protovalidate 0.1.0

Protocol Buffer Validation for Python

protovalidate-python

protovalidate-python is the Python implementation of protovalidate, designed to validate Protobuf messages at runtime based on user-defined validation constraints. Powered by Google's Common Expression Language (CEL), it provides a flexible and efficient foundation for defining and evaluating custom validation rules. The primary goal of protovalidate is to help developers ensure data consistency and integrity across the network without requiring generated code.

The protovalidate project

Head over to the core protovalidate repository for:

• The API definition: used to describe validation constraints
• Documentation: how to apply protovalidate effectively
• Migration tooling: incrementally migrate from protoc-gen-validate
• Conformance testing utilities: for acceptance testing of protovalidate implementations

Other protovalidate runtime implementations include:

• Go: protovalidate-go
• C++: protovalidate-cc

And others coming soon:

• Java: protovalidate-java
• TypeScript: protovalidate-ts

Installation

To install the package, use pip:

pip install protovalidate

Make sure you have the latest version of protovalidate-python by checking the project's PyPI page.

Usage

Implementing validation constraints

Validation constraints are defined directly within .proto files. Documentation for adding constraints can be found in the protovalidate project README and its comprehensive docs.

syntax = "proto3";

package my.package;

import "google/protobuf/timestamp.proto";
import "buf/validate/validate.proto";

message Transaction {
  uint64 id = 1 [(buf.validate.field).uint64.gt = 999];
  google.protobuf.Timestamp purchase_date = 2;
  google.protobuf.Timestamp delivery_date = 3;

  string price = 4 [(buf.validate.field).cel = {
    id: "transaction.price",
    message: "price must be positive and include a valid currency symbol ($ or £)",
    expression: "(this.startswith('$') or this.startswith('£')) and float(this[1:]) > 0"
  }];

  option (buf.validate.message).cel = {
    id: "transaction.delivery_date",
    message: "delivery date must be after purchase date",
    expression:

 "this.delivery_date > this.purchase_date"
  };
}

Example

import protovalidate
from google.protobuf.timestamp_pb2 import Timestamp
from my.package import Transaction

transaction = Transaction()
transaction.id = 1234
transaction.price = "$5.67"
transaction.purchase_date.CopyFrom(Timestamp())
transaction.delivery_date.CopyFrom(Timestamp())

try:
  protovalidate.validate(transaction)
except protovalidate.ValidationError as e:
  # Report the violations

Ecosystem

• protovalidate core repository
• Buf
• CEL Spec

Legal

Offered under the Apache 2 license.