在Docker中运行简单的Java Gradle应用

Question

I have a simple Java server app with a Gradle build. It works perfectly with gradle run on my host machine. However, I want to build this in a docker image and run as a docker container.

I'm using docker-machine (version 0.13.0):

docker-machine create --driver virtualbox --virtualbox-memory 6000 default
docker-machine start
eval $(docker-machine env default)

I have the following Dockerfile image build script in ./serverapp/Dockerfile:

FROM gradle:4.3-jdk-alpine
ADD . /code
WORKDIR /code
CMD ["gradle", "--stacktrace", "run"]

I can build perfectly:

?  docker build -t my-server-app .
Sending build context to Docker daemon  310.3kB
Step 1/4 : FROM gradle:4.3-jdk-alpine
 ---> b803ec92baec
Step 2/4 : ADD . /code
 ---> Using cache
 ---> f458b0be79dc
Step 3/4 : WORKDIR /code
 ---> Using cache
 ---> d98d04eda627
Step 4/4 : CMD ["gradle", "--stacktrace", "run"]
 ---> Using cache
 ---> 869262257870
Successfully built 869262257870
Successfully tagged my-server-app:latest

When I try to run this image:

?  docker run --rm my-server-app

FAILURE: Build failed with an exception.

* What went wrong:
Could not create service of type ScriptPluginFactory using BuildScopeServices.createScriptPluginFactory().
> Could not create service of type CrossBuildFileHashCache using BuildSessionScopeServices.createCrossBuildFileHashCache().

* Try:
Run with --info or --debug option to get more log output.

* Exception is:
org.gradle.internal.service.ServiceCreationException: Could not create service of type ScriptPluginFactory using BuildScopeServices.createScriptPluginFactory().
    at org.gradle.internal.service.DefaultServiceRegistry$FactoryMethodService.invokeMethod(DefaultServiceRegistry.java:797)

  <snip>
    ... 60 more
Caused by: org.gradle.api.UncheckedIOException: Failed to create parent directory '/code/.gradle/4.3' when creating directory '/code/.gradle/4.3/fileHashes'
    at org.gradle.util.GFileUtils.mkdirs(GFileUtils.java:271)
    at org.gradle.cache.internal.DefaultPersistentDirectoryStore.open(DefaultPersistentDirectoryStore.java:56)

Why would it have trouble creating that directory?

This should be a very easy task, can anyone tell me how they get this simple scenario working?

FYI, running current versions of everything. I'm using Gradle 4.3.1 on my host, and the official Gradle 4.3 base image from docker hub, I'm using the current version of JDK 8 on my host and the current version of docker, docker-machine, and docker-compose as well.

Answer 1

解决方法是在Dockerfile中--chown=gradle的/code目录上指定权限。许多Docker映像被设计为以root身份运行，基本Gradle映像以user身份运行gradle。

FROM gradle:4.3-jdk-alpine
ADD --chown=gradle . /code
WORKDIR /code
CMD ["gradle", "--stacktrace", "run"]

Ethan Davis建议使用/home/gradle而不是code。那可能也行得通，但是我没有想到。

docker映像维护者应该有一个简单的入门类型参考示例，该示例显示了获得基本用法的推荐方法。