Fastapi logging setup In this guide, we'll explore how to implement a comprehensive logging system in your FastAPI applications. Ten FastAPI logging tricks to debug 1 day ago · In the world of web development, logging is the unsung hero of debugging, monitoring, and maintaining reliable applications. Installation Mar 19, 2024 · Middleware FastAPI Async Logging If you are accustomed to Python’s logging module and frequently work with large datasets, you might consider implementing logging in a way that avoids blocking Aug 7, 2023 · In the world of back-end software development, proper logging is an integral part of any Application Programming Interface (API). By default, FastAPI relies on **Uvicorn**, an ASGI server, to handle incoming Sep 21, 2024 · FastAPI is a fantastic framework for building fast and efficient APIs in Python. logger import logger Feb 11, 2023 · Get your API logging set up with ease using FastAPI Logging Middleware. In this blog, we will walk through creating a middleware to log every request and response, along with useful metadata like the client's IP address, HTTP method, endpoint, and status codes. Then, you can use Structlog loggers or standard logging loggers, and they both will be processed by the Structlog pipeline (see the hello() endpoint for reference). It is working with a connection string, but I would like it to be working with managed identity. Mar 17, 2020 · You'll need to run FastAPI via some server, like Uvicorn, Hypercorn, or AsyncIO Even though logging might be configured correctly in your FastAPI files, you are running the app via the server. The following is a basic example of middleware that logs the time taken to process each request. Supports asynchronous lo Dec 5, 2024 · In the above case, configure_azure_monitor() initializes logging telemetry, but the example you provided demonstrates manual control over which loggers are tracked by specifying logger_name when calling configure_azure_monitor(). Nov 27, 2024 · When building production APIs, proper logging becomes crucial for debugging and monitoring. Loguru, the Python logging library known for its painless setup, beautiful formatting, and powerful features. Learn how to set up robust logging in FastAPI. Just use logger. As Uvicorn applies python logging module, we can override Uvicorn logging formatter by applying a new logging configuration. main:app --workers 4 -- FastAPI Learn Tutorial - User Guide CORS (Cross-Origin Resource Sharing) CORS or "Cross-Origin Resource Sharing" refers to the situations when a frontend running in a browser has JavaScript code that communicates with a backend, and the backend is in a different "origin" than the frontend. py file to log to the file named tasks. You can then deploy that container image in one of a few possible ways. Nov 11, 2023 · FastAPI Logger is a powerful Python package designed to seamlessly integrate with FastAPI applications, providing advanced request logging capabilities. Follow our detailed guide for scalable and high-performance API development. It is designed to be easy to use and highly efficient, making it a popular choice for developing web applications. May 29, 2025 · Deploy machine learning models with FastAPI and Uvicorn for scalable production environments. run, uvicorn applies their logger handlers/formatters. Configure uvicorn logs with loguru for FastAPI. One of its many features is its built-in logging capabilities. Why Use Middleware for Logging? Middleware in FastAPI is Oct 18, 2023 · Setup CRUD with MongoDB Environment Setup Create Read Update Delete Full CRUD Tagged with tutorial, python, programming, webdev. First, grab your client ID by signing up and creating an app in the Apitally dashboard. Oct 6, 2025 · fastapi structured logging middleware (accesslog, opentelemetry)fastapi-structured-logging fastapi-structured-logging is a lightweight Python module that provides structured logging utilities and a configurable FastAPI access logging middleware. With FastAPI Logger, you can capture essential details about incoming requests, including sender IP, port, processing time, and more. Operating System macOS Operating System Details macOS Monterey FastAPI Sep 22, 2025 · An overview of how to create and deploy a containerized Python web app (Flask or FastAPI) on Azure App Service. However, all log messages from within execute method don't get printed. base import BaseHTTPMiddleware from src. py from starlette. Log Level Propagation: The maximum log level observed during a request's lifecycle is propagated Apr 14, 2025 · To configure the logger, you need to use fastapi_structlog. Jul 22, 2025 · This guide will walk you through a professional, production-ready FastAPI logging setup using Loguru — complete with code snippets, middleware, and essential tips inspired by real-world projects. Aug 29, 2025 · Configure uvicorn logs with loguru for FastAPI. Origin An origin is the combination of protocol (http, https), domain (myapp. . Source: Settings - Uvicorn FastAPI framework, high performance, easy to learn, fast to code, ready for production Apr 17, 2025 · Dive deep into Python Logging: advanced configuration, structured logging, custom handlers, thread safety, and effective strategies for production environments. I referred to this blog and implemented the logging. Step-by-step configuration and optimization tips. OpenTelemetry FastAPI Instrumentation This library provides automatic and manual instrumentation of FastAPI web frameworks, instrumenting http requests served by applications utilizing the framework. Feb 14, 2023 · FastAPI is a high-performance web framework for building APIs with Python. A well-designed logging strategy helps you debug issues, monitor application health, and understand user behavior. middleware. Full disclaimer, this is very likely not the "right way" to do this in uvicorn but uvicorn. It won’t work as usual using logging modules. If this is after you tried to apply your own handler, yours would get overridden. Let’s explore how to implement a custom logging system in FastAPI that includes a TRACE level for detailed request tracking. So I have a local server hosted using Oct 7, 2024 · This diagram will help visualize the comprehensive logging and monitoring setup for a FastAPI application in production, showing how different components work together to provide insights and Nov 13, 2024 · Moreover, http errors are generated during request validation in FastAPI and are handled internally, making them harder to intercept with standard logging techniques. Aug 21, 2020 · I have a fastapi app on which I want to add python logging. com, localhost, localhost Overview ¶ This directory contains the logging configuration for the FastAPI application. We set up a basic logging setup, here we specify the file to log into, the level above which logs should be considered, and the format in which our logs should appear. Apr 26, 2021 · I am working on FastAPI - Uvicorn. info, your logs will be sent to server. Dec 12, 2024 · How to Log Every Request and Response in FastAPI 📕 A guide on efficiently storing logs for every request and response in your FastAPI app I’ve been really enjoying FastAPI recently. When I used simple print method, it got printed in the log under "celery. Nov 13, 2024 · Centralized logging is essential for modern applications to monitor, analyze, and troubleshoot issues efficiently. When running it locally the logs are displayed on the console as expe Aug 21, 2023 · Conclusion Prometheus is a powerful open-source monitoring system that can be easily integrated with FastAPI applications. This is achieved using Loguru, JSON formatting, and log identification by request ID. Feb 19, 2023 · TLDR: clone the github repo and start using datadog for logging your fastAPI application without a datadog agent May 2, 2024 · 1 Try this: uvicorn app. FastAPI uses the standard logging module in Python to log Sep 21, 2024 · In this blog, we covered the steps to set up a FastAPI project, integrate logging, and upload logs to AWS CloudWatch. The first step is to configure the logger within the FastAPI application. Call uvicorn In your FastAPI application, import and run uvicorn directly: Oct 25, 2023 · This article demonstrates some techniques for making logs structured and traceable in FastAPI applications. Apr 6, 2025 · Why Use Middleware for Logging? Middleware in FastAPI is a hook that gets executed for every request and response. Using Linux containers has several advantages including security, replicability, simplicity, and others. In this article, we saw how to set up Prometheus monitoring for a FastAPI app. Each library could have its own logging configuration/handlers, and the layers could run deep. FastAPI Logging Strategy Effective logging is a crucial aspect of developing robust FastAPI applications. This article Dec 19, 2024 · Learn how to integrate OpenTelemetry with FastAPI for enhanced observability, including automatic instrumentation, environment variables, and custom exporters. We installed the Prometheus client library and exposed metrics endpoints. Effective logging is a crucial aspect of developing robust FastAPI applications. Passing this flag while starting your application will turn off Uvicorn's access log and allow you to configure custom logging. By the end, you’ll have a reliable setup where every log from your FastAPI endpoints appears in Docker logs. log Learn how to set up a powerful logging system for your FastAPI applications and seamlessly integrate it with the ELK (Elasticsearch, Logstash, Kibana) stack along with Filebeat for effective log Jun 19, 2024 · Logging configuration for FastAPI using Gunicorn + Uvicorn workers - logger. And many could be sensitive, like secrets. I want to disable the logging by uvicorn. Setup To set up the package, you need to add the middleware and configure logging. This page, for example, describes how to configure logging levels. Jun 24, 2022 · Logging setup for FastAPI This logging setup configures Structlog to output pretty logs in development, and JSON log lines in production. FastAPI Learn Deployment FastAPI in Containers - Docker When deploying FastAPI applications a common approach is to build a Linux container image. One of its powerful features is the ability to customize behavior using middlewares. Aug 12, 2019 · I've setup the logger, added my instrumentation key, but I don't see anything going to Application Insights, or to the logs of my container. It uses asgi-correlation-id, which provides everything we need to get set up. 7+ based on standard Python type hints. How do we log? Well, we read Logging HOWTO first. Can someone please help me configure the logging. This article explains why logging matters, compares it to print statements, covers log levels, and shows how to configure logging for development and production. This guide will demonstrate how to configure logging for FastAPI applications, including setting log levels, using different handlers, and customizing log formats. You can change log levels on the fly using Prefab, allowing you to adjust the verbosity of your logs without restarting your application. Feb 8, 2022 · Description In the example code, "Task started" message from _run method get printed in the log. monitor. Most of these settings are variable (can change), like database URLs. We are utilizing the after_setup_logger signal to define a logging configuration for our background tasks. You can change the structure of the JSON log record in this method: # src/log_middleware. Jul 7, 2025 · Basic Logging: Using Python’s standard logging module with custom formatting Loguru Integration: Modern logging library with cleaner syntax and better features Production Setup: Environment-based configuration with external services Each approach builds on the previous one, showing you how to evolve your logging as your application grows. Contribute to azhig/fastapi-logging development by creating an account on GitHub. May 3, 2025 · Discover how to build efficient REST APIs using Python and FastAPI. Monitor requests, and optimize performance. Jul 28, 2025 · FastAPI is a modern, high-performance web framework for building APIs with Python 3. Learn setup, configuration, and best practices for structured logging to enhance your application's observability. Nov 23, 2021 · This article explains how request IDs can help improve your ability to debug failures. main:instance --no-access-log The reasoning is that Uvicorn configures the built-in logging module by default. Apr 5, 2024 · Short article, just to share a common issue when someone starts to work in Python FastAPI and it needs to print a log messages. There is a default log config, you could grab that and override what you need to if the case is simple enough. acess and fastapi. We show you a complete FastAPI production setup using Gunicorn and secure config tips. It provides valuable insights into the application’s behavior, helping to identify and resolve issues efficiently. This makes it an ideal place to: May 5, 2025 · # Create FastAPI app app = FastAPI() # Instrument your FastAPI application FastAPIInstrumentor. Then we read it again and again until we really understand the concepts. Join the course to unlock it! You can see the code changes implemented in this lecture below. Then, install the apitally package with the fastapi extra in your project: Mar 29, 2023 · Logging setup for FastAPI This logging setup configures Structlog to output pretty logs in development, and JSON log lines in production. The logging system is based on structured JSON logging with ELK stack integration. This involves setting up the appropriate logging levels and handlers, as well as specifying the format of the log messages. Logging May 16, 2025 · I'm building a production grade FastAPI app and would like to implement a structured logging system that: Captures per request context, like request ID, path, and method. Jan 25, 2024 · FastAPI — How to Set Up and Use Alembic for Database Migrations Alembic is a lightweight database migration tool for usage with the SQLAlchemy Database Toolkit for Python. Jun 16, 2025 · In this blog we use FastAPI and OpenAI with Python logging and QueueHandler to create LLM endpoints. To configure Uvicorn logging you'll need to use pass config to Uvicorn as dict config or Learn how to implement and use logging middleware in FastAPI applications to track requests, responses, and application events. Jun 11, 2025 · Learn how to deploy FastAPI applications with Docker using production-ready best practices. It configures structlog for JSON or console output, enriches log events with OpenTelemetry trace and span identifiers, and exposes an Apr 20, 2024 · Integrating Structlog with FastAPI With the integration of structlog into FastAPI, the goal is to: Be able to switch between human readable output and JSON output Attach one request ID to each incoming request and add it to all log messages Automatically attach certain request attributes (path, HTTP method, function, ) Make sure the uvicorn logger behaves well with structlog Handle Configure uvicorn logs with loguru for FastAPI. Azure Monitor supports distributed tracing, metric collection, and logging of Python applications through integration with OpenCensus. In this article, we will explore some best practices for optimizing FastAPI applications, including modular design, logging, and Aug 23, 2024 · Basic Middleware Setup in FastAPI To set up middleware in FastAPI, you can use the add_middleware() method, which is available on the FastAPI app instance. However, like any powerful tool, it needs to be configured correctly to unlock its full potential. Once this is done we can utilize it in our tasks. Basic Logging Jun 24, 2023 · Not exactly structured logging, but some progress. I need only the logs which are logged by the server. * Automatic Documentation: It automatically generates interactive API documentation using Swagger UI and ReDoc Aug 14, 2024 · [Backend] Logging in Python and Applied to FastAPI Developing a service, logging plays a crucial role as it allows us to track events, identify errors, and determine who called the API. Dec 27, 2024 · Logging is a critical component of any application, and FastAPI is no exception. Log requests & responses, get performance metrics & inject… Integrating FastAPI with External Services Integrating FastAPI with an external logging service is relatively straightforward. Sep 18, 2024 · Invoking Version 2 Logging Endpoints with Python FastAPI 1. The Azure libraries use the standard Python logging module, which is configured on a per-library or per-operation basis. I’m … This video will demonstrate a logging setup for the FastAPI web framework in Python. Jun 29, 2023 · # FastAPI from azure. It will cover basic config using Python's logging package, centralization of logs to Better Stack, and will logs with FastAPI and UvicornThis is probably a better question for uvicorn, but I'll take a stab at answering it. setLevel (logging. You do not need to configure handlers at FastAPI level. Basic Logging Import the Basic Logging Setup Let’s start with Python’s standard logging module and create a consistent logging setup for your FastAPI application. FastAPI Learn Tutorial - User Guide Debugging You can connect the debugger in your editor, for example with Visual Studio Code or PyCharm. handlers import queue from fastapi import FastAPI root_logger = logging. Jul 22, 2025 · Logging isn’t just about debugging errors — it’s your window into what’s happening across every layer of your API. Mainly due to a lack of direct support in Azure or Sep 15, 2023 · This built-in logging is useful for debugging and understanding the application's behavior. The following cell defines the logging config that makes uvicorn print its logs to the file. Jun 17, 2020 · # coding: utf-8 import logging import logging. Complete guide covering Dockerfile optimization, environment configuration, health checks, database migrations, logging, and scaling strategies for real-world deployments. Logging for FastAPI is configured using a logging. Dec 5, 2024 · FastAPI-Logger is a middleware that provides easy-to-use request and response logging for FastAPI applications. Celery provides us with a hook/signal that is called as soon as the initial setup is done. Mar 27, 2025 · Build Scalable Microservices with FastAPI: Architecture, Logging, and Config Made Simple Modern applications demand more than just working APIs — they need to be scalable, modular, and easy to … 4m 5s Mailgun set-up and configuration 2m 44s Sending emails and testing with Python 15m 47s Sending a confirmation email on registration 4m 49s Sending emails with background tasks 5m 59s Chapter 9 : File Uploads with FastAPI 39m Our configuration for Backblaze B2 1m 29s Internal library for Backblaze B2 9m 57s Writing our file upload endpoint Nov 14, 2025 · The Azure Functions worker itself sends logging telemetry itself without the use of the azure monitor sdk (the call to configure_azure_monitor()). instrument_app(app) # Instrument logging and system metrics FastAPI Learn Tutorial - User Guide CORS (Cross-Origin Resource Sharing) CORS or "Cross-Origin Resource Sharing" refers to the situations when a frontend running in a browser has JavaScript code that communicates with a backend, and the backend is in a different "origin" than the frontend. I followed the basic tutorial and added this, however this doesn't add API but just gunicorn logging. To implement logging in an application, two things are necessary: define the configuration and use setup_logger: Jul 2, 2024 · Continuing with our Python FastAPI learning series, this post explores the implementation of Tagged with python, logging, non, blocking. Logging in FastAPI applications Adding Logging Configuration for FastAPI Applications Want more? This lesson for enrolled students only. Configure loggers # You can use the fastapi and uvicorn loggers just like any other logging package logger. Getting started Setting Apitally up for your FastAPI project only takes a few minutes. Having the ability to see what is happening at all times with your May 28, 2023 · In this guide, we will explore how to set up monitoring for a FastAPI app using two powerful tools: Grafana and Prometheus. By default, FastAPI relies on **Uvicorn**, an ASGI server, to handle incoming May 14, 2025 · Deploy FastAPI Docker and Uvicorn the right way. It offers a solution Jun 21, 2023 · Introduction: FastAPI is a modern, fast (high-performance), web framework for building APIs with Python 3. 10 FastAPI Logging Tricks for Instant Debugging Practical, copy-pasteable recipes to see what’s breaking — right now — without drowning in noise. Oct 31, 2025 · We’ll cover Python’s logging system, Uvicorn (FastAPI’s default server) behavior, Docker’s logging mechanics, and common pitfalls to avoid. opentelemetry import configure_azure_monitor configure_azure_monitor() from fastapi import FastAPI app = FastAPI(__name__) For completeness the article also suggests the following to fix the issue: Instead, we recommend that you import the fastapi or flask modules as a whole, and then call configure_azure_monitor to configure OpenTelemetry to use Azure Monitor Jun 17, 2020 · # coding: utf-8 import logging import logging. Jan 26, 2025 · Building High-Performance AI Applications with FastAPI: A Complete Observability Setup with Prometheus, OpenTelemetry, Tempo, Loki, and Grafana In the era of Artificial Intelligence (AI) and In my opinion, the most interesting logs for us here are fastapi, unicorn, unicorn. This will cause you to possibly experience duplicate telemetry entries when sending logging telemetry. 1 day ago · In the world of web development, logging is the unsung hero of debugging, monitoring, and maintaining reliable applications. init_logging, which gets the values of the environment variables using pydantic. May 20, 2025 · Learn how to add powerful logging to your FastAPI application using Python’s built-in tools. Introduction to FastAPI and Endpoint Invocation What is FastAPI? FastAPI is a modern, high-performance web framework for building APIs Sep 7, 2022 · I have a FastAPI service that works as expected in every regard except the logging, only when it runs as a AWS Lambda function. It offers several advantages: * High Performance: FastAPI is designed for speed, leveraging asynchronous programming to handle thousands of requests per second. Jul 11, 2024 · Discover how to leverage StructLog for advanced logging in Python. This could be unrelated to FastAPI, but I'm not sure. error, unicorn. redirected" with level WARNING. By effectively logging information about requests, responses, errors, and other relevant events, you can gain valuable insights into your application’s behavior and identify potential issues. You could also try configuring your logging handlers after FastAPI starts up? Might have better luck as uvicorn won't be overriding at that point. Logging is an essential tool for debugging, monitoring, and troubleshooting FastAPI applications. You can configure the log level in FastAPI by setting the log_level parameter when creating your FastAPI app. It's normally done using Docker. What is Prometheus? Prometheus is an open-source monitoring system that collects metrics from your application and stores them in a time series database. Jan 30, 2022 · Overriding Logging in Python can be a bit confusing for newbies like myself, especially coming fresh into it. Oct 9, 2024 · I am using Celery as the background task processor with a FastAPI web server. For FastAPI—one of the most popular Python frameworks for building high-performance APIs—logging becomes critical when tracking requests, diagnosing errors, or analyzing user behavior. Tagged with python, fastapi, logging. Feb 2, 2025 · If you enable request logging, you can configure it to meet your specific needs. Mar 8, 2023 · When running FastAPI app, all the logs in console are from Uvicorn and they do not have timestamp and other useful information. Centralized logging is essential for effective monitoring and debugging, enabling you to track application behavior and quickly identify issues. This makes it much easier to trace and troubleshoot issues. This sample application walks you through the process of setting up OpenCensus for Python FAST API and sending monitoring data to Azure Monitor for logging and May 17, 2020 · How To Override Uvicorn Logger in FastAPI using Loguru Logging is very important for any web application, it helps us to debug faster, a good Logging implementation saves us a lot of time. Nov 30, 2021 · Learn how to correctly log & trace in Python, FastApi and then collect & visualize them. May 17, 2024 · But sometimes logging can be a challenge, especially if you want to make sure it works properly both locally with Uvicorn and in production. Proper logging helps monitor the application, debug issues, and gain insights into its behavior. Structured logging Let’s add a FastAPI middleware to log the requests. If you’re building with FastAPI and still using the plain old logging module, you might be missing out on massive productivity and clarity gains. May 18, 2025 · Building Enterprise Python Microservices with FastAPI in 2025 (4/10): Logging and Exception Handling Building an enterprise-grade FastAPI microservice architecture — uv, Docker, Kafka, Debezium … Aug 26, 2024 · The fastapi-gae-logging module addresses these problems by: Grouping Logs by Request: All logs generated during a request's lifecycle are grouped together, allowing for a complete view of the request flow in the Google Cloud Log Explorer. You can specify the env_prefix argument when using prefixes. Logging Configuration FastAPI Guard includes powerful logging capabilities to help you monitor and track security-related events in your application. This is the sample example with logging in Flask with Azure function from this reference. In this article, we’ll integrate FastAPI logging with Elasticsearch, Kibana Just concentrate on the setup_celery_logger () function. 6 days ago · For information about the parameters to the setup_logging function, go to the Cloud Logging Client and search for setup_logging. Feb 22, 2025 · In this post, we took a hands-on approach to setting up observability in a FastAPI app using Logfire, covering logging, distributed tracing, and real-time metrics with minimal setup. Nov 23, 2023 · CNLearn FastAPI - Logging, Logging and More Logging Thu, Nov 23, 2023 26-minute read We are going to add some logging to our project. getLogger () root_logger. It supports log rotation, custom log directory, and handles sensitive data securely by redacting sensitive headers. py Feb 24, 2025 · Integrating FastAPI with Better Stack is straightforward, using Python’s standard logging system and Better Stack’s official logging handler, logtail-python. Sep 24, 2024 · With this setup, you now have a FastAPI application with dynamic logging capabilities. While Python’s logging module provides several built-in levels, sometimes we need more granular control. For this reason it's common to provide them in Jan 5, 2023 · Intro Integrating structlog with FastAPI Configuring structlog in a FastAPI app Adding logging variables to every request Logging context variables across different layers of the app Testing with an ID that exists Testing with an ID that does not exist Load balancing and health checks Conclusion Intro I have gradually shifted to using and promoting the usage of structured logging to all the Jan 3, 2025 · I am trying to log from a FastAPI application to Azure application insights. yaml file via Uvicorn like this: uvicorn syncapp. This step-by-step guide covers console logs, JSON formatting, log rotation, and centralized logging with Better Stack to help you monitor and debug your app in production. Feb 19, 2024 · Ever wanted to set up an ELK stack and get python logging to get there with minimal fuss? Well this is the article for you. Logging in FastAPI can be tricky because Uvicorn (the server that FastAPI runs on), has its own logging mechanism. FastAPI Learn Advanced User Guide Settings and Environment Variables In many cases your application could need some external settings or configurations, for example secret keys, database credentials, credentials for email services, etc. GitHub Gist: instantly share code, notes, and snippets. run takes in a log_config keyword arg which lets you configure the loggers. In this tutorial, I'll show you how to configure FastAPI logging so that it works reliably both locally and in production environments. Learn how to properly configure Uvicorn when deploying FastAPI applications, including performance tuning, worker management, and security settings. Why Custom Logging? When building production APIs, proper logging Apr 6, 2025 · FastAPI is a modern, high-performance web framework for Python. Aug 29, 2023 · To run uvicorn from within a Python program, you could use the following. Jan 10, 2024 · Coming from a C# background — I found monitoring my python FastAPI application with Azure Application Insights stupidly difficult. auto-instrumentation using the opentelemetry-instrumentation package is also supported. There are 3 things we are going to do in this (VERY LONG) post: Understand logging Add structured logging to our project (using structlog Jun 3, 2020 · The problem with just getting the logger and configuring it seems to be that when you call uvicorn. This guide will demonstrate how to implement logging within FastAPI endpoints.