Add rust_tonic_compile rule

WORKSPACE

@@ -21,11 +21,13 @@ workspace(name = "vaticle_dependencies")
 # Load @vaticle_dependencies #
 ################################
 
-# Load //build/rust
+# Load //builder/rust
 load("//builder/rust:deps.bzl", rust_deps = "deps")
 rust_deps()
-load("@rules_rust//rust:repositories.bzl", "rust_repositories")
-rust_repositories(version = "nightly", iso_date = "2021-07-01", edition="2018")
+
+load("@rules_rust//rust:repositories.bzl", "rules_rust_dependencies", "rust_register_toolchains")
+rules_rust_dependencies()
+rust_register_toolchains(edition = "2021", include_rustc_srcs = True)
 
 # Load //builder/python
 load("//builder/python:deps.bzl", python_deps = "deps")

builder/grpc/rust/BUILD

@@ -0,0 +1,33 @@
+#
+# Copyright (C) 2022 Vaticle
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+#
+
+load("@rules_rust//rust:defs.bzl", "rust_binary")
+load("@vaticle_dependencies//tool/checkstyle:rules.bzl", "checkstyle_test")
+
+rust_binary(
+    name = "compile",
+    srcs = ["compile.rs"],
+    deps = ["@vaticle_dependencies//library/crates:tonic_build"],
+    visibility = ["//visibility:public"]
+)
+
+checkstyle_test(
+    name = "checkstyle",
+    include = glob(["*"]),
+    license_type = "agpl-header",
+    size = "small",
+)

builder/grpc/rust/compile.bzl

@@ -0,0 +1,62 @@
+#
+# Copyright (C) 2022 Vaticle
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+#
+
+def _rust_tonic_compile_impl(ctx):
+    protos = [src[ProtoInfo].direct_sources[0] for src in ctx.attr.srcs]
+
+    inputs = ctx.attr.protoc.files.to_list() + protos
+    outputs = [ctx.actions.declare_file("{}.rs".format(package)) for package in ctx.attr.packages]
+
+    ctx.actions.run(
+        inputs = inputs,
+        outputs = outputs,
+        executable = ctx.executable._compile_script,
+        env = {
+            "OUT_DIR": outputs[0].dirname,
+            "PROTOC": ctx.attr.protoc.files.to_list()[0].path,
+            "PROTOS": ";".join([src.path for src in protos]),
+            "PROTOS_ROOT": ctx.attr.srcs[0][ProtoInfo].proto_source_root,
+        },
+        mnemonic = "RustTonicCompileAction"
+    )
+
+    return [DefaultInfo(files = depset(outputs))]
+
+rust_tonic_compile = rule(
+    implementation = _rust_tonic_compile_impl,
+    attrs = {
+        "srcs": attr.label_list(
+            allow_files = True,
+            mandatory = True,
+            doc = "The .proto source files."
+        ),
+        "packages": attr.string_list(
+            mandatory = True,
+            allow_empty = False,
+            doc = "The Protobuf package names. Each package name corresponds to a single output file."
+        ),
+        "protoc": attr.label(
+            default = "@com_google_protobuf//:protoc",
+            doc = "The protoc executable."
+        ),
+        "_compile_script": attr.label(
+            executable = True,
+            cfg = "host",
+            default = "@vaticle_dependencies//builder/grpc/rust:compile",
+        ),
+    }
+)

builder/grpc/rust/compile.rs

@@ -0,0 +1,28 @@
+//
+// Copyright (C) 2022 Vaticle
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+//
+
+use std::env;
+
+fn main() -> std::io::Result<()> {
+    let protos_raw = env::var("PROTOS").expect("PROTOS environment variable is not set");
+    let protos: Vec<&str> = protos_raw.split(";").filter(|&str| !str.is_empty()).collect();
+
+    tonic_build::configure()
+        .compile(&protos, &[
+            env::var("PROTOS_ROOT").expect("PROTOS_ROOT environment variable is not set")
+        ])
+}