protoschema-plugins

The protoschema-plugins repository contains a collection of Protobuf plugins that generate different types of schema from protobuf files. This includes:

• PubSub
• JSON Schema

PubSub Protobuf Schema

Generates a schema for a given protobuf file that can be used as a PubSub schema in the form of a single self-contained messaged normalized to proto2.

Install the protoc-gen-pubsub plugin directly:

go install github.com/bufbuild/protoschema-plugins/cmd/protoc-gen-pubsub@latest

Or reference it as a Remote Plugin in buf.gen.yaml:

version: v1
plugins:
  - plugin: buf.build/bufbuild/protoschema-pubsub
    out: ./gen

For examples see testdata which contains the generated schema for test case definitions found in proto.

JSON Schema

Generates a JSON Schema for a given protobuf file. This implementation uses the latest JSON Schema Draft 2020-12.

Install the protoc-gen-jsonschema directly:

go install github.com/bufbuild/protoschema-plugins/cmd/protoc-gen-jsonschema@latest

Or reference it as a Remote Plugin in buf.gen.yaml:

version: v1
plugins:
  - plugin: buf.build/bufbuild/protoschema-jsonschema
    out: ./gen

For examples see testdata which contains the generated schema for test case definitions found in proto.

Here is a simple generated schema from the following protobuf:

message Product {
  message Location {
    float lat = 1;
    float long = 2;
  }

  int32 product_id = 1;
  string product_name = 2;
  float price = 3;
  repeated string tags = 4;
  Location location = 5;
}

Results in the following JSON Schema files:

Product.schema.json

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "type": "object",
  "properties": {
    "product_id": {
      "type": "integer"
    },
    "product_name": {
      "type": "string"
    },
    "price": {
      "type": "number"
    },
    "tags": {
      "type": "array",
      "items": {
        "type": "string"
      }
    },
    "location": {
      "type": "object",
      "properties": {
        "lat": {
          "type": "number"
        },
        "long": {
          "type": "number"
        }
      },
      "required": ["lat", "long"]
    }
  },
  "required": ["product_id", "product_name", "price", "tags", "location"]
}

Product.Location.schema.json

{
  "$id": "Product.Location.schema.json",
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "additionalProperties": false,
  "properties": {
    "lat": {
      "anyOf": [
        {
          "type": "number"
        },
        {
          "type": "string"
        },
        {
          "enum": ["NaN", "Infinity", "-Infinity"],
          "type": "string"
        }
      ]
    },
    "long": {
      "anyOf": [
        {
          "type": "number"
        },
        {
          "type": "string"
        },
        {
          "enum": ["NaN", "Infinity", "-Infinity"],
          "type": "string"
        }
      ]
    }
  },
  "type": "object"
}

Community

For help and discussion around Protobuf, best practices, and more, join us on Slack.

Status

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

Legal

Offered under the Apache 2 license.