Add linter for Go (#710)

---------

Co-authored-by: Benjamin Schimke <[email protected]>

.github/workflows/go.yaml

@@ -23,6 +23,7 @@ jobs:
     permissions:
       contents: read  # for actions/checkout to fetch code
       pull-requests: write  # for marocchino/sticky-pull-request-comment to create or update PR comment
+      checks: write # for golangci/golangci-lint-action to checks to allow the action to annotate code in the PR.
     name: Unit Tests & Code Quality
     runs-on: ubuntu-latest
 
@@ -71,6 +72,19 @@ jobs:
         # root ownership so the tests must be run as root:
         run: sudo make go.unit
 
+      - name: dqlite-for-golangci-lint
+        working-directory: src/k8s
+        run: |
+          sudo add-apt-repository ppa:dqlite/dev
+          sudo apt update
+          sudo apt install dqlite-tools libdqlite-dev
+
+      - name: golangci-lint
+        uses: golangci/golangci-lint-action@v6
+        with:
+          version: v1.61
+          working-directory: src/k8s
+
   test-binary:
     name: Binaries
     runs-on: ubuntu-latest

.golangci.yml

@@ -0,0 +1,340 @@
+# This code is licensed under the terms of the MIT license https://opensource.org/license/mit
+# Copyright (c) 2021 Marat Reymers
+
+## Golden config for golangci-lint v1.61.0
+#
+# This is the best config for golangci-lint based on my experience and opinion.
+# It is very strict, but not extremely strict.
+# Feel free to adapt and change it for your needs.
+linters:
+  disable-all: true
+  enable:
+  - gosimple
+
+# TODO(ben): Enable those linters step by step and fix existing issues.
+# - errcheck
+# - govet
+# - ineffassign
+# - staticcheck
+# - unused
+# - asasalint
+# - asciicheck
+# - bidichk
+# - bodyclose
+# - canonicalheader
+# - containedctx
+# - contextcheck
+# - copyloopvar
+# - cyclop
+# - decorder
+# - depguard
+# - dogsled
+# - dupl
+# - dupword
+# - durationcheck
+# - err113
+# - errchkjson
+# - errname
+# - errorlint
+# - exhaustive
+# - exhaustruct
+# - fatcontext
+# - forbidigo
+# - forcetypeassert
+# - funlen
+# - gci
+# - ginkgolinter
+# - gocheckcompilerdirectives
+# - gochecknoglobals
+# - gochecknoinits
+# - gochecksumtype
+# - gocognit
+# - goconst
+# - gocritic
+# - gocyclo
+# - godot
+# - godox
+# - gofmt
+# - gofumpt
+# - goheader
+# - goimports
+# - gomoddirectives
+# - gomodguard
+# - goprintffuncname
+# - gosec
+# - gosmopolitan
+# - grouper
+# - importas
+# - inamedparam
+# - interfacebloat
+# - intrange
+# - ireturn
+# - lll
+# - loggercheck
+# - maintidx
+# - makezero
+# - mirror
+# - misspell
+# - mnd
+# - musttag
+# - nakedret
+# - nestif
+# - nilerr
+# - nilnil
+# - nlreturn
+# - noctx
+# - nolintlint
+# - nonamedreturns
+# - nosprintfhostport
+# - paralleltest
+# - perfsprint
+# - prealloc
+# - predeclared
+# - promlinter
+# - protogetter
+# - reassign
+# - revive
+# - rowserrcheck
+# - sloglint
+# - spancheck
+# - sqlclosecheck
+# - stylecheck
+# - tagalign
+# - tagliatelle
+# - tenv
+# - testableexamples
+# - testifylint
+# - testpackage
+# - thelper
+# - tparallel
+# - unconvert
+# - unparam
+# - usestdlibvars
+# - varnamelen
+# - wastedassign
+# - whitespace
+# - wrapcheck
+# - wsl
+# - zerologlint
+
+run:
+  # Timeout for analysis, e.g. 30s, 5m.
+  # Default: 1m
+  timeout: 5m
+
+# This file contains only configs which differ from defaults.
+# All possible options can be found here https://github.com/golangci/golangci-lint/blob/master/.golangci.reference.yml
+linters-settings:
+  cyclop:
+    # The maximal code complexity to report.
+    # Default: 10
+    max-complexity: 30
+    # The maximal average package complexity.
+    # If it's higher than 0.0 (float) the check is enabled
+    # Default: 0.0
+    package-average: 10.0
+
+  errcheck:
+    # Report about not checking of errors in type assertions: `a := b.(MyStruct)`.
+    # Such cases aren't reported by default.
+    # Default: false
+    check-type-assertions: true
+
+  exhaustive:
+    # Program elements to check for exhaustiveness.
+    # Default: [ switch ]
+    check:
+      - switch
+      - map
+
+  exhaustruct:
+    # List of regular expressions to exclude struct packages and their names from checks.
+    # Regular expressions must match complete canonical struct package/name/structname.
+    # Default: []
+    exclude:
+      # std libs
+      - "^net/http.Client$"
+      - "^net/http.Cookie$"
+      - "^net/http.Request$"
+      - "^net/http.Response$"
+      - "^net/http.Server$"
+      - "^net/http.Transport$"
+      - "^net/url.URL$"
+      - "^os/exec.Cmd$"
+      - "^reflect.StructField$"
+      # public libs
+      - "^github.com/Shopify/sarama.Config$"
+      - "^github.com/Shopify/sarama.ProducerMessage$"
+      - "^github.com/mitchellh/mapstructure.DecoderConfig$"
+      - "^github.com/prometheus/client_golang/.+Opts$"
+      - "^github.com/spf13/cobra.Command$"
+      - "^github.com/spf13/cobra.CompletionOptions$"
+      - "^github.com/stretchr/testify/mock.Mock$"
+      - "^github.com/testcontainers/testcontainers-go.+Request$"
+      - "^github.com/testcontainers/testcontainers-go.FromDockerfile$"
+      - "^golang.org/x/tools/go/analysis.Analyzer$"
+      - "^google.golang.org/protobuf/.+Options$"
+      - "^gopkg.in/yaml.v3.Node$"
+
+  funlen:
+    # Checks the number of lines in a function.
+    # If lower than 0, disable the check.
+    # Default: 60
+    lines: 100
+    # Checks the number of statements in a function.
+    # If lower than 0, disable the check.
+    # Default: 40
+    statements: 50
+    # Ignore comments when counting lines.
+    # Default false
+    ignore-comments: true
+
+  gocognit:
+    # Minimal code complexity to report.
+    # Default: 30 (but we recommend 10-20)
+    min-complexity: 20
+
+  gocritic:
+    # Settings passed to gocritic.
+    # The settings key is the name of a supported gocritic checker.
+    # The list of supported checkers can be find in https://go-critic.github.io/overview.
+    settings:
+      captLocal:
+        # Whether to restrict checker to params only.
+        # Default: true
+        paramsOnly: false
+      underef:
+        # Whether to skip (*x).method() calls where x is a pointer receiver.
+        # Default: true
+        skipRecvDeref: false
+
+  gomodguard:
+    blocked:
+      # List of blocked modules.
+      # Default: []
+      modules:
+        - github.com/golang/protobuf:
+            recommendations:
+              - google.golang.org/protobuf
+            reason: "see https://developers.google.com/protocol-buffers/docs/reference/go/faq#modules"
+        - github.com/satori/go.uuid:
+            recommendations:
+              - github.com/google/uuid
+            reason: "satori's package is not maintained"
+        - github.com/gofrs/uuid:
+            recommendations:
+              - github.com/gofrs/uuid/v5
+            reason: "gofrs' package was not go module before v5"
+
+  govet:
+    # Enable all analyzers.
+    # Default: false
+    enable-all: true
+    # Disable analyzers by name.
+    # Run `go tool vet help` to see all analyzers.
+    # Default: []
+    disable:
+      - fieldalignment # too strict
+    # Settings per analyzer.
+    settings:
+      shadow:
+        # Whether to be strict about shadowing; can be noisy.
+        # Default: false
+        strict: true
+
+  inamedparam:
+    # Skips check for interface methods with only a single parameter.
+    # Default: false
+    skip-single-param: true
+
+  mnd:
+    # List of function patterns to exclude from analysis.
+    # Values always ignored: `time.Date`,
+    # `strconv.FormatInt`, `strconv.FormatUint`, `strconv.FormatFloat`,
+    # `strconv.ParseInt`, `strconv.ParseUint`, `strconv.ParseFloat`.
+    # Default: []
+    ignored-functions:
+      - args.Error
+      - flag.Arg
+      - flag.Duration.*
+      - flag.Float.*
+      - flag.Int.*
+      - flag.Uint.*
+      - os.Chmod
+      - os.Mkdir.*
+      - os.OpenFile
+      - os.WriteFile
+      - prometheus.ExponentialBuckets.*
+      - prometheus.LinearBuckets
+
+  nakedret:
+    # Make an issue if func has more lines of code than this setting, and it has naked returns.
+    # Default: 30
+    max-func-lines: 0
+
+  nolintlint:
+    # Exclude following linters from requiring an explanation.
+    # Default: []
+    allow-no-explanation: [ funlen, gocognit, lll ]
+    # Enable to require an explanation of nonzero length after each nolint directive.
+    # Default: false
+    require-explanation: true
+    # Enable to require nolint directives to mention the specific linter being suppressed.
+    # Default: false
+    require-specific: true
+
+  perfsprint:
+    # Optimizes into strings concatenation.
+    # Default: true
+    strconcat: false
+
+  rowserrcheck:
+    # database/sql is always checked
+    # Default: []
+    packages:
+      - github.com/jmoiron/sqlx
+
+  sloglint:
+    # Enforce not using global loggers.
+    # Values:
+    # - "": disabled
+    # - "all": report all global loggers
+    # - "default": report only the default slog logger
+    # https://github.com/go-simpler/sloglint?tab=readme-ov-file#no-global
+    # Default: ""
+    no-global: "all"
+    # Enforce using methods that accept a context.
+    # Values:
+    # - "": disabled
+    # - "all": report all contextless calls
+    # - "scope": report only if a context exists in the scope of the outermost function
+    # https://github.com/go-simpler/sloglint?tab=readme-ov-file#context-only
+    # Default: ""
+    context: "scope"
+
+  tenv:
+    # The option `all` will run against whole test files (`_test.go`) regardless of method/function signatures.
+    # Otherwise, only methods that take `*testing.T`, `*testing.B`, and `testing.TB` as arguments are checked.
+    # Default: false
+    all: true
+
+issues:
+  # Maximum count of issues with the same text.
+  # Set to 0 to disable.
+  # Default: 3
+  max-same-issues: 50
+
+  exclude-rules:
+    - source: "(noinspection|TODO)"
+      linters: [ godot ]
+    - source: "//noinspection"
+      linters: [ gocritic ]
+    - path: "_test\\.go"
+      linters:
+        - bodyclose
+        - dupl
+        - funlen
+        - goconst
+        - gosec
+        - noctx
+        - wrapcheck

src/k8s/Makefile

@@ -7,6 +7,13 @@ go.fmt:
 	go mod tidy
 	go fmt ./...
 
+go.lint:
+ifeq (, $(shell which golangci-lint))
+	echo "golangci-lint not found, installing it"
+	go install github.com/golangci/golangci-lint/cmd/[email protected]
+endif
+	golangci-lint run
+
 go.vet:
 	$(DQLITE_BUILD_SCRIPTS_DIR)/static-go-vet.sh ./...
 

src/k8s/cmd/k8s/hooks.go

@@ -66,6 +66,5 @@ func hookCheckLXD() func(*cobra.Command, []string) {
 					"https://documentation.ubuntu.com/canonical-kubernetes/latest/snap/howto/install/lxd/")
 			}
 		}
-		return
 	}
 }