Move `rustup target` before `cargo build`. Thanks to @dani-garcia!

Note from @dani-garcia:

> I don't think this is doing anything right now because the target is probably
> installed already.

docker/Dockerfile.j2

@@ -176,6 +176,13 @@ ENV OPENSSL_INCLUDE_DIR="/usr/include/arm-linux-gnueabi"
 ENV OPENSSL_LIB_DIR="/usr/lib/arm-linux-gnueabi"
 {% endif -%}
 
+{% if "alpine" in target_file %}
+RUN rustup target add x86_64-unknown-linux-musl
+
+{% elif "aarch64" in target_file %}
+RUN rustup target add aarch64-unknown-linux-gnu
+
+{% endif %}
 # Builds your dependencies and removes the
 # dummy project, except the target folder
 # This folder contains the compiled dependencies
@@ -189,16 +196,11 @@ COPY . .
 # Make sure that we actually build the project
 RUN touch src/main.rs
 
-{% if "alpine" in target_file %}
-RUN rustup target add x86_64-unknown-linux-musl
-
-{% endif %}
 # Builds again, this time it'll just be
 # your actual source files being built
 {% if "amd64" in target_file %}
 RUN cargo build --features ${DB} --release
 {% elif "aarch64" in target_file %}
-RUN rustup target add aarch64-unknown-linux-gnu
 RUN cargo build --features ${DB} --release --target=aarch64-unknown-linux-gnu
 {% endif %}
 

docker/aarch64/mysql/Dockerfile

@@ -77,6 +77,8 @@ ENV CC_aarch64_unknown_linux_gnu="/usr/bin/aarch64-linux-gnu-gcc"
 ENV CROSS_COMPILE="1"
 ENV OPENSSL_INCLUDE_DIR="/usr/include/aarch64-linux-gnu"
 ENV OPENSSL_LIB_DIR="/usr/lib/aarch64-linux-gnu"
+RUN rustup target add aarch64-unknown-linux-gnu
+
 # Builds your dependencies and removes the
 # dummy project, except the target folder
 # This folder contains the compiled dependencies
@@ -92,7 +94,6 @@ RUN touch src/main.rs
 
 # Builds again, this time it'll just be
 # your actual source files being built
-RUN rustup target add aarch64-unknown-linux-gnu
 RUN cargo build --features ${DB} --release --target=aarch64-unknown-linux-gnu
 
 ######################## RUNTIME IMAGE  ########################

docker/aarch64/sqlite/Dockerfile

@@ -71,6 +71,8 @@ ENV CC_aarch64_unknown_linux_gnu="/usr/bin/aarch64-linux-gnu-gcc"
 ENV CROSS_COMPILE="1"
 ENV OPENSSL_INCLUDE_DIR="/usr/include/aarch64-linux-gnu"
 ENV OPENSSL_LIB_DIR="/usr/lib/aarch64-linux-gnu"
+RUN rustup target add aarch64-unknown-linux-gnu
+
 # Builds your dependencies and removes the
 # dummy project, except the target folder
 # This folder contains the compiled dependencies
@@ -86,7 +88,6 @@ RUN touch src/main.rs
 
 # Builds again, this time it'll just be
 # your actual source files being built
-RUN rustup target add aarch64-unknown-linux-gnu
 RUN cargo build --features ${DB} --release --target=aarch64-unknown-linux-gnu
 
 ######################## RUNTIME IMAGE  ########################

docker/amd64/mysql/Dockerfile.alpine

@@ -47,6 +47,8 @@ COPY ./Cargo.* ./
 COPY ./rust-toolchain ./rust-toolchain
 COPY ./build.rs ./build.rs
 
+RUN rustup target add x86_64-unknown-linux-musl
+
 # Builds your dependencies and removes the
 # dummy project, except the target folder
 # This folder contains the compiled dependencies
@@ -60,8 +62,6 @@ COPY . .
 # Make sure that we actually build the project
 RUN touch src/main.rs
 
-RUN rustup target add x86_64-unknown-linux-musl
-
 # Builds again, this time it'll just be
 # your actual source files being built
 RUN cargo build --features ${DB} --release

docker/amd64/postgresql/Dockerfile.alpine

@@ -47,6 +47,8 @@ COPY ./Cargo.* ./
 COPY ./rust-toolchain ./rust-toolchain
 COPY ./build.rs ./build.rs
 
+RUN rustup target add x86_64-unknown-linux-musl
+
 # Builds your dependencies and removes the
 # dummy project, except the target folder
 # This folder contains the compiled dependencies
@@ -60,8 +62,6 @@ COPY . .
 # Make sure that we actually build the project
 RUN touch src/main.rs
 
-RUN rustup target add x86_64-unknown-linux-musl
-
 # Builds again, this time it'll just be
 # your actual source files being built
 RUN cargo build --features ${DB} --release

docker/amd64/sqlite/Dockerfile.alpine

@@ -41,6 +41,8 @@ COPY ./Cargo.* ./
 COPY ./rust-toolchain ./rust-toolchain
 COPY ./build.rs ./build.rs
 
+RUN rustup target add x86_64-unknown-linux-musl
+
 # Builds your dependencies and removes the
 # dummy project, except the target folder
 # This folder contains the compiled dependencies
@@ -54,8 +56,6 @@ COPY . .
 # Make sure that we actually build the project
 RUN touch src/main.rs
 
-RUN rustup target add x86_64-unknown-linux-musl
-
 # Builds again, this time it'll just be
 # your actual source files being built
 RUN cargo build --features ${DB} --release