feat(observability): add Sentry error and performance monitoring integration

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

app/utils/sentry.py

@@ -0,0 +1,113 @@
+"""
+Sentry integration utilities for DocuElevate.
+
+Call ``init_sentry()`` early in your application entry point (before any
+request handling) to enable error tracking and performance monitoring.  The
+function is a no-op when ``SENTRY_DSN`` is not configured, so it is safe to
+call unconditionally in all environments.
+
+Example (FastAPI)::
+
+    from app.utils.sentry import init_sentry
+    init_sentry()
+
+Example (Celery worker)::
+
+    from app.utils.sentry import init_sentry
+    init_sentry(integrations_extra=["celery"])
+"""
+
+from __future__ import annotations
+
+import logging
+
+from app.config import settings
+
+logger = logging.getLogger(__name__)
+
+
+def init_sentry(*, integrations_extra: list[str] | None = None) -> bool:
+    """
+    Initialise the Sentry SDK if ``SENTRY_DSN`` is configured.
+
+    Args:
+        integrations_extra: Optional list of additional integration names to
+            activate.  Currently recognised values: ``"celery"``.  The
+            ``FastApiIntegration``, ``SqlalchemyIntegration``, and
+            ``LoggingIntegration`` are always included when the SDK is
+            initialised.
+
+    Returns:
+        ``True`` when Sentry was successfully initialised, ``False`` otherwise
+        (e.g. DSN not configured or SDK not installed).
+    """
+    dsn = settings.sentry_dsn
+    if not dsn:
+        logger.debug("Sentry DSN not configured – error monitoring disabled")
+        return False
+
+    try:
+        import sentry_sdk
+        from sentry_sdk.integrations.fastapi import FastApiIntegration
+        from sentry_sdk.integrations.logging import LoggingIntegration
+        from sentry_sdk.integrations.sqlalchemy import SqlalchemyIntegration
+        from sentry_sdk.integrations.starlette import StarletteIntegration
+    except ImportError:
+        logger.warning(
+            "sentry-sdk is not installed.  Install it with: pip install 'sentry-sdk[fastapi,celery,sqlalchemy]'"
+        )
+        return False
+
+    integrations = [
+        StarletteIntegration(transaction_style="url"),
+        FastApiIntegration(transaction_style="url"),
+        SqlalchemyIntegration(),
+        LoggingIntegration(
+            level=logging.INFO,  # Breadcrumbs from INFO+
+            event_level=logging.ERROR,  # Send Sentry events for ERROR+
+        ),
+    ]
+
+    if integrations_extra and "celery" in integrations_extra:
+        try:
+            from sentry_sdk.integrations.celery import CeleryIntegration
+
+            integrations.append(CeleryIntegration(monitor_beat_tasks=True))
+        except ImportError:
+            logger.warning("CeleryIntegration not available – skipping")
+
+    # Clamp sample rates to [0.0, 1.0]
+    traces_rate = max(0.0, min(1.0, settings.sentry_traces_sample_rate))
+    profiles_rate = max(0.0, min(1.0, settings.sentry_profiles_sample_rate))
+
+    version = _get_app_version()
+
+    sentry_sdk.init(
+        dsn=dsn,
+        environment=settings.sentry_environment,
+        release=version,
+        integrations=integrations,
+        traces_sample_rate=traces_rate,
+        profiles_sample_rate=profiles_rate,
+        send_default_pii=settings.sentry_send_default_pii,
+        # Attach a request body snapshot to every event (helps debugging)
+        max_request_body_size="medium",
+        # Keep the SDK from attaching local variable values to stack frames
+        # by default; enable explicitly if needed for deeper debugging.
+        attach_stacktrace=True,
+    )
+
+    logger.info(
+        "Sentry initialised (environment=%s, traces_sample_rate=%s)",
+        settings.sentry_environment,
+        traces_rate,
+    )
+    return True
+
+
+def _get_app_version() -> str | None:
+    """Return the application version string for Sentry release tracking."""
+    try:
+        return settings.version or None
+    except AttributeError:  # pragma: no cover
+        return None