diff --git a/cmd/godoc/Dockerfile.prod b/cmd/godoc/Dockerfile.prod
index 21fb92d8..f357b8b7 100644
--- a/cmd/godoc/Dockerfile.prod
+++ b/cmd/godoc/Dockerfile.prod
@@ -6,7 +6,17 @@ FROM golang:1.11 AS build
 RUN apt-get update && apt-get install -y \
       zip # required for generate-index.bash
 
-ENV GODOC_REF release-branch.go1.11
+# Check out the desired version of Go, both to build the godoc binary and serve
+# as the goroot for content serving.
+ARG GO_REF
+RUN test -n "$GO_REF" # GO_REF is required.
+RUN git clone --single-branch --depth=1 -b $GO_REF https://go.googlesource.com/go /goroot
+RUN cd /goroot/src && ./make.bash
+
+ENV GOROOT /goroot
+ENV PATH=/goroot/bin:$PATH
+
+RUN go version
 
 RUN go get -v -d \
       golang.org/x/net/context \
@@ -18,11 +28,24 @@ RUN go get -v -d \
 COPY . /go/src/golang.org/x/tools
 
 WORKDIR /go/src/golang.org/x/tools/cmd/godoc
-RUN git clone --single-branch --depth=1 -b $GODOC_REF https://go.googlesource.com/go /docset
-RUN GODOC_DOCSET=/docset ./generate-index.bash
+RUN GODOC_DOCSET=/goroot ./generate-index.bash
 
 RUN go build -o /godoc -tags=golangorg golang.org/x/tools/cmd/godoc
 
+# Clean up goroot for the final image.
+RUN cd /goroot && git clean -xdf
+
+# Add build metadata.
+ARG TOOLS_HEAD
+ARG TOOLS_CLEAN
+ARG DOCKER_TAG
+RUN cd /goroot && echo "go repo HEAD: $(git rev-parse HEAD)" >> /goroot/buildinfo
+RUN echo "requested go ref: ${GO_REF}" >> /goroot/buildinfo
+RUN echo "x/tools HEAD: ${TOOLS_HEAD}" >> /goroot/buildinfo
+RUN echo "x/tools clean: ${TOOLS_CLEAN}" >> /goroot/buildinfo
+RUN echo "image: ${DOCKER_TAG}" >> /goroot/buildinfo
+
+RUN rm -rf /goroot/.git
 
 # Final image
 #############
@@ -33,7 +56,7 @@ WORKDIR /app
 COPY --from=build /godoc /app/
 COPY --from=build /go/src/golang.org/x/tools/cmd/godoc/hg-git-mapping.bin /app/
 
-COPY --from=build /docset /goroot
+COPY --from=build /goroot /goroot
 ENV GOROOT /goroot
 
 COPY --from=build /go/src/golang.org/x/tools/cmd/godoc/index.split.* /app/
diff --git a/cmd/godoc/Makefile b/cmd/godoc/Makefile
index 217515bb..aae6b763 100644
--- a/cmd/godoc/Makefile
+++ b/cmd/godoc/Makefile
@@ -4,21 +4,48 @@
 
 .PHONY: usage
 
+GO_REF ?= release-branch.go1.11
+TOOLS_HEAD := $(shell git rev-parse HEAD)
+TOOLS_CLEAN := $(shell (git status --porcelain | grep -q .) && echo dirty || echo clean)
+ifeq ($(TOOLS_CLEAN),clean)
+	DOCKER_VERSION ?= $(TOOLS_HEAD)
+else
+	DOCKER_VERSION ?= $(TOOLS_HEAD)-dirty
+endif
+GCP_PROJECT := golang-org
+DOCKER_TAG := gcr.io/$(GCP_PROJECT)/godoc:$(DOCKER_VERSION)
+
 usage:
-	echo "See Makefile"
+	echo "See Makefile and README.godoc-app"
 	exit 1
 
-docker-prod: Dockerfile.prod
-	cd ../..; docker build -f cmd/godoc/Dockerfile.prod --tag=gcr.io/golang-org/godoc:$(VERSION) .
+docker: Dockerfile.prod
+	# NOTE(cbro): move up in directory to include entire tools repo.
+	cd ../..; docker build \
+		-f cmd/godoc/Dockerfile.prod \
+		--build-arg GO_REF=$(GO_REF) \
+		--build-arg TOOLS_HEAD=$(TOOLS_HEAD) \
+		--build-arg TOOLS_CLEAN=$(TOOLS_CLEAN) \
+		--build-arg DOCKER_TAG=$(DOCKER_TAG) \
+		--tag=$(DOCKER_TAG) \
+		.
 
-push-prod: docker-prod
-	docker push gcr.io/golang-org/godoc:$(VERSION)
+push: docker
+	docker push $(DOCKER_TAG)
 
-deploy-prod: push-prod
-	gcloud -q app deploy app.prod.yaml --project golang-org --no-promote --image-url gcr.io/golang-org/godoc:$(VERSION)
+deploy: push
+	gcloud -q app deploy app.prod.yaml \
+		--project $(GCP_PROJECT) \
+		--no-promote \
+		--image-url $(DOCKER_TAG)
 
 get-latest-url:
-	@gcloud app versions list -s default --project golang-org --sort-by=~version.createTime --format='value(version.versionUrl)' --limit 1 | cut -f1
+	@gcloud app versions list \
+		-s default \
+		--project $(GCP_PROJECT) \
+		--sort-by=~version.createTime \
+		--format='value(version.versionUrl)' \
+		--limit 1 | cut -f1 # NOTE(cbro): gcloud prints out createTime as the second field.
 
 regtest:
 	./regtest.bash $(shell make get-latest-url)
diff --git a/cmd/godoc/README.godoc-app b/cmd/godoc/README.godoc-app
index 0bb81120..6a2ae3ea 100644
--- a/cmd/godoc/README.godoc-app
+++ b/cmd/godoc/README.godoc-app
@@ -37,7 +37,7 @@ Running locally, in production mode, using Docker
 
 Build the app's Docker container:
 
-  VERSION=$(git rev-parse HEAD) make docker-prod
+  make docker
 
 Make sure redis is running on port 6379:
 
@@ -68,7 +68,7 @@ Deploying to golang.org
 
 Build the image, push it to gcr.io, and deploy to Flex:
 
-  VERSION=$(git rev-parse HEAD) make deploy-prod
+  make deploy
 
 Run regression tests: