Module: RExec

Defined in:
lib/rexec.rb,
lib/rexec/task.rb,
lib/rexec/daemon.rb,
lib/rexec/server.rb,
lib/rexec/version.rb,
lib/rexec/connection.rb,
lib/rexec/daemon/base.rb,
lib/rexec/environment.rb,
lib/rexec/priviledges.rb,
lib/rexec/daemon/controller.rb,
lib/rexec/daemon/process_file.rb

Overview

Copyright © 2007, 2009, 2011 Samuel G. D. Williams. <www.oriontransfer.co.nz>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Defined Under Namespace

Modules: Daemon Classes: Connection, InvalidConnectionError, Task

Constant Summary collapse

CONNECTION_CODE =

The connection code which is sent to the client to be used for bi-directional communication.

(Pathname.new(__FILE__).dirname + "connection.rb").read
CLIENT_CODE =

The client code which sets up the connection object and initialises communciation.

(Pathname.new(__FILE__).dirname + "client.rb").read
VERSION = 
"1.6.0"

Class Method Summary collapse

Class Method Details

.change_user(user) ⇒ Object

Set the user of the current process. Supply either a user ID or a user name.

Be aware that on Mac OS X / Ruby 1.8 there are bugs when the user id is negative (i.e. it doesn’t work). For example “nobody” with uid -2 won’t work.



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# File 'lib/rexec/priviledges.rb', line 31

def self.change_user(user)
	if user.kind_of?(String)
		user = Etc.getpwnam(user).uid
	end

	Process::Sys.setuid(user)
end

.close_io(except = [$stdin, $stdout, $stderr]) ⇒ Object

Cloose all IO other than $stdin, $stdout, $stderr (or those given by the argument except)



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# File 'lib/rexec/task.rb', line 32

def self.close_io(except = [$stdin, $stdout, $stderr])
	# Make sure all file descriptors are closed
	ObjectSpace.each_object(IO) do |io|
		unless except.include?(io)
			io.close rescue nil
		end
	end
end

.current_user ⇒ Object

Get the user of the current process. Returns the user name.



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# File 'lib/rexec/priviledges.rb', line 41

def self.current_user
	uid = Process::Sys.getuid

	Etc.getpwuid(uid).name
end

.env(new_env = nil, &block) ⇒ Object

Updates the global ENV for the duration of block. Not multi-thread safe.



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# File 'lib/rexec/environment.rb', line 23

def self.env (new_env = nil, &block)
	old_env = ENV.to_hash

	ENV.update(new_env) if new_env

	yield

	ENV.clear
	ENV.update(old_env)
end

.start_server(code, command, options = {}, &block) ⇒ Object

Start a remote ruby server. This function is a structural cornerstone. This code runs the command you supply (this command should start an instance of ruby somewhere), sends it the code in connection.rb and client.rb as well as the code you supply.

Once the remote ruby instance is set up and ready to go, this code will return (or yield) the connection and pid of the executed command.

From this point, you can send and receive objects, and interact with the code you provided within a remote ruby instance.

For a local shell, you could specify “ruby” as the command. For a remote shell via SSH, you could specify “ssh example.com ruby”.

Example

Create a file called client.rb on the server. This file contains code to be executed on the client. This file can assume the existance of an object called $connection:

$connection.run do |object| case(object) when :bounce $connection.send_object(object) end end

Then, on the server, create a new program server.rb which will be used to coordinate the execution of code:

shell = “ssh example.com ruby” client_code = (Pathname.new(__FILE__).dirname + “./client.rb”).read RExec::start_server(client_code, shell) do |connection, pid| connection.send_object([:bounce, “Hello World!”]) result = connection.receive_object end



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# File 'lib/rexec/server.rb', line 71

def self.start_server(code, command, options = {}, &block)
	options[:passthrough] = :err unless options[:passthrough]

	send_code = Proc.new do |cin|
		unless options[:raw]
			cin.puts(CONNECTION_CODE)
			cin.puts(CLIENT_CODE)
		end
		
		cin.puts(code)
	end

	if block_given?
		Task.open(command, options) do |task|
			conn = Connection.build(task, options, &send_code)

			begin
				yield conn, task
			ensure
				conn.stop
			end
		end
	else
		task = Task.open(command, options)
		conn = Connection.build(task, options, &send_code)

		return conn, task
	end
end