Skip to content

observability: annotate Session+SessionPool events #1207

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Dec 6, 2024
Merged

observability: annotate Session+SessionPool events #1207

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 4 additions & 0 deletions google/cloud/spanner_v1/_helpers.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -463,6 +463,7 @@ def _retry(
retry_count=5,
delay=2,
allowed_exceptions=None,
beforeNextRetry=None,
):
"""
Retry a function with a specified number of retries, delay between retries, and list of allowed exceptions.
Expand All @@ -479,6 +480,9 @@ def _retry(
"""
retries = 0
while retries <= retry_count:
if retries > 0 and beforeNextRetry:
beforeNextRetry(retries, delay)

try:
return func()
except Exception as exc:
Expand Down
19 changes: 17 additions & 2 deletions google/cloud/spanner_v1/_opentelemetry_tracing.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -81,10 +81,11 @@ def trace_call(name, session, extra_attributes=None, observability_options=None)
tracer = get_tracer(tracer_provider)

# Set base attributes that we know for every trace created
db = session._database
attributes = {
"db.type": "spanner",
"db.url": SpannerClient.DEFAULT_ENDPOINT,
"db.instance": session._database.name,
"db.instance": "" if not db else db.name,
"net.host.name": SpannerClient.DEFAULT_ENDPOINT,
OTEL_SCOPE_NAME: TRACER_NAME,
OTEL_SCOPE_VERSION: TRACER_VERSION,
Expand All @@ -106,7 +107,10 @@ def trace_call(name, session, extra_attributes=None, observability_options=None)
yield span
except Exception as error:
span.set_status(Status(StatusCode.ERROR, str(error)))
span.record_exception(error)
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Lets not remove this exception. We are not sure if there are any cases where the span will end up not recording an exception.
I would suggest adding this back here and let us discuss more during our demo.

Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Also I was wondering that this behavior of exception getting added twice was not seen earlier since this code exists from very long.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

It's because OpenTelemetry was upgraded only recently.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

We do have locked tests to check for the exceptions to ensure that they are in there and from Span.enter. I had to dive back into OpenTelemetry-Python's code as it isn't even documented and in our demos it was very distracting to have mysteriously both errors. I think for the sake of our sanity and project stability let's leave that comment in and if anything happens it is a trivial one to add back @harshachinta

Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Hmm. But the opentelemetry documentation for Python guides to record exception for instrumentation libraries.
https://opentelemetry.io/docs/languages/python/instrumentation/#record-exceptions-in-spans

Can you share the code pointer on where the opentelemetry records exception by default when exiting?

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

@harshachinta https://github.com/open-telemetry/opentelemetry-python/blob/db4ef06f471cb9e94d810ae66964c3e5e0f5e61e/opentelemetry-sdk/src/opentelemetry/sdk/trace/__init__.py#L986-L1008

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

@harshachinta it was the cause of us seeing 2 exceptions and took a ton of confusion and time for me to debug, they don't seem to document this condition.

# OpenTelemetry-Python imposes invoking span.record_exception on __exit__
# on any exception. We should file a bug later on with them to only
# invoke .record_exception if not already invoked, hence we should not
# invoke .record_exception on our own else we shall have 2 exceptions.
raise
else:
if (not span._status) or span._status.status_code == StatusCode.UNSET:
Expand All @@ -116,3 +120,14 @@ def trace_call(name, session, extra_attributes=None, observability_options=None)
# it wasn't previously set otherwise.
# https://github.com/googleapis/python-spanner/issues/1246
span.set_status(Status(StatusCode.OK))


def get_current_span():
if not HAS_OPENTELEMETRY_INSTALLED:
return None
return trace.get_current_span()


def add_span_event(span, event_name, event_attributes=None):
if span:
span.add_event(event_name, event_attributes)
12 changes: 12 additions & 0 deletions google/cloud/spanner_v1/database.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -67,6 +67,10 @@
SpannerGrpcTransport,
)
from google.cloud.spanner_v1.table import Table
from google.cloud.spanner_v1._opentelemetry_tracing import (
add_span_event,
get_current_span,
)


SPANNER_DATA_SCOPE = "https://www.googleapis.com/auth/spanner.data"
Expand Down Expand Up @@ -1164,7 +1168,9 @@ def __init__(

def __enter__(self):
"""Begin ``with`` block."""
current_span = get_current_span()
session = self._session = self._database._pool.get()
add_span_event(current_span, "Using session", {"id": session.session_id})
batch = self._batch = Batch(session)
if self._request_options.transaction_tag:
batch.transaction_tag = self._request_options.transaction_tag
Expand All @@ -1187,6 +1193,12 @@ def __exit__(self, exc_type, exc_val, exc_tb):
extra={"commit_stats": self._batch.commit_stats},
)
self._database._pool.put(self._session)
current_span = get_current_span()
add_span_event(
current_span,
"Returned session to pool",
{"id": self._session.session_id},
)


class MutationGroupsCheckout(object):
Expand Down
173 changes: 166 additions & 7 deletions google/cloud/spanner_v1/pool.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@

import datetime
import queue
import time

from google.cloud.exceptions import NotFound
from google.cloud.spanner_v1 import BatchCreateSessionsRequest
Expand All @@ -24,6 +25,10 @@
_metadata_with_prefix,
_metadata_with_leader_aware_routing,
)
from google.cloud.spanner_v1._opentelemetry_tracing import (
add_span_event,
get_current_span,
)
from warnings import warn

_NOW = datetime.datetime.utcnow # unit tests may replace
Expand Down Expand Up @@ -196,20 +201,50 @@ def bind(self, database):
when needed.
"""
self._database = database
requested_session_count = self.size - self._sessions.qsize()
span = get_current_span()
span_event_attributes = {"kind": type(self).__name__}

if requested_session_count <= 0:
add_span_event(
span,
f"Invalid session pool size({requested_session_count}) <= 0",
span_event_attributes,
)
return

api = database.spanner_api
metadata = _metadata_with_prefix(database.name)
if database._route_to_leader_enabled:
metadata.append(
_metadata_with_leader_aware_routing(database._route_to_leader_enabled)
)
self._database_role = self._database_role or self._database.database_role
if requested_session_count > 0:
add_span_event(
span,
f"Requesting {requested_session_count} sessions",
span_event_attributes,
)

if self._sessions.full():
add_span_event(span, "Session pool is already full", span_event_attributes)
return

request = BatchCreateSessionsRequest(
database=database.name,
session_count=self.size - self._sessions.qsize(),
session_count=requested_session_count,
session_template=Session(creator_role=self.database_role),
)

returned_session_count = 0
while not self._sessions.full():
request.session_count = requested_session_count - self._sessions.qsize()
add_span_event(
span,
f"Creating {request.session_count} sessions",
span_event_attributes,
)
resp = api.batch_create_sessions(
request=request,
metadata=metadata,
Expand All @@ -218,6 +253,13 @@ def bind(self, database):
session = self._new_session()
session._session_id = session_pb.name.split("/")[-1]
self._sessions.put(session)
returned_session_count += 1

add_span_event(
span,
f"Requested for {requested_session_count} sessions, returned {returned_session_count}",
span_event_attributes,
)

def get(self, timeout=None):
"""Check a session out from the pool.
Expand All @@ -233,12 +275,43 @@ def get(self, timeout=None):
if timeout is None:
timeout = self.default_timeout

session = self._sessions.get(block=True, timeout=timeout)
age = _NOW() - session.last_use_time
start_time = time.time()
current_span = get_current_span()
span_event_attributes = {"kind": type(self).__name__}
add_span_event(current_span, "Acquiring session", span_event_attributes)

if age >= self._max_age and not session.exists():
session = self._database.session()
session.create()
session = None
try:
add_span_event(
current_span,
"Waiting for a session to become available",
span_event_attributes,
)

session = self._sessions.get(block=True, timeout=timeout)
age = _NOW() - session.last_use_time

if age >= self._max_age and not session.exists():
if not session.exists():
add_span_event(
current_span,
"Session is not valid, recreating it",
span_event_attributes,
)
session = self._database.session()
session.create()
# Replacing with the updated session.id.
span_event_attributes["session.id"] = session._session_id

span_event_attributes["session.id"] = session._session_id
span_event_attributes["time.elapsed"] = time.time() - start_time
add_span_event(current_span, "Acquired session", span_event_attributes)

except queue.Empty as e:
add_span_event(
current_span, "No sessions available in the pool", span_event_attributes
)
raise e

return session

Expand Down Expand Up @@ -312,13 +385,32 @@ def get(self):
:returns: an existing session from the pool, or a newly-created
session.
"""
current_span = get_current_span()
span_event_attributes = {"kind": type(self).__name__}
add_span_event(current_span, "Acquiring session", span_event_attributes)

try:
add_span_event(
current_span,
"Waiting for a session to become available",
span_event_attributes,
)
session = self._sessions.get_nowait()
except queue.Empty:
add_span_event(
current_span,
"No sessions available in pool. Creating session",
span_event_attributes,
)
session = self._new_session()
session.create()
else:
if not session.exists():
add_span_event(
current_span,
"Session is not valid, recreating it",
span_event_attributes,
)
session = self._new_session()
session.create()
return session
Expand Down Expand Up @@ -427,6 +519,38 @@ def bind(self, database):
session_template=Session(creator_role=self.database_role),
)

span_event_attributes = {"kind": type(self).__name__}
current_span = get_current_span()
requested_session_count = request.session_count
if requested_session_count <= 0:
add_span_event(
current_span,
f"Invalid session pool size({requested_session_count}) <= 0",
span_event_attributes,
)
return

add_span_event(
current_span,
f"Requesting {requested_session_count} sessions",
span_event_attributes,
)

if created_session_count >= self.size:
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This condition will not occur anytime as bind is called only once and that time pool is empty. We can remove this span?

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I had it in my tests as a condition for a reused pool but sure I can delete it.

add_span_event(
current_span,
"Created no new sessions as sessionPool is full",
span_event_attributes,
)
return

add_span_event(
current_span,
f"Creating {request.session_count} sessions",
span_event_attributes,
)

returned_session_count = 0
while created_session_count < self.size:
resp = api.batch_create_sessions(
request=request,
Expand All @@ -436,8 +560,16 @@ def bind(self, database):
session = self._new_session()
session._session_id = session_pb.name.split("/")[-1]
self.put(session)
returned_session_count += 1

created_session_count += len(resp.session)

add_span_event(
current_span,
f"Requested for {requested_session_count} sessions, return {returned_session_count}",
span_event_attributes,
)

def get(self, timeout=None):
"""Check a session out from the pool.

Expand All @@ -452,7 +584,26 @@ def get(self, timeout=None):
if timeout is None:
timeout = self.default_timeout

ping_after, session = self._sessions.get(block=True, timeout=timeout)
start_time = time.time()
span_event_attributes = {"kind": type(self).__name__}
current_span = get_current_span()
add_span_event(
current_span,
"Waiting for a session to become available",
span_event_attributes,
)

ping_after = None
session = None
try:
ping_after, session = self._sessions.get(block=True, timeout=timeout)
except queue.Empty as e:
add_span_event(
current_span,
"No sessions available in the pool within the specified timeout",
span_event_attributes,
)
raise e

if _NOW() > ping_after:
# Using session.exists() guarantees the returned session exists.
Expand All @@ -462,6 +613,14 @@ def get(self, timeout=None):
session = self._new_session()
session.create()

span_event_attributes.update(
{
"time.elapsed": time.time() - start_time,
"session.id": session._session_id,
"kind": "pinging_pool",
}
)
add_span_event(current_span, "Acquired session", span_event_attributes)
return session

def put(self, session):
Expand Down
Loading
Loading