Sample code

sample_docker/.dockerignore

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+data/*

sample_docker/Dockerfile

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+# base image is python3.6 installed debian, can be changed to any other os
+FROM python:3.6-stretch
+
+# copying all the files in current path to app folder which can be found in the container also
+COPY . /app
+# changing dir
+WORKDIR /app/
+
+# commands that need to be run in terminal of the image that is being built
+RUN apt-get update -y
+RUN apt-get install python3-pip python3-dev -y
+RUN apt-get install build-essential pkg-config -y
+
+RUN python3 -m pip install requirements.txt
+
+# exposing port so that can be accessed from out side container(from host system) 
+EXPOSE 1111
+# command 
+CMD ["sh","-c","python3 app.py"]

sample_docker/Readme.md

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+# Basic guide to have a dockerzie a flask app 
+
+Flask : https://flask-doc.readthedocs.io/en/latest/
+
+Docker: https://docs.docker.com/
+
+Fastapi: https://fastapi.tiangolo.com/
+
+## CMD to build docker image :
+1. Any build arguments, tags needed should be added here.
+2. By default . points to Dockerfile and u can give filename by -f argument.
+
+    ```$ sudo docker build -t imagename .```
+
+## CMD to run docker image
+1. Any environment variables needed to run the docker container goes here with -e argument
+2. port mapping is hostport:exposeddockerport
+3. -d is for detach, if you need the the logs you can do -it
+
+    ```$ sudo docker run -d -p 1111:1111 --name containername imagename```
+
+## To See current running images and containers
+1. Images
+```$ sudo docker images```
+2. Containers
+```$ sudo docker ps -a```
+3. Stats of a running container
+```$ sudo docker stats containername```
+
+
+## CMD to ssh into a running docker container
+1. Container should be running
+
+    ```$ sudo docker exec -it containername /bin/bash```
+
+
+
+## Clean up
+1. To delete all unused(not attached to any container) images.
+
+    ```$ sudo docker system prune -a```
+2. To stop a running container.
+
+    ```$ sudo docker stop containername```
+3. To delete an image., -f can be used to force
+
+    ```$ sudo docker rmi image name```
+
+
+### Things to check : 
+1. If the port being used in the flask app and the port exposed in Dockerfile are same.
+2. As we do in git to ignore files we add the path to `.gitignore`, same can be done with `.dockerignore`
+
+### Other things to checkout:
+1. Attaching volumes to a container
+2. Adding in newrelic for logging.
+3. instead of docker `run` one can try docker `compose`,`start`,`stop`
+

sample_docker/app.py

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+from flask import Flask, request, jsonify
+
+app = Flask(__name__)
+
+@app.route("/", methods=['GET,POST'])
+def index():
+    print(request.headers)
+    print(request.json)
+    print(request.body)
+
+    return jsonify("success"),200
+
+if __name__=="__main__":
+    app.run(debug=True, host='0.0.0.0',  port=1111)
+

sample_docker/requirements.txt

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+flask==1.0.1