Add generated rust code (#483)

The rust code is generated using the [`neoeinstein/protoc-gen-prost`]
(https://github.com/neoeinstein/protoc-gen-prost),
which leverages the `prost` crate for protobuf and `tonic` crate for
client/server.

The rust crates used are:

pbjson and pbjson-types: 0.7.0
prost: 0.13.1
tonic: 0.12.0

Currently, the generated code does not use `protoc-prost-serde` to
support serde, since serde and json deserialization is not necessary for
the basic use case.

Signed-off-by: Campbell He <kp.campbell.he@duskmoon314.com>

.gitignore

@@ -7,3 +7,6 @@ build
 dist
 *.egg-info
 .eggs
+
+# rust
+target/

CI/check_codegen.sh

@@ -8,6 +8,7 @@ pushd "$THIS_DIR/.." >/dev/null
 
 rm -rf go/*
 rm -rf py/p4
+rm -rf rust/src
 ./codegen/update.sh
 
 diff="$(git status --porcelain go go.mod go.sum)"
@@ -26,4 +27,14 @@ if [ ! -z "$diff" ]; then
     exit 1
 fi
 
+diff="$(git status --porcelain rust)"
+
+if [ ! -z "$diff" ]; then
+    echo "The generated Rust files are not up-to-date"
+    echo "DIFF:"
+    echo "$diff"
+    echo "You can regenerate them with './codegen/update.sh' and commit the changes"
+    exit 1
+fi
+
 popd >/dev/null

README.md

@@ -145,10 +145,11 @@ processes.
    approve.
 
 When updating the Protobuf files in a pull request, you will also need to update
-the generated Go and Python files, which are hosted in this repository under
-[go/](go/) and [py/](py/). This can be done easily by running `./codegen/update.sh`,
-provided docker is installed and your user is part of the "docker" group
-(which means that the `docker` command can be executed without `sudo`).
+the generated Go, Python and Rust files, which are hosted in this repository
+under [go/](go/), [py/](py/) and [rust/](rust/). This can be done easily by
+running `./codegen/update.sh`, provided docker is installed and your user is
+part of the "docker" group (which means that the `docker` command can be
+executed without `sudo`).
 
 ## Use generated P4Runtime library
 
@@ -177,6 +178,16 @@ pip3 install p4runtime
 pip3 install p4runtime==1.3.0
 ```
 
+### Rust
+
+To include the P4Runtime Rust crate to your project, add this repository url to
+your `Cargo.toml` file:
+
+```toml
+[dependencies]
+p4runtime = { git = "https://github.com/p4lang/p4runtime.git" }
+```
+
 ## Guidelines for using Protocol Buffers (protobuf) in backwards-compatible ways
 
 P4Runtime generally follows "Live at Head" development principles - new

codegen/Dockerfile

@@ -6,7 +6,7 @@ LABEL description="Dockerfile used for CI testing of p4lang/p4runtime"
 ARG DEBIAN_FRONTEND=noninteractive
 
 RUN apt-get update && \
-    apt-get install -y --no-install-recommends software-properties-common git curl
+    apt-get install -y --no-install-recommends software-properties-common git curl build-essential
 
 ARG GO_VERSION=1.20.5
 
@@ -26,5 +26,11 @@ ENV PATH="${PATH}:/usr/local/go/bin:/root/go/bin"
 RUN go install google.golang.org/protobuf/cmd/protoc-gen-go@v1.31
 RUN go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@v1.3
 
+RUN curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain stable --profile minimal; \
+    . $HOME/.cargo/env; \
+    cargo install protoc-gen-prost protoc-gen-prost-crate protoc-gen-prost-serde protoc-gen-tonic
+
+ENV PATH="${PATH}:/root/.cargo/bin"
+
 COPY . /p4runtime/
 WORKDIR /p4runtime/

codegen/compile_protos.sh

@@ -53,6 +53,7 @@ mkdir -p "$BUILD_DIR/cpp_out"
 mkdir -p "$BUILD_DIR/grpc_out"
 mkdir -p "$BUILD_DIR/py_out"
 mkdir -p "$BUILD_DIR/go_out"
+mkdir -p "$BUILD_DIR/rust_out"
 
 set -o xtrace
 $PROTOC $PROTOS --cpp_out "$BUILD_DIR/cpp_out" $PROTOFLAGS
@@ -65,6 +66,16 @@ $PROTOC $PROTOS --python_out "$BUILD_DIR/py_out" $PROTOFLAGS --grpc_out "$BUILD_
 
 $PROTOC $PROTOS --go_out="$BUILD_DIR/go_out" --go-grpc_out="$BUILD_DIR/go_out" $PROTOFLAGS
 
+$PROTOC $PROTOS $PROTOFLAGS \
+    --prost_out="$BUILD_DIR/rust_out/src" \
+    --prost_opt=compile_well_known_types \
+    --prost_opt=extern_path=.google.protobuf=::pbjson_types \
+    --tonic_out="$BUILD_DIR/rust_out/src" \
+    --tonic_opt=compile_well_known_types \
+    --tonic_opt=extern_path=.google.protobuf=::pbjson_types \
+    --prost-crate_out="$BUILD_DIR/rust_out" \
+    --prost-crate_opt="gen_crate=rust/Cargo.toml"
+
 set +o xtrace
 
 rm -rf "$tmpdir"

codegen/update.sh

@@ -21,6 +21,9 @@ cp -r "$tmpdir"/go_out/github.com/p4lang/p4runtime/go/* go/
 cp -r "$tmpdir"/py_out/p4 py/
 find py/p4 -type d -exec touch {}/__init__.py \;
 
+# Rust
+cp -r "$tmpdir"/rust_out/* rust/
+
 # Cleanup files owned by root user
 docker run --rm \
        -v "$tmpdir:/tmp/gen" \