Class: Arrow::AppletRegistry

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Includes:
Loggable, Enumerable
Defined in:
lib/arrow/appletregistry.rb

Overview

The Arrow::AppletRegistry class, a derivative of Arrow::Object. Instances of this class are responsible for loading and maintaining the collection of Arrow::Applets registered with an Arrow::Broker.

VCS Id

$Id$

Authors

Please see the file LICENSE in the top-level directory for licensing details.

Defined Under Namespace

Classes: AppletFile, ChainLink

Constant Summary collapse

IDENTIFIER =

Pattern for matching valid components of the uri

/^\w[-\w]*/

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Object

deprecate_class_method, deprecate_method, inherited

Constructor Details

#initialize(config) ⇒ AppletRegistry

Create a new Arrow::AppletRegistry object.



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# File 'lib/arrow/appletregistry.rb', line 226

def initialize( config )
	@config = config

	@path = @config.applets.path
	@classmap = nil
	@filemap = {}
	@urispace = {}
	@template_factory = Arrow::TemplateFactory.new( config )
	@load_time = nil

	self.load_gems
	self.load_applets

	super()
end

Instance Attribute Details

#config ⇒ Object (readonly)

The Arrow::Config object which specified the registry’s behavior.



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# File 'lib/arrow/appletregistry.rb', line 273

def config
  @config
end

#filemap ⇒ Object (readonly)

The internal hash of Entry objects keyed by the file they were loaded from



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# File 'lib/arrow/appletregistry.rb', line 270

def filemap
  @filemap
end

#load_time ⇒ Object

The Time when the registry was last loaded



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# File 'lib/arrow/appletregistry.rb', line 279

def load_time
  @load_time
end

#path ⇒ Object (readonly)

The path the registry will search when looking for new/updated/deleted applets



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# File 'lib/arrow/appletregistry.rb', line 282

def path
  @path
end

#template_factory ⇒ Object (readonly)

The Arrow::TemplateFactory which will be given to any loaded applet



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# File 'lib/arrow/appletregistry.rb', line 276

def template_factory
  @template_factory
end

#urispace ⇒ Object (readonly)

The internal hash of Entry objects, keyed by URI



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# File 'lib/arrow/appletregistry.rb', line 266

def urispace
  @urispace
end

Class Method Details

.get_safe_gemhome ⇒ Object

Get the ‘gem home’ from RubyGems and check it for sanity. Returns nil if it is not an extant, non-world-writable directory.



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# File 'lib/arrow/appletregistry.rb', line 197

def self::get_safe_gemhome
	gemhome = Pathname.new( Gem.user_home ) + 'gems'
	gemhome.untaint

	if ! gemhome.directory?
		Arrow::Logger[ self ].notice "Gem home '%s' is not a directory; ignoring it" % [ gemhome ]
		return nil
	elsif (gemhome.stat.mode & 0002).nonzero?
		Arrow::Logger[ self ].notice "Gem home '%s' is world-writable; ignoring it" % [ gemhome ]
		return nil
	end

	Arrow::Logger[ self ].info "Got safe gem home: %p" % [ gemhome ]
	return gemhome
end

Instance Method Details

#build_classmap ⇒ Object

Make and return a Hash which inverts the registry’s applet layout into a map of class name to the URIs onto which instances of them should be installed.



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# File 'lib/arrow/appletregistry.rb', line 527

def build_classmap
	classmap = Hash.new {|ary,k| ary[k] = []}

	# Invert the applet layout into Class => [ uris ] so as classes
	# load, we know where to put 'em.
	@config.applets.layout.each do |uri, klassname|
		uri = uri.to_s.sub( %r{^/}, '' )
		self.log.debug "Mapping %p to %p" % [ klassname, uri ]
		classmap[ klassname ] << uri
	end

	return classmap
end

#check_for_updates ⇒ Object

Check the applets path for new/updated/deleted applets if the poll interval has passed.



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# File 'lib/arrow/appletregistry.rb', line 411

def check_for_updates
	interval = @config.applets.pollInterval
	if interval.nonzero?
		if Time.now - self.load_time > interval
			self.log.debug "Checking for applet updates: poll interval at %ds" % [ interval ]
			self.reload_applets
			self.reload_gems
		end
	else
		self.log.debug "Dynamic applet reloading turned off, continuing"
	end
end

#find_applet_chain(uri) ⇒ Object

Find the chain of applets indicated by the given uri and return an Array of ChainLink structs.



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# File 'lib/arrow/appletregistry.rb', line 378

def find_applet_chain( uri )
	self.log.debug "Searching urispace for appletchain for %p" % [ uri ]

	uri_parts = uri.sub(%r{^/(?=.)}, '').split(%r{/}).grep( IDENTIFIER )
	appletchain = []
	args = []

	# If there's an applet installed at the base, prepend it to the
	# appletchain
	if @urispace.key?( "" )
		appletchain << ChainLink.new( @urispace[""], "", uri_parts )
		self.log.debug "Added base applet to chain."
	end

	# Only allow reference to internal handlers (handlers mapped to 
	# directories that start with '_') if allow_internal is set.
	self.log.debug "Split URI into parts: %p" % [uri_parts]

	# Map uri fragments onto registry entries, stopping at any element 
	# which isn't a valid Ruby identifier.
	uri_parts.each_index do |i|
		newuri = uri_parts[0,i+1].join("/")
		# self.log.debug "Testing %s against %p" % [ newuri, @urispace.keys.sort ]
		appletchain << ChainLink.new( @urispace[newuri], newuri, uri_parts[(i+1)..-1] ) if
			@urispace.key?( newuri )
	end

	return appletchain
end

#find_appletfiles(excludeList = []) ⇒ Object

Find applet files by looking in the applets path of the registry’s configuration for files matching the configured pattern. Return an Array of fully-qualified applet files. If the optional excludeList is given, exclude any files specified from the return value.



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# File 'lib/arrow/appletregistry.rb', line 546

def find_appletfiles( excludeList=[] )
	files = []
	dirCount = 0

	# The Arrow::Path object will only give us extant directories...
	@path.each do |path|

		# Look for files under a directory
		dirCount += 1
		pat = File.join( path, @config.applets.pattern )
		pat.untaint

		self.log.debug "Looking for applets: %p" % [ pat ]
		files.push( *Dir[ pat ] )
	end

	self.log.info "Fetched %d applet file paths from %d directories (out of %d)" %
		[ files.nitems, dirCount, @path.dirs.nitems ]

	files.each {|file| file.untaint }
	return files - excludeList
end

#initialize_copy(other) ⇒ Object

Copy initializer – reload applets for cloned registries.



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# File 'lib/arrow/appletregistry.rb', line 244

def initialize_copy( other ) # :nodoc:
	@config = other.config.dup

	@path = @config.applets.path.dup
	@classmap = nil
	@filemap = {}
	@urispace = {}
	@template_factory = Arrow::TemplateFactory.new( config )
	@load_time = nil

	self.load_gems
	self.load_applets

	super
end

#load_applets ⇒ Object Also known as: reload_applets

Load any new applets in the registry’s path, reload any previously- loaded applets whose files have changed, and discard any applets whose files have disappeared.



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# File 'lib/arrow/appletregistry.rb', line 352

def load_applets
	self.log.debug "Loading applet registry"

	@classmap = self.build_classmap
	filelist = self.find_appletfiles

	# Remove applet files which correspond to files that are no longer
	# in the list
	self.purge_deleted_applets( @filemap.keys - filelist ) unless 
		@filemap.empty?

	# Now search the applet path for applet files
	filelist.each do |appletfile|
		self.log.debug "Found applet file %p" % appletfile
		self.load_applets_from_file( appletfile )
		self.log.debug "After %s, registry has %d entries" %
			[ appletfile, @urispace.length ]
	end

	self.load_time = Time.now
end

#load_applets_from_file(path) ⇒ Object

Load the applet classes from the given path and return them in an Array. If a block is given, then each loaded class is yielded to the block in turn, and the return values are used in the Array instead.



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# File 'lib/arrow/appletregistry.rb', line 449

def load_applets_from_file( path )

	# Reload mode -- don't do anything unless the file's been updated
	if @filemap.key?( path )
		file = @filemap[ path ]

		if file.has_changed?
			self.log.info "File %p has changed since loaded. Reloading." % [path]
			self.purge_deleted_applets( path )
		elsif !file.loaded_okay?
			self.log.warning "File %s could not be loaded: %s" % 
				[path, file.exception.message]
			file.exception.backtrace.each do |frame|
				self.log.debug "  " + frame
			end
		else
			self.log.debug "File %p has not changed." % [path]
			return nil
		end
	end

	self.log.debug "Attempting to load applet objects from %p" % path
	@filemap[ path ] = AppletFile.new( path )

	@filemap[ path ].appletclasses.each do |appletclass|
		self.log.debug "Registering applet class %s from %p" % [appletclass.name, path]
		begin
			uris = self.register_applet_class( appletclass )
			@filemap[ path ].uris << uris
		rescue ::Exception => err
			frames = filter_backtrace( err.backtrace )
			self.log.error "%s loaded, but failed to initialize: %s" % [
				appletclass.normalized_name,
				err.message,
			]
			self.log.debug "  " + frames.collect {|frame| "[%s]" % frame }.join("  ")
			@filemap[ path ].exception = err
		end
	end

end

#load_gems ⇒ Object Also known as: reload_gems

Check the config for any gems to load, load them, and add their template and applet directories to the appropriate parts of the config.



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# File 'lib/arrow/appletregistry.rb', line 291

def load_gems
	self.log.info "Loading gems."

	unless @config.respond_to?( :gems )
		self.log.debug "No gems section in the config; skipping gemified applets"
		return
	end

	self.log.debug "  using gem config: %p" % [ config.gems ]

	# Make sure the 'gem home' is a directory and not world-writable; don't use it
	# otherwise
	gemhome = self.class.get_safe_gemhome
	paths = @config.gems.path.collect {|path| path.untaint }
	self.log.debug "  safe gem paths: %p" % [ paths ]
	Gem.use_paths( Apache.server_root, paths )

	@config.gems.applets.to_h.each do |gemname, reqstring|
		self.log.debug "    trying to load %s %s" % [ gemname, reqstring ]
		reqstring = '>= 0' if reqstring.nil? or reqstring.empty?

		begin
			self.log.info "Activating gem %s (%s)" % [ gemname, reqstring ]
			Gem.activate( gemname.to_s, reqstring )
			self.log.info "  gem %s activated." % [ gemname ]
		rescue LoadError => err
			self.log.crit "%s while activating '%s': %s" %
				[ err.class.name, gemname, err.message ]
			err.backtrace.each do |frame|
				self.log.debug "  " + frame
			end
		else
			datadir = Pathname.new( Gem.datadir(gemname.to_s) )
			appletdir = datadir + 'applets'
			templatedir = datadir + 'templates'
			self.log.debug "Adding appletdir %p and templatedir %p" %
				[ appletdir, templatedir ]
			@path << appletdir.to_s
			@template_factory.path << templatedir.to_s
		end
	end

	self.log.info "  done loading gems (path is now: %p)." % [ @path ]
end

#purge_deleted_applets(*missing_files) ⇒ Object

Remove the applets that were loaded from the given missing_files from the registry.



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# File 'lib/arrow/appletregistry.rb', line 427

def purge_deleted_applets( *missing_files )

	# For each filename, find the applets which were loaded from it, 
	# map the name of each applet to a uri via the classmap, and delete
	# the entries by uri
	missing_files.flatten.each do |filename|
		self.log.info "Unregistering old applets from %p" % [ filename ]

		@filemap[ filename ].uris.each do |uri|
			self.log.debug "  Removing %p, registered at %p" % [ @urispace[uri], uri ]
			@urispace.delete( uri )
		end

		@filemap.delete( filename )
	end
end

#register_applet_class(klass) ⇒ Object

Register an instance of the given klass with the broker if the classmap includes it, returning the URIs which were mapped to instances of the klass.



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# File 'lib/arrow/appletregistry.rb', line 495

def register_applet_class( klass )
	uris = []

	# Trim the Module serving as private namespace from the
	# class name
	appletname = klass.normalized_name
	self.log.debug "Registering %p applet as %p" % [ klass.name, appletname ]

	# Look for a uri corresponding to the loaded class, and instantiate it
	# if there is one.
	if @classmap.key?( appletname )
		self.log.debug "  Found one or more uris for '%s'" % appletname


		# Create a new instance of the applet for each uri it's
		# registered under, then wrap that in a RegistryEntry
		# and put it in the entries hash we'll return later.
		@classmap[ appletname ].each do |uri|
			@urispace[ uri ] = klass.new( @config, @template_factory, uri )
			uris << uri
		end
	else
		self.log.debug "No uri for '%s': Not instantiated" % appletname
	end

	return uris
end