Docker 文件 ENV 变量替换

Question

I have a case where docker image/container for same java spring boot app is built on separate servers (DEV server, QA server, PROD server). However, in my Dockerfile, I have a ENTRYPOINT line that looks as follows:

ENTRYPOINT ["java","-jar","-DskipTests","-Dspring.profiles.active=development","some.jar",">some.log","2>someerror.log"]

But I need a way to pass on the correct "-Dspring.profiles.active=development" for when I am in QA or PROD.

I noticed that if I issue this docker command on the server (QA for example):

docker exec <container id> env | grep V 

then I can clearly see that there is an environment variable defined as:

ZZ_ENVIRONMENT=QA

Seeing this, I am looking for a way such that in the Dockerfile, maybe I can use this info such that if:

if ZZ_ENVIRONMENT=QA then 
ENTRYPOINT ["java","-jar","-DskipTests","-Dspring.profiles.active=qa","some.jar",">some.log","2>someerror.log"]

if ZZ_ENVIRONMENT=PROD then 
ENTRYPOINT ["java","-jar","-DskipTests", Dspring.profiles.active=production","some.jar",">some.log","2>someerror.log"]

else
ENTRYPOINT ["java","-jar","-DskipTests","-Dspring.profiles.active=development","some.jar",">some.log","2>someerror.log"]

Is this possible? and if so I would appreciate example that I can follow. If this is the wrong way to do this, please advise the best way to do this. Please note: I do not have sudo access to the servers, just user access.

Answer 1

You can pass the environment variables while starting the docker container in the docker run command.

For example

docker run --env ZZ_ENVIRONMENT=PROD --env ENV_VAR2=value2 <docker_image_name>

If you have a list of environment variables then you can simply create a .env file and add all the varibales into it and in the docker run command can refer the env file as below

docker run --env-file .env <docker_image_name>

where your .env file counld be as

ZZ_ENVIRONMENT=PROD
ENV_VAR2=value2

Answer 2

The best way to go about this would be instead of this logic in DockerFile, you could use the SPRING_PROFILES_ACTIVE variable directly or in your enviornment file.

Docker File

ENTRYPOINT ["java","-jar","-DskipTests""some.jar",">some.log","2>someerror.log"]

Docker Run

docker run -e "SPRING_PROFILES_ACTIVE=qa" -p 8080:8080 -t test-image:v1

docker run -e "SPRING_PROFILES_ACTIVE=production" -p 8080:8080 -t test-image:v1

Alternativetly, you could explore docker compose like below (more maintainable approach)

docker-compose.yml

version: '3'
services:
  spring-boot-service:
    image: test-image:v1
    env_file:
      - spring-boot-service.env
    ports:
      - 8080:8080

spring-boot-service.env

SPRING_PROFILES_ACTIVE=production