Class: Chef::Provisioning::Transport::SSH

Inherits:
Chef::Provisioning::Transport show all
Defined in:
lib/chef/provisioning/transport/ssh.rb

Defined Under Namespace

Classes: InitialConnectTimeout, SSHResult

Constant Summary

Constants inherited from Chef::Provisioning::Transport

DEFAULT_TIMEOUT

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(host, username, init_ssh_options, options, global_config) ⇒ SSH

Create a new SSH transport.

Arguments

  • host: the host to connect to, e.g. '145.14.51.45'

  • username: the username to connect with

  • ssh_options: a list of options to Net::SSH.start

  • options: a hash of options for the transport itself, including:

    • :prefix: a prefix to send before each command (e.g. “sudo ”)

    • :ssh_pty_enable: set to false to disable pty (some instances don't support this, most do)

    • :ssh_gateway: the gateway to use, e.g. “[email protected]:222”. nil (the default) means no gateway. If the username is omitted, then the default username is used instead (i.e. the user running chef, or the username configured in .ssh/config).

    • :scp_temp_dir: a directory to use as the temporary location for files that are copied to the host via SCP. Only used if :prefix is set. Default is '/tmp' if unspecified.

  • global_config: an options hash that looks suspiciously similar to Chef::Config, containing at least the key :log_level.

The options are used in

Net::SSH.start(host, username, ssh_options)

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# File 'lib/chef/provisioning/transport/ssh.rb', line 39

def initialize(host, username, init_ssh_options, options, global_config)
  @host = host
  @username = username
  @ssh_options = init_ssh_options.clone
  @options = options
  @config = global_config
  @remote_forwards = ssh_options.delete(:remote_forwards) { Array.new }
  @never_forward_localhost = ssh_options.delete(:never_forward_localhost)
end

Instance Attribute Details

#configObject (readonly)

Returns the value of attribute config


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# File 'lib/chef/provisioning/transport/ssh.rb', line 53

def config
  @config
end

#hostObject (readonly)

Returns the value of attribute host


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# File 'lib/chef/provisioning/transport/ssh.rb', line 49

def host
  @host
end

#optionsObject (readonly)

Returns the value of attribute options


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# File 'lib/chef/provisioning/transport/ssh.rb', line 52

def options
  @options
end

#ssh_optionsObject (readonly)

Returns the value of attribute ssh_options


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# File 'lib/chef/provisioning/transport/ssh.rb', line 51

def ssh_options
  @ssh_options
end

#usernameObject (readonly)

Returns the value of attribute username


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# File 'lib/chef/provisioning/transport/ssh.rb', line 50

def username
  @username
end

Instance Method Details

#available?Boolean

Returns:

  • (Boolean)

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# File 'lib/chef/provisioning/transport/ssh.rb', line 213

def available?
  timeout = ssh_options[:timeout] || 10
  execute('pwd', :timeout => timeout)
  true
rescue Timeout::Error, Errno::EHOSTUNREACH, Errno::ENETUNREACH, Errno::EHOSTDOWN, Errno::ETIMEDOUT, Errno::ECONNREFUSED, Errno::ECONNRESET, Net::SSH::Disconnect, Net::SSH::ConnectionTimeout
  Chef::Log.debug("#{username}@#{host} unavailable: network connection failed or broke: #{$!.inspect}")
  disconnect
  false
rescue Net::SSH::AuthenticationFailed, Net::SSH::HostKeyMismatch
  Chef::Log.debug("#{username}@#{host} unavailable: SSH authentication error: #{$!.inspect} ")
  disconnect
  false
end

#disconnectObject


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# File 'lib/chef/provisioning/transport/ssh.rb', line 201

def disconnect
  if @session
    begin
      Chef::Log.info("Closing SSH session on #{username}@#{host}")
      @session.close
    rescue
    ensure
      @session = nil
    end
  end
end

#download_file(path, local_path) ⇒ Object


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# File 'lib/chef/provisioning/transport/ssh.rb', line 133

def download_file(path, local_path)
  Chef::Log.debug("Downloading file #{path} from #{username}@#{host} to local #{local_path}")
  download(path, local_path)
end

#execute(command, execute_options = {}) ⇒ Object


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# File 'lib/chef/provisioning/transport/ssh.rb', line 55

def execute(command, execute_options = {})
  Chef::Log.info("#{self.object_id} Executing #{options[:prefix]}#{command} on #{username}@#{host}")
  stdout = ''
  stderr = ''
  exitstatus = nil
  session # grab session outside timeout, it has its own timeout

  with_execute_timeout(execute_options) do
    @remote_forwards.each do |forward_info|
        # -R flag to openssh client allows optional :remote_host and
        # requires the other values so let's do that too.
        remote_host = forward_info.fetch(:remote_host, 'localhost')
        remote_port = forward_info.fetch(:remote_port)
        local_host = forward_info.fetch(:local_host)
        local_port = forward_info.fetch(:local_port)

        actual_port, actual_host = forward_port(local_port, local_host, remote_port, remote_host)
        Chef::Log.info("#{host} forwarded remote #{actual_host}:#{actual_port} to local #{local_host}:#{local_port}")
    end

    channel = session.open_channel do |channel|
      # Enable PTY unless otherwise specified, some instances require this
      unless options[:ssh_pty_enable] == false
        channel.request_pty do |chan, success|
           raise "could not get pty" if !success && options[:ssh_pty_enable]
        end
      end

      channel.exec("#{options[:prefix]}#{command}") do |ch, success|
        raise "could not execute command: #{command.inspect}" unless success

        channel.on_data do |ch2, data|
          stdout << data
          stream_chunk(execute_options, data, nil)
        end

        channel.on_extended_data do |ch2, type, data|
          stderr << data
          stream_chunk(execute_options, nil, data)
        end

        channel.on_request "exit-status" do |ch, data|
          exitstatus = data.read_long
        end
      end
    end

    channel.wait

    @remote_forwards.each do |forward_info|
        # -R flag to openssh client allows optional :remote_host and
        # requires the other values so let's do that too.
        remote_host = forward_info.fetch(:remote_host, 'localhost')
        remote_port = forward_info.fetch(:remote_port)
        local_host = forward_info.fetch(:local_host)
        local_port = forward_info.fetch(:local_port)

        session.forward.cancel_remote(remote_port, remote_host)
        session.loop { session.forward.active_remotes.include?([remote_port, remote_host]) }

        Chef::Log.info("#{host} canceled remote forward #{remote_host}:#{remote_port}")
    end
  end

  Chef::Log.info("Completed #{command} on #{username}@#{host}: exit status #{exitstatus}")
  Chef::Log.debug("Stdout was:\n#{stdout}") if stdout != '' && !options[:stream] && !options[:stream_stdout] && config[:log_level] != :debug
  Chef::Log.info("Stderr was:\n#{stderr}") if stderr != '' && !options[:stream] && !options[:stream_stderr] && config[:log_level] != :debug
  SSHResult.new(command, execute_options, stdout, stderr, exitstatus)
end

#make_url_available_to_remote(local_url) ⇒ Object


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# File 'lib/chef/provisioning/transport/ssh.rb', line 175

def make_url_available_to_remote(local_url)
  uri = URI(local_url)
  if @never_forward_localhost
    return uri.to_s
  elsif uri.scheme == 'chefzero' && !ChefZero::SocketlessServerMap.server_on_port(uri.port).server
    # There is no .server for a socketless, for a socket-d server it would
    # be a WEBrick::HTTPServer object.
    raise 'Cannot forward a socketless Chef Zero server, see https://docs.chef.io/deprecations_local_listen.html for more information'
  elsif is_local_machine(uri.host)
    port, host = forward_port(uri.port, uri.host, uri.port, 'localhost')
    if !port
      # Try harder if the port is already taken
      port, host = forward_port(uri.port, uri.host, 0, 'localhost')
      if !port
        raise "Error forwarding port: could not forward #{uri.port} or 0"
      end
    end
    uri.host = host
    uri.port = port
    Chef::Log.info("Port forwarded: local URL #{local_url} is available to #{self.host} as #{uri.to_s} for the duration of this SSH connection.")
  else
    Chef::Log.info("#{host} not forwarding non-local #{local_url}")
  end
  uri.to_s
end

#read_file(path) ⇒ Object

TODO why does #read_file download it to the target host?


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# File 'lib/chef/provisioning/transport/ssh.rb', line 126

def read_file(path)
  Chef::Log.debug("Reading file #{path} from #{username}@#{host}")
  result = StringIO.new
  download(path, result)
  result.string
end

#remote_tempfile(path) ⇒ Object


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# File 'lib/chef/provisioning/transport/ssh.rb', line 138

def remote_tempfile(path)
  File.join(scp_temp_dir, "#{File.basename(path)}.#{Random.rand(2**32)}")
end

#upload_file(local_path, path) ⇒ Object


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# File 'lib/chef/provisioning/transport/ssh.rb', line 156

def upload_file(local_path, path)
  execute("mkdir -p #{File.dirname(path)}").error!
  if options[:prefix]
    # Make a tempfile on the other side, upload to that, and sudo mv / chown / etc.
    tempfile = remote_tempfile(path)
    Chef::Log.debug("Uploading #{local_path} to #{tempfile} on #{username}@#{host}")
    Net::SCP.new(session).upload!(local_path, tempfile)
    begin
      execute("mv #{tempfile} #{path}").error!
    rescue
      # Clean up if we were unable to move
      execute("rm #{tempfile}").error!
    end
  else
    Chef::Log.debug("Uploading #{local_path} to #{path} on #{username}@#{host}")
    Net::SCP.new(session).upload!(local_path, path)
  end
end

#write_file(path, content) ⇒ Object


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# File 'lib/chef/provisioning/transport/ssh.rb', line 142

def write_file(path, content)
  execute("mkdir -p #{File.dirname(path)}").error!
  if options[:prefix]
    # Make a tempfile on the other side, upload to that, and sudo mv / chown / etc.
    tempfile = remote_tempfile(path)
    Chef::Log.debug("Writing #{content.length} bytes to #{tempfile} on #{username}@#{host}")
    Net::SCP.new(session).upload!(StringIO.new(content), tempfile)
    execute("mv #{tempfile} #{path}").error!
  else
    Chef::Log.debug("Writing #{content.length} bytes to #{path} on #{username}@#{host}")
    Net::SCP.new(session).upload!(StringIO.new(content), path)
  end
end