Gradle Remote Build Cache Optimization
Article Summary
Nelson Osacky from SoundCloud reveals how simply turning on Gradle's remote build cache got them almost zero cache hits. The real work was hunting down why.
SoundCloud's Android team faced a critical problem: build times were slowing down development. They had remote build caching enabled, but weren't seeing the benefits. This deep dive shows how they debugged cache misses using Gradle Enterprise to compare builds and identify why tasks weren't reusing cached outputs.
Key Takeaways
- BuildConfig values differed between CI and local (TEST_RETRY_COUNT was 0 vs 1)
- Disabled incremental compilation on CI broke all Kotlin compile task caching
- Gradle Enterprise build scans compare task inputs across different environments
- Moving environment checks from build time to runtime fixed cache misses
Enabling remote build cache is just step one: you need to ensure task inputs match across environments or you'll get zero cache hits.
About This Article
SoundCloud's JavaCompile and other tasks weren't getting cache hits because whitespace changes in source files caused unnecessary recompilation, even when the actual code logic stayed the same.
Nelson Osacky's team used Gradle Enterprise build scans to compare task inputs across builds. They found that whitespace was being included in the cache keys, which explained why certain inputs kept invalidating the cache.
Once the team understood how Gradle computes build cache keys based on input sensitivity, they could decide which cache misses mattered most and focus their optimization work on the highest-impact modules.