vagrant/lib/vagrant/data_store.rb

93 lines
2.8 KiB
Ruby

require 'pathname'
require 'log4r'
module Vagrant
# The Vagrant data store is a key-value store which is persisted
# as JSON in a local file which is specified in the initializer.
# The data store itself is accessed via typical hash accessors: `[]`
# and `[]=`. If a key is set to `nil`, then it is removed from the
# datastore. The data store is only updated on disk when {#commit}
# is called on the data store itself.
#
# The data store is a hash with indifferent access, meaning that
# while all keys are persisted as strings in the JSON, you can access
# them back as either symbols or strings. Note that this is only true
# for the top-level data store. As soon as you set a hash inside the
# data store, unless you explicitly use a {Util::HashWithIndifferentAccess},
# it will be a regular hash.
class DataStore < Util::HashWithIndifferentAccess
attr_reader :file_path
def initialize(file_path)
@logger = Log4r::Logger.new("vagrant::datastore")
if file_path
@logger.info("Created: #{file_path}")
@file_path = Pathname.new(file_path)
if @file_path.exist?
raise Errors::DotfileIsDirectory if @file_path.directory?
begin
merge!(JSON.parse(@file_path.read))
rescue JSON::ParserError
# Ignore if the data is invalid in the file.
@logger.error("Data store contained invalid JSON. Ignoring.")
end
end
else
@logger.info("No file path. In-memory data store.")
@file_path = nil
end
end
# Commits any changes to the data to disk. Even if the data
# hasn't changed, it will be reserialized and written to disk.
def commit
if !@file_path
raise StandardError, "In-memory data stores can't be committed."
end
clean_nil_and_empties
if empty?
# Delete the file since an empty data store is not useful
@logger.info("Deleting data store since we're empty: #{@file_path}")
@file_path.delete if @file_path.exist?
else
@logger.info("Committing data to data store: #{@file_path}")
@file_path.open("w") do |f|
f.write(to_json)
f.fsync
end
end
end
protected
# Removes the "nil" and "empty?" values from the hash (children
# included) so that the final output JSON is cleaner.
def clean_nil_and_empties(hash=self)
# Clean depth first
hash.each do |k, v|
clean_nil_and_empties(v) if v.is_a?(Hash)
end
# Clean ourselves, knowing that any children have already been
# cleaned up
bad_keys = hash.inject([]) do |acc, data|
k,v = data
acc.push(k) if v.nil?
acc.push(k) if v.respond_to?(:empty?) && v.empty?
acc
end
bad_keys.each do |key|
hash.delete(key)
end
end
end
end