(maint) fixing naming and add more go best practice

.drone.yml

@@ -1,11 +1,10 @@
 ---
 kind: pipeline
-type: docker
+type: vm
 name: default
 
-platform:
-  os: linux
-  arch: amd64
+pool:
+  use: ubuntu
 
 steps:
 - name: vet
@@ -15,6 +14,8 @@ steps:
   volumes:
   - name: gopath
     path: /go
+  depends_on:
+  - clone
 
 - name: test
   image: golang:1.15
@@ -23,6 +24,30 @@ steps:
   volumes:
   - name: gopath
     path: /go
+  depends_on:
+  - vet
+
+- name: check go.mod is up to date
+  image: golang:1.15
+  commands:
+  - cp go.mod go.mod.bak
+  - go mod tidy
+  - diff go.mod go.mod.bak || (echo "go.mod is not up to date" && exit 1)
+  volumes:
+  - name: gopath
+    path: /go
+  depends_on:
+  - vet
+
+- name: golangci-lint
+  image: golangci/golangci-lint
+  commands:
+  - golangci-lint run --timeout 500s --new-from-rev=HEAD~
+  volumes:
+  - name: gopath
+    path: /go
+  depends_on:
+  - clone
 
 volumes:
 - name: gopath

.golangci.yml

@@ -0,0 +1,130 @@
+linters-settings:
+  dupl:
+    threshold: 100
+  funlen:
+    lines: 400
+    statements: 100
+  gci:
+    local-prefixes: github.com/golangci/golangci-lint
+  goconst:
+    min-len: 3
+    min-occurrences: 3
+  gocritic:
+    enabled-tags:
+      - diagnostic
+      - experimental
+      - opinionated
+      - performance
+      - style
+    disabled-checks:
+      - dupImport # https://github.com/go-critic/go-critic/issues/845
+      - ifElseChain
+      - octalLiteral
+      - whyNoLint
+      - wrapperFunc
+  gocyclo:
+    min-complexity: 25
+  goimports:
+    local-prefixes: github.com/golangci/golangci-lint
+  gomnd:
+    settings:
+      mnd:
+        # don't include the "operation" and "assign"
+        checks: argument,case,condition,return
+  govet:
+    check-shadowing: true
+    settings:
+      printf:
+        funcs:
+          - (github.com/golangci/golangci-lint/pkg/logutils.Log).Infof
+          - (github.com/golangci/golangci-lint/pkg/logutils.Log).Warnf
+          - (github.com/golangci/golangci-lint/pkg/logutils.Log).Errorf
+          - (github.com/golangci/golangci-lint/pkg/logutils.Log).Fatalf
+  lll:
+    line-length: 200
+  maligned:
+    suggest-new: true
+  misspell:
+    locale: US
+  nolintlint:
+    allow-leading-space: true # don't require machine-readable nolint directives (i.e. with no leading space)
+    allow-unused: false # report any unused nolint directives
+    require-explanation: false # don't require an explanation for nolint directives
+    require-specific: false # don't require nolint directives to be specific about which linter is being skipped
+  nakedret:
+    max-func-lines: 100
+
+linters:
+  # please, do not use `enable-all`: it's deprecated and will be removed soon.
+  # inverted configuration with `enable-all` and `disable` is not scalable during updates of golangci-lint
+  disable-all: true
+  enable:
+    - bodyclose
+    - deadcode
+    - depguard
+    - dogsled
+    - errcheck
+    - exportloopref
+    - exhaustive
+    - funlen
+    - gochecknoinits
+    - goconst
+    - gocritic
+    - gocyclo
+    - gofmt
+    - goimports
+    - gomnd
+    - goprintffuncname
+    - gosec
+    - gosimple
+    - govet
+    - ineffassign
+    - lll
+    - misspell
+    - nakedret
+    - noctx
+    - nolintlint
+    - revive
+    - rowserrcheck
+    - staticcheck
+    - structcheck
+    - stylecheck
+    - typecheck
+    - unconvert
+    - unparam
+    - unused
+    - varcheck
+    - whitespace
+
+  # don't enable:
+  # - asciicheck
+  # - dupl
+  # - scopelint
+  # - gochecknoglobals
+  # - gocognit
+  # - godot
+  # - godox
+  # - goerr113
+  # - interfacer
+  # - maligned
+  # - nestif
+  # - prealloc
+  # - testpackage
+  # - revive
+  # - wsl
+
+issues:
+  # Excluding configuration per-path, per-linter, per-text and per-source
+  exclude-rules:
+    - path: _test\.go
+      linters:
+        - gomnd
+
+    # https://github.com/go-critic/go-critic/issues/926
+    - linters:
+        - gocritic
+      text: "unnecessaryDefer:"
+
+run:
+  skip-files:
+    - _gen\.go