Class: Arrow::AppletRegistry

Inherits:
Object
  • Object
show all
Extends:
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

  • Michael Granger

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

Defined Under Namespace

Classes: AppletFile, ChainLink

Constant Summary

IDENTIFIER =

Pattern for matching valid components of the uri 

/^\w[-\w]*/

Instance Attribute Summary

Class Method Summary

Instance Method Summary

Methods included from Loggable

#log

Methods inherited from Object

deprecate_class_method, deprecate_method, inherited

Methods included from Loggable

#log

Constructor Details

- (AppletRegistry) initialize(config)

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

- (Object) config (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

- (Object) filemap (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

- (Object) load_time

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

- (Object) path (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

- (Object) template_factory (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

- (Object) urispace (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

+ (Object) get_safe_gemhome

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

- (Object) build_classmap

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

- (Object) check_for_updates

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

- (Object) find_applet_chain(uri)

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

- (Object) find_appletfiles(excludeList = [])

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

- (Object) initialize_copy(other)

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

- (Object) load_applets 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

- (Object) load_applets_from_file(path)

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

- (Object) load_gems 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

- (Object) purge_deleted_applets(*missing_files)

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

- (Object) register_applet_class(klass)

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