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Revision: 1700 - (download)
Fri Feb 20 15:24:21 2004 UTC (16 years, 8 months ago) by pje
File size: 53602 byte(s)
Added 'ref:factory@addr' URL scheme that maps to a corresponding
'naming.Reference("factory",["addr"])'.  'factory' can be either a dotted
import string referencing a 'naming.IObjectFactory', or you can define
a factory in the 'peak.naming.factories' property space.

Added a 'zconfig.schema' factory, so that 'ref:zconfig.schema@streamURL'
will load a schema loader.  See CHANGES.txt for more details on all the
cool stuff you can do with this.
Fixes and Enhancements since Version 0.5 alpha 2

 Changed, Enhanced, or Newly Deprecated Features

 - Added 'model.Repr' type, useful for doing eval/repr conversions of simple
   Python types, and changed the N2 'htmldump' command to use it.

 - Added 'peak.util.mockets', offering imitation socket services like
   'socket()' and 'select()', allowing socket-based services to be tested
   without using real sockets.
 - Added limited support for two-phase commit of database connections to Sybase
   and Oracle.  Changed Oracle "outside transaction" semantics to allow read
   operations only, and added a property to set Oracle transactions to
   "serializable" (which effectively requires two-phase commits).  Note that
   the current version of DCOracle2 doesn't properly support two-phase commit
   except for empty (no-op) transactions, which isn't very useful.  However, if
   a later release of DCOracle2 works correctly and doesn't change its API, the
   current PEAK driver should then work correctly.  In the meantime, the
   cx_Oracle driver apparently *does* provide working support for two-phase
   commits.  The controlling properties are of the form 'DRIVER.twoPhaseCommit'
   and 'DRIVER.serializable', where 'DRIVER' is the name of the DBAPI driver
   module, e.g. 'Sybase.twoPhaseCommit' or 'cx_Oracle.serializable'.
 - Added properties to the command-line applications framework, allowing
   non-command objects access to 'stdin', 'stdout', 'argv' etc. from their

 - Added '[Named Services]' section parser to 'peak.ini'.  This new section
   type functions similarly to '[Component Factories]', except that
   the keys are property names rather than references to interfaces or other
   component keys, and the values are an expression that creates the actual
   instance, rather than the name of a factory for the service  This should be
   helpful for configuring shared services that all implement the same
   interface, such as SQL connection objects.

   Note that to look up a named service, you simply use the appropriate
   property name, as usual.  The difference is that you are guaranteed to
   always use the same *instance* of the service, within a given service area.

 - Added 'peak serve' and 'peak launch' commands, for running "CGI" apps in
   a browser from the local machine.  For example, doing this::

    PYTHONPATH=examples/trivial_cgi peak launch import:the_cgi.DemoCGI

   from the base directory of a PEAK CVS checkout or source distribution will 
   launch the 'trivial_cgi' demo program in a new or current browser window.
   Any application runnable with 'peak CGI' should also be runnable with 
   'peak serve' or 'peak launch', which makes it very useful for running
   local browser-based apps or testing an application without CGI or FastCGI
   available.  The modules that support this new functionality are
   'peak.util.WSGIServer' (which implements a web server based on Python's
   'BaseHTTPServer', that can run 'running.IRerunnableCGI' objects) and
   'peak.tools.local_server' (which provides PEAK integration.)

 - Added 'peak.ddt' framework for Document-Driven Testing.  DDT can parse HTML
   files to extract test descriptions from HTML tables, run the tests, and then
   output an annotated version of the input document, illustrating the results
   by e.g. coloring cells to highlight good/bad results.  To use it, you must
   implement 'ddt.ITableProcessor' components that know how to interpret the
   table contents.

 - Added 'fd.file:' URL scheme, for URLs like 'fd.file:stdin' that can be used
   in place of 'file:' URLs for many purposes.

 - Added 'model.ExtendedEnum', for enumerations that also support arbitrary

 - Added 'events.IEventLoop' implementation and refactored 'UntwistedReactor'
   to use it.  'UntwistedReactor' is now nothing more than an adapter from
   'events.IEventLoop' to 'running.IBasicReactor'.  Added 'twisted_support'
   versions of 'peak.events' interfaces (untested).

 - 'running.ISignalManager' is now DEPRECATED; please use 'events.ISignalSource'

 - Added 'events.ISignalSource', that returns 'events.Broadcaster' objects for
   signals.  This allows you to yield to signals in an 'events.Thread', or
   safely set one-time callbacks on them.
 - 'running.IMainLoop' has been changed to use an 'events.IReadable' for
   the 'lastActivity' attribute, and the 'setExitCode' and 'childForked'
   methods have been replaced with an 'exitWith()' method.

 - The 'peak.running.mainLoop.signalHandler' property has been replaced with
   'peak.running.mainLoop.stopOnSignals', which defaults to including SIGINT,
   SIGTERM, and SIGBREAK.  If you need custom signal handling, please use
   the event sources provided by an 'events.ISignalSource'.

 - Simplified configuration for using Twisted, roughly as proposed in
   "this message.":http://www.eby-sarna.com/pipermail/peak/2004-January/001125.html

   You can now configure a service area as using Twisted by setting its
   'peak.events.isTwisted' property, or by depending upon the
   'running.ITwistedReactor' interface, as long as it happens early enough.

   If you need to make choices based on whether a Twisted reactor is being
   used, you should use the 'events.ifTwisted()' function.  If you would like
   to try to force a service area to use a Twisted reactor, you may use
 - Added automatic installation of 'csv' module for Python < 2.3.

 - Added 'peak.events' package, supporting a simple event-driven programming
   microkernel, including event-driven "ultralight" threads powered by

 - "Global" services defined by '[Component Factories]' sections now live in
   the closest "service area" to the component that requests them.  A "service
   area" is a parent component that implements 'config.IServiceArea', such as
   a configuration root returned by 'config.makeRoot()'.  Applications loaded
   by the 'peak runIni' command are now created in their own service area,
   which means that settings in the .ini file being run will apply to services
   the application uses.  (Because the application will have its own,
   application-specific service instances, and they will use the configuration
   loaded into the service area.)

   If you need to create your own service area, you can do so by mixing in
   'config.ServiceArea' to your component class.  However, you should *not* do
   this unless you know exactly what "outside" services you may need to use
   from "inside" the newly created service area, so that you can explicitly
   connect them "into" the service area.  (In short, if you don't know *why*
   you're creating a service area, don't do it.)

 - 'config.Namespace()' objects now have a 'keys()' method that can be used
   when the namespace is bound to a context component.  It returns a list of
   strings that may be used as keys for that namespace.  Example usage::

    >>> from peak.api import *
    >>> r=config.makeRoot()
    >>> ns=config.Namespace('peak.naming.schemes',r)
    >>> ns.keys()
    ['https', 'smtp', 'logfile', 'psycopg', 'pkgfile', 'unix.dg', 'win32.dde',
    'sybase', 'timer', 'lockfile', 'pgsql', 'fd.socket', 'uuid', 'tcp', 'file',
    'gadfly', 'http', 'logger', 'icb', 'cxoracle', 'udp', 'winflockfile',
    'import', 'logging.logger', 'nulllockfile', 'nis', 'shlockfile',
    'zconfig.schema', 'flockfile', 'shellcmd', 'dcoracle2', 'config', 'ftp',
    'unix', 'ldap', 'sqlite', 'mockdb']
    >>> ns['ldap']

 - Log events don't use a positional 'message' argument any more, and
   loggers aren't responsible for interpolating message arguments any more.
   The new signature is 'Event(parent, msg=msg, args=args, ...)'.  Loggers
   also now tell events what logger name they are, via the 'ident' keyword.

 - The logging system now uses a property namespace, 'peak.logging.levels', to
   obtain log level names and values.  The various 'logs.LEVEL' constants are
   now DEPRECATED.  Please use the 'getLevelFor()' method of the nearest
   'logs.ILoggingService' instead.  Also note that URL schemes such as
   'logfile:' no longer convert their level names to numbers, since the
   level names are only meaningful in the context of a logging service.

 - Support for integration with the Python 2.3/PEP 282 logging module has been
   scaled back.  There are too many globalisms and dependencies there.  When we
   add plugin-based log configuration, it should be possible to use the logging
   package's handlers and formatters with the PEAK logging services.  At that
   point, you'll be able to replace 'logging.getLogger' and
   'logging.getLevelName' with the corresponding methods of a PEAK logging
   service, if you need to force non-PEAK packages to use PEAK's logging.

 - Logs are now accessed via a 'logs.ILoggingService' instance.  The 'logger:'
   URL scheme automatically accesses the nearest such service.  For backward
   compatibility, the old 'peak.logs' namespace is still used to supply the
   actual loggers.  This will be gradually replaced with a plugin-based

 - Added 'binding.PluginKeys' and 'binding.PluginsFor'.  These are component
   keys that can be used to 'Obtain' plugins registered within a property
   namespace.  'PluginKeys' obtains a list of the plugins' configuration keys,
   while 'PluginsFor' obtains a list of the actual plugins.

 - Replaced 'peak.config.registries.EigenRegistry' with
   'peak.config.registries.ImmutableConfig'.  The only use we had for
   'EigenRegistry' was to keep track of 'offerAs' settings within classes, and
   it didn't need all the extra complexity of eigenstate management.  The new,
   more-specialized class is shorter, simpler, and easier to use.

 - Added 'config.iterKeys()' which iterates over all available configuration
   keys in a given namespace (just property names for now).  The 'config:'
   namespace is now a 'naming.IReadContext', so you can navigate it with the
   'n2' command, and do things like 'ls -l config:peak.naming.schemes' to list
   all configured naming schemes.

 - Added 'config.parentProviding()' and 'config.parentsProviding()', which
   find the first (or all) parent components of a given component that support
   a given protocol.

 - Renamings/refactorings/deprecations in 'peak.config':

    'config.getProperty' -- use 'config.lookup()' instead

    'config.findUtility' -- use 'config.lookup()' instead

    'config.findUtilities' -- use 'config.iterValues()' instead

    'config.IPropertyMap' -- use 'config.IConfigMap' or 'config.IConfigurable'

    'config.PropertyMap' -- use 'config.ConfigMap' instead

    'config.setPropertyFor' -- DEPRECATED, see source for replacement code.

    'config.setRuleFor' -- DEPRECATED, see source for replacement code.

    'config.setDefaultFor' -- DEPRECATED, see source for replacement code.

    'config.instancePerComponent' -- DEPRECATED, use factories instead.

    'config.IConfigurationRoot' -- interface has changed; 'propertyNotFound' is
    no longer a method, and 'noMoreUtilities' is now 'noMoreValues'.

    'exceptions.PropertyNotFound' -- use 'exceptions.NameNotFound' instead.

    'exceptions.OutOfScope' -- REMOVED; it was not actually used in PEAK.

   In all cases, the old interface, class, or function is DEPRECATED and will
   go away in the alpha 4 release cycle.  Please take particular note of the
   fact that 'IConfigMap' offers virtually none of the convenience
   methods provided by 'IPropertyMap', so adjust your code accordingly.  Note
   also that even though there are plenty of references to 'IPropertyMap'
   remaining in PEAK itself, these are strictly to provide backward
   compatibility.  Once we enter the alpha 4 release cycle, these will go away.

 - Added 'config.MultiKey()' and 'config.UnionOf()' configuration key classes,
   to generalize existing specialty keys such as 'ProviderOf' and 'FactoryFor'.
   (The latter two are now defined in terms of the former two.)  Also, made
   classes and types usable as configuration keys.  This was needed for the
   above generalization, but also makes many other class-lookup concepts
   possible.  (Note that there may be some slight changes to the effective
   registration and lookup order of these and other configuration keys as of
   this change, as there were some previous errors and/or ambiguities to the
   lookup order that were not covered by the test suite.)

 - Added "[Import on Demand]" section type to .ini files, allowing you to
   define shortcuts for modules that you frequently reference in your
   configuration.  This lets you replace e.g. 'importString("foo.bar.baz:Spam")'
   with 'foo_baz.Spam' in expressions, by adding something like this::

    [Import on Demand]
    foo_bar = "foo.bar.baz"

   to your configuration.  The defined shortcut is then available for the
   remainder of that configuration file, and in any .ini files included from
   the current file.  See 'peak.ini' for an example and more info.

 - Logging-related interfaces have been moved into the 'peak.running.logs'
   module.  So, what used to be 'running.ILogger' is now 'logs.ILogger'.

 - Log events now use a standard component construction signature, and the
   class used for event objects is now configurable as the factory for
   'logs.ILogEvent'.  (See "[Component Factories]" in 'peak.ini'.)

 - By popular demand, 'logs.ILogger' (and its default implementation) now
   includes 'trace()', 'notice()', 'alert()' and 'emergency()' methods that use
   the corresponding 'syslog' priority levels.  'logs.IBasicLogger' has been
   added, to reflect the narrower interface provided by PEP 282, and there is
   an adapter that can extend PEP 282 loggers with the other methods.

 - The 'logging.logger:' URL scheme has been simplified to 'logger:'.  Please
   convert your scripts and configuration files, as the longer form will go
   away in the alpha 4 development cycle.

 - Added 'commands.lookupCommand()' to look up a command shortcut or URL, ala
   the 'peak' script or 'commands.Bootstrap' class.  Also added various
   'commands.ErrorSubcommand' subclasses to make it easier to issue errors
   from/for subcommands.

 - Added 'peak.core' as a minimal subset of 'peak.api'.  'peak.core' offers
   only "core" API packages and primitives, not the full set of available
   framework APIs.  'peak.api' will continue to expand as frameworks are added,
   but 'peak.core' will stay as small as practical.  ('peak.exceptions' may in
   fact end up being removed from 'peak.core', or at least renamed.)

 - Added 'peak.util.symbol' module, to contain 'NOT_GIVEN', 'NOT_FOUND', and
   the 'Symbol' class used to create them.

 - 'peak.running.tools' was promoted to 'peak.tools'.  'peak.running.supervisor'
   was also moved to 'peak.tools.supervisor', and a new 'peak help' command was
   added in 'peak.tools.api_help'.

 - Replaced the "[Provide Utilities]" section of .ini files with "[Component
   Factories]".  The new section type is easier to use, much more versatile,
   and does all registration and imports lazily.  See the 'peak.ini' file for
   docs.  "[Provide Utilities]" and 'config.ProvideInstance()' are now
   DEPRECATED, so please convert ASAP.

 - 'binding.Make()' now accepts configuration keys, using them to look up a
   factory object that's then invoked to create the attribute.  This makes it
   a lot easier to define a component with its own transaction service
   or other normally "global" component.  It also makes it easier to globally
   specify a factory class for some interface.  Factories are looked up under
   the 'config.FactoryFor(key)' configuration key.  (See below.)

 - Added 'config.FactoryFor(key)', a 'config.IConfigKey' implementation that
   provides a configuration namespace for factories.

   When you use 'binding.Make(ISomething)', it's roughly equivalent to::

            lambda self,d,a:
                    self, config.FactoryFor(ISomething),
                    adaptTo = binding.IRecipe

   That is, the 'config.FactoryFor(ISomething)' is looked up and invoked.

 - Added 'config.CreateViaFactory(key)', a 'config.IRule' implementation that
   creates an implementation of 'key', by looking up 'config.FactoryFor(key)'
   and invoking it.

 - Added 'config.ruleForExpr(name,expr)', that returns a 'config.IRule' that
   computes the Python expression in the string 'expr'.  This is the mechanism
   used by configuration files to create rules, factored out into an API call
   so that configuration extensions can use it, too.

 - The 'referencedType' of a 'model.StructuralFeature' can now be any
   'binding.IComponentKey', not just a type or a string.  Types are also now
   implicitly component keys, which means you can use 'binding.Obtain(SomeType)'
   to look up 'SomeType'.  (Right now, this is no different than using 'SomeType'
   without the 'binding.Obtain()', but in future releases this will use a
   "class replacement service" to allow easy replacement of model and other
   collaborator classes, while implementing AOP-like features.)

 - Added 'naming.Indirect(key)', a 'binding.IComponentKey' that can be used to
   do an indirect lookup via another 'IComponentKey' (such as a name).

   Using 'naming.Indirect()', you can replace code like this::

        socket = binding.Obtain(
            lambda self: self.lookupComponent(self.socketURL),

   with code like this::

        socket = binding.Obtain(
            naming.Indirect('socketURL'), adaptTo=[IListeningSocket]

 - Added 'peak.tools.supervisor', a mini-framework for pre-forking,
   multiprocess servers, such as for FastCGI.  The framework includes a ZConfig
   schema for process supervisors, and support for automatically forking new
   children (up to a predefined maximum, with a minimum interval between
   launches) when a socket has pending connections and all of its child
   processes are busy.  With this setup, you can take more advantage of
   multiprocessor machines for CPU-intensive services.

 - Standardized these characteristics of name and address syntax:

   * '//' at the beginning of URL bodies is *mandatory* when the URL begins
     with an "authority" as described by RFC 2396.  When the URL is not
     required to contain an authority (e.g. 'peak.storage.SQL.GenericSQL_URL'),
     the '//' is *optional*, and the canonical form of the URL will not include

   * Standardized names for RFC 2396 fields: 'user', 'passwd', 'host', and

 - Added 'peak.metamodels.ASDL', a metamodel for the Zephyr Abstract Syntax
   Description Language.  ASDL is a convenient way to describe a domain model
   for an abstract syntax tree (AST), and the models generated with the new
   ASDL tool can be combined with concrete syntax to create a complete parsing
   solution for "mini languages", possibly including the Python language
   itself.  (Future versions of the Python and Jython compilers are likely to
   use AST models based on ASDL, and in the current Python CVS sandbox there's
   already an ASDL model of Python's AST available.)

 - Enhanced 'fmtparse' and 'peak.model' to allow using types as syntax rules
   for parsing, including abstract types.  An abstract type's syntax is the
   union (using 'fmtparse.Alternatives') of the syntaxes of its subclasses
   (as specified by 'mdl_subclassNames').

 - Added 'IMainLoop.exitWith()' method, to allow reactor-driven components to
   control the mainloop's exit code.

 - Added 'IBasicReactor.crash()', which forces an immediate reactor loop exit,
   ignoring pending scheduled calls.

 - Added 'peak.running.commands.runMain()', a convenience function for starting
   an application's "main" command, that also makes it easy for forked child
   processes to exit and replace the parent process' "main".  The 'peak' script
   has now been shortened to::

       from peak.running import commands
       commands.runMain( commands.Bootstrap )

   so it's now much easier to create alternative startup scripts, if you need
   to, or to add an 'if __name__=="__main__"' clause to a module.

 - Added 'peak.util.mockdb', a "mock object" implementation of a DBAPI 2.0
   driver module.  'mockdb' connections can be told to 'expect()' queries
   and 'provide()' data to their callers, and will raise AssertionErrors when
   they are used in a way that doesn't conform to your supplied expectations.
   This is intended to be used for unit testing components that depend on
   a database connection: you can verify that they send the right SQL, and
   you can provide them with dummy data to use.  There is also a 'mockdb:' URL
   and peak.storage driver, so you can easily use a mock DB connection in place
   of a real one within a PEAK application, for testing purposes.  Note,
   however, that 'peak.util.mockdb' is a DBAPI 2.0 driver in itself, and thus
   can also be used to test DBAPI usage outside of PEAK.

 - SQL connection objects now provide an 'appConfig' attribute that is a
   driver-specific 'config.Namespace()'.  This allows you to easily set up
   configuration properties that are driver-specific.  For example, you could
   use properties to configure driver-specific SQL snippets, then access them
   via the connection's 'appConfig' namespace.  The namespaces are of the form
   'DRIVER.appConfig', where 'DRIVER' is the name of the DBAPI module for that
   connection type (e.g. 'pgdb', 'cx_Oracle', etc.).

 - Added 'config.Namespace()' convenience class for redirecting property
   lookups from one namespace to another.  See the docstring and 'peak.ini' for
   usage examples.  'PropertyName.of()' now returns 'Namespace' instances
   instead of 'PropertySet' instances.

 - DEPRECATED the 'config.PropertySet' class; please convert to using
   'config.Namespace', as 'PropertySet' will disappear in the 0.5alpha4 release

 - SQL connection objects now get their type converters from a distinct
   property namespace for each DBAPI driver.  For example a driver using the
   'cx_Oracle' module will get its type converters from the
   'cx_Oracle.sql_types' property namespace, instead of 'peak.sql_types'.  For
   backward compatibility, these driver-specific namespaces are set up to
   fall back to 'peak.sql_types' for their defaults.  Type converter
   construction has also been improved, to eliminate conversion overhead
   completely when no conversions are required for a specific query.  Also,
   SQL connections now offer a method that will create a row conversion
   function for a given result description and optional postprocessing
   function.  This new method should now be used in place of direct access to
   the 'typeMap' attribute of connection objects.

 - Added 'binding.Require', 'binding.Obtain', 'binding.Make', and
   'binding.Delegate'.  *ALL* other binding types are now DEPRECATED, and will
   go away before 0.5 beta is released:

   'requireBinding("info")' -- use 'Require("info")'

   'delegateTo("attr")' -- use 'Delegate("attr")'

   'New(type)' -- use 'Make(type)'

   'New("module.type")' -- use 'Make("module.type")'

   'bindTo(key)' -- use 'Obtain(key)'

   'Constant(value)' -- use 'Make(lambda: value)'

   'Acquire(key)' -- use 'Obtain(key, offerAs=[key,])'

   'Copy(value)' -- use 'Make(lambda: <expr to copy value>)'

   'whenAssembled(func)' -- use 'Make(func, uponAssembly=True)'

   'bindSequence(key1,key2,...)' -- use 'Obtain([key1,key,...])'

   'bindToProperty(x,y)' -- use 'Obtain(PropertyName(x),default=y)'

   'bindToParent()' -- use 'Obtain("..")'

   'bindToSelf()'  -- use 'Obtain(".")'

   'bindToUtilities()' -- no replacement; let me know if you're using this.

   Note that 'Make' and 'Obtain' also support sequences of recipes and keys,
   and in those cases will produce a sequence of the results from those recipes
   or keys.  Also, 'Make' will accept no-argument and one-argument callables,
   where 'Once' always required three-argument functions.  This should make it
   a lot easier to write short binding functions.

   Also, note that the 'activateUponAssembly' keyword is now 'uponAssembly',
   and 'isVolatile' is now 'noCache'.  (The old names will work as keyword
   arguments until the alpha 4 development cycle begins.)  The
   'binding.IActiveDescriptor' interface also changed as a result of this.
   Last, but not least, a 'binding.IRecipe' interface was added, to support the
   new 'binding.Make' type.

 - Added a 'lockName' attribute to 'runnning.AdaptiveTask', and a 'LockURL'
   setting to its ZConfig schema.  This allows a lockfile URL to be specified
   for adaptive tasks that need exclusive access to some resource while

 - A list or tuple of 'IComponentKey' instances is now treated as a single
   component key, that returns a tuple of the values returned by each
   constituent component key.  This means that 'binding.Obtain()' and
   'lookupComponent()' can now accept a list or tuple of component keys.  This
   makes 'bindSequence()' obsolete, so 'bindSequence()' is now DEPRECATED.
   'binding.bindSequence(key1,key2,...)' can now be replaced with
   'binding.Obtain([key1,key,...])', and will produce the same results.

 - 'naming.IBasicContext.lookup()' and 'naming.lookup()' now accept a 'default'
   argument, similar to that used by 'lookupComponent()' and most other
   lookup-like APIs in PEAK.  This change was made so that component lookups
   don't need to rely on catching 'exceptions.NameNotFound' errors to tell them
   when to use the default value.  This could hide 'NameNotFound' errors that
   were actually from a broken component somewhere in the lookup process.  (In
   general, it's probably a bad idea to have an exception that's used for both
   control flow and real errors!)

 - Added new 'version' tool that automatically edits files to update version
   information in them.  Just execute the 'version' file in the main PEAK
   source directory.  (Use '--help' for help.)  You can use this tool with your
   own projects by creating 'version' and 'version.dat' files in your project
   directory, similar to the ones used by PEAK.  The 'version' file is a ZConfig
   file that describes your project's version numbering scheme(s), formats,
   and the files that need to be edited, while the 'version.dat' file contains
   the current version number values.  Source for the tool, including the
   configuration file schema, is in the 'peak.tools.version' package.
   (Error handling and documentation, alas, are still minimal.)

 - Added new 'Alias' command in 'peak.running.commands'.  An 'Alias' instance
   can be used as a 'peak.running.shortcut' property that expands to another
   command with arbitrary arguments inserted before the original command's
   arguments.  Thus, one might alias 'mycommand' to 'runIni somefile --option',
   similar to command aliases in many shells.

 - 'naming.IName' is now derived from 'binding.IComponentKey', so names and
   addresses must now support the 'findComponent()' method.  All PEAK name and
   address types provide support for this.

 - The 'lookup()' method of 'binding.IComponentKey' is now called
   'findComponent()', to better distinguish it from 'lookup()' in
   'naming.IBasicContext', which does something very different.

 - 'binding.Obtain()' (formerly 'binding.bindTo()' and 'binding.bindSequence()')
   now pre-adapt their arguments to 'IComponentKey', to speed up lookups at
   runtime, and to ensure that errors due to an unusable parameter type occur
   at class creation time instead of waiting until lookup time.

 - There's a new 'peak.storage.files' module, with handy classes like
   'EditableFile'.  'EditableFile' is a class that lets you edit the contents
   of a file "in place", with atomic replacement of the original at transaction
   commit.  If the transaction is aborted, the original file is left unchanged.

 - 'peak.running.scheduler.UntwistedReactor' now supports a configuration
   property ('peak.running.reactor.checkInterval') to determine how long it
   should run 'select()' calls for, when there are no scheduled tasks.

 - 'peak.running.commands.AbstractCommand' now offers a '_run()' method that
   can be overridden in subclasses, instead of 'run()'.  If you override the
   new '_run()' method instead, you get the advantage of automatic handling
   for invocation errors and 'SystemExit' exceptions, provided for you by the
   'run()' method.

 - There is now a 'storage.DMFor(class)' function that returns a configuration
   key for registering or looking up data managers by class.  You can use the
   returned key in a binding's 'offerAs' list, or as the target of a 'bindTo()'
   or 'lookupComponent()'.  The key is constructed using

 - You can now register utilities that are keyed by the combination of an
   interface and one or more classes, using 'config.ProviderOf(iface,*classes)'
   as a configuration key.  Providers are registered under an '(iface,klass)'
   tuple for each specified class, and looked up using the MRO order of the
   class specified for lookup.  In other words, searching for a provider will
   find a provider for the requested class, or one of its base classes, with
   precedence given to the more-specific provider.  This is primarily intended
   for services like data managers and Specialists.

 - It's now possible to extend .ini file parsing with custom section types,
   and PEAK defines its own built-in section types using this extension
   mechanism.  Custom section types must include at least one space, (e.g.
   '[My Section]') or they will be treated as a plain property name.
   See the 'peak.config.iniFile.sectionParsers' section in 'peak.ini' for
   more details, along with the 'config.ISettingParser' and 'config.IIniParser'

 - When creating a 'PropertyName()', it's now possible to force conversion of
   invalid characters to '_', using the 'PropertyName.fromString()'
   constructor.  (Note that the input must be a plain-ASCII string.)  Unless
   you request that wildcards ('?' and '*') be kept, they will also be
   converted to '_' characters.  This can be convenient for converting things
   like filenames or text that might contain spaces, to property names.

 - It's now possible to declare an attribute as offering a wildcard property;
   such lookups now follow the same rules as other wildcard property lookups.
   The 'config.IConfigKey' interface has been changed to cleanly support
   implied keys at both registration and lookup time, so you can implement
   your own key types that work the way interfaces or property names do for
   configuration lookups.

 - The 'EigenRegistry' class has been moved from 'peak.util.EigenData' to
   'peak.config.registries', as it hasn't really been useful outside PEAK for
   a while now.

 - .ini files now support "smart property" objects ('config.ISmartProperty').
   If a property rule defined in an .ini file evaluates at runtime to an object
   that implements 'ISmartProperty', the object will be given a chance to
   compute a value for the property, in place of being used itself.  This helps
   to simplify definition of complex property rules in .ini files, by allowing
   the use of helper classes.  Also, 'naming.LinkRef' and 'naming.Reference'
   (indirectly) support this interface, so you can now use them in .ini files
   to refer to an object via the naming system.  (Previously, 'naming.LinkRef'
   wouldn't do the right thing unless the property was looked up via a
   'config:' URL, and 'naming.Reference' didn't exist.)

 - 'peak.util.imports.whenImported()' can now be used even when the specified
   module has already been loaded.

 - The naming system no longer has 'objectFactories' and 'stateFactories' as
   utilities; they have been replaced with new mechanisms involving adaptation.
   Previously, addresses had a 'retrieve()' method that could be used to
   retrieve the object defined by the address.  Now, to retrieve an object for
   an address, you must either define a context that processes the address, or
   the address must have a 'defaultFactory' attribute, which provides a name
   to be imported to get an 'IObjectFactory' that can construct the referenced
   object.  (This is simpler than it sounds; for URLs that reference
   ManagedConnections, for example, all you need to do is provide the fully
   qualified name of the connection class.)

   Meanwhile, writable naming contexts must have a 'serializationProtocol'
   attribute, specifying what interface an object should be adapted to before
   attempting to store it in that context.

   The naming system no longer processes the 'creationName' keyword argument;
   this is now considered the sole responsibility of 'peak.binding'.  The
   'IComponent.lookupComponent()' method still accepts the keyword argument,
   and attribute bindings still handle the creation name transparently.  It is
   just not available via naming system APIs, and naming contexts no longer
   have to deal with it.

   The naming system base classes no longer use 'attrs' as an input parameter
   or return value.  If you've subclassed anything from 'peak.naming.contexts',
   note that your '_get()' methods should now just return the lookup value,
   rather than a 'state,attrs' tuple.  For most naming contexts, this just
   means you should change 'return foo, None' statements to just 'return foo'.

 - Property definition rules in an .ini file can now refer to 'rulePrefix' and
   'ruleSuffix' variables.  'rulePrefix' is a "."-terminated string,
   representing the name the rule was defined with.  For example, if the
   rule was defined for '"foo.bar.*"', then 'rulePrefix' will be '"foo.bar."'

   The 'ruleSuffix' will be the portion of the 'propertyName' that follows
   'rulePrefix'.  So, if looking up property '"foo.bar.baz"', then the
   '"foo.bar.*"' rule will execute with a 'ruleSuffix' of '"baz"'.  This should
   make it easier to work with hierarchical property namespaces.

 - Added simple example scripts and small applications in the 'examples'

 - There is a new command-line namespace introspection tool, 'n2', which
   can be accessed by running 'peak n2'.  Type 'peak n2 -h' for help.

 - The PEAK_CONFIG environment variable can now list multiple files, separated
   by the platform's 'os.pathsep' (e.g. ':' on Unix, ';' on Windows).

 - It's no longer necessary to provide a '_defaultState()' implementation
   for an EntityDM: a default implementation is now supplied.

 - Added automatic installation of 'datetime' package for Python < 2.3.

 - CGI support has been moved from 'peak.running.zpublish' into
   'peak.running.commands' (for "raw" CGI/FastCGI) and 'peak.web' (for the
   PEAK high-level publishing framework).  You can use 'peak CGI someName' to
   adapt 'someName' to a 'running.IRerunnableCGI' and run it as a CGI/FastCGI.

 - There is now a 'peak.security' package, available from 'peak.api' as
   'security'.  It provides permission management functions: you can define
   abstract permissions by subclassing 'security.Permission', then create
   permission checking rules by subclassing 'security.RuleSet', and declare
   the permissions needed to access attributes of a class with
   'security.allow()'.  The test suite demonstrates a complex application
   ruleset with dynamic, data-driven permissions.

 - There is now an interface for "Active Descriptors":
   'binding.IActiveDescriptor'.  'peak.binding' now uses this interface to
   identify active descriptors, so you can now create your own.  (Previously,
   'peak.binding' used 'isinstance()' to detect active descriptors.)

 - REMOVED 'naming.ParsedURL'; it was deprecated as of 0.5 alpha 2.

 - The 'provides' keyword argument to various 'peak.binding' APIs has been
   renamed to 'offerAs', and it must be a sequence of configuration keys.
   (Previously, it accepted either a single key or a tuple of keys.)
   The signature of 'binding.Constant()' was changed as well; the first
   positional argument is now the constant value, and 'offerAs' is now a
   keyword argument.  (Previously, 'provides' was the first positional argument
   of 'binding.Constant()'.)  The 'registerProvider()' method of
   'config.IConfigurable()' also now accepts only a single configuration key,
   as does 'EigenRegistry.register()'.

   Also, all 'peak.binding' APIs now only accept positional parameters for
   items unique to that API.  Items common to multiple APIs (such as 'offerAs',
   'doc', 'attrName', etc.) should now be supplied as keyword arguments.

   Bindings also now automatically "suggest" the containing object as a parent
   component for the contained object, whenever a value is assigned to them or
   computed.  If a non-None 'adaptTo' is set on the binding, the value assigned
   or computed will be adapted to the specified protocol before the parent
   component is suggested.  'binding.New()' no longer relies on the
   'IComponentFactory' interface, but instead uses the new adapt/suggest

   Previously, parent components were only "suggested" when a binding was set
   via component constructor keyword arguments.  Now, this is done at any time
   bindings are set, but *not* for non-binding keyword arguments.  In other
   words, ordinary attributes of a component do not receive "suggested parent"
   notices, even when set via constructor keyword arguments.  If you want an
   attribute to do this, you must define the attribute with the binding API;
   e.g. via 'requireBinding()' or 'binding.Constant()'.  If you do *not* want
   a binding to suggest a parent component, use 'suggestParent=False' in the
   binding definition.

 Corrected Problems

  - 'peak.running.commands.CGICommand' could become confused on certain BSD
    variants (such as Mac OS/X), and assume it was running under FastCGI, even
    if it wasn't.  (Because the operating systems in question use socket pairs
    to implement pipes.)

  - Fixed some problems with the test suite when running under Python 2.3.
    PEAK itself worked fine, but the test suite was bitten by two minor
    semantic changes that took effect in 2.3, resulting in lots of error
    messages about ModuleType needing a parameter, and a test failure for
    'checkClassInfo' in the 'FrameInfoTest' test class.

  - Transaction participants that raised an error in their 'abortTransaction()'
    method, would not receive a 'finishTransaction()' call, the error was
    passed through to the transaction service's caller, and later participants
    might not have received an 'abortTransaction()' message either.

  - SQL connections didn't close their cursors before aborting a transaction

  - The logging system would raise an error if a log message with no arguments
    contained a '%' sign.

  - There was a typo in peak.naming.arithmetic that caused homogeneous non-URL
    name subtraction to fail.

  - The default reactor supplied in 'peak.running.scheduler' would consume
    CPU continuously if it was waiting for I/O and no tasks were scheduled.

  - The 'peak.util.imports.whenImported' function didn't work.

Fixes and Enhancements since Version 0.5 alpha 1

 Changed, Enhanced, or Newly Deprecated Features

 - Added a 'shellcmd:'  URL scheme that returns a function that calls
   'os.system()' on the body of the URL.  It's intended for use as a command
   factory, as is needed by the 'URLChecker' periodic task.

 - You can now define adapters from arbitrary types to 'binding.IBindingNode',
   and thus be able to use them as part of a component hierarchy - without
   needing to directly add 'getParentComponent()' or 'getComponentName()'
   methods to them.

 - Added experimental 'invoke.c' script for POSIX-ish platforms with funky
   '#!' support, or lack thereof.

   'invoke' is designed to be used like this::

     #!/usr/local/bin/invoke peak somearg otherarg...

   This should work on most sane platforms with a long-enough commandline.
   (See "this page":http://homepages.cwi.nl/~aeb/std/hashexclam-1.html for
   details on the insanely incompatible ways different Unixes interpret '#!'

   The script is not currently built or installed by setup.py.  On the
   platforms it's targeted at, you should be able to build it with::

     gcc -o invoke invoke.c

   (Yes, it really is that simple of a script.)

 - Added a ZConfig schema for 'running.commands.EventDriven' applications,
   a ZConfig component definition for adaptive tasks, and a running shortcut
   called 'EventDriven'.

   It should now be possible to do this::

     #!/usr/bin/env peak EventDriven

   at the top of a ZConfig file formatted according to the new schema, and
   have it run.  There are two periodic tasks that can be configured and
   run from such a file: 'CleanupFiles' and 'URLChecker'.  'CleanupFiles' will
   delete files matching a pattern that are older than a certain age, while
   'URLChecker' will check to see if the target of a naming system URL is
   up/available/working, and if not, runs a command to restart it.  As an
   amusing demo, try specifying a 'file:' URL with a 'shellcmd:touch theFile'
   to recreate the file, then add a 'CleanupFiles' that deletes the file the
   checker looks for.  This can be hours (well, minutes) of exciting fun as you
   watch the dueling daemons undoing each others' work.

 - Added 'zconfig.schema' URL scheme that loads an enhanced ZConfig schema
   object that can act as a command line interpreter using the 'peak' script.

   To use it, run 'peak zconfig.schema:urlToSchema urlOfConfig'.  Or, add
   a line like this::

     #!/usr/bin/env peak zconfig.schema:pkgfile:some.package/schema.xml

   to the top of a configuration file, and make the configuration file
   executable.  Note that the schema specified must convert to an object
   that's usable with the commands bootstrap framework.  Also note that
   if you have a local PEAK_CONFIG file, you can add a 'peak.running.shortcuts'
   entry to shorten the URL reference in your #! line.  E.g.::

     #!/usr/bin/env peak mySchema

   will suffice if you have defined 'peak.running.shortcuts.mySchema' as

   There is also a 'peak ZConfig urlOfSchema urlOfConfig' variant, that was
   added to support putting '#!/usr/bin/env peak ZConfig' at the top of
   schema files, but unfortunately that's not valid XML.

 - Standardized file-based URL syntaxes (e.g logfiles and lockfiles) to
   follow RFC 1738/2396, and Python 'urllib'.  This shouldn't affect much
   besides the canonical forms of the URLs.  Added 'pkgfile:some.pkg/filepath'
   URL syntax for ease of referring to files near modules.  (A convenience
   intended mainly for referencing ZConfig schemas.)

 - Added the UML 1.4 metamodel, and thus the ability to load UML 1.4
   models encoded in XMI 1.1.

 - Added support in the mof2py code generator for "unprefixing" enumerated
   values, so that UML and other metamodels' enumerations work correctly
   when loading from XMI.  Also, mof2py no longer emits 'config.setupModule()'
   calls in generated code, as in practice they are not needed.

 - Running 'peak test' from the command line is roughly equivalent to running
   'unittest.py', except that the test suite defaults to the PEAK test suite.
   You can, however run any test suite from the command line with a dotted
   module/attribute path, e.g 'peak test foo.bar.test_suite'.

 - 'binding.Acquire()' now accepts a 'default' value argument, and
   'binding.New()' no longer accepts the 'bindToOwner' flag.

 - There is a new 'binding.IComponentKey' interface that is used to implement
   'IComponent.lookupComponent()'.  Now you can implement this interface,
   or create an adapter for it, in order to make an object usable as an
   argument to 'binding.lookupComponent()' - and therefore usable as a key
   for 'binding.bindTo()' or 'binding.bindToSequence()'.  Not that it's
   necessarily very useful to do so; you're probably better off simply
   creating a naming scheme.  But it might be useful for lookups done
   in the context of classes, since naming schemes aren't usable there.
   (It was actually added in order to factor out all the type testing that
   'lookupComponent' used to do, so it doesn't matter if it's useful for
   much else.)

 - PEAK has been refactored to avoid the use of 'isImplementedBy()' and
   similar introspection, in favor of 'adapt()'.  As a result, some
   'peak.naming' interfaces have changed.  This should not affect you
   if you are only subclassing PEAK-provided naming components and not
   implementing these interfaces "from scratch".  However, the various
   'isAddress', 'isAddressClass', 'isResolver', and 'isName' APIs have
   also been removed, as they were based on 'isImplementedBy()'.

 - REMOVED ability to use '__implements__' and '__class_implements__' to
   declare support for interfaces.  Use 'protocols.advise()' or a related
   API to do this now.  The 'protocols' package is available automatically
   from 'peak.api'.

   Similarly, the ability  to use 'isImplementedBy()' with interfaces declared
   by PEAK is REMOVED.  You can still use 'isImplementedBy()' with Zope
   interfaces, of course, but we recommend you switch to 'adapt()', which
   should work with both PEAK and Zope interfaces.

 - Replaced all use of 'zope.interface' with 'protocols' package because
   the 'protocols' package:

   * is considerably smaller and simpler than 'zope.interface'

   * produces Interface objects that can be inspected with the Python
     'pydoc' and 'help()' tools

   * supports and implements the PEP 246 'adapt()' protocol

   * transparently supports transitive adaptation - i.e. if adapter AB
     adapts from A to B, and adapter BC adapts from B to C, then an adapt(x,C)
     where 'x' is an 'A', will be implemented as BC(AB(x)).

   * Supports "open protocols" that allow you to "superclass" a protocol
     to create a subset protocol; objects that support the first protocol
     will automatically support the subset protocol.  For example, if one
     person defines a "dictionary" protocol, someone else can create a
     "read-only dictionary" protocol, and all objects supporting the
     "dictionary protocol" will be considered to implement the "read-only
     dictionary" protocol.

   * can interoperate with other interface packages, including Zope's, but
     does not require them

   * works with module inheritance (for everything but moduleProvides(), and
     we should get to that by 0.5a2)

   * lets you use Interfaces as abstract base classes (i.e., you can
     inherit from an interface and turn it into an implementation, and
     you can define default attribute values or method implementations in
     your interfaces

   * Lets you mix interface declarations from any number of frameworks and
     any number of interface types, in a single 'implements()' or

   * uses adaptation as the fundamental approach to dealing with interfaces,
     and avoids the use of 'isImplementedBy()'.  In the *rare* case that you
     need to introspect rather than adapt, you can always call adapt() and
     check the result.  (But introspection usually means that you're using
     interfaces as a form of metadata; it's better to create an explicit
     interface that provides the metadata you seek, and adapt to that
     interface, than to use interfaces as data.)

   Most of these features are unavailable in 'zope.interface', and some have
   been declared by the Zope Pope to be unacceptable or undesirable features
   for Zope interfaces.  (Others may be available in some form in future
   versions of Zope X3.)  So, we no longer require or distribute

 - The signatures of the 'getObjectInstance()', 'getStateToBind()', and
   'getURLContext()' methods in the 'peak.naming' package have changed, to
   place the context or parent component as the first, non-optional argument.
   (If you don't know what these methods are for, you don't need to do anything
   about this, as they are part of the naming package's extensibility

 - 'binding.bindTo()' now accepts a 'default=' argument, whose value will be
   used in case of a 'NameNotFound' error.

 - DEPRECATED 'naming.ParsedURL'.  It will disappear in 0.5 alpha 3 or beta.
   It is replaced by the new 'naming.URL.Base'.  The 'naming.URL' package
   provides a new URL parsing framework based on 'peak.model'.  Upgrading from
   'ParsedURL' to 'URL.Base' is trivial for ParsedURL subclasses that used
   only the 'scheme' and 'body' fields, and in fact may not require any
   changes except for the choice of base class.  Also, the 'retrieve()' method
   of URLs is deprecated; please begin defining the 'getObjectInstance()'
   method instead.  This is to cut down a bit on the number of ways that the
   naming package spells the idea of retrieving something!

   For more complex URL classes, the '__init__' methods go away, 'parse'
   methods change slightly, and explicit field definitions (using
   'model.structField' or similar) are required.  See PEAK's 'URL.Base'
   subclasses for examples.  There is also a sophisticated parsing and
   formatting framework (see the 'peak.naming.URL' and 'peak.util.fmtparse'
   modules) that can be used in place of the old regex-based approach.

 - Added 'peak.util.fmtparse', a parsing and formatting framework, and
   integrated it with 'peak.model' so that any element type can have a
   syntax for parsing from, or formatting to, a string.

 - Added 'binding.whenAssembled(...)' as syntax sugar for

 - Removed 'LOG_XYZ' convenience functions from 'peak.api', and refactored
   'peak.running.logs' to use a PEP 282-like interface, 'running.ILogger'.
   Under the new scheme, messages must be sent to a specific entry point
   (e.g. 'self.logger.warning("foo")').  Components can bind an attribute
   directly to a logger object, or via configuration properties or utilities.
   PEAK components that do logging all define a 'logger' attribute, bound
   to a configuration property in the 'peak.logs' property namespace.  By
   a default in 'peak.ini', 'peak.logs.*' is configured to output messages
   of 'WARNING' priority or higher to 'sys.stderr'.

   For compatibility with the PEP 282 logging package, a 'logging.logger:'
   URL scheme has been added; looking up the URL '"logging.logger:foo.bar"'
   is equivalent to 'logging.getLogger("foo.bar")', unless the 'logging'
   package is not available, in which case the configuration property
   'peak.logs.foo.bar' will be looked up in the target context of the
   lookup.  Optionally, you can configure the 'logging.logger' URL scheme so
   that it only uses PEAK loggers, and never uses the PEP 282 loggers.

 - Added 'binding.metamethod()' wrapper for metaclass methods that might
   not be accessible from their instances if the instances (classes) also
   defined the method for *their* instances.  You must now use this wrapper
   on any such metaclass-defined methods, as PEAK no longer works around
   this via the 'x.__class__.foo(x,...)' trick that was used previously.
   In particular, if you have metaclass definitions of 'getParentComponent',
   '_getConfigData', 'getComponentName', or 'notifyUponAssembly', you need
   to wrap them with 'binding.metamethod' now.

 - Made 'NOT_GIVEN' and 'NOT_FOUND' recognizable by humans (they 'repr'
   and 'str' to their names) and by Python (they can be pickled, and
   when restored they come back as the same object).

 Corrected Problems

 - Fixed a problem in ZConfig 'schema.dtd'; I used 'PCDATA' where I should've
   used 'CDATA'.

 - Fixed a problem with 'binding.supertype()' not working correctly if the MRO
   it was searching contained a "classic" class.  Now 'supertype()' skips any
   classic classes it finds.  (It probably should be rewritten entirely.)

 - Fixed misc. problems with 'fromZConfig()' component constructor

 - Fixed source distributions missing essential setup files

 - Fixed a problem with assembly events, where a parent component that didn't
   need assembly notification, wouldn't ever notify its children of assembly
   if they requested the notification after the parent had already received

 - Fixed a bug in automatic metaclass generation that caused extra unneeded
   metaclasses to be generated.

 - Fixed 'naming.lookup()' and related APIs not setting the parent component
   of created objects without an explicitly supplied 'creationParent' keyword
   argument.  This used to "sort of work" when we had implicit configuration
   parents, but was broken when we went "all explicit" for 0.5 alpha 1.

 - Fixed a problem where initializing single-valued immutable fields of
  'peak.model' types did not perform type/value normalization.

 - Fixed a problem where bindTo would use the attribute name as the
   default value for a lookup, if the requested name/property/utility
   was not found.

 - Fixed 'mof2py' generator script not working

 - Fixed model.Element not getting parent component set when passed as a
   constructor argument.

 - Fixed property/utility lookups not working correctly on model.*

 - Fixed IndentedStream generating all-whitespace lines


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