Merge pull request #399 from mrsked/manage-ssh-connection-starts

Manage SSH connection starts

lib/mrsk/commander.rb

@@ -143,7 +143,11 @@ class Mrsk::Commander
   private
     # Lazy setup of SSHKit
     def configure_sshkit_with(config)
-      SSHKit::Backend::Netssh.configure { |ssh| ssh.ssh_options = config.ssh_options }
+      SSHKit::Backend::Netssh.pool.idle_timeout = config.sshkit.pool_idle_timeout
+      SSHKit::Backend::Netssh.configure do |sshkit|
+        sshkit.max_concurrent_starts = config.sshkit.max_concurrent_starts
+        sshkit.ssh_options = config.ssh.options
+      end
       SSHKit.config.command_map[:docker] = "docker" # No need to use /usr/bin/env, just clogs up the logs
       SSHKit.config.output_verbosity = verbosity
     end

lib/mrsk/commands/base.rb

@@ -13,12 +13,12 @@ module Mrsk::Commands
 
     def run_over_ssh(*command, host:)
       "ssh".tap do |cmd|
-        if config.ssh_proxy && config.ssh_proxy.is_a?(Net::SSH::Proxy::Jump)
-          cmd << " -J #{config.ssh_proxy.jump_proxies}"
-        elsif config.ssh_proxy && config.ssh_proxy.is_a?(Net::SSH::Proxy::Command)
-          cmd << " -o ProxyCommand='#{config.ssh_proxy.command_line_template}'"
+        if config.ssh.proxy && config.ssh.proxy.is_a?(Net::SSH::Proxy::Jump)
+          cmd << " -J #{config.ssh.proxy.jump_proxies}"
+        elsif config.ssh.proxy && config.ssh.proxy.is_a?(Net::SSH::Proxy::Command)
+          cmd << " -o ProxyCommand='#{config.ssh.proxy.command_line_template}'"
         end
-        cmd << " -t #{config.ssh_user}@#{host} '#{command.join(" ")}'"
+        cmd << " -t #{config.ssh.user}@#{host} '#{command.join(" ")}'"
       end
     end
 

lib/mrsk/configuration.rb

@@ -135,25 +135,12 @@ class Mrsk::Configuration
   end
 
 
-  def ssh_user
-    if raw_config.ssh.present?
-      raw_config.ssh["user"] || "root"
-    else
-      "root"
-    end
+  def ssh
+    Mrsk::Configuration::Ssh.new(config: self)
   end
 
-  def ssh_proxy
-    if raw_config.ssh.present? && raw_config.ssh["proxy"]
-      Net::SSH::Proxy::Jump.new \
-        raw_config.ssh["proxy"].include?("@") ? raw_config.ssh["proxy"] : "root@#{raw_config.ssh["proxy"]}"
-    elsif raw_config.ssh.present? && raw_config.ssh["proxy_command"]
-      Net::SSH::Proxy::Command.new(raw_config.ssh["proxy_command"])
-    end
-  end
-
-  def ssh_options
-    { user: ssh_user, proxy: ssh_proxy, auth_methods: [ "publickey" ] }.compact
+  def sshkit
+    Mrsk::Configuration::Sshkit.new(config: self)
   end
 
 
@@ -185,7 +172,8 @@ class Mrsk::Configuration
       service_with_version: service_with_version,
       env_args: env_args,
       volume_args: volume_args,
-      ssh_options: ssh_options,
+      ssh_options: ssh.options,
+      sshkit: sshkit.to_h,
       builder: builder.to_h,
       accessories: raw_config.accessories,
       logging: logging_args,

lib/mrsk/configuration/ssh.rb

@@ -0,0 +1,24 @@
+class Mrsk::Configuration::Ssh
+  def initialize(config:)
+    @config = config.raw_config.ssh || {}
+  end
+
+  def user
+    config.fetch("user", "root")
+  end
+
+  def proxy
+    if (proxy = config["proxy"])
+      Net::SSH::Proxy::Jump.new(proxy.include?("@") ? proxy : "root@#{proxy}")
+    elsif (proxy_command = config["proxy_command"])
+      Net::SSH::Proxy::Command.new(proxy_command)
+    end
+  end
+
+  def options
+    { user: user, proxy: proxy, auth_methods: [ "publickey" ], keepalive: true, keepalive_interval: 30 }.compact
+  end
+
+  private
+    attr_accessor :config
+end

lib/mrsk/configuration/sshkit.rb

@@ -0,0 +1,20 @@
+class Mrsk::Configuration::Sshkit
+  def initialize(config:)
+    @options = config.raw_config.sshkit || {}
+  end
+
+  def max_concurrent_starts
+    options.fetch("max_concurrent_starts", 30)
+  end
+
+  def pool_idle_timeout
+    options.fetch("pool_idle_timeout", 900)
+  end
+
+  def to_h
+    options
+  end
+
+  private
+    attr_accessor :options
+end

lib/mrsk/sshkit_with_ext.rb

@@ -54,3 +54,51 @@ class SSHKit::Backend::Abstract
   end
   prepend CommandEnvMerge
 end
+
+class SSHKit::Backend::Netssh::Configuration
+  attr_accessor :max_concurrent_starts
+end
+
+class SSHKit::Backend::Netssh
+  module LimitConcurrentStartsClass
+    attr_reader :start_semaphore
+
+    def configure(&block)
+      super &block
+      # Create this here to avoid lazy creation by multiple threads
+      if config.max_concurrent_starts
+        @start_semaphore = Concurrent::Semaphore.new(config.max_concurrent_starts)
+      end
+    end
+  end
+
+  class << self
+    prepend LimitConcurrentStartsClass
+  end
+
+  module LimitConcurrentStartsInstance
+    private
+      def with_ssh(&block)
+        host.ssh_options = self.class.config.ssh_options.merge(host.ssh_options || {})
+        self.class.pool.with(
+          method(:start_with_concurrency_limit),
+          String(host.hostname),
+          host.username,
+          host.netssh_options,
+          &block
+        )
+      end
+
+      def start_with_concurrency_limit(*args)
+        if self.class.start_semaphore
+          self.class.start_semaphore.acquire do
+            Net::SSH.start(*args)
+          end
+        else
+          Net::SSH.start(*args)
+        end
+      end
+  end
+
+  prepend LimitConcurrentStartsInstance
+end