feat: checktidy will check the go.mod and go.sum files in circleci

.circleci/config.yml

@@ -44,6 +44,7 @@ jobs:
       - run: make test-go # This uses the test cache so it may succeed or fail quickly.
       - run: make vet
       - run: make checkfmt
+      - run: make checktidy
       - run: make test-go-race # This doesn't use the test cache, and will not complete quickly.
       # TODO add these checks to the Makefile
       # - run: go get -v -t -d ./...

Makefile

@@ -107,9 +107,15 @@ chronograf/ui/build:
 fmt: $(SOURCES_NO_VENDOR)
 	gofmt -w -s $^
 
-checkfmt: $(SOURCES_NO_VENDOR)
+checkfmt:
 	./etc/checkfmt.sh
 
+tidy:
+	GO111MODULE=on go mod tidy
+
+checktidy:
+	./etc/checktidy.sh
+
 chronograf/dist/dist_gen.go: chronograf/ui/build $(UISOURCES)
 	 $(GO_GENERATE) ./chronograf/dist/...
 
@@ -167,4 +173,4 @@ run: chronogiraffe
 
 
 # .PHONY targets represent actions that do not create an actual file.
-.PHONY: all subdirs $(SUBDIRS) chronograf/ui run fmt test test-go test-js test-go-race bench clean node_modules vet nightly chronogiraffe
+.PHONY: all subdirs $(SUBDIRS) chronograf/ui run fmt checkfmt tidy checktidy test test-go test-js test-go-race bench clean node_modules vet nightly chronogiraffe

etc/checktidy.sh

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+set -e
+
+export GO111MODULE=on
+go mod tidy
+
+if ! git --no-pager diff --exit-code -- go.mod go.sum; then
+  >&2 echo "modules are not tidy, please run 'go mod tidy'"
+  exit 1
+fi