Class: DRb::DRbSSHRemoteClient

Inherits:
DRbSSHClient show all
Defined in:
lib/drbssh.rb

Overview

DRbSSH remote client - does the heavy lifting of SSH’ing to a remote server and bootstrapping its Ruby interpreter for DRb communication.

Instance Attribute Summary

Attributes inherited from DRbSSHClient

#read_fd, #receiveq, #sendq, #write_fd

Instance Method Summary collapse

Methods inherited from DRbSSHClient

#alive?, #recv_reply, #send_request

Constructor Details

#initialize(uri, server) ⇒ DRbSSHRemoteClient

Create an SSH-connection to uri, and spawn a server, so client has something to talk to



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# File 'lib/drbssh.rb', line 93

def initialize(uri, server)
	# child-to-parent, parent-to-child
	ctp_rd, ctp_wr = IO.pipe
	ptc_rd, ptc_wr = IO.pipe

	host, cmd = DRbSSHProtocol.split_uri(uri)

	# Read the source-code for this file, and add bits for initialising the remote side.
	# Since DRbSSHServer is doing all the filedescriptor read/writing, we need to start
	# a DRbSSHLocalClient immediately.
	self_code = <<-EOT
		#{File.read(__FILE__)};
		DRb.start_service("#{uri}", binding)
		DRb.thread['DRbSSHLocalClient'] = DRb::DRbSSHLocalClient.new(DRb::DRbSSHProtocol.server)
		DRb.thread.join
	EOT

	# Fork to create an SSH child-process
	if fork.nil?
		# In child - cleanup filehandles, reopen stdin/stdout, and exec ssh to connect to remote

		ctp_rd.close
		ptc_wr.close

		$stdin.reopen(ptc_rd)
		$stdout.reopen(ctp_wr)

		cmd = ['ruby'] if cmd.nil? or cmd.empty?

		# exec Ruby on remote end, and read bootstrap code.
		exec("ssh", "-oBatchMode=yes", "-T", host, "exec", *cmd, '-e', "\"eval STDIN.read(#{self_code.bytesize})\"")
		exit
	else
		# In parent - cleanup filehandles, write bootstrap-code, and hand over to superclass.

		ctp_wr.close
		ptc_rd.close

		# Bootstrap remote Ruby.
		ptc_wr.write(self_code)

		@read_fd, @write_fd = ctp_rd, ptc_wr

		super(server)
	end
end

Instance Method Details

#close ⇒ Object

Close client.



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# File 'lib/drbssh.rb', line 141

def close
	# Closing the filedescriptors should trigger an IOError in the server-thread
	# waiting, which makes it close the client attached.
	self.read_fd.close unless self.read_fd.closed?
	self.write_fd.close unless self.write_fd.closed?
end