Class: Puppet::Util::Lockfile

Inherits:
Object
  • Object
show all
Defined in:
lib/puppet/util/lockfile.rb

Overview

This class provides a simple API for managing a lock file whose contents are an (optional) String. In addition to querying the basic state (#locked?) of the lock, managing the lock (#lock, #unlock), the contents can be retrieved at any time while the lock is held (#lock_data). This can be used to store pids, messages, etc.

See Also:

Direct Known Subclasses

JsonLockfile

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(file_path) ⇒ Lockfile

Returns a new instance of Lockfile.


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# File 'lib/puppet/util/lockfile.rb', line 12

def initialize(file_path)
  @file_path = file_path
end

Instance Attribute Details

#file_path ⇒ Object (readonly)

Returns the value of attribute file_path


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# File 'lib/puppet/util/lockfile.rb', line 10

def file_path
  @file_path
end

Instance Method Details

#lock(lock_data = nil) ⇒ boolean

Returns true if lock is successfully acquired, false otherwise.

Returns:

  • (boolean) —

    true if lock is successfully acquired, false otherwise.


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# File 'lib/puppet/util/lockfile.rb', line 25

def lock(lock_data = nil)
  begin
    Puppet::FileSystem.exclusive_create(@file_path, nil) do |fd|
      fd.print(lock_data)
    end
    true
  rescue Errno::EEXIST
    false
  end
end

#lock_data ⇒ String

Retrieve the (optional) lock data that was specified at the time the file

was locked.

Returns:

  • (String) —

    the data object.


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# File 'lib/puppet/util/lockfile.rb', line 53

def lock_data
  return File.read(@file_path) if file_locked?
end

#locked? ⇒ Boolean

Returns:

  • (Boolean) 

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# File 'lib/puppet/util/lockfile.rb', line 45

def locked?  # delegate logic to a more explicit private method

  file_locked?
end

#unlock ⇒ Object 


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# File 'lib/puppet/util/lockfile.rb', line 36

def unlock
  if locked?
    Puppet::FileSystem.unlink(@file_path)
    true
  else
    false
  end
end