Tagliatelle

A linter that handles struct tags.

Supported string casing:

• camel
• pascal
• kebab
• snake
• upperSnake
• goCamel Respects Go's common initialisms (e.g. HttpResponse -> HTTPResponse).
• goPascal Respects Go's common initialisms (e.g. HttpResponse -> HTTPResponse).
• goKebab Respects Go's common initialisms (e.g. HttpResponse -> HTTPResponse).
• goSnake Respects Go's common initialisms (e.g. HttpResponse -> HTTPResponse).
• header
• upper
• lower

Source	Camel Case	Go Camel Case
GooID	gooId	gooID
HTTPStatusCode	httpStatusCode	httpStatusCode
FooBAR	fooBar	fooBar
URL	url	url
ID	id	id
hostIP	hostIp	hostIP
JSON	json	json
JSONName	jsonName	jsonName
NameJSON	nameJson	nameJSON
UneTête	uneTête	uneTête

Source	Pascal Case	Go Pascal Case
GooID	GooId	GooID
HTTPStatusCode	HttpStatusCode	HTTPStatusCode
FooBAR	FooBar	FooBar
URL	Url	URL
ID	Id	ID
hostIP	HostIp	HostIP
JSON	Json	JSON
JSONName	JsonName	JSONName
NameJSON	NameJson	NameJSON
UneTête	UneTête	UneTête

Source	Snake Case	Upper Snake Case	Go Snake Case
GooID	goo_id	GOO_ID	goo_ID
HTTPStatusCode	http_status_code	HTTP_STATUS_CODE	HTTP_status_code
FooBAR	foo_bar	FOO_BAR	foo_bar
URL	url	URL	URL
ID	id	ID	ID
hostIP	host_ip	HOST_IP	host_IP
JSON	json	JSON	JSON
JSONName	json_name	JSON_NAME	JSON_name
NameJSON	name_json	NAME_JSON	name_JSON
UneTête	une_tête	UNE_TÊTE	une_tête

Source	Kebab Case	Go KebabCase
GooID	goo-id	goo-ID
HTTPStatusCode	http-status-code	HTTP-status-code
FooBAR	foo-bar	foo-bar
URL	url	URL
ID	id	ID
hostIP	host-ip	host-IP
JSON	json	JSON
JSONName	json-name	JSON-name
NameJSON	name-json	name-JSON
UneTête	une-tête	une-tête

Source	Header Case
GooID	Goo-Id
HTTPStatusCode	Http-Status-Code
FooBAR	Foo-Bar
URL	Url
ID	Id
hostIP	Host-Ip
JSON	Json
JSONName	Json-Name
NameJSON	Name-Json
UneTête	Une-Tête

Examples

// json and camel case
type Foo struct {
    ID     string `json:"ID"` // must be "id"
    UserID string `json:"UserID"`// must be "userId"
    Name   string `json:"name"`
    Value  string `json:"val,omitempty"`// must be "value"
}

What this linter is about

This linter is about validating tags according to the rules you define. The linter also allows you to fix tags according to the rules you defined.

This linter is not intended to validate the fact a tag is valid or not.

How to use the linter

As a golangci-lint linter

Define the rules, you want via your golangci-lint configuration file:

linters:
  enable:
    - tagliatelle

  settings:
    tagliatelle:
      # Checks the struct tag name case.
      case:
        # Defines the association between tag name and case.
        # Any struct tag name can be used.
        # Supported string cases:
        # - `camel`
        # - `pascal`
        # - `kebab`
        # - `snake`
        # - `upperSnake`
        # - `goCamel`
        # - `goPascal`
        # - `goKebab`
        # - `goSnake`
        # - `upper`
        # - `lower`
        # - `header`
        rules:
          json: camel
          yaml: camel
          xml: camel
          toml: camel
          bson: camel
          avro: snake
          mapstructure: kebab
          env: upperSnake
          envconfig: upperSnake
          whatever: snake
        # Defines the association between tag name and case.
        # Important: the `extended-rules` overrides `rules`.
        # Default: empty
        extended-rules:
          json:
            # Supported string cases:
            # - `camel`
            # - `pascal`
            # - `kebab`
            # - `snake`
            # - `upperSnake`
            # - `goCamel`
            # - `goPascal`
            # - `goKebab`
            # - `goSnake`
            # - `header`
            # - `lower`
            # - `header`
            #
            # Required
            case: camel
            # Adds 'AMQP', 'DB', 'GID', 'RTP', 'SIP', 'TS' to initialisms,
            # and removes 'LHS', 'RHS' from initialisms.
            # Default: false
            extra-initialisms: true
            # Defines initialism additions and overrides.
            # Default: empty
            initialism-overrides:
              DB: true # add a new initialism
              LHS: false # disable a default initialism.
              # ...
        # Uses the struct field name to check the name of the struct tag.
        # Default: false
        use-field-name: true
        # The field names to ignore.
        # Default: []
        ignored-fields:
          - Bar
          - Foo
        # Overrides the default/root configuration.
        # Default: []
        overrides:
          -
            # The package path (uses `/` only as a separator).
            # Required
            pkg: foo/bar
            # Default: empty or the same as the default/root configuration.
            rules:
              json: snake
              xml: pascal
            # Default: empty or the same as the default/root configuration.
            extended-rules:
              # same options as the base `extended-rules`.
            # Default: false (WARNING: it doesn't follow the default/root configuration)
            use-field-name: true
            # The field names to ignore.
            # Default: [] or the same as the default/root configuration.
            ignored-fields:
              - Bar
              - Foo
            # Ignore the package (takes precedence over all other configurations).
            # Default: false
            ignore: true

Examples

Overrides case rules for the package foo/bar:

linters:
  settings:
    tagliatelle:
      case:
        rules:
          json: camel
          yaml: camel
          xml: camel
        overrides:
          - pkg: foo/bar
            rules:
              json: snake
              xml: pascal

Ignore fields inside the package foo/bar:

linters:
  settings:
    tagliatelle:
      case:
        rules:
          json: camel
          yaml: camel
          xml: camel
        overrides:
          - pkg: foo/bar
            ignored-fields:
              - Bar
              - Foo

Ignore the package foo/bar:

linters:
  settings:
    tagliatelle:
      case:
        rules:
          json: camel
          yaml: camel
          xml: camel
        overrides:
          - pkg: foo/bar
            ignore: true

More information here https://golangci-lint.run/usage/linters/#tagliatelle

Install and run it from the binary

Not recommended.

go install github.com/ldez/tagliatelle/cmd/tagliatelle@latest

then launch it manually.

Rules

Here are the default rules for the well-known and used tags, when using tagliatelle as a binary or golangci-lint linter:

• json: camel
• yaml: camel
• xml: camel
• bson: camel
• avro: snake
• header: header
• env: upperSnake
• envconfig: upperSnake

Custom Rules

The linter is not limited to the tags used in example, you can use it to validate any tag.

You can add your own tag, for example whatever and tells the linter you want to use kebab.

This option is only available via golangci-lint.

linters:
  settings:
    tagliatelle:
      # Check the struck tag name case.
      case:
        rules:
          # Any struct tag type can be used.
          # Support string case: `camel`, `pascal`, `kebab`, `snake`, `goCamel`, `goPascal`, `goKebab`, `goSnake`, `upper`, `lower`
          json: camel
          yaml: camel
          xml: camel
          toml: camel
          whatever: kebab
        # Use the struct field name to check the name of the struct tag.
        # Default: false
        use-field-name: true