node-grpc-error-details

Utility function for deserializing the grpc-status-details-bin metadata value when using the node grpc package. Error details allow sending/receiving additional data along with an error. For instance, if a request sends invalid data, a gRPC server could send back a BadRequest message identifying the field and why it failed validation.

gRPC services that send rich error details place information in the grpc-status-details-bin metadata property of the ServiceError passed to the callback of a failed gRPC method call. The value of the grpc-status-details-bin field is a serialized Status message. The Status message's details field is an array of Any messages, which consist of a type field and the serialized data for that message type.

This library, given an error, returns back the deserialized Status message and an array of deserialized detail messages.

Install

# yarn
yarn add @stackpath/node-grpc-error-details

# npm
npm install @stackpath/node-grpc-error-details

Usage

Both exported functions return the same type of object.

{
  status: Status
  details: DetailType[]
}

where status is a Google rpc Status message and details is the Status's details array with each item deserialized and unpacked from an Any message to its actual message type.

deserializeGrpcStatusDetails allows passing in the deserializeMap argument, where each key is a message type and each value is its corresponding deserialize function.

deserializeGoogleGrpcStatusDetails behaves exactly the same as deserializeGrpcStatusDetails, but provides a default deserializeMap using Google's rpc error details types.

deserializeGrpcStatusDetails(error, deserializeMap)

Example:

import { deserializeGrpcStatusDetails } from "@stackpath/node-grpc-error-details";
import {
  RetryInfo,
  DebugInfo,
  QuotaFailure,
  PreconditionFailure,
  CustomError
} from "./custom_error_pb";

// Define the types of errors we want to deserialize
const deserializeMap = {
  "stackpath.rpc.RetryInfo": RetryInfo.deserializeBinary,
  "stackpath.rpc.DebugInfo": DebugInfo.deserializeBinary,
  "stackpath.rpc.QuotaFailure": QuotaFailure.deserializeBinary,
  "stackpath.rpc.PreconditionFailure": PreconditionFailure.deserializeBinary,
  "stackpath.rpc.CustomError": CustomError.deserializeBinary
};

const point = { latitude: 409146138, longitude: -746188906 };

// Make grpc call that fails and returns a Status object with
// details in the `grpc-status-details-bin` Metadata property
stub.getFeature(point, function(err, feature) {
  if (err) {
    const grpcErrorDetails = deserializeGrpcStatusDetails(err, deserializeMap);
    if (grpcErrorDetails) {
      const { status, details } = grpcErrorDetails;

      // Search for an instance of CustomError in details and do something if found
      for (let i = 0; i < details.length; i++) {
        if (details[i] instanceof CustomError) {
          console.log(details[i].toObject());
        }
      }
    }
  } else {
    // process feature
  }
});

deserializeGoogleGrpcStatusDetails(error)

Example:

import {
  deserializeGoogleGrpcStatusDetails,
  BadRequest
} from "@stackpath/node-grpc-error-details";

const point = { latitude: 409146138, longitude: -746188906 };

// Make grpc call that fails and returns a Status object with
// details in the `grpc-status-details-bin` Metadata property
stub.getFeature(point, function(err, feature) {
  if (err) {
    const grpcErrorDetails = deserializeGoogleGrpcStatusDetails(err);
    if (grpcErrorDetails) {
      const { status, details } = grpcErrorDetails;

      // Search for an instance of BadRequest in details and do something if found
      for (let i = 0; i < details.length; i++) {
        if (details[i] instanceof BadRequest) {
          console.log(details[i].toObject());
        }
      }
    }
  } else {
    // process feature
  }
});

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