Alerta

Camel OSGI bundles adding error handling with Alerta

Installation

(Tested in OSGI container Karaf version 4.2.1 )

first, start an Alerta instance: to set up a local Alerta instance with docker-compose, follow this guideline

install and start the bundles in your karaf console:

./bin/karaf
> feature:repo-add mvn:io.guanaco.alerta/features_2.12/2.0.x/xml
> feature:install guanaco-alerta

add a io.guanaco.alerta.cfg file in /etc with your Alerta settings:

apiUrl = http://localhost:8282/api
environment = Development
brokerURL = failover:(tcp://localhost:61616)
userName = karaf
password = karaf

Getting Started

Add the guanaco-io/alerta dependency to your project. eg using maven:

Update ~/.m2/settings.xml and add your Github login info:

<settings>
    ...
  <servers>
    <server>
      <id>github</id>
      <username>USERNAME</username>
      <password>TOKEN</password>
    </server>
  </servers>

</settings>

More info about this on Configuring Apache Maven for use with GitHub Packages

Add the repository:

<repositories>
    <repository>
        <id>github</id> <!-- this should equal the server id in setting.xml -->
        <url>https://maven.pkg.github.com/guanaco-io/alerta</url>
    </repository>
</repositories>

And add the dependencies:

<dependency>
    <groupId>io.guanaco.alerta</groupId>
    <artifactId>api_2.12</artifactId>
    <version>2.0.1-SNAPSHOT</version>
</dependency>
<dependency>
    <groupId>io.guanaco.alerta</groupId>
    <artifactId>util_2.12</artifactId>
    <version>2.0.1-SNAPSHOT</version>
</dependency>

Optionally, for unit testing, include

<dependency>
    <groupId>io.guanaco.alerta</groupId>
    <artifactId>test_2.12</artifactId>
    <version>2.0.1-SNAPSHOT</version>
    <scope>test</scope>
</dependency>

in your osgi config, access the Alerta service and pass it to your class sending the alert:

<reference id="alerta" interface="io.guanaco.alerta.Alerta"/>

<bean id="yourService" class="com.example.YourService">
    <argument ref="alerta" />
</bean>

Usage

to create and send an Alert from anywhere in your code, use:

package com.example

import io.guanaco.alerta.api.Alerta
import io.guanaco.alerta.util.{AlertaConfig, AlertaSupport}

class YourService(val alerta: Alerta) extends AlertaSupport {

  case class DomainObject(id: String, content: String)

  implicit val alertaConfig = AlertaConfig("your-flow-id", Seq("service1", "service2")) { domainObject: DomainObject =>
    domainObject.id
  }

  Try {
    veryRiskyOperation(domainObject)
  } match {
    case Success(_)  => sendAlertaSuccess(domainObject)
    case Failure(ex) => sendAlertaFailure(domainObject, e)
  }
}

because we also send a success alert, this snippet can be repeated and previously failed attempts of veryRiskyOperation will eventually resolve, causing the Alert to close automatically in Alerta.

to add error handling support in your camel RouteBuilder (for more examples see AlertaRouteBuilderSupportTest)

import io.guanaco.alerta.util.{AlertaConfig, AlertaRouteBuilderSupport}

new RouteBuilder() with AlertaRouteBuilderSupport {
  implicit val config = AlertaConfig(AlertaFlowId, Seq("service")) { value: String =>
    s"${AlertaFlowId}:${value}"
  }

  override def configure(): Unit = {
    configureAlerta[String]

    //format: OFF
    from(START)
      .choice()
        .when(simple("${body} contains 'broken'"))
          .throwException(new IllegalStateException("It's broken! It really is broken!!"))
        .otherwise()
          .to(END)
    //format: ON
  }
}