Class: RunLoop::ProcessWaiter

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

Overview

A class for waiting on processes.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(process_name, options = {}) ⇒ ProcessWaiter


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# File 'lib/run_loop/process_waiter.rb', line 8

def initialize(process_name, options={})
  @options = DEFAULT_OPTIONS.merge(options)
  @process_name = process_name
end

Instance Attribute Details

#process_nameObject (readonly)

Returns the value of attribute process_name


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# File 'lib/run_loop/process_waiter.rb', line 6

def process_name
  @process_name
end

Instance Method Details

#pidsArray<Integer>

Collect a list of Integer pids.


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# File 'lib/run_loop/process_waiter.rb', line 15

def pids
  process_info = `ps x -o pid,comm | grep -v grep | grep '#{process_name}'`
  process_array = process_info.split("\n")
  process_array.map { |process| process.split(' ').first.strip.to_i }
end

#running_process?Boolean

Is the `process_name` a running?


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# File 'lib/run_loop/process_waiter.rb', line 22

def running_process?
  !pids.empty?
end

#wait_for_anyObject

Wait for `process_name` to start.


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# File 'lib/run_loop/process_waiter.rb', line 63

def wait_for_any
  return true if running_process?

  now = Time.now
  poll_until = now + @options[:timeout]
  delay = @options[:interval]
  is_alive = false
  while Time.now < poll_until
    is_alive = running_process?
    break if is_alive
    sleep delay
  end

  RunLoop.log_debug("Waited for #{Time.now - now} seconds for '#{process_name}' to start.")

  if @options[:raise_on_timeout] and !is_alive
    raise "Waited #{@options[:timeout]} seconds for '#{process_name}' to start."
  end
  is_alive
end

#wait_for_n(n) ⇒ Object

Wait for a number of process to start.

Raises:

  • (ArgumentError)

    If n < 0

  • (ArgumentError)

    If n is not an Integer


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# File 'lib/run_loop/process_waiter.rb', line 30

def wait_for_n(n)
  unless n.is_a?(Integer)
    raise ArgumentError, "Expected #{n.class} to be #{1.class}"
  end

  unless n > 0
    raise ArgumentError, "Expected #{n} to be > 0"
  end

  return true if pids.count == n

  now = Time.now
  poll_until = now + @options[:timeout]
  delay = @options[:interval]
  there_are_n = false
  while Time.now < poll_until
    there_are_n = pids.count == n
    break if there_are_n
    sleep delay
  end

  plural = n > 1 ? "es" : ''
  RunLoop.log_debug("Waited for #{Time.now - now} seconds for #{n} '#{process_name}' process#{plural} to start.")

  if @options[:raise_on_timeout] and !there_are_n
    plural = n > 1 ? "es" : ''
    raise "Waited #{@options[:timeout]} seconds for #{n} '#{process_name}' process#{plural} to start."
  end
  there_are_n
end

#wait_for_noneObject

Wait for all `process_name` to finish.


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# File 'lib/run_loop/process_waiter.rb', line 85

def wait_for_none
  return true if !running_process?

  now = Time.now
  poll_until = now + @options[:timeout]
  delay = @options[:interval]
  has_terminated = false
  while Time.now < poll_until
    has_terminated = !self.running_process?
    break if has_terminated
    sleep delay
  end

  RunLoop.log_debug("Waited for #{Time.now - now} seconds for '#{process_name}' to die.")

  if @options[:raise_on_timeout] and !has_terminated
    raise "Waited #{@options[:timeout]} seconds for '#{process_name}' to die."
  end
  has_terminated
end