class Puppet::Util::JsonLockfile

This class provides a simple API for managing a lock file whose contents are a serialized JSON object. 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 structured data (state messages, etc.) about the lock.

@see Puppet::Util::Lockfile

Public Instance Methods

lock(lock_data = nil) click to toggle source

Lock the lockfile. You may optionally pass a data object, which will be retrievable for the duration of time during which the file is locked.

@param [Hash] lock_data an optional Hash of data to associate with the lock.

This may be used to store pids, descriptive messages, etc.  The
data may be retrieved at any time while the lock is held by
calling the #lock_data method. <b>NOTE</b> that the JSON serialization
does NOT support Symbol objects--if you pass them in, they will be
serialized as Strings, so you should plan accordingly.

@return [boolean] true if lock is successfully acquired, false otherwise.

Calls superclass method Puppet::Util::Lockfile#lock
   # File lib/puppet/util/json_lockfile.rb
23 def lock(lock_data = nil)
24   return false if locked?
25 
26   super(Puppet::Util::Json.dump(lock_data))
27 end
lock_data() click to toggle source

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

was locked.

@return [Object] the data object. Remember that the serialization does not

support Symbol objects, so if your data Object originally contained symbols,
they will be converted to Strings.
Calls superclass method Puppet::Util::Lockfile#lock_data
   # File lib/puppet/util/json_lockfile.rb
34 def lock_data
35   return nil unless file_locked?
36   file_contents = super
37   return nil if file_contents.nil? or file_contents.empty?
38   Puppet::Util::Json.load(file_contents)
39 rescue Puppet::Util::Json::ParseError
40   Puppet.warning _("Unable to read lockfile data from %{path}: not in JSON") % { path: @file_path }
41   nil
42 end