*: add gRPC generation logic to build system

Makefile

@@ -8,21 +8,26 @@ VERSION=$(shell ./scripts/git-version)
 DOCKER_REPO=quay.io/ericchiang/dex
 DOCKER_IMAGE=$(DOCKER_REPO):$(VERSION)
 
+$( shell mkdir -p bin )
+
 export GOBIN=$(PWD)/bin
+# Prefer ./bin instead of system packages for things like protoc, where we want
+# to use the version dex uses, not whatever a developer has installed.
+export PATH=$(GOBIN):$(shell printenv PATH)
 export GO15VENDOREXPERIMENT=1
 
 LD_FLAGS="-w -X $(REPO_PATH)/version.Version=$(VERSION)"
 
-GOOS=$(shell go env GOOS)
-GOARCH=$(shell go env GOARCH)
-
 build: bin/dex bin/example-app
 
-bin/dex: FORCE server/templates_default.go
-	@go install -ldflags $(LD_FLAGS) $(REPO_PATH)/cmd/dex
+bin/dex: FORCE generated
+	@go install -v -ldflags $(LD_FLAGS) $(REPO_PATH)/cmd/dex
 
 bin/example-app: FORCE
-	@go install -ldflags $(LD_FLAGS) $(REPO_PATH)/cmd/example-app
+	@go install -v -ldflags $(LD_FLAGS) $(REPO_PATH)/cmd/example-app
+
+.PHONY: generated
+generated: server/templates_default.go
 
 test:
 	@go test -v -i $(shell go list ./... | grep -v '/vendor/')
@@ -39,7 +44,7 @@ fmt:
 	@go fmt $(shell go list ./... | grep -v '/vendor/')
 
 lint:
-	@for package in $(shell go list ./... | grep -v '/vendor/' | grep -v 'api/apipb'); do \
+	@for package in $(shell go list ./... | grep -v '/vendor/' | grep -v '/api'); do \
       golint -set_exit_status $$package; \
 	done
 
@@ -56,6 +61,18 @@ docker-push: docker-build
 	@docker push $(DOCKER_IMAGE)
 	@docker push $(DOCKER_REPO):latest
 
+.PHONY: grpc
+grpc: api/api.pb.go
+
+api/api.pb.go: api/api.proto bin/protoc bin/protoc-gen-go
+	@protoc --go_out=plugins=grpc:. api/*.proto
+
+bin/protoc: scripts/get-protoc
+	@./scripts/get-protoc bin/protoc
+
+bin/protoc-gen-go:
+	@go install -v $(REPO_PATH)/vendor/github.com/golang/protobuf/protoc-gen-go
+
 clean:
 	@rm bin/*
 

scripts/get-protoc

@@ -0,0 +1,28 @@
+#!/bin/bash -e
+
+# This is a script to download protoc. Rather than depending on the version on
+# a developer's machine, always download a specific version.
+
+VERSION="3.1.0"
+
+if [ $# -ne 1 ]; then
+  echo "Usage: ./get-protoc [dest]"
+  exit 2
+fi
+
+# Use the go tool to determine OS.
+OS=$( go env GOOS )
+
+if [ "$OS" = "darwin" ]; then
+  OS="osx"
+fi
+
+# TODO(ericchiang): Architectures other than amd64?
+ZIP="protoc-${VERSION}-${OS}-x86_64.zip"
+URL="https://github.com/google/protobuf/releases/download/v${VERSION}/${ZIP}"
+
+wget ${URL}
+# Unpack the protoc binary. Later we might want to grab additional data. 
+unzip -p ${ZIP} bin/protoc > $1
+chmod +x $1
+rm ${ZIP}