使用docker-compose在构建时向docker图像传递环境变量

Question

在Docker主机上，我有：

export BUILD_VERSION=1.0

app.js

console.log('BUILD_VERSION: ' + process.env.BUILD_VERSION);

DockerFile：

FROM node
ADD app.js /
ARG BUILD_VERSION
ENV BUILD_VERSION=$BUILD_VERSION
RUN echo Build Time: $BUILD_VERSION
RUN node /app.js
CMD echo Run Time: $BUILD_VERSION

version: '3'
services:
  app:
    build:
      context: .
      args:
        - BUILD_VERSION

docker build -t test --no-cache --build-arg BUILD_VERSION .

$ docker run --rm test
Run Time: 1.0
$ docker run --rm test node /app
BUILD_VERSION: 1.0

docker-compose up --build

...
Step 5/7 : RUN echo Build Time: $BUILD_VERSION
 ---> Running in 6115161f33bf
Build Time:
 ---> c691c619018a
Removing intermediate container 6115161f33bf
Step 6/7 : RUN node /app.js
 ---> Running in f51831cc5e1e
BUILD_VERSION:

$ docker run --rm test
Run Time: 1.0
$ docker run --rm test node /app
BUILD_VERSION: 1.0

我还尝试在docker-compose.yml中使用Environment，如下所示，这同样只使它在运行时可用，而不是在构建时可用：

version: '3'
services:
  app:
    build:
      context: .
    environment:
      - BUILD_VERSION

请指教，我怎样才能使它以最不费解的方式工作？

Answer 1

你的例子对我很管用。

你是否尝试删除图像并重新构建？如果图像在缓存中，Docker不会重新构建图像，尽管环境变量发生了变化。

您可以使用以下方法删除它们：

 docker-compose down --rmi all

$ cat Dockerfile
FROM alpine
ARG BUILD_VERSION
ENV BUILD_VERSION=$BUILD_VERSION
RUN echo Build Time: $BUILD_VERSION

$ cat docker-compose.yml
version: '3'
services:
  app:
    build:
      context: .
      args:
        - BUILD_VERSION

$ export BUILD_VERSION=122221
$ docker-compose up --build
Creating network "a_default" with the default driver
Building app
Step 1/4 : FROM alpine
latest: Pulling from library/alpine
8e3ba11ec2a2: Pull complete
Digest: sha256:7043076348bf5040220df6ad703798fd8593a0918d06d3ce30c6c93be117e430
Status: Downloaded newer image for alpine:latest
---> 11cd0b38bc3c
Step 2/4 : ARG BUILD_VERSION
---> Running in b0a1a79967a0
Removing intermediate container b0a1a79967a0
---> 9fa331d63f6d
Step 3/4 : ENV BUILD_VERSION=$BUILD_VERSION
---> Running in a602c27689a5
Removing intermediate container a602c27689a5
---> bf2181423c93
Step 4/4 : RUN echo Build Time: $BUILD_VERSION                <<<<<< (*)
---> Running in 9d828cefcfab
Build Time: 122221
Removing intermediate container 9d828cefcfab
---> 2b3afa3d348c
Successfully built 2b3afa3d348c
Successfully tagged a_app:latest
Creating a_app_1 ... done
Attaching to a_app_1
a_app_1 exited with code 0

$ cat docker-compose
version: '3'
services:
  app1:
    build:
      context: .
      args:
        - BUILD_VERSION=$APP1_BUILD_VERSION
  app2:
    build:
      context: .
      args:
        - BUILD_VERSION=$APP2_BUILD_VERSION

$ export APP1_BUILD_VERSION=1.1.1
$ export APP2_BUILD_VERSION=2.2.2

$ docker-compose build
Building app1
Step 1/4 : FROM alpine
latest: Pulling from library/alpine
8e3ba11ec2a2: Pull complete
Digest: sha256:7043076348bf5040220df6ad703798fd8593a0918d06d3ce30c6c93be117e430
Status: Downloaded newer image for alpine:latest
---> 11cd0b38bc3c
Step 2/4 : ARG BUILD_VERSION
---> Running in 0b66093bc2ef
Removing intermediate container 0b66093bc2ef
---> 906130ee5da8
Step 3/4 : ENV BUILD_VERSION=$BUILD_VERSION
---> Running in 9d89b48c875d
Removing intermediate container 9d89b48c875d
---> ca2480695149
Step 4/4 : RUN echo Build Time: $BUILD_VERSION
---> Running in 52dec27874ec
Build Time: 1.1.1
Removing intermediate container 52dec27874ec
---> 1b3654924297
Successfully built 1b3654924297
Successfully tagged a_app1:latest
Building app2
Step 1/4 : FROM alpine
---> 11cd0b38bc3c
Step 2/4 : ARG BUILD_VERSION
---> Using cache
---> 906130ee5da8
Step 3/4 : ENV BUILD_VERSION=$BUILD_VERSION
---> Running in d29442339459
Removing intermediate container d29442339459
---> 8b26def5ef3a
Step 4/4 : RUN echo Build Time: $BUILD_VERSION
---> Running in 4b3de2d223e5
Build Time: 2.2.2
Removing intermediate container 4b3de2d223e5
---> 89033b10b61e
Successfully built 89033b10b61e
Successfully tagged a_app2:latest