CODEWITHSUNDEEP
node.jsgitlabenvironment-variablesdevopsgitlab-ci
Mark Heimer
Mark Heimer

Reputation: 49

How to build docker-image with environment variables while not pushing .env-file

Iam new to Dev-Ops and find myself a bit confused. I have a node-project which starts a server. One endpoint of that server should write to a database. On my local machine I test this behavior with a local DB. I created a .env.prod-file and a .env.dev-file to determine whether I use the local DB or my server DB (running on my server). I also read in blog posts that I should never ever push my .env-files to a remote repository.

Than I created a Dockerfile for building and shipping my application.

On my remote Gitlab-Repository I created a .gitlab-ci.yml which should build the docker-image from the Dockerfile every time there is a new commit to master.

But now I am faced with the issue that when I want to build the docker-image I need the .env.prod file but I should never push this file so GitLab has no access to it.

Is this described way an appropriate solution or do I do something entirely wrong(am I missing some core-concept in Dev-ops)?

This is my Dockerfile

FROM node:12.7-alpine AS build

WORKDIR /usr/graphql-server
COPY package.json /usr/graphql-server/

RUN npm install
COPY ./ /usr/graphql-server

RUN npm run build
COPY ./ /usr/graphql-server

EXPOSE 4000

CMD ["npm", "run", "start:prod"]

and the npm run start:prod does this:

tsc && cross-env NODE_ENV=prod node dist/index.js

That is how I determine which configuration to use (index.ts):

function getConfig(): void {
  let path;
  if (process.env.NODE_ENV === 'prod') {
    path = `${__dirname}/../src/.env.prod`;
  } else {
    path = `${__dirname}/../src/.env.dev`;
  }
  dotenv.config({ path });
}

Upvotes: 0

Views: 3423

Answers (1)

Mark Heimer
Mark Heimer

Reputation: 49

Finally thanks to @AndreasJägle I came up with a completely different solution for then what I first thought of. I dont need a .env-file and dont use the described getConfig() method for this solution anymore. As well there is no need to store environment-variables in Gitlab.

First I now start my node process by passing environment variables at the end of the node command like node dist/index.js variable1. This environment variable can be read at runtime: const baseUrl = process.argv[2]. The baseUrl-variable can than be used to send requests to this certain url.

Second because I'am building my project using docker I have to inject the values for the environment-variables into my docker-image. For this I modified my dockerfile like this.

FROM node:12.7-alpine AS build

ENV BASE_URL=localhost
    
...

CMD ["sh", "-c", "node dist/index.js $BASE_URL"]

(note that localhost is the default value for the BASE_URL environment variable and will be overridden)

Finally I use the previously build image in a docker-compose file on my server and set the environment variable like this.

version: "3"

    services:
      test-service:
        image: my-image:latest
        container_name: 'my-container'
        environment:
          - BASE_URL=mydomain.com

Upvotes: 1

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