)
 		}
 		if ctx.Agent.Respawn {

src/mig/agent/context.go

@@ -49,6 +49,8 @@ import (
 	"runtime"
 	"time"
 
+	"bufio"
+
 	"bitbucket.org/kardianos/osext"
 	"github.com/streadway/amqp"
 )
@@ -349,6 +351,7 @@ func initMQ(orig_ctx Context, try_proxy bool) (ctx Context, err error) {
 	if err != nil {
 		panic(err)
 	}
+	ctx.Channels.Log <- mig.Log{Desc: fmt.Sprintf("AMQP: host=%s, port=%d, vhost=%s", amqp_uri.Host, amqp_uri.Port, amqp_uri.Vhost)}.Debug()
 	if amqp_uri.Scheme == "amqps" {
 		ctx.MQ.UseTLS = true
 	}
@@ -357,34 +360,62 @@ func initMQ(orig_ctx Context, try_proxy bool) (ctx Context, err error) {
 	var dialConfig amqp.Config
 	dialConfig.Heartbeat = 2 * ctx.Sleeper
 	if try_proxy {
-		panic("no proxy support available")
-		dialConfig.Dial = func(network, addr string) (net.Conn, error) {
+		// if in try_proxy mode, the agent will try to connect to the relay using a CONNECT proxy
+		// but because CONNECT is a HTTP method, not available in AMQP, we need to establish
+		// that connection ourselves.
+		//
+		// the code below looks for HTTP(S)_PROXY environment variables and, if present, tries
+		// to connect to the relay through the proxy, and returns the net.Conn pointer back
+		ctx.Channels.Log <- mig.Log{Desc: "Attempting connection to relay using environment proxies"}.Debug()
+		dialConfig.Dial = func(network, addr string) (conn net.Conn, err error) {
 			// make a fake request object to get the proxy from env
-			target := "http://" + amqp_uri.Host + ":" + fmt.Sprintf("%d", amqp_uri.Port) + amqp_uri.Vhost
+			target := "http://" + addr
 			req, err := http.NewRequest("GET", target, nil)
 			if err != nil {
-				return nil, err
+				return
 			}
 			proxy_url, err := http.ProxyFromEnvironment(req)
 			if err != nil {
-				return nil, err
+				return
 			}
+			if proxy_url == nil {
+				err = fmt.Errorf("Failed to find a suitable proxy in environment")
+				return
+			}
+			ctx.Channels.Log <- mig.Log{Desc: fmt.Sprintf("Found proxy at %s", proxy_url.Host)}.Debug()
 			// connect to the proxy
-			conn, err := net.DialTimeout("tcp", proxy_url.Host, 2*ctx.Sleeper)
+			conn, err = net.DialTimeout("tcp", proxy_url.Host, 5*time.Second)
 			if err != nil {
-				return nil, err
+				return
 			}
 			// write a CONNECT request in the tcp connection
 			fmt.Fprintf(conn, "CONNECT "+req.Host+" HTTP/1.1\r\nHost: "+req.Host+"\r\n\r\n")
-			return conn, nil
+			// verify status is 200, and flush the buffer
+			status, err := bufio.NewReader(conn).ReadString('\n')
+			if err != nil {
+				return
+			}
+			if status == "" || len(status) < 12 {
+				err = fmt.Errorf("Invalid status received from proxy: '%s'", status[0:len(status)-1])
+				return
+			}
+			// 9th character in response should be "2"
+			// HTTP/1.0 200 Connection established
+			//          ^
+			if status[9] != '2' {
+				err = fmt.Errorf("Invalid status received from proxy: '%s'", status[0:len(status)-1])
+				return
+			}
+			return
 		}
 	} else {
 		dialConfig.Dial = func(network, addr string) (net.Conn, error) {
-			return net.DialTimeout(network, addr, 2*ctx.Sleeper)
+			return net.DialTimeout(network, addr, 5*time.Second)
 		}
 	}
 
 	if ctx.MQ.UseTLS {
+		ctx.Channels.Log <- mig.Log{Desc: "Loading AMQPS TLS parameters"}.Debug()
 		// import the client certificates
 		cert, err := tls.X509KeyPair([]byte(AGENTCERT), []byte(AGENTKEY))
 		if err != nil {
@@ -403,9 +434,11 @@ func initMQ(orig_ctx Context, try_proxy bool) (ctx Context, err error) {
 
 		dialConfig.TLSClientConfig = &TLSconfig
 	}
-	// Open a non-encrypted AMQP connection
+	// Open AMQP connection
+	ctx.Channels.Log <- mig.Log{Desc: "Establishing connection to relay"}.Debug()
 	ctx.MQ.conn, err = amqp.DialConfig(AMQPBROKER, dialConfig)
 	if err != nil {
+		ctx.Channels.Log <- mig.Log{Desc: "Connection failed"}.Debug()
 		panic(err)
 	}