The Android CI job recompiled all native C++ (whisper.cpp, reanimated,
worklets, gesture-handler) from scratch every push — ~41 min on the
shared runner — because nothing survived the `COPY . .` layer
invalidation, and `--load` exported the whole ~15GB image just to copy
one APK out.
Dockerfile (docker/android.Dockerfile):
- Install ccache and patch the NDK CMake toolchain file so every module's
externalNativeBuild routes C/C++ compiles + links through ccache (the
third-party modules don't honor ccache on their own). ccache dir is a
persistent BuildKit cache mount, so objects survive across builds.
- Mount GRADLE_USER_HOME as a cache and pass --build-cache --parallel, so
Kotlin/Java/resource/dex tasks and resolved deps persist too.
- Cache-mount the bun install dir; move the nodejs install into the cached
toolchain layer (was reinstalling on every source change).
- New `apk` stage (FROM scratch) holding just the signed APK, for
--output type=local extraction without loading the 15GB image.
CI (.gitea/workflows/ci.yml):
- build-apk now builds `--target apk --output type=local,dest=./out` and
streams ./out/app-release.apk to /srv/wisp/wisp.apk — no --load, no
docker create/cp, and the build image no longer piles up on the host.
Validated locally (arm64, real sign+assemble path):
cold gradle 5m5s -> warm gradle 57s; 61/61 C++ compiles served from
ccache (100% hit); 226/578 Gradle tasks from cache; export-only build
60s wall, APK valid + v2/v3 signed. The first server build after this
is still cold (~41 min) to populate the caches; pushes after that are
much faster.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
NilsBriggen
e256508c44