added linter conf, more code cleanup

.golangci.yaml

@@ -0,0 +1,92 @@
+linters-settings:
+  dupl:
+    threshold: 100
+  goconst:
+    min-len: 3
+    min-occurrences: 4
+  gocritic:
+    enabled-tags:
+      - diagnostic
+      - experimental
+      - opinionated
+      - performance
+      - style
+    disabled-checks:
+      - whyNoLint
+      - filepathJoin
+  gomnd:
+    checks:
+      - argument
+      - case
+      - condition
+      - return
+    ignored-numbers:
+      - '0'
+      - '1'
+      - '2'
+      - '3'
+      - '4'
+      - '5'
+      - '6'
+      - '7'
+      - '8'
+      - '9'
+      - '10'
+      - '100'
+      - '1000'
+    ignored-functions:
+      - strings.SplitN
+      - os.OpenFile
+      - os.MkdirAll
+      - os.WriteFile
+  govet:
+    check-shadowing: false
+  lll:
+    line-length: 140
+  misspell:
+    locale: US
+  nolintlint:
+    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
+  tagliatelle:
+    case:
+      use-field-name: true
+      rules:
+        # Any struct tag type can be used.
+        # Support string case: `camel`, `pascal`, `kebab`, `snake`, `upperSnake`, `goCamel`, `goPascal`, `goKebab`, `goSnake`, `upper`, `lower`, `header`.
+        json: snake
+        yaml: snake
+        xml: camel
+
+linters:
+  enable-all: true
+  disable:
+    - gochecknoglobals
+    - depguard
+    - gci
+    - gofumpt
+    - goimports
+    - varnamelen
+    - funlen
+    - cyclop
+    - wsl
+    - nosnakecase
+    - nlreturn
+    - godot
+    - nestif
+    - wrapcheck
+    - gocognit
+    - gocyclo
+    - maintidx
+    - nonamedreturns
+    - exhaustivestruct
+    - exhaustruct
+    - forcetypeassert
+    - godox
+    - nakedret
+    - tagalign
+    - maligned
+    # remove for new projects
+    - errname
+    - goerr113

main.go

@@ -52,7 +52,7 @@ func (m UploadManager) Upload() (float64, error) {
 	if err != nil {
 		return 0, err
 	}
-	if reBandwidth.MatchString(string(out)) {
+	if reBandwidth.MatchString(string(out)) { //nolint:mirror
 		up, err := strconv.Atoi(reBandwidth.FindAllStringSubmatch(string(out), -1)[0][1])
 		if err != nil {
 			return 0, err