Class: SimplePid

Inherits:
Object
  • Object
show all
Defined in:
lib/simple_pid.rb

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(path) ⇒ SimplePid

Returns a new instance of SimplePid.



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# File 'lib/simple_pid.rb', line 7

def initialize(path)
  @path = path.to_absolute_path
end

Class Method Details

.cleanup(path) ⇒ Object 



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# File 'lib/simple_pid.rb', line 23

def self.cleanup(path)
  p = self.new(path)
  if p.running?
    return false
  else
    p.cleanup
    return true
  end
end

.cleanup!(path) ⇒ Object 



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# File 'lib/simple_pid.rb', line 33

def self.cleanup!(path)
  p = self.new(path)
  p.cleanup if p.exists?
end

.drop(path) ⇒ Object 



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# File 'lib/simple_pid.rb', line 11

def self.drop(path)
  p = self.new(path)
  if p.exists?
    unless p.running?
      p.cleanup
      p.write!
    end
  else
    p.write!
  end
end

Instance Method Details

#cleanup ⇒ Object Also known as: zap 



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# File 'lib/simple_pid.rb', line 76

def cleanup
  begin
    File.delete(@path)
  rescue Errno::ENOENT
    File.delete("/tmp/#{Pathname.new(@path).basename}")
  end
end

#ensure_stopped! ⇒ Object 



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# File 'lib/simple_pid.rb', line 69

def ensure_stopped!
  if self.running?
    puts "Process already running with id #{self.pid}"
    exit 1
  end
end

#exists? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/simple_pid.rb', line 38

def exists?
  File.exists?(@path)
end

#pid ⇒ Object

Return the pid contained in the pidfile, or nil



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# File 'lib/simple_pid.rb', line 63

def pid
  return nil unless self.exists?

  File.open( @path ) { |f| return f.gets.to_i }
end

#running? ⇒ Boolean

Returns true if the process is running

Returns:

  • (Boolean) 


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# File 'lib/simple_pid.rb', line 43

def running?
  return false unless self.exists?

  # Check if process is in existence
  # The simplest way to do this is to send signal '0'
  # (which is a single system call) that doesn't actually
  # send a signal
  begin
    Process.kill(0, self.pid)
    return true
  rescue Errno::ESRCH
    return false
  rescue ::Exception   # for example on EPERM (process exists but does not belong to us)
    return true
  #rescue Errno::EPERM
  #  return false
  end
end

#write! ⇒ Object 



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# File 'lib/simple_pid.rb', line 85

def write!
  begin
    File.open(@path, "w") { |f| f.puts Process.pid }
  rescue Errno::ENOENT, Errno::EACCES
    File.open("/tmp/#{Pathname.new(@path).basename}", "w") { |f| f.puts Process.pid }
  end
end