mirror of
https://mau.dev/maunium/synapse.git
synced 2024-12-15 10:23:53 +01:00
Merge pull request #2961 from matrix-org/rav/run_in_background
Factor run_in_background out from preserve_fn
This commit is contained in:
commit
b984dd0b73
2 changed files with 32 additions and 27 deletions
|
@ -279,9 +279,9 @@ Obviously that option means that the operations done in
|
||||||
that might be fixed by setting a different logcontext via a ``with
|
that might be fixed by setting a different logcontext via a ``with
|
||||||
LoggingContext(...)`` in ``background_operation``).
|
LoggingContext(...)`` in ``background_operation``).
|
||||||
|
|
||||||
The second option is to use ``logcontext.preserve_fn``, which wraps a function
|
The second option is to use ``logcontext.run_in_background``, which wraps a
|
||||||
so that it doesn't reset the logcontext even when it returns an incomplete
|
function so that it doesn't reset the logcontext even when it returns an
|
||||||
deferred, and adds a callback to the returned deferred to reset the
|
incomplete deferred, and adds a callback to the returned deferred to reset the
|
||||||
logcontext. In other words, it turns a function that follows the Synapse rules
|
logcontext. In other words, it turns a function that follows the Synapse rules
|
||||||
about logcontexts and Deferreds into one which behaves more like an external
|
about logcontexts and Deferreds into one which behaves more like an external
|
||||||
function — the opposite operation to that described in the previous section.
|
function — the opposite operation to that described in the previous section.
|
||||||
|
@ -293,7 +293,7 @@ It can be used like this:
|
||||||
def do_request_handling():
|
def do_request_handling():
|
||||||
yield foreground_operation()
|
yield foreground_operation()
|
||||||
|
|
||||||
logcontext.preserve_fn(background_operation)()
|
logcontext.run_in_background(background_operation)
|
||||||
|
|
||||||
# this will now be logged against the request context
|
# this will now be logged against the request context
|
||||||
logger.debug("Request handling complete")
|
logger.debug("Request handling complete")
|
||||||
|
|
|
@ -292,36 +292,41 @@ class PreserveLoggingContext(object):
|
||||||
|
|
||||||
|
|
||||||
def preserve_fn(f):
|
def preserve_fn(f):
|
||||||
"""Wraps a function, to ensure that the current context is restored after
|
"""Function decorator which wraps the function with run_in_background"""
|
||||||
|
def g(*args, **kwargs):
|
||||||
|
return run_in_background(f, *args, **kwargs)
|
||||||
|
return g
|
||||||
|
|
||||||
|
|
||||||
|
def run_in_background(f, *args, **kwargs):
|
||||||
|
"""Calls a function, ensuring that the current context is restored after
|
||||||
return from the function, and that the sentinel context is set once the
|
return from the function, and that the sentinel context is set once the
|
||||||
deferred returned by the funtion completes.
|
deferred returned by the funtion completes.
|
||||||
|
|
||||||
Useful for wrapping functions that return a deferred which you don't yield
|
Useful for wrapping functions that return a deferred which you don't yield
|
||||||
on.
|
on.
|
||||||
"""
|
"""
|
||||||
def g(*args, **kwargs):
|
current = LoggingContext.current_context()
|
||||||
current = LoggingContext.current_context()
|
res = f(*args, **kwargs)
|
||||||
res = f(*args, **kwargs)
|
if isinstance(res, defer.Deferred) and not res.called:
|
||||||
if isinstance(res, defer.Deferred) and not res.called:
|
# The function will have reset the context before returning, so
|
||||||
# The function will have reset the context before returning, so
|
# we need to restore it now.
|
||||||
# we need to restore it now.
|
LoggingContext.set_current_context(current)
|
||||||
LoggingContext.set_current_context(current)
|
|
||||||
|
|
||||||
# The original context will be restored when the deferred
|
# The original context will be restored when the deferred
|
||||||
# completes, but there is nothing waiting for it, so it will
|
# completes, but there is nothing waiting for it, so it will
|
||||||
# get leaked into the reactor or some other function which
|
# get leaked into the reactor or some other function which
|
||||||
# wasn't expecting it. We therefore need to reset the context
|
# wasn't expecting it. We therefore need to reset the context
|
||||||
# here.
|
# here.
|
||||||
#
|
#
|
||||||
# (If this feels asymmetric, consider it this way: we are
|
# (If this feels asymmetric, consider it this way: we are
|
||||||
# effectively forking a new thread of execution. We are
|
# effectively forking a new thread of execution. We are
|
||||||
# probably currently within a ``with LoggingContext()`` block,
|
# probably currently within a ``with LoggingContext()`` block,
|
||||||
# which is supposed to have a single entry and exit point. But
|
# which is supposed to have a single entry and exit point. But
|
||||||
# by spawning off another deferred, we are effectively
|
# by spawning off another deferred, we are effectively
|
||||||
# adding a new exit point.)
|
# adding a new exit point.)
|
||||||
res.addBoth(_set_context_cb, LoggingContext.sentinel)
|
res.addBoth(_set_context_cb, LoggingContext.sentinel)
|
||||||
return res
|
return res
|
||||||
return g
|
|
||||||
|
|
||||||
|
|
||||||
def make_deferred_yieldable(deferred):
|
def make_deferred_yieldable(deferred):
|
||||||
|
|
Loading…
Reference in a new issue