Module: MJ::Tools::SubProcess::ClassMethods

Defined in:
lib/mj/tools/subprocess.rb

Instance Method Summary collapse

Instance Method Details

#adjust_environment(wd = nil, env = nil, lang = "C") ⇒ Object

Helper method to adjust LANG to “C”



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# File 'lib/mj/tools/subprocess.rb', line 50

def adjust_environment( wd=nil, env=nil, lang="C" )
    if wd and !$noop
        cwd = Dir.getwd
        Dir.chdir(wd)
    end
    # Set the environment the user wants
    oldenv = Hash.new
    if env
        env.each do |var, value|
            oldenv[var] = ENV[var]
            if value.nil? or value == ""
                next if ENV.has_key?( value )
                ENV[var] = nil
                logger.verbose  "Removing #{var} from environment"
            else
                logger.verbose  "#{var} = #{value}"
                ENV[var] = value
            end
        end
    end
    # Save old LANG setting and switch to 'C'
    oldlang = ENV['LANG']
    ENV['LANG'] = lang
    yield
    # Reset the old LANG setting
    ENV['LANG'] = oldlang
    # Reset our changes to ENV
    oldenv.each do |var, value|
        ENV[var] = value
    end
    # Reset the current working directory
    if wd and !$noop
        Dir.chdir(cwd)
    end
end

#execute(command, wd = ENV["HOME"], env = nil) ⇒ Object

Executes command

Executes the given command and yields each line of output. Returns $? .



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# File 'lib/mj/tools/subprocess.rb', line 15

def execute( command, wd = ENV["HOME"], env = nil )
    logger.trace "(#{wd}) > #{command} 2>&1"
    if !$noop
        adjust_environment( wd, env ) {
            IO.popen( "#{command} 2>&1" ) {
                |f|
                begin
                    while
                        line = f.readline
                        if block_given?
                            yield line.chomp
                        else
                            logger.verbose line.chomp
                        end
                    end
                rescue EOFError
                    # Expected. Do nothing
                end
            }
            if $?.coredump? or $?.signaled?
                raise CoreDumpError, "Command '#{command}' core dumped because of signal #{$?.termsig}!"
            end
            logger.trace "= #{$?.exitstatus}"
            return $?.exitstatus
        }
    else
        adjust_environment( wd, env ) {
            logger.trace "= 0 # noop" 
        }
        return 0
    end

end