What problem does it solve? CI Dockerfiles are built for reproducibility from a clean state, so every local build pays the full cost of downloading dependencies and recompiling from scratch. This Skill rewrites them to maximize BuildKit layer-cache reuse, turning source-only edits into minutes-long rebuilds instead of full rebuilds. ## Core Features & Use Cases - Cache-mount rewriting: Adds --mount=type=cache with explicit project-prefixed id= values to every RUN that downloads or compiles, with sharing=locked on compile-output mounts. - Language-specific rules: Applies Go layered COPY (go.mod/go.sum → go mod download → source) or Rust full-COPY with partitioned cargo cache mounts, based on the detected build language. - Ready-to-run build command: Assembles the nerdctl command with four-case proxy build args, NO_PROXY, and harbor registry tagging, resolving the proxy from the environment rather than hardcoding it. - Use Case: You have a Go service whose CI Dockerfile takes 25 minutes to rebuild locally after every code edit. Run this Skill to produce a Dockerfile.local that caches the module graph and build cache, so subsequent builds only recompile changed source. ## Quick Start Convert my CI Dockerfile at docker/Dockerfile into a cache-optimized Dockerfile.local and give me the nerdctl build command to run it.
