diff options
Diffstat (limited to 'vendor/gems/couchrest_session_store/lib/couchrest/model/rotation.rb')
| -rw-r--r-- | vendor/gems/couchrest_session_store/lib/couchrest/model/rotation.rb | 263 |
1 files changed, 0 insertions, 263 deletions
diff --git a/vendor/gems/couchrest_session_store/lib/couchrest/model/rotation.rb b/vendor/gems/couchrest_session_store/lib/couchrest/model/rotation.rb deleted file mode 100644 index 9e1a5c3..0000000 --- a/vendor/gems/couchrest_session_store/lib/couchrest/model/rotation.rb +++ /dev/null @@ -1,263 +0,0 @@ -module CouchRest - module Model - module Rotation - extend ActiveSupport::Concern - include CouchRest::Model::DatabaseMethod - - included do - use_database_method :rotated_database_name - end - - def create(*args) - super(*args) - rescue CouchRest::NotFound => exc - raise storage_missing(exc) - end - - def update(*args) - super(*args) - rescue CouchRest::NotFound => exc - raise storage_missing(exc) - end - - def destroy(*args) - super(*args) - rescue CouchRest::NotFound => exc - raise storage_missing(exc) - end - - private - - # returns a special 'storage missing' exception when the db has - # not been created. very useful, since this happens a lot and a - # generic 404 is not that helpful. - def storage_missing(exc) - if exc.http_body =~ /no_db_file/ - CouchRest::StorageMissing.new(exc.response, database) - else - exc - end - end - - public - - module ClassMethods - # - # Set up database rotation. - # - # base_name -- the name of the db before the rotation number is - # appended. - # - # options -- one of: - # - # * :every -- frequency of rotation - # * :expiration_field - what field to use to determine if a - # document is expired. - # * :timestamp_field - alternately, what field to use for the - # document timestamp. - # * :timeout -- used to expire documents with only a timestamp - # field (in minutes) - # - def rotate_database(base_name, options={}) - @rotation_base_name = base_name - @rotation_every = (options.delete(:every) || 30.days).to_i - @expiration_field = options.delete(:expiration_field) - @timestamp_field = options.delete(:timestamp_field) - @timeout = options.delete(:timeout) - if options.any? - raise ArgumentError.new('Could not understand options %s' % options.keys) - end - end - - # - # Check to see if dbs should be rotated. The :window - # argument specifies how far in advance we should - # create the new database (default 1.day). - # - # This method relies on the assumption that it is called - # at least once within each @rotation_every period. - # - def rotate_database_now(options={}) - window = options[:window] || 1.day - - now = Time.now.utc - current_name = rotated_database_name(now) - current_count = now.to_i/@rotation_every - - next_time = window.from_now.utc - next_name = rotated_database_name(next_time) - next_count = current_count+1 - - prev_name = current_name.sub(/(\d+)$/) {|i| i.to_i-1} - replication_started = false - old_name = prev_name.sub(/(\d+)$/) {|i| i.to_i-1} # even older than prev_name - trailing_edge_time = window.ago.utc - - if !database_exists?(current_name) - # we should have created the current db earlier, but if somehow - # it is missing we must make sure it exists. - create_new_rotated_database(:from => prev_name, :to => current_name) - replication_started = true - end - - if next_time.to_i/@rotation_every >= next_count && !database_exists?(next_name) - # time to create the next db in advance of actually needing it. - create_new_rotated_database(:from => current_name, :to => next_name) - end - - if trailing_edge_time.to_i/@rotation_every == current_count - # delete old dbs, but only after window time has past since the last rotation - if !replication_started && database_exists?(prev_name) - # delete previous, but only if we didn't just start replicating from it - self.server.database(db_name_with_prefix(prev_name)).delete! - end - if database_exists?(old_name) - # there are some edge cases, when rotate_database_now is run - # infrequently, that an older db might be left around. - self.server.database(db_name_with_prefix(old_name)).delete! - end - end - end - - def rotated_database_name(time=nil) - unless @rotation_base_name && @rotation_every - raise ArgumentError.new('missing @rotation_base_name or @rotation_every') - end - time ||= Time.now.utc - units = time.to_i / @rotation_every.to_i - "#{@rotation_base_name}_#{units}" - end - - # - # create a new empty database. - # - def create_database!(name=nil) - db = if name - self.server.database!(db_name_with_prefix(name)) - else - self.database! - end - create_rotation_filter(db) - if self.respond_to?(:design_doc) - design_doc.sync!(db) - # or maybe this?: - #self.design_docs.each do |design| - # design.migrate(to_db) - #end - end - return db - end - - protected - - # - # Creates database named by options[:to]. Optionally, set up - # continuous replication from the options[:from] db, if it exists. The - # assumption is that the from db will be destroyed later, cleaning up - # the replication once it is no longer needed. - # - # This method will also copy design documents if present in the from - # db, in the CouchRest::Model, or in a database named after - # @rotation_base_name. - # - def create_new_rotated_database(options={}) - from = options[:from] - to = options[:to] - to_db = self.create_database!(to) - if database_exists?(@rotation_base_name) - base_db = self.server.database(db_name_with_prefix(@rotation_base_name)) - copy_design_docs(base_db, to_db) - end - if from && from != to && database_exists?(from) - from_db = self.server.database(db_name_with_prefix(from)) - replicate_old_to_new(from_db, to_db) - end - end - - def copy_design_docs(from, to) - params = {:startkey => '_design/', :endkey => '_design0', :include_docs => true} - from.documents(params) do |doc_hash| - design = doc_hash['doc'] - begin - to.get(design['_id']) - rescue CouchRest::NotFound - design.delete('_rev') - to.save_doc(design) - end - end - end - - def create_rotation_filter(db) - name = 'rotation_filter' - filter_string = if @expiration_field - NOT_EXPIRED_FILTER % {:expires => @expiration_field} - elsif @timestamp_field && @timeout - NOT_TIMED_OUT_FILTER % {:timestamp => @timestamp_field, :timeout => (60 * @timeout)} - else - NOT_DELETED_FILTER - end - filters = {"not_expired" => filter_string} - db.save_doc("_id" => "_design/#{name}", "filters" => filters) - rescue CouchRest::Conflict - end - - # - # Replicates documents from_db to to_db, skipping documents that have - # expired or been deleted. - # - # NOTE: It would be better if we could do this: - # - # from_db.replicate_to(to_db, true, false, - # :filter => 'rotation_filter/not_expired') - # - # But replicate_to() does not support a filter argument, so we call - # the private method replication() directly. - # - def replicate_old_to_new(from_db, to_db) - create_rotation_filter(from_db) - from_db.send(:replicate, to_db, true, :source => from_db.name, :filter => 'rotation_filter/not_expired') - end - - # - # Three different filters, depending on how the model is set up. - # - # NOT_EXPIRED_FILTER is used when there is a single field that - # contains an absolute time for when the document has expired. The - # - # NOT_TIMED_OUT_FILTER is used when there is a field that records the - # timestamp of the last time the document was used. The expiration in - # this case is calculated from the timestamp plus @timeout. - # - # NOT_DELETED_FILTER is used when the other two cannot be. - # - NOT_EXPIRED_FILTER = "" + -%[function(doc, req) { - if (doc._deleted) { - return false; - } else if (typeof(doc.%{expires}) != "undefined") { - return Date.now() < (new Date(doc.%{expires})).getTime(); - } else { - return true; - } -}] - - NOT_TIMED_OUT_FILTER = "" + -%[function(doc, req) { - if (doc._deleted) { - return false; - } else if (typeof(doc.%{timestamp}) != "undefined") { - return Date.now() < (new Date(doc.%{timestamp})).getTime() + %{timeout}; - } else { - return true; - } -}] - - NOT_DELETED_FILTER = "" + -%[function(doc, req) { - return !doc._deleted; -}] - - end - end - end -end |