*: enable golangci-lint (#5437)

* *: enable golangci-lint

Signed-off-by: Simon Pasquier <spasquie@redhat.com>

* Remove freebsd from supported platforms for lint

Signed-off-by: Simon Pasquier <spasquie@redhat.com>

* Update CONTRIBUTING.md

Signed-off-by: Simon Pasquier <spasquie@redhat.com>

* Update CONTRIBUTING.md

Signed-off-by: Simon Pasquier <spasquie@redhat.com>

* Add common-staticcheck for compatibility

Signed-off-by: Simon Pasquier <spasquie@redhat.com>

.circleci/config.yml

@@ -15,7 +15,7 @@ jobs:
     steps:
     - checkout
     - run: make promu
-    - run: make check_license style unused staticcheck build check_assets
+    - run: make check_license style unused lint build check_assets
     - run:
        command: |
          curl -s -L https://github.com/protocolbuffers/protobuf/releases/download/v3.5.1/protoc-3.5.1-linux-x86_64.zip > /tmp/protoc.zip

.gitignore

@@ -13,5 +13,6 @@ benchmark.txt
 
 !/.travis.yml
 !/.promu.yml
+!/.golangci.yml
 /documentation/examples/remote_storage/remote_storage_adapter/remote_storage_adapter
 /documentation/examples/remote_storage/example_write_adapter/example_writer_adapter

.golangci.yml

@@ -0,0 +1,8 @@
+run:
+  modules-download-mode: vendor
+
+# Run only staticcheck for now. Additional linters will be enabled one-by-one.
+linters:
+  enable:
+  - staticcheck
+  disable-all: true

.travis.yml

@@ -14,5 +14,5 @@ before_install:
 - travis_retry make deps
 
 script:
-- make check_license style unused test staticcheck check_assets
+- make check_license style unused test lint check_assets
 - git diff --exit-code

CONTRIBUTING.md

@@ -40,6 +40,8 @@ go build ./cmd/prometheus/
 make test         # Make sure all the tests pass before you commit and push :)
 ```
 
+We use `golangci-lint`[https://github.com/golangci/golangci-lint] for linting the code. If it reports an issue and you think that the warning needs to be disregarded or is a false-positive, you can add a special comment `//nolint:linter1[,linter2,...]` before the offending line. Use this sparingly though, fixing the code to comply with the linter's recommendation is in general the preferred course of action.
+
 All our issues are regularly tagged so that you can also filter down the issues involving the components you want to work on. For our labeling policy refer [the wiki page](https://github.com/prometheus/prometheus/wiki/Label-Names-and-Descriptions).
 
 ## Pull Request Checklist

Makefile

@@ -16,10 +16,6 @@ DOCKER_ARCHS ?= amd64 armv7 arm64
 
 include Makefile.common
 
-STATICCHECK_IGNORE = \
-  github.com/prometheus/prometheus/pkg/textparse/promlex.l.go:SA4006 \
-  github.com/prometheus/prometheus/pkg/textparse/openmetricslex.l.go:SA4006
-
 DOCKER_IMAGE_NAME       ?= prometheus
 
 .PHONY: assets

Makefile.common

@@ -72,14 +72,13 @@ endif
 PROMU_VERSION ?= 0.3.0
 PROMU_URL     := https://github.com/prometheus/promu/releases/download/v$(PROMU_VERSION)/promu-$(PROMU_VERSION).$(GO_BUILD_PLATFORM).tar.gz
 
-STATICCHECK :=
-# staticcheck only supports linux, freebsd, darwin and windows platforms on i386/amd64
+GOLANGCI_LINT :=
+GOLANGCI_LINT_VERSION ?= v1.16.0
+# golangci-lint only supports linux, darwin and windows platforms on i386/amd64.
 # windows isn't included here because of the path separator being different.
-ifeq ($(GOHOSTOS),$(filter $(GOHOSTOS),linux freebsd darwin))
+ifeq ($(GOHOSTOS),$(filter $(GOHOSTOS),linux darwin))
 	ifeq ($(GOHOSTARCH),$(filter $(GOHOSTARCH),amd64 i386))
-		STATICCHECK := $(FIRST_GOPATH)/bin/staticcheck
-		STATICCHECK_VERSION ?= 2019.1
-		STATICCHECK_URL := https://github.com/dominikh/go-tools/releases/download/$(STATICCHECK_VERSION)/staticcheck_$(GOHOSTOS)_$(GOHOSTARCH)
+		GOLANGCI_LINT := $(FIRST_GOPATH)/bin/golangci-lint
 	endif
 endif
 
@@ -107,7 +106,7 @@ endif
 %: common-% ;
 
 .PHONY: common-all
-common-all: precheck style check_license staticcheck unused build test
+common-all: precheck style check_license lint unused build test
 
 .PHONY: common-style
 common-style:
@@ -159,21 +158,24 @@ common-vet:
 	@echo ">> vetting code"
 	GO111MODULE=$(GO111MODULE) $(GO) vet $(GOOPTS) $(pkgs)
 
-.PHONY: common-staticcheck
-common-staticcheck: $(STATICCHECK)
-ifdef STATICCHECK
-	@echo ">> running staticcheck"
-	chmod +x $(STATICCHECK)
+.PHONY: common-lint
+common-lint: $(GOLANGCI_LINT)
+ifdef GOLANGCI_LINT
+	@echo ">> running golangci-lint"
 ifdef GO111MODULE
 # 'go list' needs to be executed before staticcheck to prepopulate the modules cache.
 # Otherwise staticcheck might fail randomly for some reason not yet explained.
 	GO111MODULE=$(GO111MODULE) $(GO) list -e -compiled -test=true -export=false -deps=true -find=false -tags= -- ./... > /dev/null
-	GO111MODULE=$(GO111MODULE) $(STATICCHECK) -ignore "$(STATICCHECK_IGNORE)" $(pkgs)
+	GO111MODULE=$(GO111MODULE) $(GOLANGCI_LINT) run $(pkgs)
 else
-	$(STATICCHECK) -ignore "$(STATICCHECK_IGNORE)" $(pkgs)
+	$(GOLANGCI_LINT) run $(pkgs)
 endif
 endif
 
+# For backward-compatibility.
+.PHONY: common-staticcheck
+common-staticcheck: lint
+
 .PHONY: common-unused
 common-unused: $(GOVENDOR)
 ifdef GOVENDOR
@@ -241,10 +243,10 @@ proto:
 	@echo ">> generating code from proto files"
 	@./scripts/genproto.sh
 
-ifdef STATICCHECK
-$(STATICCHECK):
+ifdef GOLANGCI_LINT
+$(GOLANGCI_LINT):
 	mkdir -p $(FIRST_GOPATH)/bin
-	curl -s -L $(STATICCHECK_URL) > $(STATICCHECK)
+	curl -sfL https://install.goreleaser.com/github.com/golangci/golangci-lint.sh | sh -s -- -b $(FIRST_GOPATH)/bin $(GOLANGCI_LINT_VERSION)
 endif
 
 ifdef GOVENDOR