Class: Xampl::RedisPersister

Inherits:
Persister show all
Defined in:
lib/xamplr/persisters/redis.rb

Constant Summary collapse

REPOSITORIES_KEY = 
"XAMPL::REPOSITORIES"
@@default_redis_options = 
{
        :repo_properties => {
                # DB Properties, maybe only set when the DB is created for the first time.
                :mentions => true,
                },
         # Connect Properties
        :thread_safe => true, # redis connections will be thread safe
        :redis_server => "redis://127.0.0.1:6379/0", #This is the format expected by redis-rb, just use it
        :clobbering_allowed => false,
        :allow_connections => true,
        :connect_to_known => true, # will connect to repos already in the redis db
        :connect_to_unknown => true, # will connect to repose not in the redis db
        :testing => false
}

Instance Attribute Summary collapse

Attributes inherited from Persister

#automatic, #block_changes, #cache_hits, #expunged, #format, #last_write_count, #name, #read_count, #rolled_back, #slow_sync, #syncing, #total_cache_hits, #total_read_count, #total_rollback_count, #total_sync_count, #total_write_count, #write_count

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Persister

#busy, #count_changed, #do_sync_write, #done_sync_write, #expunge, #find_known, #find_xampl, #has_changed, #has_not_changed, #introduce, #is_busy, #lazy_load, #lookup, #optimise, #print_stats, #put_changed, #query_implemented, #realise, replace, #represent, #rollback, #shutdown, #start_sync_write, #sync

Constructor Details

#initialize(name = nil, format = nil, options = {}) ⇒ RedisPersister

Returns a new instance of RedisPersister.



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# File 'lib/xamplr/persisters/redis.rb', line 29

def initialize(name=nil, format=nil, options={})
  super(name, format)

  @repo_name = name
#      puts "#{File.basename(__FILE__)}:#{__LINE__} [#{ __method__ }] @@default_redis_options: #{ @@default_redis_options.inspect }"
#      puts "#{File.basename(__FILE__)}:#{__LINE__} [#{ __method__ }] Xampl.raw_persister_options: #{ Xampl.raw_persister_options.inspect }"
#      puts "#{File.basename(__FILE__)}:#{__LINE__} [#{ __method__ }] options: #{ options.inspect }"

  @instance_options = {}
  @instance_options = @instance_options.merge(@@default_redis_options)
  @instance_options = @instance_options.merge(Xampl.raw_persister_options)
  @instance_options = @instance_options.merge(options) if options

  @suggested_repo_properties = @instance_options.delete(:repo_properties)

  clear_cache
  ensure_connected
end

Instance Attribute Details

#client ⇒ Object (readonly)

Returns the value of attribute client.



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# File 'lib/xamplr/persisters/redis.rb', line 5

def client
  @client
end

#instance_options ⇒ Object (readonly)

Returns the value of attribute instance_options.



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# File 'lib/xamplr/persisters/redis.rb', line 5

def instance_options
  @instance_options
end

#repo_name ⇒ Object (readonly)

Returns the value of attribute repo_name.



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# File 'lib/xamplr/persisters/redis.rb', line 5

def repo_name
  @repo_name
end

#repo_properties ⇒ Object (readonly)

Returns the value of attribute repo_properties.



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# File 'lib/xamplr/persisters/redis.rb', line 5

def repo_properties
  @repo_properties
end

#suggested_repo_properties ⇒ Object (readonly)

Returns the value of attribute suggested_repo_properties.



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# File 'lib/xamplr/persisters/redis.rb', line 5

def suggested_repo_properties
  @suggested_repo_properties
end

Class Method Details

.kind ⇒ Object 



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# File 'lib/xamplr/persisters/redis.rb', line 48

def RedisPersister.kind
  :redis
end

Instance Method Details

#cache(xampl) ⇒ Object

Raises:



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# File 'lib/xamplr/persisters/redis.rb', line 194

def cache(xampl)
  # this is called by xampl for the temporary new_cache
  raise NotXamplPersistedObject.new(xampl) unless xampl.kind_of?(XamplPersistedObject)

  key = key_for_xampl(xampl)

  existing = @new_cache[key]
  raise DuplicateXamplInPersister.new(existing, xampl, self) if existing && (existing != xampl)

  existing = @cache[key]
  begin
#        raise DuplicateXamplInPersister.new(existing, xampl, self) if existing && (existing.weakref_alive?) && (existing.__getobj__ != xampl)
    raise DuplicateXamplInPersister.new(existing, xampl, self) if existing && (existing.__getobj__ != xampl)
  rescue WeakRef::RefError => e
    # key is there but the original object isn't...
  end

  @new_cache[key] = xampl
end

#clear_cache ⇒ Object Also known as: fresh_cache 



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# File 'lib/xamplr/persisters/redis.rb', line 141

def clear_cache
  @cache_hits = 0
  @cache = {}
  @new_cache = {}
end

#clobber ⇒ Object 



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# File 'lib/xamplr/persisters/redis.rb', line 109

def clobber
  # TODO -- this is a BAD idea if there are any other connections to this repo (i.e. in different processes)

  unless @instance_options[:clobbering_allowed] then
    raise IncompatiblePersisterConfiguration.new('redis', "clobbering is not enabled for this connection to repo: '#{ repo_name }' in #{ @instance_options[:redis_server] }")
  end

  #TODO -- getting the keys outside the multi might allow some new key to sneak in there
  keys = @client.keys("#{ common_key_prefix }*")
  @client.multi do
    @client.del(repo_properties_key)
    @client.srem(REPOSITORIES_KEY, repo_name)

    keys.each do |key|
      @client.del(key)
    end
  end

  ensure_disconnected
end

#close ⇒ Object 



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# File 'lib/xamplr/persisters/redis.rb', line 149

def close
  ensure_disconnected
  clear_cache
end

#common_key_prefix ⇒ Object 



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# File 'lib/xamplr/persisters/redis.rb', line 154

def common_key_prefix
  "XAMPL::#{ @repo_name }::"
end

#ensure_connected ⇒ Object 



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# File 'lib/xamplr/persisters/redis.rb', line 56

def ensure_connected
  return if @client
  return unless instance_options[:allow_connections]

  server = @instance_options[:redis_server]
  thread_safe = @instance_options[:thread_safe]
  @client = Redis.connect(:url => server, :thread_safe => thread_safe)

  # This check is necessary to make sure that the connection is made, otherwise the exception will be sometime in the future
  # the redis exceptions are good enough, so don't bother trapping right here
  @client.ping

  # check to see if the repository with this name is known (in redis) already
  load_repo_properties

  if @repo_properties && !@instance_options[:connect_to_known] then
    ensure_disconnected
    raise IncompatiblePersisterConfiguration.new('redis', "prevent connections to existing repos named: '#{ repo_name }' in #{ server }")
  end
  if @repo_properties.nil? && !@instance_options[:connect_to_unknown] then
    ensure_disconnected
    raise IncompatiblePersisterConfiguration.new('redis', "prevent connections to unknown repos named: '#{ repo_name }' in #{ server }")
  end

  return if @repo_properties

  # if it is unknown, then set it up

  @repo_properties = {}
  suggested_repo_properties.each do |k, v|
    @repo_properties[k] = v
  end
  @repo_properties['name'] = repo_name
  @repo_properties['created_at'] = DateTime.now.to_s

  @client.multi do
    @client.mapped_hmset(repo_properties_key, @repo_properties)
    @client.sadd(REPOSITORIES_KEY, repo_name)
  end

  load_repo_properties
end

#ensure_disconnected ⇒ Object 



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# File 'lib/xamplr/persisters/redis.rb', line 99

def ensure_disconnected
  return unless client
  return unless instance_options[:allow_connections]

  @client.quit
ensure
  @repo_properties = nil
  @client = nil
end

#in_any_cache?(klass, index) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/xamplr/persisters/redis.rb', line 236

def in_any_cache?(klass, index)
  in_new_cache?(klass, index) || in_cache?(klass, index)
end

#in_new_cache?(klass, index) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/xamplr/persisters/redis.rb', line 231

def in_new_cache?(klass, index)
  key = key_for_class(klass, index)
  @new_cache.include?(key)
end

#in_perm_cache?(klass, index) ⇒ Boolean Also known as: in_cache?

Returns:

  • (Boolean) 


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# File 'lib/xamplr/persisters/redis.rb', line 222

def in_perm_cache?(klass, index)
  key = key_for_class(klass, index)
  xampl = @cache[key]

  (xampl && xampl.weakref_alive?) ? true : false
end

#key_for_class(klass, index) ⇒ Object 



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# File 'lib/xamplr/persisters/redis.rb', line 158

def key_for_class(klass, index)
  #NOTE -- the XAMPL::#{ @repo_name }:: is a prefix common to all keys specific to this repository
  "#{ common_key_prefix }#{ klass.persistence_class.name }[#{ index }]"
end

#key_for_xampl(xampl) ⇒ Object 



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# File 'lib/xamplr/persisters/redis.rb', line 163

def key_for_xampl(xampl)
  key_for_class(xampl.class, xampl.get_the_index)
end

#kind ⇒ Object 



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# File 'lib/xamplr/persisters/redis.rb', line 52

def kind
  RedisPersister.kind
end

#known_repos ⇒ Object 



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# File 'lib/xamplr/persisters/redis.rb', line 167

def known_repos
  return @client.smembers(REPOSITORIES_KEY)
end

#load_repo_properties ⇒ Object 



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# File 'lib/xamplr/persisters/redis.rb', line 135

def load_repo_properties
  key = repo_properties_key()
  @repo_properties = @client.hgetall(key)
  @repo_properties = nil if @repo_properties.empty?
end

#perm_cache(xampl) ⇒ Object

Raises:



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# File 'lib/xamplr/persisters/redis.rb', line 171

def perm_cache(xampl)
  raise NotXamplPersistedObject.new(xampl) unless xampl.kind_of?(XamplPersistedObject)

  key = key_for_xampl(xampl)
  existing = @cache[key]

  begin
#        raise DuplicateXamplInPersister.new(existing, xampl, self) if existing && (existing.weakref_alive?) && (existing.__getobj__ != xampl)
    raise DuplicateXamplInPersister.new(existing, xampl, self) if existing && (existing.__getobj__ != xampl)
  rescue WeakRef::RefError => e
    # key is there but the original object isn't...
  end

  @cache[key] = WeakRef.new(xampl)
end

#perm_uncache(xampl) ⇒ Object

Raises:



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# File 'lib/xamplr/persisters/redis.rb', line 187

def perm_uncache(xampl)
  raise NotXamplPersistedObject.new(xampl) unless xampl.kind_of?(XamplPersistedObject)

  key = key_for_xampl(xampl)
  @cache.delete(key).__getobj__
end

#read(klass, pid, target = nil) ⇒ Object 



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# File 'lib/xamplr/persisters/redis.rb', line 309

def read(klass, pid, target=nil)
  xampl, target = read_from_cache(klass, pid, target)
  return xampl if xampl and !target

  key = key_for_class(klass, pid)
  xml = client.get(key)
  unless xml
    puts "#{File.basename(__FILE__)}:#{__LINE__} [#{ __method__ }] TEST ME"
    return nil
  end

  xampl = realise(xml, target)
  Xampl.store_in_cache(@cache, xampl, self) { xampl }
  xampl.introduce_persister(self)

  @read_count = @read_count + 1
  xampl.changes_accepted
  @changed.delete(xampl)
  return xampl
end

#read_from_cache(klass, index, target = nil) ⇒ Object 



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# File 'lib/xamplr/persisters/redis.rb', line 240

def read_from_cache(klass, index, target=nil)

  key = key_for_class(klass, index)

  xampl = @cache[key]
  begin
    xampl = xampl.__getobj__ if xampl
  rescue WeakRef::RefError => e
    #not there
    xampl = nil
  end
#      xampl = (xampl && xampl.weakref_alive?) ? xampl.__getobj__ : nil

  unless xampl then
    xampl = @new_cache[key]
  end

  return nil, target unless xampl

  if target and target != xampl then
    puts "#{File.basename(__FILE__)}:#{__LINE__} [#{ __method__ }] TEST ME"
    target.invalidate
    raise XamplException.new(:cache_conflict)
  end
  unless xampl.load_needed then
    @cache_hits = @cache_hits + 1
    return xampl, target
  end
  return xampl, xampl
end

#repo_properties_key ⇒ Object 



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# File 'lib/xamplr/persisters/redis.rb', line 130

def repo_properties_key
  key = "XAMPL::PROPERTIES::#{ @repo_name }"
  return key
end

#rollback_cleanup ⇒ Object 



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# File 'lib/xamplr/persisters/redis.rb', line 330

def rollback_cleanup

  @new_cache.each { |name, xampl|
    if xampl then
      @changed.delete(xampl)
      xampl.invalidate

#          map.each { |name2, map2|
#            if map2 then
#              map2.each { |pid, xampl|
#                @changed.delete(xampl)
#                xampl.invalidate
#              }
#            end
#          }
    end
  }
  @changed.each { |xampl, ignore|
    xampl.force_load
  }
  @new_cache = {}

  super
end

#sync_done ⇒ Object 



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# File 'lib/xamplr/persisters/redis.rb', line 271

def sync_done
  # simply moves the new_cache to the permanent cache
  (@new_cache || {}).each do |key, xampl|
    @cache[key] = WeakRef.new(xampl)
  end
  @new_cache = {}
end

#uncache(xampl) ⇒ Object

Raises:



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# File 'lib/xamplr/persisters/redis.rb', line 214

def uncache(xampl)
  # this is called by xampl for the temporary new_cache
  raise NotXamplPersistedObject.new(xampl) unless xampl.kind_of?(XamplPersistedObject)

  key = key_for_xampl(xampl)
  @new_cache.delete(key)
end

#write(xampl) ⇒ Object 



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# File 'lib/xamplr/persisters/redis.rb', line 279

def write(xampl)
  unless xampl.get_the_index
    puts "#{File.basename(__FILE__)}:#{__LINE__} [#{ __method__ }] TEST ME"
    raise NotXamplPersistedObject.new(xampl)
  end

  #TODO -- honour the mentions config information (FROM THE DB not the configuration!!)
  mentions = []
  xml = represent(xampl, mentions)
  key = key_for_xampl(xampl)

  #TODO save the modified-time-like value to support multi processing

#      puts "#{File.basename(__FILE__)}:#{__LINE__} [#{ __method__ }] redis #{ self }"
#      puts "#{File.basename(__FILE__)}:#{__LINE__} [#{ __method__ }] write: #{ xampl } --> #{ xml }"
#      puts "#{File.basename(__FILE__)}:#{__LINE__} [#{ __method__ }] key: #{ key }"

  client.set(key, xml)
  @write_count = @write_count + 1
  xampl.changes_accepted
  return true

rescue NotXamplPersistedObject => nxpo
  raise nxpo
rescue => e
  puts "#{File.basename(__FILE__)}:#{__LINE__} [#{ __method__ }] #{ e }"
  puts e.backtrace
  return false
end