From 52c0f86f759a8090585768171e99165bcd474d04 Mon Sep 17 00:00:00 2001
From: Thomas Fan <thomasjpfan@gmail.com>
Date: Tue, 8 May 2018 18:34:30 -0400
Subject: [PATCH] ENH: Adds seamless reloads (#19)

---
 haproxy.cfg                          |  1 +
 haproxy.tmpl                         |  1 +
 proxy/ha_proxy.go                    | 10 ++++++++-
 proxy/ha_proxy_test.go               | 32 ++++++++++++++++++++++++++++
 proxy/test_configs/tmpl/haproxy.tmpl |  1 +
 proxy/util.go                        |  5 +++++
 test_configs/reload-error.cfg        |  1 +
 test_configs/reload.cfg              |  1 +
 8 files changed, 51 insertions(+), 1 deletion(-)

diff --git a/haproxy.cfg b/haproxy.cfg
index 5e5c35f7..37e556a7 100644
--- a/haproxy.cfg
+++ b/haproxy.cfg
@@ -1,5 +1,6 @@
 global
     pidfile /var/run/haproxy.pid
+    stats socket /var/run/haproxy.sock mode 660 level admin expose-fd listeners
 
 defaults
     mode    http
diff --git a/haproxy.tmpl b/haproxy.tmpl
index eafa1964..b1a2e62c 100644
--- a/haproxy.tmpl
+++ b/haproxy.tmpl
@@ -1,5 +1,6 @@
 global
     pidfile /var/run/haproxy.pid
+    stats socket /var/run/haproxy.sock mode 660 level admin expose-fd listeners
     tune.ssl.default-dh-param 2048{{.ExtraGlobal}}
 
     # disable sslv3, prefer modern ciphers
diff --git a/proxy/ha_proxy.go b/proxy/ha_proxy.go
index 21d110f9..66531331 100644
--- a/proxy/ha_proxy.go
+++ b/proxy/ha_proxy.go
@@ -165,7 +165,15 @@ func (m HaProxy) Reload() error {
 			return fmt.Errorf("Could not read the %s file\n%s", pidPath, err.Error())
 		}
 		reloadStrategy := m.getReloadStrategy()
-		cmdArgs := []string{reloadStrategy, string(pid)}
+		haproxySocket := "/var/run/haproxy.sock"
+		socketOn := haSocketOn(haproxySocket)
+
+		var cmdArgs []string
+		if socketOn {
+			cmdArgs = []string{"-x", haproxySocket, reloadStrategy, string(pid)}
+		} else {
+			cmdArgs = []string{reloadStrategy, string(pid)}
+		}
 		reloadErr = HaProxy{}.RunCmd(cmdArgs)
 		if reloadErr == nil {
 			logPrintf("Proxy config was reloaded")
diff --git a/proxy/ha_proxy_test.go b/proxy/ha_proxy_test.go
index 38b576ba..da7896f5 100644
--- a/proxy/ha_proxy_test.go
+++ b/proxy/ha_proxy_test.go
@@ -31,6 +31,7 @@ func TestHaProxyUnitTestSuite(t *testing.T) {
 	s := new(HaProxyTestSuite)
 	s.TemplateContent = `global
     pidfile /var/run/haproxy.pid
+    stats socket /var/run/haproxy.sock mode 660 level admin expose-fd listeners
     tune.ssl.default-dh-param 2048
 
     # disable sslv3, prefer modern ciphers
@@ -122,6 +123,9 @@ func (s *HaProxyTestSuite) SetupTest() {
 	readPidFile = func(fileName string) ([]byte, error) {
 		return []byte(s.Pid), nil
 	}
+	haSocketOn = func(adddress string) bool {
+		return true
+	}
 }
 
 // GetCertPaths
@@ -2570,6 +2574,30 @@ func (s *HaProxyTestSuite) Test_Reload_ReturnsError_WhenReadPidFails() {
 	s.Error(err)
 }
 
+func (s *HaProxyTestSuite) Test_HaProxySocketNotOn_RunsRunCmd() {
+	actual := HaProxyTestSuite{}.mockHaExecCmd()
+	haSocketOnOrig := haSocketOn
+	defer func() {
+		haSocketOn = haSocketOnOrig
+	}()
+	haSocketOn = func(address string) bool {
+		return false
+	}
+	expected := []string{
+		"-f",
+		"/cfg/haproxy.cfg",
+		"-D",
+		"-p",
+		"/var/run/haproxy.pid",
+		"-sf",
+		s.Pid,
+	}
+
+	HaProxy{}.Reload()
+
+	s.Equal(expected, *actual)
+}
+
 func (s *HaProxyTestSuite) Test_Reload_RunsRunCmd() {
 	actual := HaProxyTestSuite{}.mockHaExecCmd()
 	expected := []string{
@@ -2578,6 +2606,8 @@ func (s *HaProxyTestSuite) Test_Reload_RunsRunCmd() {
 		"-D",
 		"-p",
 		"/var/run/haproxy.pid",
+		"-x",
+		"/var/run/haproxy.sock",
 		"-sf",
 		s.Pid,
 	}
@@ -2596,6 +2626,8 @@ func (s *HaProxyTestSuite) Test_Reload_Terminate_RunsRunCmd() {
 		"-D",
 		"-p",
 		"/var/run/haproxy.pid",
+		"-x",
+		"/var/run/haproxy.sock",
 		"-st",
 		s.Pid,
 	}
diff --git a/proxy/test_configs/tmpl/haproxy.tmpl b/proxy/test_configs/tmpl/haproxy.tmpl
index 8ea1dfb4..05cb3465 100644
--- a/proxy/test_configs/tmpl/haproxy.tmpl
+++ b/proxy/test_configs/tmpl/haproxy.tmpl
@@ -1,5 +1,6 @@
 global
     pidfile /var/run/haproxy.pid
+    stats socket /var/run/haproxy.sock mode 660 level admin expose-fd listeners
     tune.ssl.default-dh-param 2048{{.ExtraGlobal}}
 
     # disable sslv3, prefer modern ciphers
diff --git a/proxy/util.go b/proxy/util.go
index 79f05e40..19aab212 100644
--- a/proxy/util.go
+++ b/proxy/util.go
@@ -72,6 +72,11 @@ var readFile = ioutil.ReadFile
 var logPrintf = log.Printf
 var readPidFile = ioutil.ReadFile
 var readConfigsDir = ioutil.ReadDir
+var haSocketOn = func(address string) bool {
+	conn, err := net.Dial("unix", address)
+	defer conn.Close()
+	return err == nil
+}
 var getSecretOrEnvVarSplit = func(key, defaultValue string) string {
 	value := getSecretOrEnvVar(key, defaultValue)
 	if len(value) > 0 {
diff --git a/test_configs/reload-error.cfg b/test_configs/reload-error.cfg
index 9ae9e72f..5e024005 100644
--- a/test_configs/reload-error.cfg
+++ b/test_configs/reload-error.cfg
@@ -1,5 +1,6 @@
 global
     pidfile /var/run/haproxy.pid
+    stats socket /var/run/haproxy.sock mode 660 level admin expose-fd listeners
     tune.ssl.default-dh-param 2048
 
 defaults
diff --git a/test_configs/reload.cfg b/test_configs/reload.cfg
index 63cffac3..fa7c7edc 100644
--- a/test_configs/reload.cfg
+++ b/test_configs/reload.cfg
@@ -1,5 +1,6 @@
 global
     pidfile /var/run/haproxy.pid
+    stats socket /var/run/haproxy.sock mode 660 level admin expose-fd listeners
     tune.ssl.default-dh-param 2048
 
 defaults