Uvicorn worker timeout. It causes restart after that requests.
Uvicorn worker timeout I have the following python code: from fastapi… May 25, 2022 · Question Currently I'm using 24 Uvicorn workers in production server. , a web browser or an API client) takes too long to receive a response from Jan 27, 2022 · Facing this issue while using docker. This package allows you to run ASGI applications, leverages Uvicorn 's high-performance capabilities, and provides Gunicorn's robust process management. Using an environment configuration file with the --env-file flag is intended for configuring the ASGI application that uvicorn runs, rather than configuring uvicorn itself. “FastAPI Under Fire: Load Testing With Gunicorn & Uvicorn Workers” is published by Nikulsinh Rajput. We also document the signals used internally by Gunicorn to communicate with the workers. I have read that the 30 seconds timeout is not per request. In async workers, the worker is not blocked and stays responsive to fulfill other requests even when the request takes long. 5 GB Memory, OS: Linux). run(app, host="0. Is it possible to handle such a signal from the FastAPI application (shutdown signal doesn't help) before the application restart? Apr 18, 2025 · This document details the lifecycle of a Uvicorn server, from initialization to shutdown, including signal handling and lifespan protocol communication with ASGI applications. Gunicorn’s --graceful-timeout option can be set to allow for graceful termination. now on the timeout would you please include a log on the trace level using log_level=trace that would maybe help. and from uvicorn doc limit-concurrency Maximum number of concurrent connections or tasks to allow, before issuing HTTP 503 responses. Jun 7, 2022 · Uvicorn 是基于 uvloop 和 httptools 构建的非常快速的 ASGI 服务器。 Uvicorn 提供一个轻量级的方法来运行多个工作进程，比如 -workers 4 ，但是并没有提供进程的监控。 May 21, 2021 · It may be that your liveness check in kubernetes is killing your workers. The timeout here is the Gunicorn worker timeout, and using -t / --timeout sets this to a specific value. Overview Uvicorn's configuration system is built around the Config class, which Jan 9, 2023 · I'm currently using FastApi with Gunicorn/Uvicorn as my server engine. UvicornWorker --timeout 86400 --graceful-timeout 86400 Inside my main function, I am reading an sql query and converting it into a pandas dataframe. Apr 18, 2025 · Configuration System Relevant source files This page documents Uvicorn's configuration system, which allows you to customize server behavior through various configuration options. For the non sync workers it just Nov 24, 2024 · You might see an output similar to this: Out of memory: Killed process 776660 (gunicorn) This indicates your worker was terminated due to insufficient memory. Server Model ¶ Gunicorn is based on the pre-fork worker model. What is your problem with dropping the connection for a heartbeat? Oct 26, 2022 · A FastAPI application restarts after gunicorn worker timeout. So we managed to improve the services logic such that the timeout wasn't a problem anymore. UvicornWorker" # ASGI compatibility timeout = 120 # Time in seconds to wait before killing unresponsive workers Aug 28, 2024 · 设置响应超时时间 Uvicorn 提供了多种命令行参数来控制服务器的行为，其中就包括设置请求超时时间的选项。 可以通过 --timeout 参数来设置等待客户端响应的最大时间（以秒为单位）。 例如，如果希望设置超时时间为 10 秒，可以按照以下方式启动 Uvicorn： Oct 19, 2024 · I’m implementing a WebSocket connection using FastAPI with Uvicorn as the server. Run gunicorn -k uvicorn. 在上面的代码中，我们将uvicorn作为FastAPI的工作器，并通过设置timeout_keep_alive参数将超时时间增加到60秒。 使用后台任务 如果我们的应用程序在处理某些请求时需要更长的时间，而这些请求对于用户来说并不是立即需要返回结果的，我们可以考虑使用后台任务来处理这些请求。 FastAPI提供了一个名为 The docling-serve executable allows to configure the server via command line options as well as environment variables. Discover the breakdown of May 26, 2020 · i post many requests to the server, the gunicorn worker will raise the error " [CRITICAL] WORKER TIMEOUT (pid:45)". 1:8000 Timeout: -t INT or --timeout INT Workers silent for more than this many seconds are killed and restarted. Apr 6, 2020 · This is not the case for uvicorn. Finally, run everything behind a CDN for caching Jan 27, 2022 · Facing this issue while using docker. You can set this using gunicorn timeout settings. My load is a bit high (concurrent users may exceed 100s). Uvicorn includes a Gunicorn worker class allowing you to run ASGI applications, with all of Uvicorn's performance benefits, while also giving you Gunicorn's fully-featured process management. gunicorn -k uvicorn. According to this info, both settings variable doing the same thing. 1w次，点赞11次，收藏14次。本文探讨了在Docker部署Gunicorn+Flask项目时，模型加载导致worker超时的问题。通过分析发现，超时设置过短，解决办法是增大gunicorn的超时时间，既可在命令行指定--timeout参数，也可在配置文件中调整。确保模型加载效率，提升服务稳定性。 Signal Handling ¶ A brief description of the signals handled by Gunicorn. I have noticed that too, under high load memory is left allocated but for single requests memory gets cleared up. 9 Adding timeout Running directly with uvicorn without gunicorn Can someone please point me in Jul 14, 2020 · using reload and workers at the same time has no effect on the # of workers spawned, we maybe should throw a warning for that use-case. In case if you have any issues with processing power, you can add more cores/instances/workers to the celery, but it won't affect the main API server, and that's the main benefit. All requests and responses are handled completely by worker processes. Waits for workers to finish their current requests up to the graceful_timeout. Additionally run behind Nginx for self-hosted deployments. I'm trying to understand synchronous APIs and workers and how they affect scalability. Sep 1, 2023 · This can help pinpoint slow functions, database queries, or external requests. 0:8000 --timeout 300 Is it correct way to pass timeout value? How can i fix it ? May 27, 2025 · When deploying FastAPI applications in production, developers often face confusion about whether to use Gunicorn, Uvicorn, or both. 1:8888 --workers 4 --worker-class uvicorn. Uvicorn is the high performance ASGI server that actually runs your Mar 17, 2013 · The opener. Overview This post applies to both App Service Linux using Python - since these images use Gunicorn, and, any custom image used on Web Apps for Containers that utilize Gunicorn for Learn how to properly configure Uvicorn when deploying FastAPI applications, including performance tuning, worker management, and security settings. An ASGI web server, for Python. FastAPI uses Uvicorn as its default web server because Uvicorn is very fast, reliable, and easy to use. (This seems like a bug. /manage. When I tried to add Uvicorn workers by setting the environment variable WEB_CONCURRENCY=4, I found that responses from LLMs were not coming back, and the chat Production Deployment with Gunicorn Relevant source files This document describes how to deploy LightRAG in production using Gunicorn as the multi-process WSGI server. Sep 22, 2024 · FastAPI Uvicorn Non-Blocking Solution uvicorn. 0:8080 --max-requests 1000 --max-requests-jitter 50 -w 2 -k uvicorn. Working perfectly fine if run directly with gunicorn -w 1 -k uvicorn. 0:8080 main:app. The WebSocket works fine when tested through Postman, but disconnects after 60-70 seconds when accessed through web Sep 21, 2022 · uvicorn. If your liveness check is configured as an http request to an endpoint in your service, your main request may block the health check request, and the worker gets killed by your platform because the platform thinks that the worker is unresponsive. This means that there is a central master process that manages a set of worker processes. This can be useful if your application often takes longer than 30 seconds (the default) to process requests. I'm using the following config for Gunicorn: TIMEOUT 0 GRACEFUL_TIMEOUT 120 KEEP_ALIVE 5 WORKERS 10 Uvicorn has all default Apr 3, 2022 · uvicorn --host 0. Jul 23, 2025 · It seamlessly integrates with UVICORN, a lightweight ASGI server, which excels in handling multiple connections and events concurrently. In extremely rare cases (~1 in 100. My Dockerfile loo Oct 9, 2023 · I am trying to set a keepalive timeout for a websocket connection however I have found that the --timeout-keep-alive variable doesnt impact the lifetime of the websocket connection. Is there a way to Nov 4, 2020 · App Services in Azure time out after 230 seconds by default and - AFAIK - this timeout can't be configured. py file like so: uvicorn. 0:8000 --graceful-timeout 60 This allows Gunicorn to wait up to 60 seconds for workers to finish processing before shutting down. gunicorn main:app --keep-alive 300 -w 3 -k uvicorn. As a general rule, you probably want to: Run uvicorn --reload from the command line for local development. So, by default, because both settings are set to 30 seconds, there is no graceful restart enabled. That was my case. Solution 2: Adjusting Timeout Settings Another frequent reason behind worker termination You can use multiple worker processes with the --workers CLI option with the fastapi or uvicorn commands to take advantage of multi-core CPUs, to run multiple processes in parallel. Nov 30, 2023 · 504 Gateway Time-out I want to increase the timeout of api due to long backend processing. 0", port=9000, headers=headers, workers=1, ws_ping_interval=None, ws_ping_timeout=None, use_colors=True, log_level='debug', timeout_keep_alive=30) Oct 8, 2025 · Gunicorn is a pre fork server that spawns multiple worker processes, listens on a socket, and hands requests to those workers. sleep. The configuration system handles everything from server networking parameters to protocol selection, logging setup, and reload behavior. Then I found that the lifespan in uvicorn requires FastAPI instance to be assigned to a module variable as soon as the module is initially loaded by uvicorn, but have not really figured out why uvicorn works that way. Uvicorn processes are currently configured to send a heartbeat every ~10 seconds or so. See full list on fastapi. --num_workers Default: 1 The number of uvicorn workers to spin up. Master process ¶ QUIT, INT: Quick shutdown TERM: Graceful shutdown. sleep with time. By using this package, you can dynamically adjust the number of worker processes, restart them gracefully, and execute server Feb 14, 2025 · The web UI absolutely won't load fully if you've got an enabled ollama endpoint that's not responding (ask me how I know, wake on LAN never seems to work with my windows gpu rig) and will run out whatever the timeout on your backend is. So I made a simple basic fastapi app with about the same settings that we use on kubernetes. UvicornWorker" to . But it‘s probably no great idea to set this to 10 minutes. UvicornWorker: Specifies the worker class to be UvicornWorker. WORKER TIMEOUT means your application cannot response to the request in a defined amount of time. And have some workers randomly freezeing. ie worker timeout and request timeout are different Apr 6, 2023 · In this command: -w 4: Sets the number of worker processes to 4. g. (c5. 0", port=8000, env_file=". The worker timeout appears to be counting from the time Gunicorn hands over the request, rather than when the worker begins processing it. run("app:central_system", host="0. Nov 10, 2023 · FastAPI worker timing outDescription I am running the code using gunicorn inside my virtual environment with the command python -m gunicorn main:app --bind 127. The timeout in gunicorn is about how long to wait before re-starting unresponsive processes. However, it shouldn't prevent the uvicorn process from spawning. 2xlarge) gunicorn main:app --workers 24 --worker-class uvicorn. 7 Docker-Image on an Azure App Service (B2: 200 ACU, 2 Cores, 3. UvicornWorker for production. It worked Aug 18, 2020 · From the gunicorn doc worker-connections The maximum number of simultaneous clients. api:app --loop asyncio --port 7474 This forces uvicorn to use asyncio loop. For the non sync workers it just means that the worker process is still communicating and is not tied to the length of time required to handle a single request. It can remain stable and efficient when handling a large number of concurrent connections. send I use uvicorn workers in Kubernetes (1 pod - 1 uvicorn worker). Shouldn't the act of assigning a request make the worker busy?) Maybe adding worker_class="uvicorn. -t 60: Sets the worker timeout to 60 seconds. Generally, the default of thirty seconds should suffice. UvicornWorker. Tried to pass time out as below but it does not work at all. UvicornWorker --bind unix:/tmp/asgi. 0:8080' backlog = 2048 accesslog = '-' errorlog = '-' Initially, I was running a single Flask app and Nginx in Docker and Gunicorn never had an issue. server. Later I added another app and configured my Nginx to redirect Nov 19, 2024 · workers = 4 # Number of worker processes worker_class = "uvicorn. You shipped the endpoint. so: can we do the timeout per request for uvicorn? Nov 4, 2020 · Now that Uvicorn supports managing workers with --workers, including restarting dead ones, there's no need for Gunicorn. Mar 6, 2025 · 文章浏览阅读2. It aims to ensure graceful behavior to either server or client errors, and resilience to poor client behavior or denial of service attacks. The default is 30 seconds. Nov 2, 2020 · Faced a similar issue on a project I was working on, I was manually increasing the guvicorn timeout in my main. I'm confused. and not able to connect to app insights too since its doesn't support app hosted in linux platforms. Sep 29, 2025 · Eight battle-tested Uvicorn/Gunicorn settings for FastAPI — workers, timeouts, keep-alive, uvloop, concurrency limits, recycling, proxy headers, and sockets. UvicornWorker -b 0. May 28, 2024 · Added ¶ Add --timeout-worker-healthcheck option (#2711) Add os. Concurrency: If you have a lot of IO-bound tasks (like HTTP requests to external services or database queries), consider using Gunicorn's gthread worker type with multiple threads or using an asynchronous worker like gevent or uvicorn (for ASGI apps). The python processes are staying alive but stop serving requests. 7 from 3. When hardcoded, when I would check the app service logs it would show as being set at timeout=120 Gunicorn/ Uvicorn worker times out on AWS Fargate Asked 4 years, 9 months ago Modified 4 years, 9 months ago Viewed 2k times Nov 10, 2017 · Default: 30 Workers silent for more than this many seconds are killed and restarted. It bugged me when the second request will not be processed while the first-arrived request is being … Jan 10, 2025 · Uvicorn, on the other hand, is a high-performance ASGI server implemented with uvloop and httptools, which can handle HTTP requests asynchronously. The most basic way Mar 5, 2020 · 43 Cloud Run has scaled down one of your instances, and the gunicorn arbiter is considering it stalled. Step-by-step configuration and optimization tips. Both periods actually refer to time at the start of request processing. 9 Adding timeout Running directly with uvicorn without gunicorn Can someone please point me in May 29, 2020 · Which often seems the problem with this [CRITICAL] WORKER TIMEOUT log. Contribute to Kludex/uvicorn development by creating an account on GitHub. Master ¶ The master process is a simple loop that Apr 3, 2017 · Seems like how I interpreted timeout and graceful_timeout is wrong. Configurations are divided between the settings used for the uvicorn asgi server and the actual app-specific configurations. my aim is request timeout, so killing the worker wont work except if a worker can be limited to one request. This… Dec 7, 2021 · 12 From the uvicorn docs: --timeout-keep-alive <int> - Close Keep-Alive connections if no new data is received within this timeout. open() call in line four runs into a timeout when running in Gunicorn, when running with . Workers still alive after the timeout (starting from the receipt of the restart signal) are force killed. How does FastAPI (or Starlette or Uvicorn underneath) do ping/pong heartbeats? Is this configurable? I cannot find it in the Jun 20, 2023 · Increase Gunicorn timeout setting: You may increase the timeout duration for Gunicorn workers to respond. PathLike [str] type to ssl_ca_certs (#2676) Mar 5, 2025 · 4 We observed an issue with our containerized Python FastAPI application, which we deploy using Gunicorn and Uvicorn on Kubernetes. My question is the following: After receiving a restart signal, workers have this much time to finish serving requests. Now I am trying to move this changes to gunicorn and uvicorn as worker, but I am couldn't find a way to pass this loop to uvicorn. Oct 7, 2019 · gunicorn -w 8 -k uvicorn. Another thing that may affect this is choosing the worker type The default synchronous workers assume that your application is resource-bound in terms of CPU and network bandwidth. So there's no need for Gunicorn to manage multiple workers in a single container. As a result I receive 502 responses from the nginx server. . run expects to be run in the main thread. Setting it to 0 has the effect of infinite timeouts by disabling timeouts for all workers entirely. Nov 11, 2020 · I did some perf tests about running quart app with 'hypercorn vs gunicorn with uvicorn worker', and found an issue about gunicorn with uvicorn worker / or just uvicorn only. Sep 1, 2023 · Worker Timeout error is commonly associated with Gunicorn, a popular web server gateway interface (WSGI) server for Python web applications. Uvicorn is designed with particular attention to connection and resource management, in order to provide a robust server implementation. The only way I have found to manage this is to build my own keepalive timeouts on the application layer (which doesnt have access to the ping/pong logic). Otherewise uvicorn does what it's supposed to do If you're OK with blocking a worker, then the you'll need to configure the timeout as above. Only set this noticeably higher if you’re sure of the repercussions for sync workers. Default: 5. Client-side Timeout A client-side timeout occurs when the client (e. You could modify the example Dockerfile from above, adding the --workers option to Uvicorn, like: Sep 12, 2023 · uvicorn myapp. Apr 25, 2024 · I have gunicorn managing a Flask app run using the following docker command CMD gunicorn flask_app:app -b 0. pid' worker_tmp_dir = '/dev/shm' worker_class = 'gthread' workers = 1 worker_connections = 1000 timeout = 30 keepalive = 1 threads = 2 proc_name = 'app' bind = '0. Thus, total potential connections = N * (pool_size + max_overflow). You're using the PyPy compliant uvicorn worker class - is your system based on PyPy? If you're running on cpython then I suggest you try out the cpython implementation uvicorn. and it can not deal with the last request before restart。 Sep 18, 2020 · Since the default timeout of uvicorn is 30 seconds, I don't undertand why the workers are being terminated before they require ~30 seconds to respond. UvicornWorker --bind 0. 🦄. This page covers the Gunicorn-specific deployment architecture Design ¶ A brief description of the architecture of Gunicorn. It causes restart after that requests. That also means that it's much simpler to build a Docker image from scratch now, I updated the docs to explain it. Deployment Server deployment is a complex area, that will depend on what kind of service you're deploying Uvicorn onto. Mar 7, 2022 · Bind: -b ADDRESS1 gunicorn -b 127. UvicornWorker --timeout 100 --graceful-timeout 10 Jul 1, 2024 · Gunicorn - ‘ [CRITICAL] Worker Timeout’ on App Service Linux 7 minute read | By Anthony Salemo This blog post will quickly cover a few scenarios where ‘ [CRITICAL] WORKER TIMEOUT’ may be encountered and why. If I do something like --graceful-timeout 15 --timeout 30 that should mean graceful restart is initiated at 15 seconds and worker is force killed at 30 虽然worker被多余的tcp连接阻塞了，但是，gunicorn会在timeout时间后，重启worker，关闭连接。 如图，默认timeout是30秒 gunicorn中的timeout到底是什么意思？ 直接贴官网文档。 timeout只在sync worker起作用，除了代表一个请求最长的处理时间之外，超过timeout还会造成worker的 Worker config, threading, and benchmarking FastAPI under massive traffic. Jan 28, 2025 · Adding Uvicorn workerHi, I'm trying to deploy OpenWebUI in a multi-user environment. 2xlarge's vCpu == 8) Jan 27, 2023 · more often i am getting [CRITICAL] WORKER TIMEOUT (pid:130) not able to solve it . 0 --workers 10 --backlog 20 --timeout-keep-alive 65 my_python_main:app The service works OK most of the time, but after a while it can get a "heavy" request which will cause the memory of the machine to rise up, as a result the OOM killer start killing many processes (but not this service). When I am calling an endpoint the average response time is ~1 seconds. It covers how Uvicorn ma Jul 13, 2023 · Hi there, Render has a 100-minute timeout. main:app: Points to your FastAPI application instance. Gunicorn manages multiple Uvicorn worker processes to handle concurrent requests efficiently while coordinating shared resources like the knowledge graph storage. starlette. 000) a single request seem to be silently dropped / not correctly processed by the the gunicorn master process or the uvicorn workers. If increasing this doesn’t help, it is because something is occurring within your application that is causing the request to be stuck, and the request is still taking longer than the timeout you set. I'm running the uvicorn-gunicorn-fastapi:python3. Oct 10, 2019 · @euri10 you're right there, sorry! I've tried a few things and the only way I could reproduce this was by starting a background task that blocked the worker - try replacing asyncio. Currently running uvicorn this way you'll be using the reloader only. Aug 3, 2022 · timeout-keep-alive：数字，如果在此超时时间内未收到新数据，则关闭保持活动状态的连接，默认为5 ssl-keyfile：字符串，SSL密钥文件，默认为None Dec 12, 2021 · 事象 ALB + ECS Fargate + FastAPI（Gunicorn + Uvicorn）で構成していました。 ALB の Idle Timeout は60秒に設定しているので、60秒かかったリクエストには Gateway Timeout（504）を返します。 Oct 24, 2020 · I got the same message, and exception if I started uvicorn with the option --lifespan on. tiangolo. I have a gunicorn app with a single uvicorn worker, which Apr 25, 2024 · We have encountered a relatively rare connection error which is probably due to a race condition as uvicorn worker is trying to shutdown. If we do not have a memory leak, we will improve performance by removing Nov 25, 2022 · Multiple Workers If you definitely want to have multiple workers on a single container, Uvicorn now supports handling subprocesses, including restarting dead ones. The choice of UVICORN for FastAPI is driven by its exceptional performance, ease of integration with FastAPI, and its ability to serve numerous incoming requests. None of the following suggested solutions worked: Assigning more memory Changing worker class to gevent Changing python version to 3. In this case, it's ok to have 2 uvicorn workers for FastAPI and 3 workers (1 per 1 vCPU) for the Celery instance. This happens faster than the time it takes for a worker to get flagged as busy. So uvicorn --limit-concurrency 100 application:demo_app is almost same as gunicorn --worker-connections 100 An ASGI web server, for Python. Master ¶ The master process is a simple loop that Nov 13, 2025 · I ran gunicorn with gunicorn mysite. UvicornWorker your_app:app -w 4 -b 0. 0. Apr 29, 2024 · My guess is that, when a worker becomes available, requests start getting assigned to it one by one. Design ¶ A brief description of the architecture of Gunicorn. Some application need more time to response than another. env", workers=workers, timeout=600) The fix was to set this via environment variable rather than hardcoding it. com Generally set to thirty seconds. We would like to show you a description here but the site won’t allow us. -k uvicorn. This works as expected. websocket to listen for incoming websockets. Therefore If i have 8 processes, I can make use of whole cores (c5. 0:80 I've learn that one process runs on one core. Here is the setup Nov 13, 2025 · Uvicorn workers multiply pools: If you run Uvicorn with --workers N, each worker process gets its own SQLAlchemy connection pool. Value is a positive number or 0. Sep 11, 2020 · I am using FastAPI with @app. HUP: Reload the configuration, start the new worker processes with a new May 31, 2018 · This is a misunderstanding about what gunicorn's "timeout" setting does. Usage: Jan 13, 2022 · pidfile = 'app. Only set this noticeably higher if you’re sure of the repercussions for sync May 29, 2025 · Deploy machine learning models with FastAPI and Uvicorn for scalable production environments. However, when I am load testing the API with 5 concurrent users the average response time goes to ~4-5 seconds per request and then some uvicorn workers start to timeout and get killed. The Uvicorn Worker is a package designed for the mature and comprehensive server and process manager, Gunicorn. 0 app:app --timeout 10 So after exposing it to the web, I run a load test which makes 30-40 requests in parallel to the fastapi. Generally Also note that UVICORN_* prefixed settings cannot be used from within an environment configuration file. Apr 6, 2020 · Async workers behave differently from sync workers: In sync workers, the worker will be blocked from fulfilling the request, so if a request takes longer than timeout, the worker will be killed and so will the request. I found that some operations, like document uploading, make the OpenWebUI process locked. Gunicorn Docs on Worker Timeouts Hope this solves it. asgi:application --pythonpath mysite --timeout 15 --max-requests 10000 --worker-class uvicorn. You should add --timeout 0 to your gunicorn invocation to disable the worker timeout entirely, it's unnecessary for Cloud Run. sock --max-requests is a gunicorn config for a memory leak. Uvicorn Uvicorn can run FastAPI application even with multiple workers, convenient during development thanks to the reload capability but even their documentation suggests to run with Gunicorn in production Workers Workers are pre-forked processes spawn by Gunicorn. UvicornH11Worker -b 0. The master never knows anything about individual clients. workers. When the query has 5M rows, there In my case, freeze is happening somehere in middleware. This leads to premature timeouts and unnecessary worker replacement. Jan 27, 2023 · In thos post we’ll go over how to make Gunicorn target different worker classes for different types of applications - and other general settings we can configure through Gunicorn. py runserver everytihng works fine (and the api call only takes a few miliseconds. If you find this is the case, consider reviewing your application’s memory usage and optimizing your code or increasing memory limits for the pod. run would help. qyax baucepd khnbu jwfpnhl wsqx wan zghpm gwarvv gtqnjxds lukp jnpkev gab mgate kgrhpk vxhy