Class: HostMachine

Inherits:
Object
  • Object
show all
Defined in:
lib/drbman/host_machine.rb

Overview

HostMachine is used to interface with a host machine

Notes

A host machine may be either another machine or the localhost. By supporting localhost, it is likely that the process will be on a different core than the current processes.

Once HostMachine opens an ssh connection, it does not close the connection until a disconnect() is invoked.

Class Attribute Summary collapse

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(host_string, logger, choices) ⇒ HostMachine

Returns a new instance of HostMachine.

Parameters:

  • host_string (String) —

    describes the host to connect to. The format is “user{:password@}machine:port”

  • logger (Logger) —

    the logger to use

  • choices (UserChoices, Hash)

Options Hash (choices):

  • :keys (Array<String>) — default: ['~/.ssh/id_dsa', '~/.ssh/id_rsa'] —

    array of ssh key file names.



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# File 'lib/drbman/host_machine.rb', line 24

def initialize(host_string, logger, choices)
  @logger = logger
  @choices = choices
  @machine = 'localhost'
  @user = ENV['USER']
  @port = 9000
  keys = choices[:keys] || ["~/.ssh/id_dsa", "~/.ssh/id_rsa"]
  @password = {:keys => keys.collect{|name| name.gsub('~', ENV['HOME'])}.select{|name| File.exist?(name)}}
  case host_string
  when /^(\S+)\:(\S+)\@(\S+)\:(\d+)$/
    @user = $1
    @password = {:password => $2}
    @machine = $3
    @port = $4.to_i
  when /^(\S+)\:(\S+)\@(\S+)$/
    @user = $1
    @password = {:password => $2}
    @machine = $3
  when /^(\S+)\@(\S+)\:(\d+)$/
    @user = $1
    @machine = $2
    @port = $3.to_i
  when /^(\S+)\@(\S+)$/
    @user = $1
    @machine = $2
  when /^(\S+)\:(\d+)$/
    @machine = $1
    @port = $2.to_i
  when /^(\S+)$/
    @machine = $1
  end
  @name = "#{user}@#{machine}:#{port}"
  @ssh = nil
  @logger.debug { self.pretty_inspect }
end

Class Attribute Details

.connection_mutex ⇒ Object

Returns the value of attribute connection_mutex.



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# File 'lib/drbman/host_machine.rb', line 15

def connection_mutex
  @connection_mutex
end

Instance Attribute Details

#controller ⇒ Object

Returns the value of attribute controller.



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# File 'lib/drbman/host_machine.rb', line 11

def controller
  @controller
end

#dir ⇒ Object

Returns the value of attribute dir.



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# File 'lib/drbman/host_machine.rb', line 11

def dir
  @dir
end

#machine ⇒ Object (readonly)

Returns the value of attribute machine.



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# File 'lib/drbman/host_machine.rb', line 12

def machine
  @machine
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/drbman/host_machine.rb', line 12

def name
  @name
end

#port ⇒ Object (readonly)

Returns the value of attribute port.



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# File 'lib/drbman/host_machine.rb', line 12

def port
  @port
end

#user ⇒ Object (readonly)

Returns the value of attribute user.



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# File 'lib/drbman/host_machine.rb', line 12

def user
  @user
end

#uuid ⇒ Object

Returns the value of attribute uuid.



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# File 'lib/drbman/host_machine.rb', line 11

def uuid
  @uuid
end

Instance Method Details

#alive? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/drbman/host_machine.rb', line 60

def alive?
  result = true
  begin
    session do |host|
      response = host.sh('uptime')
      @logger.debug { "#{host.name} #{response}" }
      raise Exception.new('no response from uptime') if response.strip.empty?
    end
  rescue Exception => e
    @logger.warn { "#{@name} is not responding: #{e}" }
    result = false
  end
  result
end

#download(remote_src, local_dest) ⇒ Object

download a directory structure from the host machine.

Parameters:

  • remote_src (String) —

    the source directory on the host machine

  • local_dest (String) —

    the destination directory on the local machine

Raises:

  • (Exception) —

    if the files are not copied



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# File 'lib/drbman/host_machine.rb', line 124

def download(remote_src, local_dest)
  result = nil
  unless @ssh.nil?
    begin
      @ssh.scp.download!(local_src, remote_dest, :recursive => true) do |ch, name, sent, total|
        @logger.debug { "#{name}: #{sent}/#{total}" }
      end
      @ssh.loop
    rescue Exception => e
      # only raise the exception if the files differ
      raise e unless same_files?(local_dest, remote_src)
    end
  end
end

#session {|HostMachine| ... } ⇒ Object

Connect to the host, execute the given block, then disconnect from the host host_machine = HostMachine.new(‘localhost’, @logger) host_machine.session do |host|

host.upload(local_dir, "#{host.dir}/#{File.basename(local_dir)}")
@logger.debug { host.sh("ls -lR #{host.dir}") }

end

Yields:



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# File 'lib/drbman/host_machine.rb', line 83

def session(&block)
  begin
    # this is ugly but apparently net-ssh can fail public_key authentication
    # when ran in parallel.
    HostMachine.connection_mutex.synchronize do
      connect
    end
    yield self
  rescue Net::SSH::AuthenticationFailed => e
    @logger.error { "Authentication Failed for #{e}" }
    raise e
  ensure
    disconnect
  end
end

#sh(command, opts = {}) ⇒ String?

run a command on the host machine Note that the environment on the host machine is the default environment instead of the user’s environment. So by default we try to source ~/.profile and ~/.bashrc

Parameters:

  • command (String) —

    the command to run

  • opts (Hash) (defaults to: {})

Options Hash (opts):

  • :source (Array<String>) — default: ['~/.profile', '~/.bashrc'] —

    array of files to source.

Returns:

  • (String, nil) —

    the output from running the command



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# File 'lib/drbman/host_machine.rb', line 147

def sh(command, opts={})
  unless @ssh.nil?
    opts[:source] = ['~/.profile', '~/.bashrc'] if opts[:source].blank?
    result = nil
    commands = pre_commands(opts[:source])
    commands << command
    command_line = commands.join(' && ')
    @logger.debug { "sh: \"#{command_line}\""}
    result = @ssh.exec!(command_line)
    @logger.debug { "=> #{result}" }
  end
  result
end

#upload(local_src, remote_dest) ⇒ Object

upload a directory structure to the host machine.

Parameters:

  • local_src (String) —

    the source directory on the local machine

  • remote_dest (String) —

    the destination directory on the host machine

Raises:

  • (Exception) —

    if the files are not copied



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# File 'lib/drbman/host_machine.rb', line 103

def upload(local_src, remote_dest)
  @logger.debug { "upload(\"#{local_src}\", \"#{remote_dest}\")" }
  result = nil
  unless @ssh.nil?
    begin
      @ssh.scp.upload!(local_src, remote_dest, :recursive => true) do |ch, name, sent, total|
        @logger.debug { "#{name}: #{sent}/#{total}" }
      end
      @ssh.loop
    rescue Exception => e
      # only raise the exception if the files differ
      @logger.debug { e }
      raise e unless same_files?(local_src, remote_dest)
    end
  end
end