feat: set containerfile rust version via makefile

also set the RUSTUP_TOOLCHAIN env var via the dockerfile, and pass it to deployers

Containerfile

@@ -1,5 +1,6 @@
 #syntax=docker/dockerfile-upstream:1.4.0-rc1
-FROM rust:1.65.0-buster as shuttle-build
+ARG RUSTUP_TOOLCHAIN
+FROM rust:${RUSTUP_TOOLCHAIN}-buster as shuttle-build
 RUN apt-get update &&\
     apt-get install -y curl
 # download protoc binary and unzip it in usr/bin
@@ -26,7 +27,8 @@ COPY --from=cache /build .
 ARG folder
 RUN cargo build --bin shuttle-${folder}
 
-FROM rust:1.65.0-buster as shuttle-common
+ARG RUSTUP_TOOLCHAIN
+FROM rust:${RUSTUP_TOOLCHAIN}-buster as shuttle-common
 RUN apt-get update &&\
     apt-get install -y curl
 RUN rustup component add rust-src
@@ -37,4 +39,6 @@ ARG folder
 COPY ${folder}/prepare.sh /prepare.sh
 RUN /prepare.sh
 COPY --from=builder /build/target/debug/shuttle-${folder} /usr/local/bin/service
+ARG RUSTUP_TOOLCHAIN
+ENV RUSTUP_TOOLCHAIN=${RUSTUP_TOOLCHAIN}
 ENTRYPOINT ["/usr/local/bin/service"]

Makefile

@@ -20,6 +20,9 @@ endif
 
 BUILDX_FLAGS=$(BUILDX_OP) $(PLATFORM_FLAGS) $(CACHE_FLAGS)
 
+# the rust version used by our containers
+RUSTUP_TOOLCHAIN=1.65.0
+
 TAG?=$(shell git describe --tags)
 BACKEND_TAG?=$(TAG)
 DEPLOYER_TAG?=$(TAG)
@@ -107,6 +110,7 @@ down: docker-compose.rendered.yml
 shuttle-%: ${SRC} Cargo.lock
 	docker buildx build \
 	       --build-arg folder=$(*) \
+		   --build-arg RUSTUP_TOOLCHAIN=$(RUSTUP_TOOLCHAIN) \
 	       --tag $(CONTAINER_REGISTRY)/$(*):$(COMMIT_SHA) \
 	       --tag $(CONTAINER_REGISTRY)/$(*):$(TAG) \
 	       --tag $(CONTAINER_REGISTRY)/$(*):latest \

gateway/src/project.rs

@@ -481,13 +481,8 @@ impl ProjectCreating {
             name: self.container_name(ctx),
         };
 
-        // Get the version of rustc gateway was compiled with, matching the deployer
-        // RUSTUP_TOOLCHAIN override with the version from our Containerfile
-        let rustc_version = rustc_version_runtime::version().to_string();
-        debug!(
-            "got installed rustc version for deployer toolchain override: {}",
-            rustc_version
-        );
+        let rustup_toolchain =
+            std::env::var("RUSTUP_TOOLCHAIN").expect("rustup toolchain should be set");
 
         let container_config = self
             .from
@@ -525,7 +520,7 @@ impl ProjectCreating {
                         "RUST_LOG=debug",
                         // If we don't set this, users' dependencies with a `rust-toolchain.toml`
                         // override will compile with incompatible versions of rust.
-                        format!("RUSTUP_TOOLCHAIN={rustc_version}")
+                        format!("RUSTUP_TOOLCHAIN={rustup_toolchain}")
                     ]
                 })
             });