Remove vendor directory and enable go modules

Makefile

@@ -65,9 +65,6 @@ BASE_IMAGE ?= quay.io/kubernetes-ingress-controller/nginx:e3c49c52f4b74fe47ad65d
 
 GOARCH=$(ARCH)
 
-# use vendor directory instead of go modules https://github.com/golang/go/wiki/Modules
-GO111MODULE=off
-
 help:  ## Display this help
 	@awk 'BEGIN {FS = ":.*##"; printf "\nUsage:\n  make \033[36m<target>\033[0m\n"} /^[a-zA-Z_-]+:.*?##/ { printf "  \033[36m%-15s\033[0m %s\n", $$1, $$2 } /^##@/ { printf "\n\033[1m%s\033[0m\n", substr($$0, 5) } ' $(MAKEFILE_LIST)
 
@@ -189,12 +186,6 @@ check_dead_links: ## Check if the documentation contains dead links.
 	  --allow-dupe \
 	  --allow-redirect $(shell find $$PWD -mindepth 1 -name "*.md" -printf '%P\n' | grep -v vendor | grep -v Changelog.md)
 
-.PHONY: dep-ensure
-dep-ensure: check-go-version ## Update and vendo go dependencies.
-	GO111MODULE=on go mod tidy -v
-	find vendor -name '*_test.go' -delete
-	GO111MODULE=on go mod vendor
-
 .PHONY: dev-env
 dev-env: check-go-version ## Starts a local Kubernetes cluster using kind, building and deploying the ingress controller.
 	@build/dev-env.sh

build/build-plugin.sh

@@ -44,8 +44,6 @@ if [ "$missing" = true ]; then
 fi
 
 export CGO_ENABLED=0
-# use vendor directory instead of go modules https://github.com/golang/go/wiki/Modules
-export GO111MODULE=off
 
 release=cmd/plugin/release
 

build/cover.sh

@@ -27,11 +27,6 @@ if [ -z "${PKG}" ]; then
   exit 1
 fi
 
-export CGO_ENABLED=1
-export GODEBUG=netdns=cgo+2
-# use vendor directory instead of go modules https://github.com/golang/go/wiki/Modules
-export GO111MODULE=off
-
 rm -rf coverage.txt
 for d in $(go list "${PKG}/..." | grep -v vendor | grep -v '/test/e2e' | grep -v images); do
   t=$(date +%s);

build/run-in-docker.sh

@@ -56,7 +56,6 @@ docker run                                            \
   --rm                                                \
   ${DOCKER_OPTS}                                      \
   -e GOCACHE="/go/src/${PKG}/.cache"                  \
-  -e GO111MODULE=off                                  \
   -e DIND_TASKS=0                                     \
   -v "${HOME}/.kube:${HOME}/.kube"                    \
   -v "${KUBE_ROOT}:/go/src/${PKG}"                    \

build/test.sh

@@ -28,11 +28,5 @@ if [ -z "${PKG}" ]; then
   exit 1
 fi
 
-# enabled to use host dns resolver
-export CGO_ENABLED=1
-export GODEBUG=netdns=cgo+2
-# use vendor directory instead of go modules https://github.com/golang/go/wiki/Modules
-export GO111MODULE=off
-
 go test -v \
   $(go list "${PKG}/..." | grep -v vendor | grep -v '/test/e2e' | grep -v images | grep -v "docs/examples")

hack/update-codegen.sh

@@ -18,10 +18,17 @@ set -o errexit
 set -o nounset
 set -o pipefail
 
-export GO111MODULE=off
-
 SCRIPT_ROOT=$(dirname ${BASH_SOURCE})/..
-CODEGEN_PKG=${CODEGEN_PKG:-$(cd "${SCRIPT_ROOT}"; ls -d -1 ./vendor/k8s.io/code-generator 2>/dev/null || echo ../code-generator)}
+CODEGEN_VERSION=$(grep 'k8s.io/code-generator' go.sum | awk '{print $2}' | sed 's/\/go.mod//g' | head -1)
+CODEGEN_PKG=$(echo `go env GOPATH`"/pkg/mod/k8s.io/code-generator@${CODEGEN_VERSION}")
+
+if [[ ! -d ${CODEGEN_PKG} ]]; then
+    echo "${CODEGEN_PKG} is missing. Running 'go mod download'."
+    go mod download
+fi
+
+# Ensure we can execute.
+chmod +x ${CODEGEN_PKG}/generate-groups.sh
 
 # generate the code with:
 # --output-base    because this script should also be able to run inside the vendor dir of
@@ -31,11 +38,8 @@ CODEGEN_PKG=${CODEGEN_PKG:-$(cd "${SCRIPT_ROOT}"; ls -d -1 ./vendor/k8s.io/code-
 #  k8s.io/ingress-nginx/pkg/client k8s.io/ingress-nginx/pkg/apis \
 #  nginxingress:v1alpha1 \
 #  --output-base "$(dirname ${BASH_SOURCE})/../../.."
-mkdir -p ${CODEGEN_PKG}/hack
-cp ${SCRIPT_ROOT}/hack/boilerplate/boilerplate.go.txt ${CODEGEN_PKG}/hack/boilerplate.go.txt
-chmod +x ${CODEGEN_PKG}/*.sh
-
 ${CODEGEN_PKG}/generate-groups.sh "deepcopy" \
   k8s.io/ingress-nginx/internal k8s.io/ingress-nginx/internal \
   .:ingress \
-  --output-base "$(dirname ${BASH_SOURCE})/../../.."
+  --output-base "$(dirname ${BASH_SOURCE})/../../.." \
+  --go-header-file ${SCRIPT_ROOT}/hack/boilerplate/boilerplate.go.txt

test/e2e/run.sh

@@ -83,7 +83,7 @@ export EXIT_CODE=-1
 echo "
 make -C ${DIR}/../../ clean-image build image
 make -C ${DIR}/../e2e-image image
-make -C ${DIR}/../../images/fastcgi-helloserver/ GO111MODULE=\"on\" build image
+make -C ${DIR}/../../images/fastcgi-helloserver/ build image
 make -C ${DIR}/../../images/httpbin/ image
 make -C ${DIR}/../../images/echo/ image
 make -C ${DIR}/../../images/cfssl/ image