Class: Cuboid::Processes::Manager

Inherits:
Object
  • Object
show all
Includes:
Singleton
Defined in:
lib/cuboid/processes/manager.rb

Overview

Helper for managing processes.

Author:

  • Tasos “Zapotek” Laskos <tasos.laskos@gmail.com>

Constant Summary collapse

RUNNER = 
"#{File.dirname( __FILE__ )}/executables/base.rb"
SPAWN_RETRIES = 
10

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Manager

Returns a new instance of Manager.



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# File 'lib/cuboid/processes/manager.rb', line 19

def initialize
    reset
end

Instance Attribute Details

#pids ⇒ Array<Integer> (readonly)

Returns PIDs of all running processes.

Returns:

  • (Array<Integer>) —

    PIDs of all running processes.



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# File 'lib/cuboid/processes/manager.rb', line 17

def pids
  @pids
end

Class Method Details

.method_missing(sym, *args, &block) ⇒ Object 



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# File 'lib/cuboid/processes/manager.rb', line 286

def self.method_missing( sym, *args, &block )
    if instance.respond_to?( sym )
        instance.send( sym, *args, &block )
    else
        super( sym, *args, &block )
    end
end

.respond_to?(m) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/cuboid/processes/manager.rb', line 294

def self.respond_to?( m )
    super( m ) || instance.respond_to?( m )
end

Instance Method Details

#<<(pid) ⇒ Integer

Returns ‘pid`.

Parameters:

  • pid (Integer) —

    Adds a PID to the #pids and detaches the process.

Returns:

  • (Integer) —

    ‘pid`



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# File 'lib/cuboid/processes/manager.rb', line 32

def <<( pid )
    @pids << pid
    Process.detach pid
    pid
end

#alive?(pid) ⇒ Boolean

Returns ‘true` if the process is alive, `false` otherwise.

Parameters:

  • pid (Integer)

Returns:

  • (Boolean) —

    ‘true` if the process is alive, `false` otherwise.



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# File 'lib/cuboid/processes/manager.rb', line 138

def alive?( pid )
    # Windows is not big on POSIX so try it its own way if possible.
    if Cuboid.windows?
        begin
            alive = false
            processes = wmi.ExecQuery( "select ProcessId from win32_process where ProcessID='#{pid}'" )
            processes.each do |proc|
                proc.ole_free
                alive = true
            end
            processes.ole_free

            return alive
        rescue WIN32OLERuntimeError
        end
    end

    !!(Process.kill( 0, pid ) rescue false)
end

#discard_output ⇒ Object 



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# File 'lib/cuboid/processes/manager.rb', line 186

def discard_output
    @discard_output = true
end

#discard_output? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/cuboid/processes/manager.rb', line 190

def discard_output?
    @discard_output
end

#find(bin) ⇒ Object 



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# File 'lib/cuboid/processes/manager.rb', line 73

def find( bin )
    find_in_path( bin ) || find_in_applications( bin ) ||
        find_in_program_files( bin )
end

#find_in_applications(bin) ⇒ Object 



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# File 'lib/cuboid/processes/manager.rb', line 94

def find_in_applications( bin )
    return if !Cuboid.mac?

    @find_in_applications ||= {}
    return @find_in_applications[bin] if @find_in_applications.include?( bin )

    paths = ENV['PATH'].split( File::PATH_SEPARATOR ) | [
      '/Applications/'
    ]

    paths.each do |root|
        glob = File.join( "#{root}/*/Contents/MacOS", '**', bin )

        exe = Dir.glob( glob ).find { |f| File.executable?( f ) }
        return @find_in_applications[bin] = exe if exe
    end

    @find_in_applications[bin] = nil
end

#find_in_path(bin) ⇒ Object 



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# File 'lib/cuboid/processes/manager.rb', line 78

def find_in_path( bin )
    @find_in_path ||= {}
    return @find_in_path[bin] if @find_in_path.include?( bin )

    if Cuboid.windows?
        bin = "#{bin}.exe"
    end

    ENV['PATH'].split( File::PATH_SEPARATOR ).each do |path|
        f = File.join( path, bin )
        return @find_in_path[bin] = f if File.exist?( f )
    end

    @find_in_path[bin] = nil
end

#find_in_program_files(bin) ⇒ Object 



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# File 'lib/cuboid/processes/manager.rb', line 114

def find_in_program_files( bin )
    return if !Cuboid.windows?

    @find_in_program_files ||= {}
    return @find_in_program_files[bin] if @find_in_program_files.include?( bin )

    [
        ENV['PROGRAMFILES']      || '\\Program Files',
        ENV['ProgramFiles(x86)'] || '\\Program Files (x86)',
        ENV['ProgramW6432']      || '\\Program Files'
    ].each do |root|
        glob = File.join( root, '**', "#{bin}.exe" )
        glob.tr!( '\\', '/' )

        exe = Dir.glob( glob ).find { |f| File.executable?( f ) }
        return @find_in_program_files[bin] = exe if exe
    end

    @find_in_program_files[bin] = nil
end

#kill(pid) ⇒ Object

Parameters:

  • pid (Integer) —

    PID of the process to kill.



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# File 'lib/cuboid/processes/manager.rb', line 40

def kill( pid )
    fail 'Cannot kill self.' if pid == Process.pid

    Timeout.timeout 10 do
        while sleep 0.1 do
            begin
                Process.kill( Cuboid.windows? ? 'KILL' : 'TERM', pid )

            # Either kill was successful or we don't have enough perms or
            # we hit a reused PID for someone else's process, either way,
            # consider the process gone.
            rescue Errno::ESRCH, Errno::EPERM,
                # Don't kill ourselves.
                SignalException

                @pids.delete pid
                return
            end
        end
    end
rescue Timeout::Error
    # SIGTERM didn't take in 10s — escalate. Ruby's default TERM
    # handler only raises SignalException on the main thread; if
    # the main thread already exited but a non-daemon Application
    # thread is keeping the runtime up (audit workers, browser
    # cluster manager, etc.) then no amount of TERMs will land.
    # Without this escalation the spec suite leaks engine
    # subprocesses every time a kill_instance / killall fails to
    # land cleanly.
    Process.kill( 'KILL', pid ) rescue nil
    @pids.delete pid
end

#kill_many(pids) ⇒ Object

Parameters:

  • pids (Array<Integer>) —

    PIDs of the process to #kill.



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# File 'lib/cuboid/processes/manager.rb', line 160

def kill_many( pids )
    pids.each { |pid| kill pid }
end

#kill_reactor ⇒ Object

Stops the Reactor.



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# File 'lib/cuboid/processes/manager.rb', line 171

def kill_reactor
    Raktr.stop
rescue
    nil
end

#killall ⇒ Object

Kills all processes.



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# File 'lib/cuboid/processes/manager.rb', line 165

def killall
    kill_many @pids.dup
    @pids.clear
end

#preserve_output ⇒ Object

Overrides the default setting of discarding process outputs.



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# File 'lib/cuboid/processes/manager.rb', line 178

def preserve_output
    @discard_output = false
end

#preserve_output? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/cuboid/processes/manager.rb', line 182

def preserve_output?
    !discard_output?
end

#reset ⇒ Object 



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# File 'lib/cuboid/processes/manager.rb', line 23

def reset
    @pids           = []
    @discard_output = true
end

#spawn(executable, options = {}) ⇒ Integer

Returns PID of the process.

Parameters:

  • executable (String) —

    Name of the executable Ruby script found in OptionGroups::Paths#executables without the ‘.rb’ extension.

  • options (Hash) (defaults to: {}) —

    Options to pass to the script – can be retrieved from ‘$options`.

Returns:

  • (Integer) —

    PID of the process.



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# File 'lib/cuboid/processes/manager.rb', line 202

def spawn( executable, options = {} )
    fail ArgumentError, 'Fork not supported.' if options.delete(:fork)

    stdin      = options.delete(:stdin)
    stdout     = options.delete(:stdout)
    stderr     = options.delete(:stderr)
    new_pgroup = options.delete(:new_pgroup)
    daemonize  = options.delete(:daemonize)

    spawn_options = {}

    if new_pgroup
        if Cuboid.windows?
            spawn_options[:new_pgroup] = new_pgroup
        else
            spawn_options[:pgroup] = new_pgroup
        end
    end

    spawn_options[:in]  = stdin  if stdin
    spawn_options[:out] = stdout if stdout
    spawn_options[:err] = stderr if stderr

    # `:detached` decouples "child outlives spawner" from
    # `:daemonize`, which only controls whether THIS thread
    # `waitpid`s. MCP and the spec helpers spawn with
    # `daemonize: true` but want the child tethered (die with
    # parent); only Agent-managed instances genuinely want to
    # outlive their spawner. Default = tethered; Agent's
    # `spawn_instance` opts out by passing `detached: true`.
    # base.rb's parent-death watchdog reads `$options[:ppid]`;
    # a missing ppid means "no tether" and the watchdog
    # short-circuits.
    detached = options.delete( :detached )
    options[:ppid]   = Process.pid if !detached
    options[:tmpdir] = Options.paths.tmpdir

    cuboid_options = Options.dup.update( options.delete(:options) || {} ).to_h
    encoded_cuboid_options = Base64.strict_encode64( Marshal.dump( cuboid_options ) )

    if executable.is_a? Symbol
        executable = "#{Options.paths.executables}/#{executable}.rb"
    elsif !File.exist?( executable )
        raise ArgumentError, "Executable does not exist: #{executable}"
    end

    encoded_options = Base64.strict_encode64( Marshal.dump( options ) )
    argv            = [executable, encoded_options]


    pid = nil
    SPAWN_RETRIES.times do |i|
        begin
            # It's very, **VERY** important that we use this argument format as
            # it bypasses the OS shell and we can thus count on a 1-to-1 process
            # creation and that the PID we get will be for the actual process.
            pid = Process.spawn(
                {
                    'CUBOID_SPAWN_OPTIONS' => encoded_cuboid_options
                },
                RbConfig.ruby,
                RUNNER,
                *(argv + [spawn_options])
            )
            break if alive? pid
            end
    end

    self << pid

    if !daemonize
        begin
            Process.waitpid( pid )
        rescue Errno::ECHILD
            @pids.delete pid
            return
        rescue Interrupt
            exit 0
        end
    end

    pid
end