How to cache Android NDK in Azure devops pipeline?

Issue

While creating a task in Azure devops pipeline, I am requred to cache the NDK to reduce the build time. Hence, I am trying to write a task for the same.

For example here is what I am using for caching the gradle and konan repos

variables:
  GRADLE_USER_HOME: $(Pipeline.Workspace)/.gradle
  KONAN_USER_HOME: /Users/runner/.konan

steps:
  - bash: env
    displayName: env vars

  - task: Cache@2
    inputs:
      key: 'gradle | "$(Agent.OS)"'
      restoreKeys: gradle
      path: $(GRADLE_USER_HOME)
    displayName: Gradle build cache

  - task: Cache@2
    inputs:
      key: 'konan | "$(Agent.OS)" | cache'
      restoreKeys: konan
      path: $(KONAN_USER_HOME)
    displayName: Konan build cache

they work just fine!

But for NDK, how do I know the relative repository path for my NDK and cache it, assuming the task will be something like this

  - task: Cache@2
    inputs:
      key: 'ndk | "$(Agent.OS)"'
      restoreKeys: ndk
      path: $(NDK_PATH)
    displayName: NDK build cache

Any help in this is highly helpful.

Solution

So, I figured this out, forgot to post here and this is what I found. 1 - to get the relative path of android-ndk from devops setup (I dont have those permissions). 2 - Then run the caching task to cache into that path

1 - get relative env vars with this bash output. CREDITS So In steps I write:

steps:
  - bash: env
    displayName: env vars

prints all the env variables available example gist with some vars intentionally removed from that I picked up the path relevant to my use

2021-01-19T16:17:44.4273060Z ANDROID_HOME=/Users/runner/Library/Android/sdk

2021-01-19T16:17:44.4276800Z ANDROID_SDK_ROOT=/Users/runner/Library/Android/sdk

2021-01-19T16:17:44.4320010Z ANDROID_NDK_18R_PATH=/Users/runner/Library/Android/sdk/ndk/18.1.5063045

2021-01-19T16:17:44.4328690Z ANDROID_NDK_HOME=/Users/runner/Library/Android/sdk/ndk-bundle

now the most relevant path was to ANDROID_SDK_ROOT as this makes sense to then append /ndk to it.

then comes my task

2 the caching task:

• create variable for path NDK_HOME: /Users/runner/Library/Android/sdk/ndk

and add it in the cache task which completely looks like this

variables:
  GRADLE_USER_HOME: $(Pipeline.Workspace)/.gradle
  KONAN_USER_HOME: /Users/runner/.konan
  NDK_HOME: /Users/runner/Library/Android/sdk/ndk

pool:
  vmImage: 'macos-latest'

name: $(date:yyyy).$(Month)$(rev:.r)

steps:
  - bash: env
    displayName: env vars

  - task: Cache@2
    inputs:
      key: 'gradle | "$(Agent.OS)"'
      restoreKeys: gradle
      path: $(GRADLE_USER_HOME)
    displayName: Gradle build cache

  - task: Cache@2
    inputs:
      key: 'konan | "$(Agent.OS)" | cache'
      restoreKeys: konan
      path: $(KONAN_USER_HOME)
    displayName: Konan build cache

  - task: Cache@2
    inputs:
      key: 'ndk | "$(Agent.OS)"'
      restoreKeys: ndk
      path: $(NDK_HOME)/ndk
    displayName: NDK build cache

Works like a charm 🤞

One other way to dynamically create your variable from this answer. Thank you then my task looks like

steps:
  - bash: env
    displayName: env vars

  - bash: echo "##vso[task.setvariable variable=ANDROID_SDK_ROOT;]$ANDROID_SDK_ROOT"

  - task: Cache@2
    inputs:
      key: 'ndk | "$(Agent.OS)"'
      restoreKeys: ndk
      path: $(ANDROID_SDK_ROOT)/ndk
    displayName: NDK build cache

works in same manner

Answered By - sud007