Re: [libvirt] [sandbox PATCH 03/11] Image: Add Hooking Mechanism

Any custom source provider can be added to virt-sandbox-image as a source --- virt-sandbox-image/sources/Source.py | 8 ++++++++ virt-sandbox-image/virt-sandbox-image.py | 30 +++++++++++++++++++++++++++++- 2 files changed, 37 insertions(+), 1 deletion(-) create mode 100644 virt-sandbox-image/sources/Source.py diff --git a/virt-sandbox-image/sources/Source.py b/virt-sandbox-image/sources/Source.py new file mode 100644 index 0000000..cfc75d3 --- /dev/null +++ b/virt-sandbox-image/sources/Source.py @@ -0,0 +1,8 @@ +#!/usr/bin/python + +from abc import ABCMeta, abstractmethod + +class Source(): + __metaclass__ = ABCMeta + def __init__(self): + pass diff --git a/virt-sandbox-image/virt-sandbox-image.py b/virt-sandbox-image/virt-sandbox-image.py index 324e568..99ed46e 100644 --- a/virt-sandbox-image/virt-sandbox-image.py +++ b/virt-sandbox-image/virt-sandbox-image.py @@ -1,5 +1,5 @@ #!/usr/bin/python -Es -# +# -*- coding: utf-8 -*- # Authors: Daniel P. Berrange <berrange(a)redhat.com&gt; # Eren Yagdiran <erenyagdiran(a)gmail.com&gt; # @@ -38,6 +38,34 @@ default_template_dir = "/var/lib/libvirt/templates" debug = True verbose = True +sys.dont_write_bytecode = True + + +##Hook mechanism starts## +import __builtin__ +from sources.Source import Source +__builtin__.hookHolder = {} +def add_hook(driverName,clazz): + holder = __builtin__.hookHolder + if not issubclass(clazz,Source): + raise Exception("Loading %s failed. Make sure it is a subclass Of %s" %(clazz,Source)) + holder[driverName] = clazz + +def init_from_name(name): + holder = __builtin__.hookHolder + return holder.get(name,None) + +__builtin__.add_hook = add_hook +__builtin__.init_from_name = init_from_name +from sources import * + +def dynamic_source_loader(name): + obj = init_from_name(name) + if obj == None: + raise IOError + return obj() +##Hook mechanism ends