diff --git a/synapse/logging/opentracing.py b/synapse/logging/opentracing.py
index 2c34b54702..8c574ddd28 100644
--- a/synapse/logging/opentracing.py
+++ b/synapse/logging/opentracing.py
@@ -239,8 +239,7 @@ _homeserver_whitelist = None
def only_if_tracing(func):
- """Executes the function only if we're tracing. Otherwise return.
- Assumes the function wrapped may return None"""
+ """Executes the function only if we're tracing. Otherwise returns None."""
@wraps(func)
def _only_if_tracing_inner(*args, **kwargs):
@@ -252,6 +251,41 @@ def only_if_tracing(func):
return _only_if_tracing_inner
+def ensure_active_span(message, ret=None):
+ """Executes the operation only if opentracing is enabled and there is an active span.
+ If there is no active span it logs message at the error level.
+
+ Args:
+ message (str): Message which fills in "There was no active span when trying to %s"
+ in the error log if there is no active span and opentracing is enabled.
+ ret (object): return value if opentracing is None or there is no active span.
+
+ Returns (object): The result of the func or ret if opentracing is disabled or there
+ was no active span.
+ """
+
+ def ensure_active_span_inner_1(func):
+ @wraps(func)
+ def ensure_active_span_inner_2(*args, **kwargs):
+ if not opentracing:
+ return ret
+
+ if not opentracing.tracer.active_span:
+ logger.error(
+ "There was no active span when trying to %s."
+ " Did you forget to start one or did a context slip?",
+ message,
+ )
+
+ return ret
+
+ return func(*args, **kwargs)
+
+ return ensure_active_span_inner_2
+
+ return ensure_active_span_inner_1
+
+
@contextlib.contextmanager
def _noop_context_manager(*args, **kwargs):
"""Does exactly what it says on the tin"""
@@ -349,26 +383,24 @@ def start_active_span(
if opentracing is None:
return _noop_context_manager()
- else:
- # We need to enter the scope here for the logcontext to become active
- return opentracing.tracer.start_active_span(
- operation_name,
- child_of=child_of,
- references=references,
- tags=tags,
- start_time=start_time,
- ignore_active_span=ignore_active_span,
- finish_on_close=finish_on_close,
- )
+ return opentracing.tracer.start_active_span(
+ operation_name,
+ child_of=child_of,
+ references=references,
+ tags=tags,
+ start_time=start_time,
+ ignore_active_span=ignore_active_span,
+ finish_on_close=finish_on_close,
+ )
def start_active_span_follows_from(operation_name, contexts):
if opentracing is None:
return _noop_context_manager()
- else:
- references = [opentracing.follows_from(context) for context in contexts]
- scope = start_active_span(operation_name, references=references)
- return scope
+
+ references = [opentracing.follows_from(context) for context in contexts]
+ scope = start_active_span(operation_name, references=references)
+ return scope
def start_active_span_from_request(
@@ -465,19 +497,19 @@ def start_active_span_from_edu(
# Opentracing setters for tags, logs, etc
-@only_if_tracing
+@ensure_active_span("set a tag")
def set_tag(key, value):
"""Sets a tag on the active span"""
opentracing.tracer.active_span.set_tag(key, value)
-@only_if_tracing
+@ensure_active_span("log")
def log_kv(key_values, timestamp=None):
"""Log to the active span"""
opentracing.tracer.active_span.log_kv(key_values, timestamp)
-@only_if_tracing
+@ensure_active_span("set the traces operation name")
def set_operation_name(operation_name):
"""Sets the operation name of the active span"""
opentracing.tracer.active_span.set_operation_name(operation_name)
@@ -486,7 +518,7 @@ def set_operation_name(operation_name):
# Injection and extraction
-@only_if_tracing
+@ensure_active_span("inject the span into a header")
def inject_active_span_twisted_headers(headers, destination, check_destination=True):
"""
Injects a span context into twisted headers in-place
@@ -522,7 +554,7 @@ def inject_active_span_twisted_headers(headers, destination, check_destination=T
headers.addRawHeaders(key, value)
-@only_if_tracing
+@ensure_active_span("inject the span into a byte dict")
def inject_active_span_byte_dict(headers, destination, check_destination=True):
"""
Injects a span context into a dict where the headers are encoded as byte
@@ -559,7 +591,7 @@ def inject_active_span_byte_dict(headers, destination, check_destination=True):
headers[key.encode()] = [value.encode()]
-@only_if_tracing
+@ensure_active_span("inject the span into a text map")
def inject_active_span_text_map(carrier, destination, check_destination=True):
"""
Injects a span context into a dict
@@ -591,6 +623,7 @@ def inject_active_span_text_map(carrier, destination, check_destination=True):
)
+@ensure_active_span("get the active span context as a dict", ret={})
def get_active_span_text_map(destination=None):
"""
Gets a span context as a dict. This can be used instead of manually
@@ -603,7 +636,7 @@ def get_active_span_text_map(destination=None):
dict: the active span's context if opentracing is enabled, otherwise empty.
"""
- if not opentracing or (destination and not whitelisted_homeserver(destination)):
+ if destination and not whitelisted_homeserver(destination):
return {}
carrier = {}
@@ -614,6 +647,7 @@ def get_active_span_text_map(destination=None):
return carrier
+@ensure_active_span("get the span context as a string.", ret={})
def active_span_context_as_string():
"""
Returns:
|
