diff options
| -rw-r--r-- | synapse/metrics/background_process_metrics.py | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/synapse/metrics/background_process_metrics.py b/synapse/metrics/background_process_metrics.py index b24e2fab4a..c53d2a0d40 100644 --- a/synapse/metrics/background_process_metrics.py +++ b/synapse/metrics/background_process_metrics.py @@ -175,7 +175,7 @@ def run_as_background_process(desc, func, *args, **kwargs): Args: desc (str): a description for this background process type - func: a function, which may return a Deferred + func: a function, which may return a Deferred or a coroutine args: positional args for func kwargs: keyword args for func @@ -199,11 +199,13 @@ def run_as_background_process(desc, func, *args, **kwargs): _background_processes.setdefault(desc, set()).add(proc) try: - # We ensureDeferred here to handle coroutines result = func(*args, **kwargs) - # We need this check because ensureDeferred doesn't like when - # func doesn't return a Deferred or coroutine. + # We probably don't have an ensureDeferred in our call stack to handle + # coroutine results, so we need to ensureDeferred here. + # + # But we need this check because ensureDeferred doesn't like being + # called on immediate values (as opposed to Deferreds or coroutines). if iscoroutine(result): result = defer.ensureDeferred(result) |