Use cargo-chef (#549)

cargo-chef allows to split downloading and building dependencies
from building the actual project. This allows docker to cache a layer
that downloads and builds dependencies and rebuild only the project
instead.

This change reduced the incremental build for me by over 60% from 327s to 130s.

Signed-off-by: Piotr Jastrzebski <[email protected]>

Dockerfile

@@ -1,10 +1,27 @@
 # build sqld
-FROM rust:slim-bullseye AS builder
+FROM rust:slim-bullseye AS chef
 RUN apt update \
     && apt install -y libclang-dev clang \
         build-essential tcl protobuf-compiler file \
         libssl-dev pkg-config git\
-    && apt clean
+    && apt clean \
+    && cargo install cargo-chef
+# We need to install and set as default the toolchain specified in rust-toolchain.toml
+# Otherwise cargo-chef will build dependencies using wrong toolchain
+# This also prevents planner and builder steps from installing the toolchain over and over again
+COPY rust-toolchain.toml rust-toolchain.toml
+RUN cat rust-toolchain.toml | grep "channel" | awk '{print $3}' | sed 's/\"//g' > toolchain.txt \
+    && rustup update $(cat toolchain.txt) \
+    && rustup default $(cat toolchain.txt) \
+    && rm toolchain.txt rust-toolchain.toml
+
+FROM chef AS planner
+COPY . .
+RUN cargo chef prepare --recipe-path recipe.json
+
+FROM chef AS builder
+COPY --from=planner /recipe.json recipe.json
+RUN cargo chef cook --release --recipe-path recipe.json
 COPY . .
 RUN cargo build -p sqld --release