Install and configure golangci-lint (#118)

.golangci.yaml

@@ -0,0 +1,116 @@
+---
+linters:
+  enable:
+    # check when errors are compared without errors.Is
+    - errorlint
+
+    # check imports order and makes it always deterministic.
+    - gci
+
+    # Very Basic spell error checker
+    - misspell
+
+    # Fast, configurable, extensible, flexible, and beautiful linter for Go.
+    # Drop-in replacement of golint.
+    - revive
+
+    # make sure to use t.Helper() when needed
+    - thelper
+
+    # ensure that lint exceptions have explanations. Consider the case below:
+    - nolintlint
+
+    # detect duplicated words in code
+    - dupword
+
+    # mirror suggests rewrites to avoid unnecessary []byte/string conversion
+    - mirror
+
+    # testify checks good usage of github.com/stretchr/testify.
+    - testifylint
+
+linters-settings:
+  dupword:
+    # Keywords used to ignore detection.
+    # Default: []
+    ignore:
+      - "FAIL" # "FAIL FAIL" is tolerated
+
+  nolintlint:
+    # Disable to ensure that all nolint directives actually have an effect.
+    # Default: false
+    allow-unused: true  # too many false positive reported
+    # Exclude following linters from requiring an explanation.
+    # Default: []
+    allow-no-explanation: []
+    # 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
+
+  revive:
+    rules:
+      - name: bare-return
+      - name: blank-imports
+      - name: comment-spacings
+      - name: context-as-argument
+        arguments:
+          - allowTypesBefore: "*testing.T"
+      - name: context-keys-type
+      - name: defer
+        arguments:
+          - ["call-chain", "loop"]
+      - name: dot-imports
+      - name: early-return
+      - name: empty-block
+      - name: error-return
+      - name: error-strings
+      - name: error-naming
+      - name: errorf
+      - name: exported
+        arguments:
+          # enables checking public methods of private types
+          - "checkPrivateReceivers"
+          # make error messages clearer
+          - "sayRepetitiveInsteadOfStutters"
+      - name: if-return
+      - name: import-shadowing
+      - name: increment-decrement
+      - name: indent-error-flow
+      - name: exported
+      - name: var-naming
+      - name: var-declaration
+      - name: package-comments
+      - name: range
+      - name: receiver-naming
+      - name: redefines-builtin-id
+      - name: superfluous-else
+      - name: time-naming
+      - name: time-equal
+      - name: unexported-return
+      - name: use-any
+      - name: unreachable-code
+      - name: unhandled-error
+        arguments:
+          - "fmt.Print.*"
+          - "fmt.Fprint.*"
+          - "bytes.Buffer.Write.*"
+          - "strings.Builder.Write.*"
+      - name: unused-parameter
+      - name: unused-receiver
+      - name: useless-break
+
+  # define the import orders
+  gci:
+    sections:
+      # Standard section: captures all standard packages.
+      - standard
+      # Default section: catchall that is not standard or custom
+      - default
+      # Custom section: groups all imports with the specified Prefix.
+      - prefix(github.com/mfridman)
+

Makefile

@@ -21,6 +21,16 @@ errcheck:
 imports:
 	goimports -local $(ROOT) -w $(shell find . -type f -name '*.go' -not -path './vendor/*')
 
+.PHONY: lint
+lint: tools
+	@golangci-lint run ./... --fix
+
+.PHONY: tools
+tools:
+# Install latest golangci-lint with recommended method https://golangci-lint.run/welcome/install/#local-installation
+# Only install it if missing, as we don't want to mess up with any local existing golangci-lint version
+	@which golangci-lint 2>/dev/null || curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b $(shell go env GOPATH)/bin
+
 test:
 	go test -count=1 ./...