Note: Note: There are tags for each build date. If you need to "pin" the Docker image version you use, you can select one of those tags. E.g.
Docker image with uWSGI and Nginx for Flask web applications in Python 3.6 and above, and Python 2.7 running in a single container. Optionally using Alpine Linux.
The combination of uWSGI with Nginx is a common way to deploy Python Flask web applications. It is widely used in the industry and would give you decent performance. (*)
There is also an Alpine version. If you want it, check the tags from above.
If you are starting a new project, you might benefit from a newer and faster framework based on ASGI instead of WSGI (Flask and Django are WSGI-based).
You could use an ASGI framework like:
FastAPI, or Starlette, would give you about 800% (8x) the performance achievable with Flask using this image (tiangolo/uwsgi-nginx-flask). You can see the third-party benchmarks here.
Also, if you want to use new technologies like WebSockets it would be easier (and possible) with a newer framework based on ASGI, like FastAPI or Starlette. As the standard ASGI was designed to be able to handle asynchronous code like the one needed for WebSockets.
If you need to use Flask (instead of something based on ASGI) and you need to have the best performance possible, you can use the alternative image: tiangolo/meinheld-gunicorn-flask.
tiangolo/meinheld-gunicorn-flask will give you about 400% (4x) the performance of this image (tiangolo/uwsgi-nginx-flask).
It is very similar to tiangolo/uwsgi-nginx-flask, so you can still use many of the ideas described here.
GitHub repo: https://github.com/tiangolo/uwsgi-nginx-flask-docker
Docker Hub image: https://hub.docker.com/r/tiangolo/uwsgi-nginx-flask/
python3.8tag: general Flask web application:
python3.8tag: general Flask web application, structured as a package, for bigger Flask projects, with different submodules. Use it only as an example of how to import your modules and how to structure your own project:
static/index.htmlserved directly in
/, e.g. for Vue, React, Angular, or any other Single-Page Application that uses a static
index.html, not modified by Python:
You don't have to clone this repo, you should be able to use this image as a base image for your project with something in your
FROM tiangolo/uwsgi-nginx-flask:python3.8 COPY ./app /app
There are several image tags available for Python 3.6 and above, and Python 2.7, but for new projects you should use the latest version available.
There are several template projects that you can download (as a
.zip file) to bootstrap your project in the section "Examples (project templates)" above.
This Docker image is based on tiangolo/uwsgi-nginx. That Docker image has uWSGI and Nginx installed in the same container and was made to be the base of this image.
Note: You can download the example-flask-python3.8.zip project example and use it as the template for your project from the section Examples above.
Or you may follow the instructions to build your project from scratch:
FROM tiangolo/uwsgi-nginx-flask:python3.8 COPY ./app /app
appdirectory and enter in it
main.pyfile (it should be named like that and should be in your
from flask import Flask app = Flask(__name__) @app.route("/") def hello(): return "Hello World from Flask" if __name__ == "__main__": # Only for debugging while developing app.run(host='0.0.0.0', debug=True, port=80)
the main application object should be named
app (in the code) as in this example.
Note: The section with the
main() function is for debugging purposes. To learn more, read the Advanced instructions below.
. ├── app │ └── main.py └── Dockerfile
Dockerfileis, containing your
docker build -t myimage .
docker run -d --name mycontainer -p 80:80 myimage
...and you have an optimized Flask server in a Docker container.
There are several project generators that you can use to start your project, with everything already configured.
All these project generators include automatic and free HTTPS certificates generation provided by:
...using the ideas from DockerSwarm.rocks.
It would take about 20 minutes to read that guide and have a Docker cluster (of one or more servers) up and running ready for your projects.
You can have several projects in the same cluster, all with automatic HTTPS, even if they have different domains or sub-domains.
Then you can use one of the following project generators.
It would take about 5 extra minutes to generate one of these projects.
And it would take about 3 more minutes to deploy them in your cluster.
In total, about 28 minutes to start from scratch and get an HTTPS Docker cluster with your full application(s) ready.
These are the project generators:
Project link: https://github.com/tiangolo/flask-frontend-docker
Minimal project generator with a Flask backend, a modern frontend (Vue, React or Angular) using Docker multi-stage building and Nginx, a Traefik load balancer with HTTPS, Docker Compose (and Docker Swarm mode) etc.
Project Link: https://github.com/tiangolo/full-stack
Full stack project generator with Flask backend, PostgreSQL DB, PGAdmin, SQLAlchemy, Alembic migrations, Celery asynchronous jobs, API testing, CI integration, Docker Compose (and Docker Swarm mode), Swagger, automatic HTTPS, Vue.js, etc.
Project Link: https://github.com/tiangolo/full-stack-flask-couchbase
Full stack project generator with Flask backend, Couchbase, Couchbase Sync Gateway, Celery asynchronous jobs, API testing, CI integration, Docker Compose (and Docker Swarm mode), Swagger, automatic HTTPS, Vue.js, etc.
Similar to the one above (
full-stack), but with Couchbase instead of PostgreSQL, and some more features.
Project Link: https://github.com/tiangolo/full-stack-flask-couchdb
Full stack project generator with Flask backend, CouchDB, Celery asynchronous jobs, API testing, CI integration, Docker Compose (and Docker Swarm mode), Swagger, automatic HTTPS, Vue.js, etc.
full-stack-flask-couchbase, but with CouchDB instead of Couchbase (or PostgreSQL).
If you want to serve your (compiled) frontend code by the same backend (Flask) Docker container, you would have to copy the code to the container after compiling it.
That means that you would need to have all the frontend tools installed on the building machine (it might be your computer, a remote server, etc).
That also means that you would have to, somehow, always remember to compile the frontend code right before building the Docker image.
And it might also mean that you could then have to add your compiled frontend code to your
git repository (hopefully you are using Git already, or learning how to use
Adding your compiled code to Git is a very bad idea for several reasons, some of those are:
For these reasons, it is not recommended that you serve your frontend code from the same backend (Flask) Docker container.
There's a much better alternative to serving your frontend code from the same backend (Flask) Docker container.
You can have another Docker container with all the frontend tools installed (Node.js, etc) that:
To learn the specifics of this process for the frontend building in Docker you can read:
After having one backend (Flask) container and one frontend container, you need to serve both of them.
And you might want to serve them under the same domain, under a different path. For example, the backend (Flask) app at the path
/api and the frontend at the "root" path
You can then use Traefik to handle that.
And it can also automatically generate HTTPS certificates for your application using Let's Encrypt. All for free, in a very easy setup.
If you want to use this alternative, check the project generators above, they all use this idea.
In this scenario, you would have 3 Docker containers:
If you want to check the previous (deprecated) documentation on adding a frontend to the same container, you can read the deprecated guide for single page apps.
Note: You can download the example-flask-package-python3.8.zip project example and use it as an example or template for your project from the section Examples above.
You should be able to follow the same instructions as in the "QuickStart" section above, with some minor modifications:
app/directory, put it in a directory
__init__.pyinside of that
app/directory (that is copied to
/app/uwsgi.iniinside the container).
[uwsgi] module = app.main callable = app
The explanation of the
uwsgi.ini is as follows:
app.main. So, in the package
/app/app), get the
app = Flask(__name__)).
Your file structure would look like:
. ├── app │ ├── app │ │ ├── __init__.py │ │ ├── main.py │ └── uwsgi.ini └── Dockerfile
. ├── app │ ├── main.py └── Dockerfile
If you are using static files in the same container, make sure the
STATIC_PATH environment variable is set accordingly, for example to change the default value of
/app/app/static you could add this line to your
ENV STATIC_PATH /app/app/static
...after that, everything should work as expected. All the other instructions would apply normally.
. ├── app │ ├── app │ │ ├── api │ │ │ ├── api.py │ │ │ ├── endpoints │ │ │ │ ├── __init__.py │ │ │ │ └── user.py │ │ │ ├── __init__.py │ │ │ └── utils.py │ │ ├── core │ │ │ ├── app_setup.py │ │ │ ├── database.py │ │ │ └── __init__.py │ │ ├── __init__.py │ │ ├── main.py │ │ └── models │ │ ├── __init__.py │ │ └── user.py │ └── uwsgi.ini └── Dockerfile
Make sure you follow the official docs while importing your modules:
For example, if you are in
app/app/main.py and want to import the module in
app/app/core/app_setup.py you would write it like:
from .core import app_setup
from app.core import app_setup
app/app/api/endpoints/user.pyand you want to import the
app/app/core/database.pyyou would write it like:
from ...core.database import users
from app.core.database import users
You can customize several things using environment variables.
Notice: this technique is deprecated, as it can create several issues with modern frontend frameworks. For the details and better alternatives, read the section above.
Setting the environment variable
STATIC_INDEX to be
1 you can configure Nginx to serve the file in the URL
/static/index.html when requested for
That would improve speed as it would not involve uWSGI nor Python. Nginx would serve the file directly. To learn more follow the section above "QuickStart for SPAs".
For example, to enable it, you could add this to your
ENV STATIC_INDEX 1
By default, the image starts with 2 uWSGI processes running. When the server is experiencing a high load, it creates up to 16 uWSGI processes to handle it on demand.
If you need to configure these numbers you can use environment variables.
The starting number of uWSGI processes is controlled by the variable
UWSGI_CHEAPER, by default set to
The maximum number of uWSGI processes is controlled by the variable
UWSGI_PROCESSES, by default set to
Have in mind that
UWSGI_CHEAPER must be lower than
So, if, for example, you need to start with 4 processes and grow to a maximum of 64, your
Dockerfile could look like:
FROM tiangolo/uwsgi-nginx-flask:python3.8 ENV UWSGI_CHEAPER 4 ENV UWSGI_PROCESSES 64 COPY ./app /app
You can set a custom maximum upload file size using an environment variable
NGINX_MAX_UPLOAD, by default it has a value of
0, that allows unlimited upload file sizes. This differs from Nginx's default value of 1 MB. It's configured this way because that's the simplest experience an inexperienced developer in Nginx would expect.
For example, to have a maximum upload file size of 1 MB (Nginx's default) add a line in your
ENV NGINX_MAX_UPLOAD 1m
By default, the container made from this image will listen on port 80.
To change this behavior, set the
LISTEN_PORT environment variable. You might also need to create the respective
EXPOSE Docker instruction.
You can do that in your
Dockerfile, it would look something like:
FROM tiangolo/uwsgi-nginx-flask:python3.8 ENV LISTEN_PORT 8080 EXPOSE 8080 COPY ./app /app
There is a default file in
/app/uwsgi.ini with app specific configurations (on top of the global
It only contains:
[uwsgi] module = main callable = app
module = mainrefers to the file
callable = apprefers to the
Flask"application", in the variable
You can customize
uwsgi by replacing that file with your own, including all your configurations.
For example, to extend the default one above and enable threads, you could have a file:
[uwsgi] module = main callable = app enable-threads = true
You can override where the image should look for the app
uwsgi.ini file using the envirnoment variable
With that you could change the default directory for your app from
/app to something else, like
For example, to make the image use the file in
/application/uwsgi.ini, you could add this to your
ENV UWSGI_INI /application/uwsgi.ini COPY ./application /application WORKDIR /application
WORKDIR is important, otherwhise uWSGI will try to run the app in
Note: you would also have to configure the
static files path, read below.
You can make Nginx use a custom directory path with the files to serve directly (without having uWSGI involved) with the environment variable
For example, to make Nginx serve the static content using the files in
/app/custom_static/ you could add this to your
ENV STATIC_PATH /app/custom_static
Then, when the browser asked for a file in, for example, http://example.com/static/index.html, Nginx would answer directly using a file in the path
Note: you would also have to configure Flask to use that as its
As another example, if you needed to put your application code in a different directory, you could configure Nginx to serve those static files from that different directory.
If you needed to have your static files in
/application/static/ you could add this to your
ENV STATIC_PATH /application/static
You can also make Nginx serve the static files in a different URL, for that, you can use the environment variable
For example, if you wanted to change the URL
/content you could add this to your
ENV STATIC_URL /content
Then, when the browser asked for a file in, for example, http://example.com/content/index.html, Nginx would answer directly using a file in the path
If you need to run anything before starting the app, you can add a file
prestart.sh to the directory
/app. The image will automatically detect and run it before starting everything.
For example, if you want to add Alembic SQL migrations (with SQLAlchemy), you could create a
./app/prestart.sh file in your code directory (that will be copied by your
#! /usr/bin/env bash # Let the DB start sleep 10; # Run migrations alembic upgrade head
and it would wait 10 seconds to give the database some time to start and then run that
If you need to run a Python script before starting the app, you could make the
/app/prestart.sh file run your Python script, with something like:
#! /usr/bin/env bash # Run custom Python script before starting python /app/my_custom_prestart_script.py
Note: The image uses
source to run the script, so for example, environment variables would persist. If you don't understand the previous sentence, you probably don't need it.
By default, Nginx will start one "worker process".
If you want to set a different number of Nginx worker processes you can use the environment variable
You can use a specific single number, e.g.:
ENV NGINX_WORKER_PROCESSES 2
or you can set it to the keyword
auto and it will try to auto-detect the number of CPUs available and use that for the number of workers.
For example, using
auto, your Dockerfile could look like:
FROM tiangolo/uwsgi-nginx-flask:python3.8 ENV NGINX_WORKER_PROCESSES auto COPY ./app /app
By default, Nginx will start with a maximum limit of 1024 connections per worker.
If you want to set a different number you can use the environment variable
ENV NGINX_WORKER_CONNECTIONS 2048
It cannot exceed the current limit on the maximum number of open files. See how to configure it in the next section.
The number connections per Nginx worker cannot exceed the limit on the maximum number of open files.
You can change the limit of open files with the environment variable
ENV NGINX_WORKER_OPEN_FILES 2048
If you need to configure Nginx further, you can add
*.conf files to
/etc/nginx/conf.d/ in your
Just have in mind that the default configurations are created during startup in a file at
/etc/nginx/conf.d/upload.conf. So you shouldn't overwrite them. You should name your
*.conf file with something different than
upload.conf, for example:
Note: if you are customizing Nginx, maybe copying configurations from a blog or a StackOverflow answer, have in mind that you probably need to use the configurations specific to uWSGI, instead of those for other modules, like for example,
If you need to configure Nginx even further, completely overriding the defaults, you can add a custom Nginx configuration to
It will be copied to
/etc/nginx/nginx.conf and used instead of the generated one.
Have in mind that, in that case, this image won't generate any of the Nginx configurations, it will only copy and use your configuration file.
That means that all the environment variables described above that are specific to Nginx won't be used.
It also means that it won't use additional configurations from files in
/etc/nginx/conf.d/*.conf, unless you explicitly have a section in your custom file
If you want to add a custom
/app/nginx.conf file but don't know where to start from, you can use the
nginx.conf used for the tests and customize it or modify it further.
The combination of uWSGI with Nginx is a common way to deploy Python Flask web applications.
Nginx is a web server, it takes care of the HTTP connections and also can serve static files directly and more efficiently.
uWSGI is an application server, that's what runs your Python code and it talks with Nginx.
Your Python code has the actual Flask web application, and is run by uWSGI.
It uses the official Python Docker image, installs uWSGI and on top of that (with the least amount of modifications) adds the official Nginx image.
And it controls all these processes with Supervisord.
The image (and tags) created by this repo is based on the image tiangolo/uwsgi-nginx. This image adds Flask and sensible defaults on top of it.
If you follow the instructions and keep the root directory
/app in your container, with a file named
main.py and a Flask object named
app in it, it should "just work".
There's already a
uwsgi.ini file in the
/app directory with the uWSGI configurations for it to "just work". And all the other required parameters are in another
uwsgi.ini file in the image, inside
If you need to change the main file name or the main Flask object, you would have to provide your own
uwsgi.ini file. You may use the one in this repo as a template to start with (and you only would have to change the 2 corresponding lines).
You can have a
/app/static directory and those files will be efficiently served by Nginx directly (without going through your Flask code or even uWSGI), it's already configured for you. But you can configure it further using environment variables (read above).
Supervisord takes care of running uWSGI with the
uwsgi.ini file in
/app file (including also the file in
/etc/uwsgi/uwsgi.ini) and starting Nginx.
There's the rule of thumb that you should have "one process per container".
That helps, for example, isolating an app and its database in different containers.
But if you want to have a "micro-services" approach you may want to have more than one process in one container if they are all related to the same "service", and you may want to include your Flask code, uWSGI and Nginx in the same container (and maybe run another container with your database).
That's the approach taken in this image.
This image (and tags) have some default files, so if you run it by itself (not as the base image of your own project) you will see a default "Hello World" web app.
When you build a
Dockerfile with a
COPY ./app /app you replace those default files with your app code.
The main default file is only in
/app/main.py. And in the case of the tags with
-index, also in
But those files render a "(default)" text in the served web page, so that you can check if you are seeing the default code or your own code overriding the default.
Your app code should be in the container's
/app directory, it should have a
main.py file and that
main.py file should have a Flask object
If you follow the instructions above or use one of the downloadable example templates, you should be OK.
There is also a
/app/uwsgi.ini file inside the images with the default parameters for uWSGI.
The downloadable examples include a copy of the same
uwsgi.ini file for debugging purposes. To learn more, read the "Advanced development instructions" below.
While developing, you might want to make your code directory a volume in your Docker container.
With that you would have your files (temporarily) updated every time you modify them, without needing to build your container again.
To do this, you can use the command
pwd (print working directory) inside your
docker run and the flag
-v for volumes.
With that you could map your
./app directory to your container's
But first, as you will be completely replacing the directory
/app in your container (and all of its contents) you will need to have a
uwsgi.ini file in your
./app directory with:
[uwsgi] module = main callable = app
and then you can do the Docker volume mapping.
uwsgi.ini file is included in the downloadable examples.
uwsgi.inifile in your
docker build -t myimage .
./app) to your container's
docker run -d --name mycontainer -p 80:80 -v $(pwd)/app:/app myimage
If you go to your Docker container URL you should see your app, and you should be able to modify files in
./app/static/ and see those changes reflected in your browser just by reloading.
...but, as uWSGI loads your whole Python Flask web application once it starts, you won't be able to edit your Python Flask code and see the changes reflected.
To be able to (temporarily) debug your Python Flask code live, you can run your container overriding the default command (that starts Supervisord which in turn starts uWSGI and Nginx) and run your application directly with
python, in debug mode, using the
flask command with its environment variables.
So, with all the modifications above and making your app run directly with
flask, the final Docker command would be:
docker run -d --name mycontainer -p 80:80 -v $(pwd)/app:/app -e FLASK_APP=main.py -e FLASK_DEBUG=1 myimage flask run --host=0.0.0.0 --port=80
Or in the case of a package project, you would set
docker run -d --name mycontainer -p 80:80 -v $(pwd)/app:/app -e FLASK_APP=main/main.py -e FLASK_DEBUG=1 myimage flask run --host=0.0.0.0 --port=80
Now you can edit your Flask code in your local machine and once you refresh your browser, you will see the changes live.
Remember that you should use this only for debugging and development, for deployment in production you shouldn't mount volumes and you should let Supervisord start and let it start uWSGI and Nginx (which is what happens by default).
An alternative for these last steps to work when you don't have a package, but just a flat structure with single files (modules), your Python Flask code could have that section with:
if __name__ == "__main__": # Only for debugging while developing app.run(host='0.0.0.0', debug=True, port=80)
...and you could run it with
python main.py. But that will only work when you are not using a package structure and don't plan to do it later. In that specific case, if you didn't add the code block above, your app would only listen to
localhost (inside the container), in another port (5000) and not in debug mode.
Note: The example project example-flask-python3.8 includes a
docker-compose.override.yml with all these configurations, if you are using Docker Compose.
Also, if you want to do the same live debugging using the environment variable
STATIC_INDEX=1 (to serve
/app/static/index.html directly when requested for
/) your Nginx won't serve it directly as it won't be running (only your Python Flask app in debug mode will be running).
from flask import Flask, send_file
@app.route('/') def route_root(): index_path = os.path.join(app.static_folder, 'index.html') return send_file(index_path)
...that makes sure your app also serves the
/app/static/index.html file when requested for
/. Or if you are using a package structure, the
And if you are using a SPA framework, to allow it to handle the URLs in the browser, your Python Flask code should have the section with:
# Everything not declared before (not a Flask route / API endpoint)... @app.route('/<path:path>') def route_frontend(path): # ...could be a static file needed by the front end that # doesn't use the `static` path (like in `<script src="bundle.js">`) file_path = os.path.join(app.static_folder, path) if os.path.isfile(file_path): return send_file(file_path) # ...or should be handled by the SPA's "router" in front end else: index_path = os.path.join(app.static_folder, 'index.html') return send_file(index_path)
/) URL but also makes sure that your frontend SPA handles all the other URLs that are not defined in your Flask app.
That's how it is written in the tutorial above and is included in the downloadable examples.
Note: The example project example-flask-python3.8-index includes a
docker-compose.override.yml with all these configurations, if you are using Docker Compose.
If you follow the instructions above, it's probable that at some point, you will write code that will break your Flask debugging server and it will crash.
And since the only process running was your debugging server, that now is stopped, your container will stop.
Then you will have to start your container again after fixing your code and you won't see very easily what is the error that is crashing your server.
So, while developing, you could do the following (that's what I normally do, although I do it with Docker Compose, as in the example projects):
docker run -d --name mycontainer -p 80:80 -v $(pwd)/app:/app -e FLASK_APP=main.py -e FLASK_DEBUG=1 myimage bash -c "while true ; do sleep 10 ; done"
docker run -d --name mycontainer -p 80:80 -v $(pwd)/app:/app -e FLASK_APP=main/main.py -e FLASK_DEBUG=1 myimage bash -c "while true ; do sleep 10 ; done"
docker exec -it mycontainer bash
You will now be inside your container in the
flask run --host=0.0.0.0 --port=80
You will see your Flask debugging server start, you will see how it sends responses to every request, you will see the errors thrown when you break your code, and how they stop your server, and you will be able to re-start it very fast, by just running the command above again.
All the image tags, configurations, environment variables and application options are tested.
Updates are announced in the releases.
You can click the "watch" button at the top right and select "Releases only" to receive an email notification when there's a new release.
ENV STATIC_INDEX 1instead).
tiangolo/uwsgi-nginx-flask:python3.8-2019-10-14. PR #154.
/app/prestart.shfunctionality to parent image. PR #134.
uwsgi-nginxand PR #121.
/app/nginx.conffile that overrides the generated one. PR #51 in the parent image
uwsgi-nginxand PR #122.
NGINX_WORKER_CONNECTIONSto set the maximum number of Nginx worker connections and
NGINX_WORKER_OPEN_FILESto set the maximum number of open files. Thanks to ronlut in this PR.
Improvements from parent image:
Make uWSGI require an app to run, instead of going in "full dynamic mode" while there was an error. Supervisord doesn't terminate itself but tries to restart uWSGI and shows the errors. Uses
need-app as suggested by luckydonald in this comment.
/app/prestart.shscript to run arbitrary code before starting the app (for example, Alembic - SQLAlchemy migrations). The documentation for the
/app/prestart.shis in the main README.
/appis part of the
PYTHONPATHenvironment variable. That allows global imports from several places, easier Alembic integration, etc.
2017-09-10: Updated examples and sample project to work with SPAs even when structuring the app as a package (with subdirectories).
flask runcommands, that allows running a package application while developing more easily.
2017-08-10: Many changes:
python2.7-index. All the other images are deprecated in favor is this ones.
latestwill point to Python 3.6 and the other tags will be removed.
tiangolo/uwsgi-nginxthat improved this image too.
uwsgi.inifile (that allows using a custom directory different than
UWSGI_INI(using the ideas by @bercikr in #5 ).
FROM tiangolo/uwsgi-nginx-flask:python3.6 COPY ./app /app
and then customize with environment variables.
This project is licensed under the terms of the Apache license.