protoc-gen-validate (PGV)

https://github.com/envoyproxy/protoc-gen-validate

This project is currently in alpha. The API should be considered unstable and likely to change

PGV is a protoc plugin to generate polyglot message validators. While protocol buffers effectively guarantee the types of structured data, they cannot enforce semantic rules for values. This plugin adds support to protoc-generated code to validate such constraints.

Developers import the PGV extension and annotate the messages and fields in their proto files with constraint rules:

syntax = "proto3";

package examplepb;

import "validate/validate.proto";

message Person {
  uint64 id    = 1 [(validate.rules).uint64.gt    = 999];

  string email = 2 [(validate.rules).string.email = true];

  string name  = 3 [(validate.rules).string = {
                      pattern:   "^[^[0-9]A-Za-z]+( [^[0-9]A-Za-z]+)*$",
                      max_bytes: 256,
                   }];

  Location home = 4 [(validate.rules).message.required = true];

  message Location {
    double lat = 1 [(validate.rules).double = { gte: -90,  lte: 90 }];
    double lng = 2 [(validate.rules).double = { gte: -180, lte: 180 }];
  }
}

Executing protoc with PGV and the target language's default plugin will create Validate methods on the generated types:

p := new(Person)

err := p.Validate() // err: Id must be greater than 999
p.Id = 1000

err = p.Validate() // err: Email must be a valid email address
p.Email = "example@lyft.com"

err = p.Validate() // err: Name must match pattern '^[^ds]+( [^ds]+)*$'
p.Name = "Protocol Buffer"

err = p.Validate() // err: Home is required
p.Home = &Location{37.7, 999}

err = p.Validate() // err: Home.Lng must be within [-180, 180]
p.Home.Lng = -122.4

err = p.Validate() // err: nil

This project is currently in alpha. The API should be considered unstable and likely to change

Developers import the PGV extension and annotate the messages and fields in their proto files with constraint rules:

syntax = "proto3";

package examplepb;

import "validate/validate.proto";

message Person {
  uint64 id    = 1 [(validate.rules).uint64.gt    = 999];

  string email = 2 [(validate.rules).string.email = true];

  string name  = 3 [(validate.rules).string = {
                      pattern:   "^[^[0-9]A-Za-z]+( [^[0-9]A-Za-z]+)*$",
                      max_bytes: 256,
                   }];

  Location home = 4 [(validate.rules).message.required = true];

  message Location {
    double lat = 1 [(validate.rules).double = { gte: -90,  lte: 90 }];
    double lng = 2 [(validate.rules).double = { gte: -180, lte: 180 }];
  }
}

Executing protoc with PGV and the target language's default plugin will create Validate methods on the generated types:

p := new(Person)

err := p.Validate() // err: Id must be greater than 999
p.Id = 1000

err = p.Validate() // err: Email must be a valid email address
p.Email = "example@lyft.com"

err = p.Validate() // err: Name must match pattern '^[^ds]+( [^ds]+)*$'
p.Name = "Protocol Buffer"

err = p.Validate() // err: Home is required
p.Home = &Location{37.7, 999}

err = p.Validate() // err: Home.Lng must be within [-180, 180]
p.Home.Lng = -122.4

err = p.Validate() // err: nil