Add Open Telemetry

Author: marvinbuss

code/function/fastapp/main.py

@@ -1,6 +1,7 @@
 from fastapi import FastAPI
 from fastapp.api.v1.api_v1 import api_v1_router
 from fastapp.core.config import settings
+from fastapp.utils import setup_tracer
 
 
 def get_app() -> FastAPI:
@@ -24,7 +25,7 @@ def get_app() -> FastAPI:
 @app.on_event("startup")
 async def startup_event():
     """Gracefully start the application before the server reports readiness."""
-    pass
+    setup_tracer(app=app)
 
 
 @app.on_event("shutdown")

code/function/fastapp/utils.py

@@ -1,7 +1,13 @@
 import logging
 from logging import Logger
 
+from azure.monitor.opentelemetry.exporter import AzureMonitorTraceExporter
+from fastapi import FastAPI
 from fastapp.core.config import settings
+from opentelemetry.instrumentation.fastapi import FastAPIInstrumentor
+from opentelemetry.sdk.resources import SERVICE_NAME, Resource
+from opentelemetry.sdk.trace import TracerProvider
+from opentelemetry.sdk.trace.export import BatchSpanProcessor
 
 
 def setup_logging(module) -> Logger:
@@ -20,3 +26,18 @@ def setup_logging(module) -> Logger:
     )
     logger.addHandler(logger_stream_handler)
     return logger
+
+
+def setup_tracer(app: FastAPI):
+    """Setup tracer for Open Telemetry.
+
+    app (FastAPI): The app to be instrumented by Open Telemetry.
+    RETURNS (None): Nothing is being returned.
+    """
+    if settings.APPLICATIONINSIGHTS_CONNECTION_STRING:
+        exporter = AzureMonitorTraceExporter.from_connection_string(
+            settings.APPLICATIONINSIGHTS_CONNECTION_STRING
+        )
+        tracer = TracerProvider(resource=Resource({SERVICE_NAME: "api"}))
+        tracer.add_span_processor(BatchSpanProcessor(exporter))
+        FastAPIInstrumentor.instrument_app(app, tracer_provider=tracer)

code/function/requirements.txt

@@ -5,3 +5,5 @@
 azure-functions~=1.14.0
 fastapi~=0.96.1
 aiohttp~=3.8.4
+opentelemetry-instrumentation-fastapi==0.39b0
+azure-monitor-opentelemetry-exporter==1.0.0b14