How can I cache Android NDK in my Github Actions workflow? - github

Question

I want to cache the Android NDK in my Github Actions workflow. The reason is that I require a specific version of the NDK and CMake which aren't pre-installed on MacOS runners.
I tried to use the following workflow job to achieve this:
jobs:
build:
runs-on: macos-latest
steps:
- name: Cache NDK
id: cache-primes
uses: actions/cache#v1
with:
path: ${{ env.ANDROID_NDK_HOME }}
key: ${{ runner.os }}-ndk-${{ hashFiles(env.ANDROID_NDK_HOME) }}
- name: Install NDK
run: echo "y" | $ANDROID_HOME/tools/bin/sdkmanager "ndk;21.0.6113669" "cmake;3.10.2.4988404"
The problem with this is that the env context doesn't contain the ANDROID_NDK_HOME variable. So this means build.steps.with.path evaluates empty.
The regular environment variable is present and prints the correct path if I debug using the following step:
jobs:
build:
steps:
- name: Debug print ANDROID_NDK_HOME
run: echo $ANDROID_NDK_HOME
But the regular environment variable can only be used in shell scripts and not in build.steps.with as far as I understand.

Answer 1

- name: Prepare NDK dir for caching ( workaround for https://github.com/actions/virtual-environments/issues/1337 )
run: |
sudo mkdir -p /usr/local/lib/android/sdk/ndk
sudo chmod -R 777 /usr/local/lib/android/sdk/ndk
sudo chown -R $USER:$USER /usr/local/lib/android/sdk/ndk
- name: NDK Cache
id: ndk-cache
uses: actions/cache#v2
with:
path: /usr/local/lib/android/sdk/ndk
key: ndk-cache-21.0.6113669-v2
- name: Install NDK
if: steps.ndk-cache.outputs.cache-hit != 'true'
run: echo "y" | sudo /usr/local/lib/android/sdk/tools/bin/sdkmanager --install "ndk;21.0.6113669"
Here is a config I use in my project.
Couple of note:
You need to create ndk directory and change permission to workaround https://github.com/actions/virtual-environments/issues/1337
Make sure
you use proper id (ndk-cache in example above) in if statement so
you can actually use cache

Answer 2

You can easily specify the NDK installation directory to be cached.
- name: Cache (NDK)
uses: actions/cache#v2
with:
path: ${ANDROID_HOME}/ndk/21.0.6113669
key: ndk-cache
- name: Install NDK
run: echo "y" | sudo ${ANDROID_HOME}/tools/bin/sdkmanager --install 'ndk;21.0.6113669'

Answer 3

As long as you're using an NDK version that is pre-installed with Github Actions runners, then you no longer need to worry about caching your NDK :)
Find the runners list here:
https://docs.github.com/en/actions/using-github-hosted-runners/about-github-hosted-runners#supported-software
Example runner list:
https://github.com/actions/runner-images/blob/main/images/linux/Ubuntu2204-Readme.md
For the Ubuntu 22.04 runner, it comes with three NDKs pre-installed
23.2.8568313
24.0.8215888
25.2.9519653 (default)