Merge pull request #64 from febus982/opentelemetry-metrics

Opentelemetry metrics

Author: febus982

Makefile

@@ -9,6 +9,9 @@ containers:
 dev:
 	poetry run uvicorn http_app:create_app --host 0.0.0.0 --port 8000 --factory --reload
 
+otel:
+	OTEL_SERVICE_NAME=bootstrap-fastapi OTEL_TRACES_EXPORTER=none OTEL_METRICS_EXPORTER=none OTEL_LOGS_EXPORTER=none poetry run opentelemetry-instrument uvicorn http_app:create_app --host 0.0.0.0 --port 8000 --factory
+
 run:
 	poetry run uvicorn http_app:create_app --host 0.0.0.0 --port 8000 --factory
 

config.py

@@ -28,7 +28,7 @@ class AppConfig(BaseSettings):
     DEBUG: bool = False
 
 
-def init_logger(config: AppConfig):
+def init_logger(config: AppConfig) -> None:
     """
     Configure structlog and stdlib logging with shared handler and formatter.
 
@@ -43,7 +43,7 @@ def init_logger(config: AppConfig):
         structlog.stdlib.PositionalArgumentsFormatter(),
         structlog.processors.add_log_level,
         structlog.processors.StackInfoRenderer(),
-        add_logging_open_telemetry_spans,
+        _add_logging_open_telemetry_spans,
     ]
 
     log_level = logging.DEBUG if config.DEBUG else logging.INFO
@@ -94,7 +94,7 @@ def init_logger(config: AppConfig):
         logging.getLogger(_log).propagate = True
 
 
-def add_logging_open_telemetry_spans(_, __, event_dict):
+def _add_logging_open_telemetry_spans(_, __, event_dict):
     span = trace.get_current_span()
     if not span.is_recording():
         event_dict["span"] = None

http_app/__init__.py

@@ -1,6 +1,7 @@
 from typing import Union
 
 from fastapi import FastAPI, Request
+from opentelemetry.instrumentation.asgi import OpenTelemetryMiddleware
 from starlette.responses import JSONResponse
 from starlette_prometheus import PrometheusMiddleware, metrics
 from structlog import get_logger
@@ -24,9 +25,20 @@ def create_app(
 
     init_routes(app)
 
+    """
+    OpenTelemetry prometheus exporter does not work together with automatic
+    instrumentation, for now we keep the prometheus middleware even if
+    having 2 different middlewares will add overhead.
+    """
     app.add_middleware(PrometheusMiddleware)
     app.add_route("/metrics/", metrics)
 
+    """
+    OpenTelemetry middleware has to be the last one to make sure the
+    tracing data handling is the outermost logic
+    """
+    app.add_middleware(OpenTelemetryMiddleware)
+
     return app