Sha256: 1fc4076df6c960567006a243a25d04b95600d5f0e2b2d4ed7698842eea337b53
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Versions: 21
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Contents
module AssetCloud
class BucketChain < Bucket
# returns a new Bucket class which writes to each given Bucket
# but only uses the first one for reading
def self.chain(*klasses)
Class.new(self) do
attr_reader :chained_buckets
define_method 'initialize' do |cloud, name|
super(cloud, name)
@chained_buckets = klasses.map {|klass| klass.new(cloud,name)}
end
end
end
def ls(key=nil)
first_possible_bucket {|b| b.ls(key)}
end
def read(key)
first_possible_bucket {|b| b.read(key)}
end
def stat(key=nil)
first_possible_bucket {|b| b.stat(key)}
end
def read_version(key, version)
first_possible_bucket {|b| b.read_version(key, version)}
end
def versions(key)
first_possible_bucket {|b| b.versions(key)}
end
def write(key, data)
every_bucket_with_transaction_on_key(key) {|b| b.write(key, data)}
end
def delete(key)
every_bucket_with_transaction_on_key(key) {|b| b.delete(key)}
end
def respond_to?(sym)
@chained_buckets.any? {|b| b.respond_to?(sym)}
end
def method_missing(sym, *args)
first_possible_bucket {|b| b.send(sym, *args)}
end
private
def first_possible_bucket(&block)
@chained_buckets.each do |bucket|
begin
return yield(bucket)
rescue NoMethodError, NotImplementedError => e
nil
end
end
end
def every_bucket_with_transaction_on_key(key, i=0, &block)
return unless bucket = @chained_buckets[i]
old_value = begin
bucket.read(key)
rescue AssetCloud::AssetNotFoundError
nil
end
result = yield(bucket)
begin
every_bucket_with_transaction_on_key(key, i+1, &block)
return result
rescue StandardError => e
if old_value
bucket.write(key, old_value)
else
bucket.delete(key)
end
raise e
end
end
end
end
Version data entries
21 entries across 21 versions & 1 rubygems