First version of new command exection library

git-svn-id: http://svn.opennebula.org/one/trunk@343 3034c82b-c49b-4eb3-8279-a7acafdc01c0

src/mad/ruby/CommandManager.rb

@@ -0,0 +1,131 @@
+
+require 'pp'
+require 'open3'
+
+# Generic command executor that holds the code shared by all the command
+# executors. Commands can have an associated callback that will be
+# after they finish.
+class GenericCommand
+    attr_accessor :value, :code, :stdout, :stderr, :command
+    attr_accessor :callback
+    
+    # Creates the new command:
+    # +command+: string with the command to be executed
+    def initialize(command)
+        @command=command
+        @callback=nil
+    end
+    
+    # Runs the command and calls the callback if it is defined
+    # +data+: variable to pass to the callaback to provide data
+    # or to share with other callbacks
+    def run(data=nil)
+        (@stdout, @stderr)=execute
+        @code=get_exit_code(@stderr)
+        
+        @callback.call(self, data) if @callback
+        
+        return @code
+    end
+    
+private
+
+    # Gets exit code from STDERR
+    def get_exit_code(str)
+        tmp=str.scan(/^ExitCode: (\d*)$/)
+        return nil if !tmp[0]
+        tmp[0][0].to_i
+    end
+    
+    # Low level command execution. This method has to be redefined
+    # for each kind of command execution. Returns an array with
+    # +stdout+ and +stderr+ of the command execution.
+    def execute
+        puts "About to execute \"#{@command}\""
+        ["", "ExitCode: 0"]
+    end
+    
+end
+
+# Executes commands in the machine where it is called. See documentation
+# for GenericCommand
+class LocalCommand < GenericCommand
+private
+
+    def execute
+        std=Open3.popen3(
+            "#{command} ;"+
+            " echo ExitCode: $? 1>&2")
+        [std[1].read, std[2].read]
+    end
+end
+
+# Executes commands in a remote machine ussing ssh. See documentation
+# for GenericCommand
+class SSHCommand < GenericCommand
+    attr_accessor :host
+    
+    # This one takes another parameter. +host+ is the machine
+    # where de command is going to be executed
+    def initialize(command, host)
+        @host=host
+        super(command)
+    end
+    
+private
+
+    def execute
+        std=Open3.popen3(
+            "ssh -n #{host} #{command} ;"+
+            " echo ExitCode: $? 1>&2")
+        std[0].close
+        [std[1].read, std[2].read]
+    end
+end
+
+
+if $0 == __FILE__
+    
+    data={}
+    
+    command=GenericCommand.new("uname -a")
+    command.callback=lambda {|obj,data|
+        puts obj.stderr
+        
+        data[1]=[obj.command, obj.code]
+    }
+    
+    command.run(data)
+    
+    local_command=LocalCommand.new("uname -a")
+    local_command.callback=lambda {|obj,data|
+        puts "STDOUT:"
+        puts obj.stdout
+        puts
+        puts "STDERR:"
+        puts obj.stderr
+        
+        data[2]=[obj.command, obj.code]
+    }
+    
+    local_command.run(data)
+    
+    ssh_command=SSHCommand.new("uname -a", "localhost")
+    ssh_command.callback=lambda {|obj,data|
+        puts "STDOUT:"
+        puts obj.stdout
+        puts
+        puts "STDERR:"
+        puts obj.stderr
+        
+        data[3]=[obj.command, obj.host, obj.code]
+    }
+    
+    ssh_command.run(data)
+    
+    pp data
+end
+
+
+
+