Each time I execute docker run ./gradlew command, it downloads all the gradle files and dependencies. How to download and install only once?

Question

I have a simple dockerfile that configured to build android apps
It's all working nicely, but the problem is that each time i run the ./gradlew command, it downloads and installs all the Gradle artifacts and dependencies. How can i just install once?

this is the dockerfile:

FROM openjdk:8

ENV SDK_URL="https://dl.google.com/android/repository/sdk-tools-linux-3859397.zip" \
    ANDROID_HOME="/usr/local/android-sdk" \
    ANDROID_VERSION=26 \
    ANDROID_BUILD_TOOLS_VERSION=26.0.2

# Download Android SDK
RUN mkdir "$ANDROID_HOME" .android \
    && cd "$ANDROID_HOME" \
    && curl -o sdk.zip $SDK_URL \
    && unzip sdk.zip \
    && rm sdk.zip \
    && yes | $ANDROID_HOME/tools/bin/sdkmanager --licenses

# Install Android Build Tool and Libraries
RUN $ANDROID_HOME/tools/bin/sdkmanager --update
RUN $ANDROID_HOME/tools/bin/sdkmanager "build-tools;${ANDROID_BUILD_TOOLS_VERSION}" \
    "platforms;android-${ANDROID_VERSION}" \
    "platform-tools"

RUN mkdir /application
WORKDIR /application

and this is the command :

docker run -it --rm -v "$PWD":/application packsdkandroiddocker.image bash  ./gradlew assembleRelease --debug

score 1 · Answer 1 · answered Aug 05 '20 at 07:29

1

Based on your Dockerfile, your gradle's cache directory is /root/.gradle. So, you need to mount a volume to the cache directory to persist cache.

Use host volumes

docker run -it --rm -v $PWD/.gradle:/root/.gradle -v $PWD:/application packsdkandroiddocker.image bash ./gradlew assembleDebug

Use named volumes

docker volume create gradle-cache
docker run -it --rm -v gradle-cache:/root/.gradle -v $PWD:/application packsdkandroiddocker.image bash ./gradlew assembleDebug

answered Aug 05 '20 at 07:29

atyc

1,056
7
7

Thanks, it helped, how can i make that this new $PWD/.gradle created will not be root on creation? – user63898 Aug 05 '20 at 08:11
Use this environment variable `GRADLE_USER_HOME` to specify the cache directory that you want – atyc Aug 06 '20 at 10:11
where ? as it runnes from docker – user63898 Aug 06 '20 at 13:30

score 0 · Answer 2 · answered Aug 05 '20 at 07:10

The problem, as you've no doubt discovered, is that enumerating all possible dependencies of all Gradle tasks and downloading them is...non-trivial.

It's not the most elegant solution, but I've solved this problem previously (in the context of GitLab CI Docker runners) by mounting a directory on the host to be the GRADLE_USER_HOME directory. This way, the image itself is fresh every run, but the caches are shared across runs. It does mean that you'll still have an initial slow run per host, but it dramatically reduces the time taken for subsequent runs.

Depending on exactly what you're trying to do, this may or may not be a satisfactory solution.

Each time I execute docker run ./gradlew command, it downloads all the gradle files and dependencies. How to download and install only once?

2 Answers2