Add proto machinery and CI test

Signed-off-by: Adolfo García Veytia (Puerco) <puerco@carabiner.dev>

Author: puerco

.github/workflows/go-test.yml

@@ -20,10 +20,21 @@ jobs:
           go-version: "1.24"
           check-latest: true
 
+      - name: Setup Buf
+        uses: bufbuild/buf-setup-action@a47c93e0b1648d5651a065437926377d060baa99 # v1.50.0
+
+      - name: Setup protoc
+        uses: arduino/setup-protoc@c65c819552d16ad3c9b72d9dfd5ba5237b9c906b # @v3.0.0
+
       - name: Run Go tests
         run: |
           go test ./sourcetool/...
 
       - name: Check generated fakes
         run: |
           hack/verify-fakes.sh
+
+      - name: Check protobuf generated codew
+        run: |
+          go install google.golang.org/protobuf/cmd/protoc-gen-go@latest
+          hack/verify-protos.sh

Makefile

@@ -1,4 +1,18 @@
+BOLD :=  \033[1m
+CYAN :=  \033[36m
+GREEN := \033[32m
+WHITE := \033[37m
+RESET := \033[0m
+
+.PHONY: help
+help:
+	@printf "${BOLD}${WHITE}SLSA Source Tooling Makefile Help\n=================================${RESET}\n"
+	@grep -Eh '^[a-zA-Z_-]+:.*?## .*$$' ${MAKEFILE_LIST} | sort | awk 'BEGIN {FS = ":.*?## "}; {printf "${BOLD}${CYAN}%-25s${RESET}%s\n", $$1, $$2}'
+
 .PHONY: fakes
 fakes: ## Rebuild the implementation fakes
 	go generate ./sourcetool/...
 
+.PHONY: proto
+proto: ## Rebuild the policies and provenance predicate from protocol buffer definitions
+	buf generate

hack/verify-protos.sh

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+set -o xtrace
+
+source hack/common.sh
+
+make proto
+git diff --exit-code || exit_with_msg "Code from protocol definitions is not up to date. Please run 'make proto' and commit the result"