build_process.md

Docker build process 🐳

First create your docker file within the root of your project. Below you can see a Dockerfile in a simple form, which uses a python image, runs pipenv to install the dependencies and then copies all files in the root dir to /app and then runs the script.

Dockerfile for Python using Pipenv

# select an image to use from Docker - https://hub.docker.com/_/python
FROM python:3.9.2-slim-buster

# install required modules via pipenv
COPY Pipfile Pipfile.lock ./
RUN python -m pip install --upgrade pip
RUN pip install pipenv && pipenv install --dev --system --deploy

# copy all files to /app and list it as the WORKDIR
COPY . /app
WORKDIR /app

# run the script app.py
CMD python app.py

Once we have the Dockerfile created it's time to build our image.

Build the image

Include the period at the end, as this tells docker to use the root

docker build -t <image name> .

# use this to build to a registry
docker build -t <registry>/<image name>:<tag name> .

Pushing to DockerHub

Once you have built your image for this example lets build a simple python image using the above Dockerfile.

> docker build -t python_test .

Then we need to grab the ID of that image so we're able to tag it, run docker images this will list all the images on your dev machines.

> docker images
REPOSITORY    TAG       IMAGE ID       CREATED              SIZE
python_test   latest    e156018cae60   About a minute ago   160MB

Now lets tag your image.

> docker tag e156018cae60 yourhubusername/yourhubrepo:tag-name

The number must match the image ID and :tag-name is the tag. In general, a good choice for a tag is something that will help you understand what this container should be used in conjunction with, or what it represents. Whatever will help you understand what this particular image is intended for.

Now we can push this to Docker Hub

> docker push yourhubusername/yourhubrepo:tag-name

Pulling from Docker Hub.

Now you're image is up in DockerHub you're able to pull this (using the pull cmd) from DockerHub and run it. To do so, you can go into your image via docker hub and get the cmd and copy it, for example mine is:

docker pull yourhubusername/yourhubrepo:tag-name

To run the pulled image simply type > docker run yourhubusername/yourhubrepo:tag-name in your terminal, and this will then open a container with your app running.

Pushing to a registery

docker container commit <container ID> <image name>:latest

docker push <registry>/<image name>:latest

Run the image

docker run <image name>

# use this if you're using enviroment variables
docker run -d --env-file .env <image name>

Using --env-file .env allows you to add your enviroment variables into your container.

Check that it's running (locally)

docker ps

-- Out
CONTAINER ID   IMAGE                   COMMAND                  CREATED          STATUS          PORTS      NAMES
7f413d44d549   sellers_json_analysis   "/usr/local/bin/guni…"   3 seconds ago    Up 2 seconds    5000/tcp   suspicious_dijkstra