Makefile: add checkmetrics target, use in CI (#797)

Makefile

@@ -16,6 +16,7 @@ GOPATH := $(firstword $(subst :, ,$(shell $(GO) env GOPATH)))
 GOARCH := $(shell $(GO) env GOARCH)
 GOHOSTARCH := $(shell $(GO) env GOHOSTARCH)
 
+PROMTOOL    ?= $(GOPATH)/bin/promtool
 PROMU       ?= $(GOPATH)/bin/promu
 STATICCHECK ?= $(GOPATH)/bin/staticcheck
 pkgs         = $(shell $(GO) list ./... | grep -v /vendor/)
@@ -48,6 +49,12 @@ else
     test-e2e := skip-test-e2e
 endif
 
+ifeq ($(MACH), ppc64le)
+	e2e-out = collector/fixtures/e2e-ppc64le-output.txt
+else
+	e2e-out = collector/fixtures/e2e-output.txt
+endif
+
 # 64bit -> 32bit mapping for cross-checking. At least for amd64/386, the 64bit CPU can execute 32bit code but not the other way around, so we don't support cross-testing upwards.
 cross-test = skip-test-32bit
 define goarch_pair
@@ -65,7 +72,7 @@ $(eval $(call goarch_pair,arm64,arm))
 $(eval $(call goarch_pair,mips64,mips))
 $(eval $(call goarch_pair,mips64el,mipsel))
 
-all: format vet staticcheck build test $(cross-test) $(test-e2e)
+all: format vet staticcheck checkmetrics build test $(cross-test) $(test-e2e)
 
 style:
 	@echo ">> checking code style"
@@ -93,6 +100,10 @@ test-e2e: build collector/fixtures/sys/.unpacked
 skip-test-e2e:
 	@echo ">> SKIP running end-to-end tests on $(OS_detected)"
 
+checkmetrics: $(PROMTOOL)
+	@echo ">> checking metrics for correctness"
+	./checkmetrics.sh $(PROMTOOL) $(e2e-out)
+
 format:
 	@echo ">> formatting code"
 	@$(GO) fmt $(pkgs)
@@ -124,6 +135,9 @@ test-docker:
 	@echo ">> testing docker image"
 	./test_image.sh "$(DOCKER_IMAGE_NAME):$(DOCKER_IMAGE_TAG)" 9100
 
+$(GOPATH)/bin/promtool promtool:
+	@GOOS= GOARCH= $(GO) get -u github.com/prometheus/prometheus/cmd/promtool
+
 $(GOPATH)/bin/promu promu:
 	@GOOS= GOARCH= $(GO) get -u github.com/prometheus/promu
 
@@ -131,10 +145,10 @@ $(GOPATH)/bin/staticcheck:
 	@GOOS= GOARCH= $(GO) get -u honnef.co/go/tools/cmd/staticcheck
 
 
-.PHONY: all style format build test test-e2e vet tarball docker promu staticcheck
+.PHONY: all style format build test test-e2e vet tarball docker promtool promu staticcheck checkmetrics
 
 # Declaring the binaries at their default locations as PHONY targets is a hack
 # to ensure the latest version is downloaded on every make execution.
 # If this is not desired, copy/symlink these binaries to a different path and
 # set the respective environment variables.
-.PHONY: $(GOPATH)/bin/promu $(GOPATH)/bin/staticcheck
+.PHONY: $(GOPATH)/bin/promtool $(GOPATH)/bin/promu $(GOPATH)/bin/staticcheck

checkmetrics.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+
+if [[ ( -z "$1" ) || ( -z "$2" ) ]]; then
+    echo "usage: ./checkmetrics.sh /usr/bin/promtool e2e-output.txt"
+    exit 1
+fi
+
+# Only check node_exporter's metrics, as the Prometheus Go client currently
+# exposes a metric with a unit of microseconds.  Once that is fixed, remove
+# this filter.
+lint=$($1 check metrics < $2 2>&1 | grep "node_")
+
+if [[ ! -z $lint ]]; then
+    echo -e "Some Prometheus metrics do not follow best practices:\n"
+    echo "$lint"
+
+    exit 1
+fi

end-to-end-test.sh

@@ -148,4 +148,4 @@ get "127.0.0.1:${port}/metrics" | grep -E -v "${skip_re}" > "${tmpdir}/e2e-outpu
 
 diff -u \
   "${fixture}" \
-  "${tmpdir}/e2e-output.txt"
+  "${tmpdir}/e2e-output.txt"