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Ashok Nagaraj
Ashok Nagaraj

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Auto-instrumentation: No-code approach to instrument Python

#opentelemetry #python #instrumentation #beginners

In the previous post we saw instrumenting a python application with OTel emitting metrics and traces along the way. While this is good, it can still be intimidating to an instrumentation-newbie.
To get over this barrier and to allow a quick-start, some languages have auto-instrumentation support. One only needs to install some libraries to get going.

Our sample web-app

import datetime import flask ###################### ## initialization ###################### app = flask.Flask(__name__) start = datetime.datetime.now() ###################### ## routes ###################### @app.route('/', methods=['GET']) def root(): return flask.jsonify({'message': 'flask app root/'}) @app.route('/healthz', methods=['GET']) def healthz(): now = datetime.datetime.now() return flask.jsonify({'message': f'up and running since {(now - start)}'}) ###################### if __name__ == '__main__': ######################  app.run(debug=True, host='0.0.0.0', port=5000)
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Install necessary libraries

$ pip install flask $ pip install opentelemetry-distro opentelemetry-instrumentation-flask
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Note: some corner case made my install opentelemetry-api as well, but is not needed as per official documentation.

Initialize (to install extra libraries as needed)
$ opentelemetry-bootstrap -a install

Run your code

$ opentelemetry-instrument --traces_exporter console --metrics_exporter console flask run * Serving Flask app 'app' * Debug mode: on WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead. * Running on all addresses (0.0.0.0) * Running on http://127.0.0.1:5000 * Running on http://192.168.1.7:5000 Press CTRL+C to quit * Restarting with stat * Debugger is active! * Debugger PIN: 121-673-590 127.0.0.1 - - [17/Oct/2022 07:21:05] "GET /healthz HTTP/1.1" 200 - { "name": "/healthz", "context": { "trace_id": "0xd0850752865577d2d8cd11aaef169574", "span_id": "0x29c8ad5fd974de41", "trace_state": "[]" }, "kind": "SpanKind.SERVER", "parent_id": null, "start_time": "2022-10-17T01:52:45.522806Z", "end_time": "2022-10-17T01:52:45.523615Z", "status": { "status_code": "UNSET" }, "attributes": { "http.method": "GET", "http.server_name": "127.0.0.1", "http.scheme": "http", "net.host.port": 5000, "http.host": "localhost:5000", "http.target": "/healthz", "net.peer.ip": "127.0.0.1", "http.user_agent": "curl/7.79.1", "net.peer.port": 55838, "http.flavor": "1.1", "http.route": "/healthz", "http.status_code": 200 }, "events": [], "links": [], "resource": { "attributes": { "telemetry.sdk.language": "python", "telemetry.sdk.name": "opentelemetry", "telemetry.sdk.version": "1.13.0", "telemetry.auto.version": "0.34b0", "service.name": "unknown_service" }, "schema_url": "" } } {"resource_metrics": [{"resource": {"attributes": {"telemetry.sdk.language": "python", "telemetry.sdk.name": "opentelemetry", "telemetry.sdk.version": "1.13.0", "telemetry.auto.version": "0.34b0", "service.name": "unknown_service"}, "schema_url": ""}, "scope_metrics": [], "schema_url": ""}]}
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As of this post, most popular frameworks like Django, FastAPI, Flask have instrumentation libraries for HTTP context propagation

Code size implications

Auto-instrumentation does add some extra libraries. This was the result in my case

$ du -sh manual/venv/ auto/venv/ 29M manual/venv/ 30M auto/venv/
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Always refer to the official documentation which is up-to-date
Official documentation

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