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bonobo/docs/guide/future/services.rst
2018-01-16 06:27:25 +01:00

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Services
========
.. warning::
This is a "future" document, that does not exist, it's only kept here not to lose the data until we organize better
documentation versioning.
Future and proposals
::::::::::::::::::::
This is a first implementation and it will evolve. Base concepts will stay the same though.
May or may not happen, depending on discussions.
* Singleton or prototype based injection (to use spring terminology, see
https://www.tutorialspoint.com/spring/spring_bean_scopes.htm), allowing smart factory usage and efficient sharing of
resources.
* Lazily resolved parameters, eventually overriden by command line or environment, so you can for example override the
database DSN or target filesystem on command line (or with shell environment vars).
* Pool based locks that ensure that only one (or n) transformations are using a given service at the same time.
* Simple config implementation, using a python file for config (ex: bonobo run ... --services=services_prod.py).
* Default configuration for services, using an optional callable (`def get_services(args): ...`). Maybe tie default
configuration to graph, but not really a fan because this is unrelated to graph logic.
* Default implementation for a service in a transformation or in the descriptor. Maybe not a good idea, because it
tends to push forward multiple instances of the same thing, but maybe...
A few ideas on how it can be implemented, from the user perspective.
.. code-block:: python
# using call
http = Service('http.client')(requests)
# using more explicit call
http = Service('http.client').set_default_impl(requests)
# using a decorator
@Service('http.client')
def http(self, services):
import requests
return requests
# as a default in a subclass of Service
class HttpService(Service):
def get_default_impl(self, services):
import requests
return requests
# ... then use it as another service
http = HttpService('http.client')
This is under development, let us know what you think (slack may be a good place for this).
The basics already work, and you can try it.