taurus.core.resource
Resource scheme extension for taurus core mode. The resource extension is a special extension that acts like a name map for actual model names.
This allows to indirect the hardcoded model names of your application and keep the actual specific model names grouped in one place for better portability and reusability of your application.
The scheme name is ‘res’. The map can be implemented either as python modules or as dicts (see below).
The main class for the extension module is ResourcesFactory and
you can add resource maps with ResourcesFactory.loadResource().
By default, the ResourcesFactory will always try to load a resource
module named ‘taurus_resources’ from the application directory (so you can
create a file called taurus_resources.py in your application directory and
skip the step of calling ResourcesFactory.loadResource().
Mapping implemented as python modules
If a resource is a python module, the factory will use its global variables as the resource keys. The variable value, which must be a string will be used as the mapped model. For example, if the taurus_resources.py file in the application directory contains the following definitions:
my_device = 'tango:a/b/c'
my_state = my_device + '/state'
Then, in your code, you can access the Device and Attribute objects by doing:
>>> import taurus
>>> my_device_obj = taurus.Device('res:my_device')
>>> my_state_obj = taurus.Attribute('res:my_state')
Note that you can use python code to automate the contents of the module. Example:
base = 'my/motor/'
g = globals()
for i in xrange(256):
i_str = str(i)
g['mym"+i_str] = base + i_str
Mapping implemented as dictionaries
Dictionaries can also be registered (as an alternative to modules) as resource maps:
>>> d = {'my_device':'tango:a/b/c', 'my_state':'tango:a/b/c/state'}
>>> import taurus
>>> factory = taurus.Factory('res')
>>> factory.loadResource(d)
>>> my_device_obj = taurus.Device('res:my_device')
>>> my_state_obj = taurus.Attribute('res:my_state')
Note: for coherence with the file mapping, valid key names are restricted to valid variable names (i.e. to the following regexp: [a-zA-Z_][a-zA-Z0-9_]*
Important: Models object type is the mapped type
The model objects returned by the ResourcesFactory will be of the
mapped model type. In other words: if the model name ‘eval:Q(rand())’ is mapped
to the myattr resource name, calling taurus.Attribute(‘res:myattr’) will
return a EvaluationAttribute, not a ResAttribute (ResAttribute is
not even defined).
Submodules
Classes