Ignore __lbheartbeat__ requests in Sentry (#363)

In this commit, we:

- use dynamic sampling to ignore `/__lbheartbeat__` requests in Sentry
The sentry_traces_sample_rateenvironment variable is still present so that we can control the global sample rate of non-`/__lbheartbeat__` requests.

- update the way we initialize Sentry to be in line with current documentation

- rename test_main to test_app. 
`main.py` was renamed to `app.py`, but we didn't rename the complementary test module at that time

Author: grahamalama

jbi/app.py

@@ -4,13 +4,11 @@
 import logging
 import time
 from pathlib import Path
-from typing import Awaitable, Callable
+from typing import Any, Awaitable, Callable
 
 import sentry_sdk
 from fastapi import FastAPI, Request, Response
 from fastapi.staticfiles import StaticFiles
-from sentry_sdk.integrations.fastapi import FastApiIntegration
-from sentry_sdk.integrations.starlette import StarletteIntegration
 
 from jbi.environment import get_settings, get_version
 from jbi.log import format_request_summary_fields
@@ -21,13 +19,20 @@
 settings = get_settings()
 version_info = get_version()
 
+
+def traces_sampler(sampling_context: dict[str, Any]) -> float:
+    """Function to dynamically set Sentry sampling rates"""
+
+    request_path = sampling_context.get("asgi_scope", {}).get("path")
+    if request_path == "/__lbheartbeat__":
+        # Drop all __lbheartbeat__ requests
+        return 0
+    return settings.sentry_traces_sample_rate
+
+
 sentry_sdk.init(
     dsn=settings.sentry_dsn,
-    integrations=[
-        StarletteIntegration(),
-        FastApiIntegration(),
-    ],
-    traces_sample_rate=settings.sentry_traces_sample_rate,
+    traces_sampler=traces_sampler,
 )
 
 

poetry.lock

@@ -14,7 +14,7 @@ atlassian-python-api = "^3.32.1"
 dockerflow = "2022.8.0"
 Jinja2 = "^3.1.2"
 pydantic-yaml = {extras = ["pyyaml","ruamel"], version = "^0.8.1"}
-sentry-sdk = "^1.12.1"
+sentry-sdk = {extras = ["fastapi"], version = "^1.12.1"}
 backoff = "^2.2.1"
 statsd = "^4.0.1"
 requests = "^2.28.1"

pyproject.toml

@@ -4,7 +4,8 @@
 import pytest
 from fastapi.testclient import TestClient
 
-from jbi.app import app
+from jbi.app import app, traces_sampler
+from jbi.environment import get_settings
 from jbi.models import BugzillaWebhookRequest
 
 
@@ -33,6 +34,32 @@ def test_request_summary_defaults_user_agent_to_empty_string(caplog):
             assert summary.agent == ""
 
 
+@pytest.mark.parametrize(
+    "sampling_context,expected",
+    [
+        # /__lbheartbeat__
+        ({"asgi_scope": {"path": "/__lbheartbeat__"}}, 0),
+        # path that isn't /__lbheartbeat__
+        (
+            {"asgi_scope": {"path": "/"}},
+            get_settings().sentry_traces_sample_rate,
+        ),
+        # context w/o an asgi_scope
+        (
+            {"parent_sampled": None},
+            get_settings().sentry_traces_sample_rate,
+        ),
+        # context w/o an asgi_scope.path
+        (
+            {"asgi_scope": {"type": "lifespan"}},
+            get_settings().sentry_traces_sample_rate,
+        ),
+    ],
+)
+def test_traces_sampler(sampling_context, expected):
+    assert traces_sampler(sampling_context) == expected
+
+
 def test_errors_are_reported_to_sentry(
     anon_client, webhook_create_example: BugzillaWebhookRequest
 ):