ST - Struct Tagger for Go
st is a command line utility for tagging structs in your Go code.
Get it:
go get github.com/alistanis/st
If you want to run the tests, you'll need the goconvey package:
go get github.com/smartystreets/goconvey
st -h or st --help
usage: st [flags] [path ...]
-a Sets mode to append mode. Will append to existing tags. Default behavior skips existing tags.
-append
Sets mode to append mode. Will append to existing tags. Default behavior skips existing tags.
-c Sets the struct tag to camel case.
-camel
Sets the struct tag to camel case
-i string
A comma separated list of fields to ignore. Will use the format json:"-".
-ignored-fields string
A comma separated list of fields to ignore. Will use the format json:"-".
-ignored-structs string
A comma separated list of structs to ignore. Will not tag any fields in the struct.
-is string
A comma separated list of structs to ignore. Will not tag any fields in the struct.
-o Sets mode to overwrite mode. Will overwrite existing tags (completely). Default behavior skips existing tags.
-overwrite
Sets mode to overwrite mode. Will overwrite existing tags (completely). Default behavior skips existing tags.
-s Sets the struct tag to snake case.
-snake
Sets the struct tag to snake case.
-t string
The struct tag to use when tagging. Example: -t=json (default "json")
-tag-name string
The struct tag to use when tagging. Example: --tag-name=json (default "json")
-v Sets mode to verbose.
-verbose
Sets mode to verbose.
-w Sets mode to write to source file. The default is a dry run that prints the results to stdout.
-write
Sets mode to write to source file. The default is a dry run that prints the results to stdout.
#Notes:
Defaults are set to what I consider to be reasonable. This means that ST won't write to your source file unless you provide the -w or --write flags, it will simply print what the result will be to your buffer. The default tag it will use if no tag is specified is json, and the default case it uses is snake case. ST, by default, will skip any struct fields that already have tags. That behavior can be overridden by using the overwrite mode (-o or --overwrite), or append mode (-a or --append).
Overwrite mode will completely overwrite an existing tag. Append mode is a little trickier. If an existing tag is there for the tag that you have specified, let's use json as our example, it will leave that tag alone. If you specify a different tag, like msgpack, it will append to the existing tag with the msgpack key/value.
#Overwrite Examples:
st --overwrite --tag-name=msgpack $GOFILE
type Test struct { F field `json:"f"`}
becomes
type Test struct { F field `msgpack:"f"`}st --overwrite --tag-name=json --case=camel $GOFILE
type Test struct { F field `json:"f"`}
becomes
type Test struct { F field `json:"F"`}#Append Examples:
st --append --case=camel --tag-name=json $GOFILE
type Test struct { F field `json:"f"`}
becomes (the tag is left alone because it is already there)
type Test struct { F field `json:"f"`}st --append --tag-name=msgpack $GOFILE
type Test struct { F field `json:"f"`}
becomes
type Test struct { F field `msgpack:"f" json:"f"`}Further examples
Contents of etc.go before running
package etc
type TestStruct struct {
Int int
Int64 int64
IntSlice []int
Int64Slice []int64
String string
StringSlice []string
Float float64
FloatSlice []float64
UIntPointer uintptr
Rune rune
RuneSlice []rune
Byte byte
ByteSlice []byte
MapStringString map[string]string
MapStringInt map[string]int
MapIntString map[int]string
}
type TestStructWithTagsSnake struct {
Int int `json:"int"`
Int64 int64 `json:"int_64"`
IntSlice []int `json:"int_slice"`
Int64Slice []int64 `json:"int_64_slice"`
String string `json:"string"`
StringSlice []string `json:"string_slice"`
Float float64 `json:"float"`
FloatSlice []float64 `json:"float_slice"`
UIntPointer uintptr `json:"u_int_pointer"`
Rune rune `json:"rune"`
RuneSlice []rune `json:"rune_slice"`
Byte byte `json:"byte"`
ByteSlice []byte `json:"byte_slice"`
MapStringString map[string]string `json:"map_string_string"`
MapStringInt map[string]int `json:"map_string_int"`
MapIntString map[int]string `json:"map_int_string"`
}
type TestStructWithTagsCamel struct {
Int int `json:"Int"`
Int64 int64 `json:"Int64"`
IntSlice []int `json:"IntSlice"`
Int64Slice []int64 `json:"Int64Slice"`
String string `json:"String"`
StringSlice []string `json:"StringSlice"`
Float float64 `json:"Float"`
FloatSlice []float64 `json:"FloatSlice"`
UIntPointer uintptr `json:"UIntPointer"`
Rune rune `json:"Rune"`
RuneSlice []rune `json:"RuneSlice"`
Byte byte `json:"Byte"`
ByteSlice []byte `json:"ByteSlice"`
MapStringString map[string]string `json:"MapStringString"`
MapStringInt map[string]int `json:"MapStringInt"`
MapIntString map[int]string `json:"MapIntString"`
}
type TestUnexportedField struct {
unexportedField int
ExportedField int
}- Append to existing tags with the tag msgpack (use -w flag to write to original source file)
st -s -a -v -t=msgpack $GOPATH/src/github.com/alistanis/st/etc/etc.go
package etc
type TestStruct struct {
Int int `msgpack:"int"`
Int64 int64 `msgpack:"int_64"`
IntSlice []int `msgpack:"int_slice"`
Int64Slice []int64 `msgpack:"int_64_slice"`
String string `msgpack:"string"`
StringSlice []string `msgpack:"string_slice"`
Float float64 `msgpack:"float"`
FloatSlice []float64 `msgpack:"float_slice"`
UIntPointer uintptr `msgpack:"u_int_pointer"`
Rune rune `msgpack:"rune"`
RuneSlice []rune `msgpack:"rune_slice"`
Byte byte `msgpack:"byte"`
ByteSlice []byte `msgpack:"byte_slice"`
MapStringString map[string]string `msgpack:"map_string_string"`
MapStringInt map[string]int `msgpack:"map_string_int"`
MapIntString map[int]string `msgpack:"map_int_string"`
}
type TestStructWithTagsSnake struct {
Int int `msgpack:"int" json:"int"`
Int64 int64 `msgpack:"int_64" json:"int_64"`
IntSlice []int `msgpack:"int_slice" json:"int_slice"`
Int64Slice []int64 `msgpack:"int_64_slice" json:"int_64_slice"`
String string `msgpack:"string" json:"string"`
StringSlice []string `msgpack:"string_slice" json:"string_slice"`
Float float64 `msgpack:"float" json:"float"`
FloatSlice []float64 `msgpack:"float_slice" json:"float_slice"`
UIntPointer uintptr `msgpack:"u_int_pointer" json:"u_int_pointer"`
Rune rune `msgpack:"rune" json:"rune"`
RuneSlice []rune `msgpack:"rune_slice" json:"rune_slice"`
Byte byte `msgpack:"byte" json:"byte"`
ByteSlice []byte `msgpack:"byte_slice" json:"byte_slice"`
MapStringString map[string]string `msgpack:"map_string_string" json:"map_string_string"`
MapStringInt map[string]int `msgpack:"map_string_int" json:"map_string_int"`
MapIntString map[int]string `msgpack:"map_int_string" json:"map_int_string"`
}
type TestStructWithTagsCamel struct {
Int int `msgpack:"int" json:"Int"`
Int64 int64 `msgpack:"int_64" json:"Int64"`
IntSlice []int `msgpack:"int_slice" json:"IntSlice"`
Int64Slice []int64 `msgpack:"int_64_slice" json:"Int64Slice"`
String string `msgpack:"string" json:"String"`
StringSlice []string `msgpack:"string_slice" json:"StringSlice"`
Float float64 `msgpack:"float" json:"Float"`
FloatSlice []float64 `msgpack:"float_slice" json:"FloatSlice"`
UIntPointer uintptr `msgpack:"u_int_pointer" json:"UIntPointer"`
Rune rune `msgpack:"rune" json:"Rune"`
RuneSlice []rune `msgpack:"rune_slice" json:"RuneSlice"`
Byte byte `msgpack:"byte" json:"Byte"`
ByteSlice []byte `msgpack:"byte_slice" json:"ByteSlice"`
MapStringString map[string]string `msgpack:"map_string_string" json:"MapStringString"`
MapStringInt map[string]int `msgpack:"map_string_int" json:"MapStringInt"`
MapIntString map[int]string `msgpack:"map_int_string" json:"MapIntString"`
}
type TestUnexportedField struct {
unexportedField int
ExportedField int `msgpack:"exported_field"`
}- Ignore a specific field (-i) and ignore a specific struct (-is)
st -s -a -v -i=ExportedField -is=TestStructWithTagsCamel -t=msgpack $GOPATH/src/github.com/alistanis/st/etc/etc.go
package etc
type TestStruct struct {
Int int `msgpack:"int"`
Int64 int64 `msgpack:"int_64"`
IntSlice []int `msgpack:"int_slice"`
Int64Slice []int64 `msgpack:"int_64_slice"`
String string `msgpack:"string"`
StringSlice []string `msgpack:"string_slice"`
Float float64 `msgpack:"float"`
FloatSlice []float64 `msgpack:"float_slice"`
UIntPointer uintptr `msgpack:"u_int_pointer"`
Rune rune `msgpack:"rune"`
RuneSlice []rune `msgpack:"rune_slice"`
Byte byte `msgpack:"byte"`
ByteSlice []byte `msgpack:"byte_slice"`
MapStringString map[string]string `msgpack:"map_string_string"`
MapStringInt map[string]int `msgpack:"map_string_int"`
MapIntString map[int]string `msgpack:"map_int_string"`
}
type TestStructWithTagsSnake struct {
Int int `msgpack:"int" json:"int"`
Int64 int64 `msgpack:"int_64" json:"int_64"`
IntSlice []int `msgpack:"int_slice" json:"int_slice"`
Int64Slice []int64 `msgpack:"int_64_slice" json:"int_64_slice"`
String string `msgpack:"string" json:"string"`
StringSlice []string `msgpack:"string_slice" json:"string_slice"`
Float float64 `msgpack:"float" json:"float"`
FloatSlice []float64 `msgpack:"float_slice" json:"float_slice"`
UIntPointer uintptr `msgpack:"u_int_pointer" json:"u_int_pointer"`
Rune rune `msgpack:"rune" json:"rune"`
RuneSlice []rune `msgpack:"rune_slice" json:"rune_slice"`
Byte byte `msgpack:"byte" json:"byte"`
ByteSlice []byte `msgpack:"byte_slice" json:"byte_slice"`
MapStringString map[string]string `msgpack:"map_string_string" json:"map_string_string"`
MapStringInt map[string]int `msgpack:"map_string_int" json:"map_string_int"`
MapIntString map[int]string `msgpack:"map_int_string" json:"map_int_string"`
}
type TestStructWithTagsCamel struct {
Int int `json:"Int"`
Int64 int64 `json:"Int64"`
IntSlice []int `json:"IntSlice"`
Int64Slice []int64 `json:"Int64Slice"`
String string `json:"String"`
StringSlice []string `json:"StringSlice"`
Float float64 `json:"Float"`
FloatSlice []float64 `json:"FloatSlice"`
UIntPointer uintptr `json:"UIntPointer"`
Rune rune `json:"Rune"`
RuneSlice []rune `json:"RuneSlice"`
Byte byte `json:"Byte"`
ByteSlice []byte `json:"ByteSlice"`
MapStringString map[string]string `json:"MapStringString"`
MapStringInt map[string]int `json:"MapStringInt"`
MapIntString map[int]string `json:"MapIntString"`
}
type TestUnexportedField struct {
unexportedField int
ExportedField int `msgpack:"-"`
}#Contributing If you would like to contribute, don't be shy! Fork the project, write tests for any new code and ensure that you don't break existing functionality by running the current tests. If you're looking to submit changes upstream, it would be a good idea to discuss it with me first. I'm available via email (ccooper@sessionm.com), through Github, or on the Gophers slack team under the st channel (https://blog.gopheracademy.com/gophers-slack-community/).
If you do submit a pull request, I will review it and I will merge it if it's in line with my vision for the project.