[FIXED] Dockerfile with env file

Issue

how to use .env in Dockerfile if i dont push the .env file on my repository ? because i want to use dockerfile to work with jenkins on my repository

my dockerfile like this

FROM node:lts-alpine

COPY ./ ./

RUN npm install

EXPOSE 8090

CMD ["npm", "run" , 'dev']

i am very new about this, and here i am trying to deploy my nodejs api with docker and integration with jenkins for Continues deployment , i have follow some articles so i tried to using dockerfile and jenkisfile on my linux server

my .env is something like this , for mongod db

DB_USERNAME=for_USERNAME_DB
DB_PASSWORD=for_PASSWORD_DB
DB_NAME=for_DATABASE_NAME

my example Jenkinsfile

pipeline {
    agent any

    stages {
        stage('Build') {
            steps {
                sh 'docker build -t mygithub/express-api:latest'
            }
        }

        stage('Test') {
            steps {
                sh 'docker run mygithub/express-api:latest npm test'
            }
        }

        stage('Deploy') {
            when {
                branch 'master'
            }
            steps {
                sh 'docker push mygithub/express-api:latest'
            }
        }
    }

    post {
        failure {
            echo 'build is broken. notify team!'
        }
    }
}

Solution

You can create .env or env_file_name at run time by using a script in Jenkins or Configuration tool with your environment values as below.

DB_USERNAME=for_USERNAME_DB
DB_PASSWORD=for_PASSWORD_DB
DB_NAME=for_DATABASE_NAME

In Jenkins use --env-file option while running the container to pass the environment variable inside the container for application. In this way you are not showing your environment variable in Dockerfile.

stage('Test') 
{
  steps 
  {
    sh 'docker run --env-file=env_file_name mygithub/express-api:latest npm test'
  }
}

Answered By - Mahattam
Answer Checked By - Clifford M. (JavaFixing Volunteer)