https://github.com/favadi/protoc-go-inject-tag
Inject custom tags to protobuf golang struct
https://github.com/favadi/protoc-go-inject-tag
Last synced: 7 days ago
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Inject custom tags to protobuf golang struct
- Host: GitHub
- URL: https://github.com/favadi/protoc-go-inject-tag
- Owner: favadi
- License: bsd-2-clause
- Created: 2016-04-06T04:56:08.000Z (almost 9 years ago)
- Default Branch: master
- Last Pushed: 2024-03-14T08:40:29.000Z (11 months ago)
- Last Synced: 2025-02-07T16:08:33.402Z (14 days ago)
- Language: Go
- Size: 319 KB
- Stars: 1,199
- Watchers: 18
- Forks: 148
- Open Issues: 9
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# protoc-go-inject-tag
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## Why?
Golang [protobuf](https://github.com/golang/protobuf) doesn't support
[custom tags to generated structs](https://github.com/golang/protobuf/issues/52).
This tool injects custom tags to generated protobuf files, which is commonly
used for validating fields, omitting fields from JSON data, etc.
## Install
- [protobuf version 3](https://github.com/google/protobuf)
For OS X:
```console
brew install protobuf
```
- go support for protobuf: `go get -u github.com/golang/protobuf/{proto,protoc-gen-go}`
- `go install github.com/favadi/protoc-go-inject-tag@latest` or download the
binaries from the releases page.
## Usage
```console
$ protoc-go-inject-tag -h
Usage of protoc-go-inject-tag:
-XXX_skip string
tags that should be skipped (applies 'tag:"-"') for unknown fields (deprecated since protoc-gen-go v1.4.0)
-input string
pattern to match input file(s)
-verbose
verbose logging
-remove_tag_comment
removes tag comments from the generated file(s)
```
Add a comment with the following syntax before fields, and these will be
injected into the resulting `.pb.go` file. This can be specified above the
field, or trailing the field.
```proto
// @gotags: custom_tag:"custom_value"
```
## Example
```proto
// file: test.proto
syntax = "proto3";
package pb;
option go_package = "/pb";
message IP {
// @gotags: valid:"ip"
string Address = 1;
// Or:
string MAC = 2; // @gotags: validate:"omitempty"
}
```
Generate your `.pb.go` files with the protoc command as normal:
```console
protoc --proto_path=. --go_out=paths=source_relative:. test.proto
```
Then run `protoc-go-inject-tag` against the generated files (e.g `test.pb.go`):
```console
$ protoc-go-inject-tag -input=./test.pb.go
# or
$ protoc-go-inject-tag -input="*.pb.go"
```
The custom tags will be injected to `test.pb.go`:
```go
type IP struct {
// @gotags: valid:"ip"
Address string `protobuf:"bytes,1,opt,name=Address,json=address" json:"Address,omitempty" valid:"ip"`
}
```
## Remove gotag comments from generated output
Utilizing the `-remove_tag_comment` flag, you can remove the gotag comment that
is normally annotated to the generated code. This allows more seamless support with
libraries like swag/openapi generators that use code comments to generate openapi
files.
## Deprecated functionality
### Skip `XXX_*` fields
To skip the tag for the generated `XXX_*` fields (unknown fields), use the
`-XXX_skip=yaml,xml` flag. This is deprecated, as this functionality hasn't
existed in `protoc-gen-go` since v1.4.x.
#### `inject_tag` keyword
Since **v1.3.0**, we recommend using `@gotags:` rather than `@inject_tags:`,
as `@gotags` is more indicative of the language the comment is for. We don't
plan on removing `@inject_tags:` support anytime soon, however we strongly
recommend switching to `@gotags`.