Important: This crate's functionality was incorporated into [tonic-types] and will be actively maintained there. This repository is no longer maintained.

Tonic Richer Error

Assets for implementation of the gRPC Richer Error Model with tonic.

This crate introduces the [WithErrorDetails] trait and implements it in [tonic::Status], allowing the implementation of the [gRPC Richer Error Model] with [tonic] in a convenient way.

[Examples] | [Website] | [Docs]

Usage

The [WithErrorDetails] trait adds associated functions to [tonic::Status] that can be used on the server side to create a status with error details, that can then be returned to the gRPC client. Moreover, the trait also adds methods to [tonic::Status] that can be used by a tonic client to extract error details, and handle them with ease.

Getting Started

To build this crate you must have the Protocol Buffer Compiler, protoc, installed. Instructions can be found here.

[dependencies] tonic = "0.8" tonic-richer-error = "0.3"

Examples

The examples bellow cover a basic use case. More complete server and client implementations can be found at the [examples] directory.

Server Side: Generating tonic::Status with an ErrorDetails struct

```rust use tonic::{Code, Status}; use tonicrichererror::{ErrorDetails, WithErrorDetails};

// ... // Inside a gRPC server endpoint that returns Result<Response<T>, Status>

// Create empty ErrorDetails struct let mut err_details = ErrorDetails::new();

// Add error details conditionally if somecondition { errdetails.addbadrequestviolation( "fielda", "description of why the field_a is invalid" ); }

if othercondition { errdetails.addbadrequestviolation( "fieldb", "description of why the field_b is invalid", ); }

// Check if any error details were set and return error status if so if errdetails.hasbadrequestviolations() {

// Add additional error details if necessary
err_details
    .add_help_link("description of link", "https://resource.example.local")
    .set_localized_message("en-US", "message for the user");

let status = Status::with_error_details(
    Code::InvalidArgument,
    "bad request",
    err_details,
);

return Err(status);

}

// Handle valid request

// ... ```

Client Side: Extracting an ErrorDetails struct from tonic::Status

```rust use tonic::{Response, Status}; use tonicrichererror::WithErrorDetails;

// ...

// Where req_result was returned by a gRPC client endpoint method fn handlerequestresult(reqresult: Result, Status>) { match reqresult { Ok(response) => { // Handle successful response }, Err(status) => { let errdetails = status.geterrordetails(); if let Some(badrequest) = errdetails.badrequest { // Handle badrequest details } if let Some(help) = errdetails.help { // Handle help details } if let Some(localizedmessage) = errdetails.localizedmessage { // Handle localizedmessage details } } }; } ```

Send different standard error messages

Multiple examples are provided at the [ErrorDetails] doc. Instructions about how to use the fields of the standard error message types correctly are provided at [error_details.proto].

Alternative tonic::Status associated functions and methods

In the [WithErrorDetails] doc, an alternative way of interacting with [tonic::Status] is presented, using vectors of error details structs wrapped with the [ErrorDetail] enum. This approach can provide more control over the vector of standard error messages that will be generated or that was received, if necessary. To see how to adopt this approach, please check the [WithErrorDetails::with_error_details_vec] and [WithErrorDetails::get_error_details_vec] docs, and also the [examples] directory.

Besides that, multiple examples with alternative error details extraction methods are provided in the [WithErrorDetails] doc, which can be specially useful if only one type of standard error message is being handled by the client. For example, using [WithErrorDetails::get_details_bad_request] is a more direct way of extracting a [BadRequest] error message from [tonic::Status].

License

This project is licensed under the MIT license.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion by you, shall be licensed as MIT, without any additional terms or conditions.