Optimize Dockerfile for dependency caching

Refactor Dockerfile to improve dependency caching and build stages.

Dockerfile

@@ -1,68 +1,32 @@
-# syntax=docker/dockerfile:1
-# ============================================================================
-# Stage 1: PLANNER — Generate a dependency-only recipe from the full source
-# ============================================================================
-# cargo-chef inspects the real project structure (lib.rs + main.rs, features,
-# build scripts, profile settings) and produces a minimal recipe.json that
-# fingerprints ONLY dependency-relevant metadata. Source code changes that
-# don't affect dependencies will NOT invalidate this layer.
-FROM rust:1.93.0-alpine3.23 AS planner
-WORKDIR /app
-RUN cargo install cargo-chef --locked
-COPY Cargo.toml Cargo.lock ./
-COPY src src
-RUN cargo chef prepare --recipe-path recipe.json
-
-# ============================================================================
-# Stage 2: COOK — Build all dependencies (cached until recipe.json changes)
-# ============================================================================
-# This stage compiles every dependency listed in recipe.json with the exact
-# same profile, features, and target layout as the real build. Because it
-# uses BuildKit cache mounts for the cargo registry and git checkouts,
-# even a full rebuild after `docker system prune` only re-downloads crates
-# that changed upstream — not the entire registry.
-FROM rust:1.93.0-alpine3.23 AS cook
+# Stage 1: Cache dependencies
+FROM rust:1.93.0-alpine3.23 AS cacher
 WORKDIR /app
 RUN apk --no-cache upgrade && \
     apk add --no-cache musl-dev pkgconfig postgresql-dev gcc perl make
-COPY --from=planner /usr/local/cargo/bin/cargo-chef /usr/local/cargo/bin/cargo-chef
-COPY --from=planner /app/recipe.json recipe.json
-# Cook dependencies only — no application source code is present.
-# BuildKit cache mounts persist the cargo registry and target dir across
-# builds so incremental recompilation works even for dependency updates.
-RUN --mount=type=cache,target=/usr/local/cargo/registry,sharing=locked \
-    --mount=type=cache,target=/usr/local/cargo/git,sharing=locked \
-    --mount=type=cache,target=/app/target,sharing=locked \
-    cargo chef cook --release --recipe-path recipe.json && \
-    # Copy built artifacts out of the cache mount so the next stage can access them
-    cp -r /app/target /app/target-out
-
-# ============================================================================
-# Stage 3: BUILD — Compile application source on top of pre-built deps
-# ============================================================================
-# Only this layer is invalidated when .rs files change. Dependencies are
-# already compiled and linked from the cook stage.
+COPY Cargo.toml Cargo.lock ./
+# Create a minimal project to download and cache dependencies
+RUN mkdir -p src && \
+    echo 'fn main() { println!("Dummy build for caching dependencies"); }' > src/main.rs && \
+    cargo build --release && \
+    rm -rf src target/release/deps/oxicloud*
+# Stage 2: Build the application
 FROM rust:1.93.0-alpine3.23 AS builder
 WORKDIR /app
 RUN apk --no-cache upgrade && \
     apk add --no-cache musl-dev pkgconfig postgresql-dev gcc perl make
-# Bring in pre-compiled dependencies from cook
-COPY --from=cook /app/target-out target
-COPY --from=cook /usr/local/cargo/registry /usr/local/cargo/registry
-# Copy project metadata and full source
+# Copy cached dependencies (only target dir and cargo registry)
+COPY --from=cacher /app/target target
+COPY --from=cacher /usr/local/cargo/registry /usr/local/cargo/registry
+# Copy source and static (login.html is embedded at compile-time via include_str!)
 COPY Cargo.toml Cargo.lock ./
 COPY src src
 COPY static static
 COPY db db
 # Build with all optimizations (DATABASE_URL only needed at compile-time for sqlx)
 ARG DATABASE_URL="postgres://postgres:postgres@localhost/oxicloud"
-RUN --mount=type=cache,target=/usr/local/cargo/registry,sharing=locked \
-    --mount=type=cache,target=/usr/local/cargo/git,sharing=locked \
-    DATABASE_URL="${DATABASE_URL}" cargo build --release
+RUN DATABASE_URL="${DATABASE_URL}" cargo build --release
 
-# ============================================================================
-# Stage 4: RUNTIME — Minimal production image (~25 MB)
-# ============================================================================
+# Stage 3: Create minimal final image
 FROM alpine:3.23.3
 
 # OCI image metadata