如何将ARG值传递给ENTRYPOINT？

Question

Docker 1.9允许将参数传递给dockerfile.请参阅链接:https://docs.docker.com/engine/reference/builder/#arg

我怎样才能在ENTRYPOINT指令中传递相同的句子？

我的dockerfile有

ARG $ Version = 3.1
ENTRYPOINT /tmp/folder-$Version/sample.sh start

使用上面的dockerfile创建容器时出错.请建议在ENTRYPOINT指令中指定参数的正确方法是什么？

Answer 1

像布雷克米切尔最高审计机关,不能使用ARG在ENTRYPOINT.但是,您可以使用它ARG作为值ENV,这样您就可以使用它ENTRYPOINT:

Dockerfile

ARG my_arg
ENV my_env_var=$my_arg

ENTRYPOINT echo $my_env_var

Answer 2

简短的回答:你需要使用 ENV

双方ARG并ENV没有在扩大ENTRYPOINT或CMD.(https://docs.docker.com/engine/reference/builder/#environment-replacement)但是,因为ENVs是作为环境的一部分传入的,所以它们在运行时可用,因此shell可以扩展它们.(这意味着你不能使用ENTRYPOINT或的数组形式CMD.)

这是一个例子:

$ cat arg/Dockerfile
FROM debian:jessie
ARG FOO=bar
ENTRYPOINT echo ${FOO:-foo}
$ sudo docker build arg
Sending build context to Docker daemon 2.048 kB
Step 1 : FROM debian:jessie
 ---> f50f9524513f
Step 2 : ARG FOO=bar
 ---> Using cache
 ---> 2cfdcb514b62
Step 3 : ENTRYPOINT echo ${FOO:-foo}
 ---> Running in 21fb9b42c10d
 ---> 75e5018bad83
Removing intermediate container 21fb9b42c10d
Successfully built 75e5018bad83
$ sudo docker run 75e5018bad83
foo
$ sudo docker run -e FOO=bas 75e5018bad83
bas
$ sudo docker build --build-arg FOO=bas arg
Sending build context to Docker daemon 2.048 kB
Step 1 : FROM debian:jessie
 ---> f50f9524513f
Step 2 : ARG FOO=bar
 ---> Using cache
 ---> 2cfdcb514b62
Step 3 : ENTRYPOINT echo ${FOO:-foo}
 ---> Using cache
 ---> 75e5018bad83
Successfully built 75e5018bad83
$ sudo docker run 75e5018bad83
foo
$ cat env/Dockerfile
FROM debian:jessie
ARG FOO=bar
ENV FOO=${FOO}
ENTRYPOINT echo ${FOO:-foo}
$ sudo docker build env
Sending build context to Docker daemon 2.048 kB
Step 1 : FROM debian:jessie
 ---> f50f9524513f
Step 2 : ARG FOO=bar
 ---> Using cache
 ---> 2cfdcb514b62
Step 3 : ENV FOO ${FOO}
 ---> Running in f157a07c1b3e
 ---> a5e8c5b65a17
Removing intermediate container f157a07c1b3e
Step 4 : ENTRYPOINT echo ${FOO:-foo}
 ---> Running in 66e9800ef403
 ---> 249fe326e9ce
Removing intermediate container 66e9800ef403
Successfully built 249fe326e9ce
$ sudo docker run 249fe326e9ce
bar
$ sudo docker run -e FOO=bas 249fe326e9ce
bas
$ sudo docker build --build-arg FOO=bas env
Sending build context to Docker daemon 2.048 kB
Step 1 : FROM debian:jessie
 ---> f50f9524513f
Step 2 : ARG FOO=bar
 ---> Using cache
 ---> 2cfdcb514b62
Step 3 : ENV FOO ${FOO}
 ---> Running in 6baf31684b9f
 ---> 8f77ad154798
Removing intermediate container 6baf31684b9f
Step 4 : ENTRYPOINT echo ${FOO:-foo}
 ---> Running in 892ac47cabed
 ---> fa97da85bf8a
Removing intermediate container 892ac47cabed
Successfully built fa97da85bf8a
$ sudo docker run fa97da85bf8a
bas
$

Answer 3

万一您有多个参数要传递给 ENTRYPOINT 或 CMD，您可以这样做：

FROM openjdk:8-jdk-alpine
ARG PROFILE
ENV PROFILE=${PROFILE}
...
CMD java -jar -Dspring.profiles.active=$(echo ${PROFILE}) /app/server.jar

Answer 4

我为此苦苦挣扎了一天，感谢 @Rotareti 的提及。它需要先存在ENV才能用于ENTRYPOINT.

ENV variable=$from_ARG_variable
ENTRYPOINT exec your_exec_sh_file $variable

希望这可以帮助。