Class: Train::Transports::SSH::Connection

Inherits:
BaseConnection
  • Object
show all
Defined in:
lib/train/transports/ssh_connection.rb

Overview

A Connection instance can be generated and re-generated, given new connection details such as connection port, hostname, credentials, etc. This object is responsible for carrying out the actions on the remote host such as executing commands, transferring files, etc.

Author:

Defined Under Namespace

Classes: OS

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(options) ⇒ Connection 



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# File 'lib/train/transports/ssh_connection.rb', line 34

def initialize(options)
  super(options)
  @username               = @options.delete(:username)
  @hostname               = @options.delete(:hostname)
  @port                   = @options[:port] # don't delete from options
  @connection_retries     = @options.delete(:connection_retries)
  @connection_retry_sleep = @options.delete(:connection_retry_sleep)
  @max_wait_until_ready   = @options.delete(:max_wait_until_ready)
  @max_ssh_sessions       = @options.delete(:max_ssh_connections) { 9 }
  @session                = nil
  @transport_options      = @options.delete(:transport_options)
  @cmd_wrapper            = nil
  @cmd_wrapper            = CommandWrapper.load(self, @transport_options)
end

Instance Attribute Details

#hostname ⇒ Object (readonly)

rubocop:disable Metrics/ClassLength



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# File 'lib/train/transports/ssh_connection.rb', line 33

def hostname
  @hostname
end

Instance Method Details

#close ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 50

def close
  return if @session.nil?
  logger.debug("[SSH] closing connection to #{self}")
  session.close
ensure
  @session = nil
end

#download(remotes, local) ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 154

def download(remotes, local)
  waits = []
  Array(remotes).map do |remote|
    opts = file(remote).directory? ? { recursive: true } : {}
    waits.push session.scp.download(remote, local, opts) do |_ch, name, recv, total|
      logger.debug("Downloaded #{name} (#{total} bytes)") if recv == total
    end
    waits.shift.wait while waits.length >= @max_ssh_sessions
  end
  waits.each(&:wait)
rescue Net::SSH::Exception => ex
  raise Train::Transports::SSHFailed, "SCP download failed (#{ex.message})"
end

#file(path) ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 62

def file(path)
  @files[path] ||= \
    if os.aix?
      Train::File::Remote::Aix.new(self, path)
    elsif os.solaris?
      Train::File::Remote::Unix.new(self, path)
    elsif os[:name] == 'qnx'
      Train::File::Remote::Qnx.new(self, path)
    else
      Train::File::Remote::Linux.new(self, path)
    end
end

#login_command ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 120

def 
  level = logger.debug? ? 'VERBOSE' : 'ERROR'
  fwd_agent = options[:forward_agent] ? 'yes' : 'no'

  args  = %w{ -o UserKnownHostsFile=/dev/null }
  args += %w{ -o StrictHostKeyChecking=no }
  args += %w{ -o IdentitiesOnly=yes } if options[:keys]
  args += %W( -o LogLevel=#{level} )
  args += %W( -o ForwardAgent=#{fwd_agent} ) if options.key?(:forward_agent)
  Array(options[:keys]).each do |ssh_key|
    args += %W( -i #{ssh_key} )
  end
  args += %W( -p #{@port} )
  args += %W( #{@username}@#{@hostname} )

  LoginCommand.new('ssh', args)
end

#os ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 58

def os
  @os ||= OS.new(self)
end

#run_command(cmd) ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 76

def run_command(cmd)
  stdout = stderr = ''
  exit_status = nil
  cmd.dup.force_encoding('binary') if cmd.respond_to?(:force_encoding)
  logger.debug("[SSH] #{self} (#{cmd})")

  session.open_channel do |channel|
    # wrap commands if that is configured
    cmd = @cmd_wrapper.run(cmd) unless @cmd_wrapper.nil?

    if @transport_options[:pty]
      channel.request_pty do |_ch, success|
        fail Train::Transports::SSHPTYFailed, 'Requesting PTY failed' unless success
      end
    end

    channel.exec(cmd) do |_, success|
      abort 'Couldn\'t execute command on SSH.' unless success

      channel.on_data do |_, data|
        stdout += data
      end

      channel.on_extended_data do |_, _type, data|
        stderr += data
      end

      channel.on_request('exit-status') do |_, data|
        exit_status = data.read_long
      end

      channel.on_request('exit-signal') do |_, data|
        exit_status = data.read_long
      end
    end
  end
  @session.loop

  CommandResult.new(stdout, stderr, exit_status)
rescue Net::SSH::Exception => ex
  raise Train::Transports::SSHFailed, "SSH command failed (#{ex.message})"
end

#upload(locals, remote) ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 139

def upload(locals, remote)
  waits = []
  Array(locals).each do |local|
    opts = File.directory?(local) ? { recursive: true } : {}

    waits.push session.scp.upload(local, remote, opts) do |_ch, name, sent, total|
      logger.debug("Uploaded #{name} (#{total} bytes)") if sent == total
    end
    waits.shift.wait while waits.length >= @max_ssh_sessions
  end
  waits.each(&:wait)
rescue Net::SSH::Exception => ex
  raise Train::Transports::SSHFailed, "SCP upload failed (#{ex.message})"
end

#uri ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 180

def uri
  "ssh://#{@username}@#{@hostname}:#{@port}"
end

#wait_until_ready ⇒ Object 



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# File 'lib/train/transports/ssh_connection.rb', line 169

def wait_until_ready
  delay = 3
  session(
    retries: @max_wait_until_ready / delay,
    delay:   delay,
    message: "Waiting for SSH service on #{@hostname}:#{@port}, " \
             "retrying in #{delay} seconds",
  )
  execute(PING_COMMAND.dup)
end