kivio / go-dotenv-dockerfile

Simple renderer to add .env variables as Dockerfile envs

How to

This simple command line will provide you option for render DOTENV with source from .env file. Best to describe it is to show example - files for this example you can find in example directory.

First of all our files, first Dockerfile.env that will be our template:

FROM node:10.17.0 AS build-env
WORKDIR /opt/app
COPY package*.json ./
RUN npm install
COPY . .

FROM gcr.io/distroless/nodejs
COPY --from=build-env /opt/app /opt/app
WORKDIR /opt/app
EXPOSE 8080

DOTENV # check at https://github.com/kivio/go-dotenv-dockerfile

CMD ["app.js"]

Second .env file with out variables:

SERVICE_NAME='my-nodejs-app'
SERVICE_CONF='config.app'
PORT='8080'

Now we will run our command. By default it use files with names as we have here and produce Dockerfile. Output will look like:

FROM node:10.17.0 AS build-env
WORKDIR /opt/app
COPY package*.json ./
RUN npm install
COPY . .

FROM gcr.io/distroless/nodejs
COPY --from=build-env /opt/app /opt/app
WORKDIR /opt/app
EXPOSE 8080

ENV SERVICE_NAME my-nodejs-app
ENV SERVICE_CONF config.app
ENV PORT 8080

CMD ["app.js"]

To configure file names let's look to help of our program:

Usage of ./dotenv2dockerfile:
  -dockerfile-file string
        path to Dockerfile before rendering (default "Dockerfile.env")
  -dotenv-file string
        path to .env file or it different name (default ".env")
  -output string
        path to output Dockerfile (default "Dockerfile")

How Docker image works

To work with this tool as container (usage - as step for dockerized CI/CD) you need to mount few things:

• first of all file with dotenv configuration
• second file with Dockerfile template
• and last one - volume where you output should be produced