Integrate MicroProfile Fault Tolerance 2.0

In  microprofile

Overview

Integrate support for Eclipse MicroProfile (MP) Fault Tolerance (FT) for applications deployed in WildFly. This proposal pertains to MP FT version 2.0 given the timing of this RFE. The integration is based on SmallRye project, specifically smallrye-fault-tolerance module. The smallrye-fault-tolerance module is already in use by projects Thorntail (WildFly Swarm) and Quarkus.

MicroProfile Fault Tolerance specification simplifies the challenges brought by the distributed nature of microservices. This is because the communication with external systems is inherently unreliable. This increases demand on resiliency of applications.

The patterns brought by this specification are annotations such as @Timeout, @Retry, @Fallback, @CircuitBreaker, @Bulkhead and @Asynchronous.

Issue Metadata

Issue

Dev Contacts

QE Contacts

Testing By

[ ] Engineering

[x] QE

Affected Projects or Components

Other Interested Projects

Not interested in our integration per se, but projects that have already integrated MP FT:

Requirements

  • Support Eclipse MicroProfile Fault Tolerance version 2.0 for all applications deployed in WildFly.

  • The extension will be provided as Galleon layer called microprofile-fault-tolerance.

  • The extension will not be part of default configurations provided by WildFly (standalone and domain mode) – instead a galleon layer microprofile-fault-tolerance will be provided.

  • Upstream Eclipse MicroProfile Fault Tolerance TCK test suite will be added to microprofile-tck WildFly upstream test suite.

  • Add integration tests above the scope of TCK (e.g. from Thorntail)

  • Support for multiple deployments. Only the first deployment processed will however configure the underlying Hystrix library, the subsequent deployment issues a warning message.

Nice-to-Have Requirements

  • Create a MicroProfile Fault Tolerance quickstart – delivered via separate RFE above of scope of this one.

Items that are currently only being taken into consideration with next version of this feature:

  • The underlying library used by SmallRye FT implementation is Hystrix which is currently in "maintenance" mode and a final release of the project (version 1.5.18) has been released. The discussion/efforts about replacing the library are ongoing.

  • WildFly’s standard management model will be configuration-less:

    • all configuration is done through MicroProfile Config specification

    • given the maintenance problem above it is not desirable to expose a management model which will change in near future as concepts are not cleanly mappable to a different underlying library

Non-Requirements

  • N/A

Implementation Plan

  • Add dependencies on smallrye-fault-tolerance and microprofile-fault-tolerance-api artifacts.

  • Add a new microprofile-fault-tolerance-smallrye extension to provide Fault Tolerance APIs support for deployments.

  • Add configuration-less MicroProfile Fault Tolerance subsystem.

  • Support configuration of Hystrix from MicroProfile Config specifications. The configuration is queried for Hystrix properties which are then applied through Archaius configuration mechanism. Since Hystrix configuration is singleton only globally scoped configuration is queried and applied.

Test Plan

  • The smallrye-fault-tolerance component is passing the MicroProfile Fault Tolerance TCK during its release process.

  • WildFly integration test suite will be enhanced with tests that deploys Java archives which uses the MicroProfile Fault Tolerance API.

Community Documentation

The feature will be documented in WildFly Administration Guide in a new MicroProfile Fault Tolerance section. Since WildFly integration does not impose any special requirements and subsystem configuration, this section will just contain how to configure Hystrix and link to MP FT specification. This section will also describe migration path from Thorntail primarily regarding Hystrix configuration.