Singleton per request object

[omarkohl]

One issue I ran into with your dbsession service example (that uses a service factory) is the following:

When looking for the service different sessions are returned depending on the context. This is by design. Citing the documentation:

The factory will be used at most once per request/context/name combination.

Having different DB session in one request is quite ugly and I can think of no use case for it. How did I end up with different contexts? By using the request object outside a view function invoked directly with pyramid.threadlocal.get_current_request . In that case the context is None.

This example by Jon Rosebaugh - What the Zope Transaction Manager Means To Me (and you) would work but I wanted to use pyramid_services (for consistency, because I'm already using it in other parts of the application).

I'm aware that this might not be the place for this since it classifies more as a question than an issue, but you could at least fix the example to be more clear that

request.find_service(name='db')

will return different sessions depending on the request context.

My workaround is to always pass context=None:

request.find_service(name='db', context=None)

Is there a simpler solution (e.g. a singleton per request)? register_service() would register a singleton object for the whole application, but I do want a different DB session for every request.

[mmerickel]

I see what you're saying. Ideally we would use the original context interface as the cache key, not the context supplied.

[mmerickel]

We can certainly make that change. I'm not sure it's entirely obvious how to go about it right now, but if you want to investigate please feel free to open a PR with a fix or even just add a test case to the test suite.