I have a simple python application that I want to run in a Docker Image. The application looks like this
from flask import Flask
app = Flask(__name__)
@app.route('/')
def hello_world():
return 'Hello World!'
if __name__ == '__main__':
app.run()
and a dockerfile that looks like this:
FROM python:3
RUN pip install --upgrade pip
RUN pip install flask
CMD ["python","app.py"]
COPY app.py /app.py
In addition to these two files the rest of the folder structure looks like this:
├───.idea
│ └───inspectionProfiles
├───static
├───templates
├───venv
│ ├───Include
│ ├───Lib
│ │ ├───site-packages
│ │ │ └───pip-19.0.3-py3.7.egg
│ │ │ ├───EGG-INFO
│ │ │ └───pip
│ │ │ ├───_internal
│ │ │ │ ├───cli
│ │ │ │ ├───commands
│ │ │ │ ├───models
│ │ │ │ ├───operations
│ │ │ │ ├───req
│ │ │ │ ├───utils
│ │ │ │ └───vcs
│ │ │ └───_vendor
│ │ │ ├───cachecontrol
│ │ │ │ └───caches
│ │ │ ├───certifi
│ │ │ ├───chardet
│ │ │ │ └───cli
│ │ │ ├───colorama
│ │ │ ├───distlib
│ │ │ │ └───_backport
│ │ │ ├───html5lib
│ │ │ │ ├───filters
│ │ │ │ ├───treeadapters
│ │ │ │ ├───treebuilders
│ │ │ │ ├───treewalkers
│ │ │ │ └───_trie
│ │ │ ├───idna
│ │ │ ├───lockfile
│ │ │ ├───msgpack
│ │ │ ├───packaging
│ │ │ ├───pep517
│ │ │ ├───pkg_resources
│ │ │ ├───progress
│ │ │ ├───pytoml
│ │ │ ├───requests
│ │ │ ├───urllib3
│ │ │ │ ├───contrib
│ │ │ │ │ └───_securetransport
│ │ │ │ ├───packages
│ │ │ │ │ ├───backports
│ │ │ │ │ └───ssl_match_hostname
│ │ │ │ └───util
│ │ │ └───webencodings
│ │ └───tcl8.6
│ └───Scripts
└───__pycache__
From Powershell I then build the Docker image by writing the command:
docker build . -t myusername/flaskapp
PS C:\Users\mypcuser\projects\flask_docker_test> docker build . -t myusername/flaskapp
Sending build context to Docker daemon 19.49MB
Step 1/5 : FROM python:3
---> f88b2f81f83a
Step 2/5 : RUN pip install --upgrade pip
---> Running in 56dc287d7501
Requirement already up-to-date: pip in /usr/local/lib/python3.8/site-packages (20.0.2)
Removing intermediate container 56dc287d7501
---> 2dff8ebf09c6
Step 3/5 : RUN pip install flask
---> Running in 5b59f8968a63
Collecting flask
Downloading Flask-1.1.1-py2.py3-none-any.whl (94 kB)
Collecting Werkzeug>=0.15
Downloading Werkzeug-1.0.0-py2.py3-none-any.whl (298 kB)
Collecting click>=5.1
Downloading click-7.1.1-py2.py3-none-any.whl (82 kB)
Collecting Jinja2>=2.10.1
Downloading Jinja2-2.11.1-py2.py3-none-any.whl (126 kB)
Collecting itsdangerous>=0.24
Downloading itsdangerous-1.1.0-py2.py3-none-any.whl (16 kB)
Collecting MarkupSafe>=0.23
Downloading MarkupSafe-1.1.1-cp38-cp38-manylinux1_x86_64.whl (32 kB)
Installing collected packages: Werkzeug, click, MarkupSafe, Jinja2, itsdangerous, flask
Successfully installed Jinja2-2.11.1 MarkupSafe-1.1.1 Werkzeug-1.0.0 click-7.1.1 flask-1.1.1 itsdangerous-1.1.0
Removing intermediate container 5b59f8968a63
---> 7583bc2d8be6
Step 4/5 : CMD ["python","app.py"]
---> Running in 9394be530612
Removing intermediate container 9394be530612
---> 53e72fb77552
Step 5/5 : COPY app.py /app.py
---> 5925b08ae09e
Successfully built 5925b08ae09e
Successfully tagged myusername/flaskapp:latest
SECURITY WARNING: You are building a Docker image from Windows against a non-Windows Docker host. All files and directories added to build context will have '-rwxr-xr-x' permissions. It is recommended to double check and reset permissions for sensitive files and directories.
PS C:\Users\mypcuser\projects\flask_docker_test>
I then go ahead and run my app using this command:
docker run -p 5001:5000 -t myusername/flaskapp
And get this output:
* Serving Flask app "app" (lazy loading)
* Environment: production
WARNING: This is a development server. Do not use it in a production deployment.
Use a production WSGI server instead.
* Debug mode: off
* Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
But when I go to this URL in both Firefox, Google Chrome and Postman I get this:
