protovalidate-python

Protovalidate provides standard annotations to validate common constraints on messages and fields, as well as the ability to use CEL to write custom constraints. It's the next generation of protoc-gen-validate, the only widely used validation library for Protobuf.

With Protovalidate, you can annotate your Protobuf messages with both standard and custom validation rules:

syntax = "proto3";

package banking.v1;

import "buf/validate/validate.proto";

message MoneyTransfer {
  string to_account_id = 1 [
    // Standard rule: `to_account_id` must be a UUID
    (buf.validate.field).string.uuid = true
  ];

  string from_account_id = 2 [
    // Standard rule: `from_account_id` must be a UUID
    (buf.validate.field).string.uuid = true
  ];

  // Custom rule: `to_account_id` and `from_account_id` can't be the same.
  option (buf.validate.message).cel = {
    id: "to_account_id.not.from_account_id"
    message: "to_account_id and from_account_id should not be the same value"
    expression: "this.to_account_id != this.from_account_id"
  };
}

Once you've added protovalidate-python to your project, validation is idiomatic Python:

try:
    protovalidate.validate(message)
except protovalidate.ValidationError as e:
    # Handle failure.

Installation

Tip

The easiest way to get started with Protovalidate for RPC APIs are the quickstarts in Buf's documentation. There's one available for Python and gRPC.

To install the package, use pip:

pip install protovalidate

Documentation

Comprehensive documentation for Protovalidate is available in Buf's documentation library.

Highlights for Python developers include:

• The developer quickstart
• A comprehensive RPC quickstart for Python and gRPC
• A migration guide for protoc-gen-validate users

Additional Languages and Repositories

Protovalidate isn't just for Python! You might be interested in sibling repositories for other languages:

• protovalidate-go (Go)
• protovalidate-java (Java)
• protovalidate-cc (C++)
• protovalidate-es (TypeScript and JavaScript, coming soon!)

Additionally, protovalidate's core repository provides:

• Protovalidate's Protobuf API
• Conformance testing utilities for acceptance testing of protovalidate implementations

Contribution

We genuinely appreciate any help! If you'd like to contribute, check out these resources:

• Contributing Guidelines: Guidelines to make your contribution process straightforward and meaningful
• Conformance testing utilities: Utilities providing acceptance testing of protovalidate implementations

Related Sites

• Buf: Enterprise-grade Kafka and gRPC for the modern age
• Common Expression Language (CEL): The open-source technology at the core of Protovalidate

Legal

Offered under the Apache 2 license.