README.md

# Apache Safeguard
Apache Safeguard is a library around Fault Tolerance, giving your application resilience in a highly distributed microservices framework. It is designed for use with CDI applications.

## What is Fault Tolerance?

In today's microservices runtimes, Fault Tolerance allows an application to handle the situations where another service it is consuming is unavialable.  

## Types of Fault Tolerance

Fault Tolerance is a broad subject, has multiple areas of support typically found in a framework.

### Fallback

When a given invocation fails, you can declare a Fallback for that method.

### Timeout

Allows method invocations to be bounded to a specific duration.  Once that boundary hits, an exception is thrown or a fallback is invoked.

### Retry

Allows a method to be invoked a number of times, as well as for a given duration.

### Circuit Breaker

Allows invocations to a given method as long as it is returning successfully.  Based on thresholds defined, when a method begins failing invocations will be blocked.  After a duration has passed invocations will begin to attempt again.

### Bulkhead

A bulkhead throttles concurrent access to a method.  The throttling can either by based on a semaphore or a thread pool.  Semaphores are invoked on the caller's thread and are not bound by any limit to pending requests.  Thread pools are used to invoke the component asynchronously and have a finite amount of waiting invocations.

## Getting Started

Apache Safeguard is currently in development.  You can use our snapshots from the Apache Snapshots repository.  These builds are in no way endorsed.

```xml
<repositories>
    <repository>
        <id>apache-snapshot-repository</id>
        <url>http://repository.apache.org/snapshots/</url>
        <releases>
            <enabled>false</enabled>
        </releases>
        <snapshots>
            <enabled>true</enabled>
        </snapshots>
    </repository>
</repositories>
<dependencies>
    <dependency>
        <artifactId>safeguard-api</artifactId>
        <groupId>org.apache.geronimo.safeguard</groupId>
        <version>1.0-SNAPSHOT</version>
    </dependency>
    <dependency>
        <artifactId>safeguard-impl</artifactId>
        <groupId>org.apache.geronimo.safeguard</groupId>
        <version>1.0-SNAPSHOT</version>
    </dependency>
</dependencies>
```

Apache Safeguard implements the [MicroProfile Fault Tolerance v1.0 specification](https://github.com/eclipse/microprofile-fault-tolerance/releases/tag/1.0)