enhancement(api): Separate Go module for API definitions (#1801)

* enhancement(api): Separate Go module for API definitions

Make the generated protobuf code available as a separate module so that
they can be shared with other projects without pulling in all Cerbos
dependencies.

The `replace` directive in `go.mod` will have to be removed in a
separate PR because it's impossible to work with unpublished modules in
Go without `replace` directives.

Signed-off-by: Charith Ellawala <charith@cerbos.dev>

* Simplify Makefile

Signed-off-by: Charith Ellawala <charith@cerbos.dev>

---------

Signed-off-by: Charith Ellawala <charith@cerbos.dev>

.gitignore

@@ -23,6 +23,3 @@ unit.cover
 integration.cover
 junit.*.xml
 test-times.json
-
-go.work
-go.work.sum

Makefile

@@ -19,7 +19,7 @@ all: clean build
 
 .PHONY: clean
 clean:
-	@-rm -rf $(GEN_DIR)
+	@-rm -rf $(GEN_DIR)/cerbos
 	@-rm -rf $(MOCK_DIR)
 	@-rm -rf $(DOCS_OUT_DIR)
 	@-rm -rf $(JSONSCHEMA_DIR)
@@ -40,23 +40,24 @@ lint-helm:
 	@ deploy/charts/validate.sh
 
 .PHONY: generate
-generate: clean generate-proto-code generate-json-schemas generate-testdata-json-schemas generate-mocks deps confdocs
+generate: clean generate-proto-code generate-json-schemas generate-testdata-json-schemas generate-mocks confdocs
 
 .PHONY: generate-proto-code
-generate-proto-code: proto-gen-deps
-	@-rm -rf $(GEN_DIR)
+generate-proto-code: $(BUF)
+	@-rm -rf $(GEN_DIR)/cerbos
 	@ $(BUF) format -w
-	@ $(BUF) generate --template '$(BUF_GEN_TEMPLATE)' .
+	@ cd tools && $(BUF) generate --template=api.gen.yaml --output=.. ..
+	@ GOWORK=off go mod tidy -C $(GEN_DIR)
 
 .PHONY: generate-json-schemas
-generate-json-schemas: proto-gen-deps
+generate-json-schemas: $(BUF)
 	@-rm -rf $(JSONSCHEMA_DIR)
-	@ $(BUF) generate --template '$(JSONSCHEMA_BUF_GEN_TEMPLATE)' api/public
+	@ cd tools && $(BUF) generate --template=jsonschema.gen.yaml --output=.. ../api/public
 
 .PHONY: generate-testdata-json-schemas
-generate-testdata-json-schemas: proto-gen-deps
+generate-testdata-json-schemas: $(BUF)
 	@-rm -rf $(TESTDATA_JSONSCHEMA_DIR)
-	@ $(BUF) generate --template '$(TESTDATA_JSONSCHEMA_BUF_GEN_TEMPLATE)' api/private
+	@ cd tools && $(BUF) generate --template=testdata_jsonschema.gen.yaml --output=.. ../api/private
 	@ mv $(TESTDATA_JSONSCHEMA_DIR)/cerbos/private/v1/*TestCase.schema.json $(TESTDATA_JSONSCHEMA_DIR)/cerbos/private/v1/QueryPlannerTestSuite.schema.json $(TESTDATA_JSONSCHEMA_DIR)
 	@ rm -rf $(TESTDATA_JSONSCHEMA_DIR)/cerbos
 

api/genpb/go.mod

@@ -0,0 +1,20 @@
+module github.com/cerbos/cerbos/api/genpb
+
+go 1.21.1
+
+require (
+	github.com/envoyproxy/protoc-gen-validate v1.0.2
+	github.com/grpc-ecosystem/grpc-gateway/v2 v2.18.0
+	google.golang.org/genproto/googleapis/api v0.0.0-20230911183012-2d3300fd4832
+	google.golang.org/grpc v1.58.0
+	google.golang.org/protobuf v1.31.0
+)
+
+require (
+	github.com/golang/protobuf v1.5.3 // indirect
+	golang.org/x/net v0.15.0 // indirect
+	golang.org/x/sys v0.12.0 // indirect
+	golang.org/x/text v0.13.0 // indirect
+	google.golang.org/genproto v0.0.0-20230803162519-f966b187b2e5 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20230822172742-b8732ec3820d // indirect
+)

api/genpb/go.sum

@@ -0,0 +1,31 @@
+github.com/envoyproxy/protoc-gen-validate v1.0.2 h1:QkIBuU5k+x7/QXPvPPnWXWlCdaBFApVqftFV6k087DA=
+github.com/envoyproxy/protoc-gen-validate v1.0.2/go.mod h1:GpiZQP3dDbg4JouG/NNS7QWXpgx6x8QiMKdmN72jogE=
+github.com/golang/glog v1.1.0 h1:/d3pCKDPWNnvIWe0vVUpNP32qc8U3PDVxySP/y360qE=
+github.com/golang/glog v1.1.0/go.mod h1:pfYeQZ3JWZoXTV5sFc986z3HTpwQs9At6P4ImfuP3NQ=
+github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
+github.com/golang/protobuf v1.5.3 h1:KhyjKVUg7Usr/dYsdSqoFveMYd5ko72D+zANwlG1mmg=
+github.com/golang/protobuf v1.5.3/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiuN0vRsmY=
+github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
+github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/grpc-ecosystem/grpc-gateway/v2 v2.18.0 h1:RtRsiaGvWxcwd8y3BiRZxsylPT8hLWZ5SPcfI+3IDNk=
+github.com/grpc-ecosystem/grpc-gateway/v2 v2.18.0/go.mod h1:TzP6duP4Py2pHLVPPQp42aoYI92+PCrVotyR5e8Vqlk=
+golang.org/x/net v0.15.0 h1:ugBLEUaxABaB5AJqW9enI0ACdci2RUd4eP51NTBvuJ8=
+golang.org/x/net v0.15.0/go.mod h1:idbUs1IY1+zTqbi8yxTbhexhEEk5ur9LInksu6HrEpk=
+golang.org/x/sys v0.12.0 h1:CM0HF96J0hcLAwsHPJZjfdNzs0gftsLfgKt57wWHJ0o=
+golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/text v0.13.0 h1:ablQoSUd0tRdKxZewP80B+BaqeKJuVhuRxj/dkrun3k=
+golang.org/x/text v0.13.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+google.golang.org/genproto v0.0.0-20230803162519-f966b187b2e5 h1:L6iMMGrtzgHsWofoFcihmDEMYeDR9KN/ThbPWGrh++g=
+google.golang.org/genproto v0.0.0-20230803162519-f966b187b2e5/go.mod h1:oH/ZOT02u4kWEp7oYBGYFFkCdKS/uYR9Z7+0/xuuFp8=
+google.golang.org/genproto/googleapis/api v0.0.0-20230911183012-2d3300fd4832 h1:4E7rZzBdR5LmiZx6n47Dg4AjH8JLhMQWywsYqvXNLcs=
+google.golang.org/genproto/googleapis/api v0.0.0-20230911183012-2d3300fd4832/go.mod h1:KjSP20unUpOx5kyQUFa7k4OJg0qeJ7DEZflGDu2p6Bk=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20230822172742-b8732ec3820d h1:uvYuEyMHKNt+lT4K3bN6fGswmK8qSvcreM3BwjDh+y4=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20230822172742-b8732ec3820d/go.mod h1:+Bk1OCOj40wS2hwAMA+aCW9ypzm63QTBBHp6lQ3p+9M=
+google.golang.org/grpc v1.58.0 h1:32JY8YpPMSR45K+c3o6b8VL73V+rR8k+DeMIr4vRH8o=
+google.golang.org/grpc v1.58.0/go.mod h1:tgX3ZQDlNJGU96V6yHh1T/JeoBQ2TXdr43YbYSsCJk0=
+google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
+google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=
+google.golang.org/protobuf v1.31.0 h1:g0LDEJHgrBl9N9r17Ru3sqWhkIx2NB67okBHPwC7hs8=
+google.golang.org/protobuf v1.31.0/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqwMG9pJV4I=

go.mod

@@ -1,6 +1,6 @@
 module github.com/cerbos/cerbos
 
-go 1.20
+go 1.21.1
 
 require (
 	contrib.go.opencensus.io/exporter/prometheus v0.4.2
@@ -13,12 +13,12 @@ require (
 	github.com/bluele/gcache v0.0.2
 	github.com/bufbuild/protovalidate-go v0.3.1
 	github.com/cenkalti/backoff/v4 v4.2.1
+	github.com/cerbos/cerbos/api/genpb v0.0.0-unpublished
 	github.com/cerbos/cloud-api v0.1.7
 	github.com/cespare/xxhash v1.1.0
 	github.com/cespare/xxhash/v2 v2.2.0
 	github.com/dgraph-io/badger/v4 v4.2.0
 	github.com/doug-martin/goqu/v9 v9.18.0
-	github.com/envoyproxy/protoc-gen-validate v1.0.2
 	github.com/fatih/color v1.15.0
 	github.com/fatih/structtag v1.2.0
 	github.com/fergusstrange/embedded-postgres v1.24.0
@@ -97,7 +97,7 @@ require (
 	golang.org/x/sync v0.3.0
 	golang.org/x/tools v0.13.0
 	gonum.org/v1/gonum v0.14.0
-	google.golang.org/genproto/googleapis/api v0.0.0-20230822172742-b8732ec3820d
+	google.golang.org/genproto/googleapis/api v0.0.0-20230911183012-2d3300fd4832
 	google.golang.org/grpc v1.58.0
 	google.golang.org/protobuf v1.31.0
 	gopkg.in/natefinch/lumberjack.v2 v2.2.1
@@ -165,6 +165,7 @@ require (
 	github.com/docker/go-units v0.5.0 // indirect
 	github.com/dustin/go-humanize v1.0.1 // indirect
 	github.com/emirpasic/gods v1.18.1 // indirect
+	github.com/envoyproxy/protoc-gen-validate v1.0.2 // indirect
 	github.com/felixge/httpsnoop v1.0.3 // indirect
 	github.com/gdamore/encoding v1.0.0 // indirect
 	github.com/go-git/gcfg v1.5.1-0.20230307220236-3a3c6141e376 // indirect
@@ -290,3 +291,5 @@ require (
 	modernc.org/token v1.1.0 // indirect
 	sigs.k8s.io/yaml v1.3.0 // indirect
 )
+
+replace github.com/cerbos/cerbos/api/genpb v0.0.0-unpublished => ./api/genpb