Open FichteFoll opened 2 months ago
I just realized that you would probably want to unload the while_serving
hooks in reverse order, much like a stack, which doesn't fare well with my proposal. This is not something that quart is currently doing, but it might be worth considering. The problem is that this makes determining the after serving hook order much harder.
Thinking about this again randomly, unwinding the stack in reverse order for unloading is actually quite reasonable, if you think of a while_serving
exactly like I did in my workaround: splitting them into before_serving
and after_serving
.
Implementation-wise, you would use a single stack for all lifecycle hooks, i.e. before_saving
, while_serving
and after_serving
, to honor their registration order. Then, when executing the before hooks you would also run the while hooks in order until they yield. When unwinding the application, you would iterate the stack in reverse order and execute the after_saving
hooks as well as the second parts of the paused while_serving
hooks. That would be predictable and not really complicated either.
I'm building an application where I want to intialize a few things and I am registering the
while_serving
andbefore_serving
hooks in mycreate_app
, i.e. the main prodedure that generates the application. Some of these hooks have dependencies on others, e.g. settings must be loaded & validated first, then the connection to the database is established and then I do some initialization based on the database.before_serving
hooks are executed in order, so that is good.However, because I want to register the database setup in a
while_serving
so that I can also easily and precisely release the database resources (registered in the same generator function) once the application shuts down, the FIFO registering of hooks isn't working anymore because allbefore_serving
hooks are called first and only then are thewhile_serving
hooks executed/iterated. For me, it would be ideal if they were instead executed in the order of their registration.I haven't mentioned
after_serving
yet and that's because I don't actually use it currently, but if I were to I believe that the the same ordering should apply, i.e. "unload"while_serving
hooks andafter_serving
hooks in the order they were registered.The abstract example code that illustrates this problem is as follows:
My current workaround, after splitting the
init_db
generator into two functions: