Implement ssh multiplexing the right way

src/Host/Host.php

@@ -0,0 +1,182 @@
+<?php
+/* (c) Anton Medvedev <anton@medv.io>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Deployer\Host;
+
+class Host
+{
+    private $hostname;
+    private $user;
+    private $port;
+    private $configFile;
+    private $identityFile;
+    private $forwardAgent = true;
+    private $multiplexing = true;
+    private $options = [];
+
+    /**
+     * Host constructor.
+     * @param string $hostname
+     */
+    public function __construct(string $hostname)
+    {
+        $this->hostname = $hostname;
+    }
+
+    public function generateOptionsString()
+    {
+        return '';
+    }
+
+    /**
+     * Returns pair user/hostname
+     *
+     * @return string
+     */
+    public function __toString()
+    {
+        $user = empty($this->user) ? '' : "{$this->user}@";
+        $hostname = $this->hostname;
+        return "$user$hostname";
+    }
+
+    /**
+     * @return string
+     */
+    public function getHostname()
+    {
+        return $this->hostname;
+    }
+
+    /**
+     * @param string $hostname
+     */
+    public function setHostname(string $hostname)
+    {
+        $this->hostname = $hostname;
+    }
+
+    /**
+     * @return string
+     */
+    public function getUser()
+    {
+        return $this->user;
+    }
+
+    /**
+     * @param string $user
+     */
+    public function setUser(string $user)
+    {
+        $this->user = $user;
+    }
+
+    /**
+     * @return int
+     */
+    public function getPort()
+    {
+        return $this->port;
+    }
+
+    /**
+     * @param int $port
+     */
+    public function setPort(int $port)
+    {
+        $this->port = $port;
+    }
+
+    /**
+     * @return string
+     */
+    public function getConfigFile()
+    {
+        return $this->configFile;
+    }
+
+    /**
+     * @param string $configFile
+     */
+    public function setConfigFile(string $configFile)
+    {
+        $this->configFile = $configFile;
+    }
+
+    /**
+     * @return string
+     */
+    public function getIdentityFile()
+    {
+        return $this->identityFile;
+    }
+
+    /**
+     * @param string $identityFile
+     */
+    public function setIdentityFile(string $identityFile)
+    {
+        $this->identityFile = $identityFile;
+    }
+
+    /**
+     * @return bool
+     */
+    public function isForwardAgent()
+    {
+        return $this->forwardAgent;
+    }
+
+    /**
+     * @param bool $forwardAgent
+     */
+    public function setForwardAgent(bool $forwardAgent)
+    {
+        $this->forwardAgent = $forwardAgent;
+    }
+
+    /**
+     * @return bool
+     */
+    public function isMultiplexing()
+    {
+        return $this->multiplexing;
+    }
+
+    /**
+     * @param bool $multiplexing
+     */
+    public function setMultiplexing(bool $multiplexing)
+    {
+        $this->multiplexing = $multiplexing;
+    }
+
+    /**
+     * @return array
+     */
+    public function getOptions()
+    {
+        return $this->options;
+    }
+
+    /**
+     * @param array $options
+     */
+    public function setOptions(array $options)
+    {
+        $this->options = $options;
+    }
+
+    /**
+     * @param string $option
+     */
+    public function addOption(string $option)
+    {
+        $this->options[] = $option;
+    }
+}

src/Ssh/Client.php

@@ -7,7 +7,9 @@
 
 namespace Deployer\Ssh;
 
+use Deployer\Exception\Exception;
 use Deployer\Exception\RuntimeException;
+use Deployer\Host\Host;
 use Symfony\Component\Console\Output\OutputInterface;
 use Symfony\Component\Process\Process;
 
@@ -27,23 +29,39 @@ class Client
         $this->output = $output;
     }
 
-
-    public function run($host, $command, $options = [])
+    /**
+     * @param Host $host
+     * @param string $command
+     * @param array $config
+     * @return string
+     * @throws RuntimeException
+     */
+    public function run(Host $host, string $command, array $config = [])
     {
+        $hostname = $host->getHostname();
         $defaults = [
             'timeout' => 300,
             'tty' => false,
         ];
-        $options = array_merge($defaults, $options);
+        $config = array_merge($defaults, $config);
 
-        $hostname = $host;
-        $ssh = "ssh $hostname 'bash -s; printf \"[exit_code:%s]\" $?;'";
+        $options = $host->generateOptionsString();
+
+        if ($host->isMultiplexing()) {
+            $options = $this->initMultiplexing($host);
+        }
+
+        if ($config['tty']) {
+            $options .= ' -tt';
+        }
+
+        $ssh = "ssh $options $host 'bash -s; printf \"[exit_code:%s]\" $?;'";
 
         $process = new Process($ssh);
         $process
             ->setInput($command)
-            ->setTimeout($options['timeout'])
-            ->setTty($options['tty']);
+            ->setTimeout($config['timeout'])
+            ->setTty($config['tty']);
 
         $callback = function ($type, $buffer) use ($hostname) {
             if ($this->output->isDebug()) {
@@ -105,4 +123,76 @@ class Client
         $exitCode = (int)$match[1];
         return $exitCode;
     }
+
+    /**
+     * Init multiplexing by adding options for ssh command
+     *
+     * @param Host $host
+     * @return string Host options
+     */
+    private function initMultiplexing(Host $host)
+    {
+        $options = $host->generateOptionsString();
+        $controlPath = $this->generateControlPath($host);
+
+        $options .= " -o ControlMaster=auto";
+        $options .= " -o ControlPersist=60";
+        $options .= " -o ControlPath=$controlPath";
+        
+        $process = new Process("ssh $options -O check -S $controlPath $host 2>&1");
+        $process->run();
+
+        if (!preg_match('/Master running/', $process->getOutput())) {
+            $this->writeln(Process::OUT, $host->getHostname(), 'ssh multiplexing initialization');
+        }
+
+        return $options;
+    }
+
+    /**
+     * Return SSH multiplexing control path
+     *
+     * When ControlPath is longer than 104 chars we can get:
+     *
+     *     SSH Error: unix_listener: too long for Unix domain socket
+     *
+     * So try to get as descriptive path as possible.
+     * %C is for creating hash out of connection attributes.
+     *
+     * @param Host $host
+     * @return string ControlPath
+     * @throws Exception
+     */
+    private function generateControlPath(Host $host)
+    {
+        $connectionData = "{$host->getUser()}_{$host->getHostname()}_{$host->getPort()}";
+        $tryLongestPossible = 0;
+        $controlPath = '';
+        do {
+            switch ($tryLongestPossible) {
+                case 1:
+                    $controlPath = "~/.ssh/deployer_mux_$connectionData";
+                    break;
+                case 2:
+                    $controlPath = "~/.ssh/deployer_mux_%C";
+                    break;
+                case 3:
+                    $controlPath = "~/deployer_mux_$connectionData";
+                    break;
+                case 4:
+                    $controlPath = "~/deployer_mux_%C";
+                    break;
+                case 5:
+                    $controlPath = "~/mux_%C";
+                    break;
+                case 6:
+                    throw new Exception("The multiplexing control path is too long. Control path is: $controlPath");
+                default:
+                    $controlPath = "~/.ssh/deployer_mux_$connectionData";
+            }
+            $tryLongestPossible++;
+        } while (strlen($controlPath) > 104); // Unix socket max length
+
+        return $controlPath;
+    }
 }