Sonatype Nexus not returning the latest releases through REST interface

Sonatype's Nexus Maven repository behaves strangely after using Rebuild Metadata feature from the Nexus UI. For some reason this feature updates all maven-metadata.xml files under repository and adds this line to all of them

<latest>0.0.48</latest>

The added line breaks Nexus's REST query API so that it always returns the version given in the latest element instead of the real latest released version. So, for example this query would always return version 0.0.48, if the latest element is in maven-metadata.xml file.

$ curl
"http://<hostname>:<port>/nexus/service/local/artifact/maven/redirect?r=releases-repository-name&g=com.group&a=artifact-name&e=jar.md5&v=LATEST

To fix this, you can run the following command under the broken repository to remove all latest elements.

$ find . -name maven-metadata.xml -exec sed -i -r "/<latest>.+<\/latest>/d" \{\} \;

An alternative way to query the latest releases is the following.

$ curl
"http://<hostname>:<port>/nexus/service/local/artifact/maven/redirect?r=releases-repository-name&g=com.group&a=artifact-name&e=jar.md5&v=RELEASE

This query works even with the latest element.

It seems that latest element is not affecting queries of the latest SNAPSHOTs.

For more information about this subject.

• https://oss.sonatype.org/nexus-restlet1x-plugin/default/docs/path__artifact_maven_redirect.html
• http://articles.javatalks.ru/articles/3

How to make Ubuntu play music over bluetooth

After installing latest Ubuntu version 14.04 (Trusty Tahr) I found out by accident that Ubuntu is able to play music from bluetooth source. Here's how it works on my laptop (Sony Vaio VPCEA2S1E, perhaps there's differences in the bluetooth adapters?).

Check has PulseAudio already loaded module-bluetooth-discover.
$ pactl list | grep -i module-bluetooth-discover

If this command does not return anything, you should load the module with the following command.
$ pactl load-module module-bluetooth-discover

Now the first command shows that the module is loaded.
$ pactl list | grep -i module-bluetooth-discover
Name: module-bluetooth-discover

After executing the command, you should be able to add your for example your phone as the source of audio. In my Windows Phone Lumia 1020, I navigate to Settings -> Accessories -> add using bluetooth. If you have music playing on your phone and you connect to your Ubuntu via bluetooth, your phone will show text connected music. And the music is coming out of your computer's speakers!

I also discovered that in the latest Ubuntu version my bluetooth keyboard Logitech diNovo Edge settings have to be adjusted manually. The mouse pointer does not move fast enough when using keyboard's touchpad. In the previous version Ubuntu 12.04 I was able to set the speed and acceleration of pointer fast enough from System Settings UI. In 14.04, I cannot. However, it's easy to change the acceleration and speed of pointer from command line. Here's the command.
$ xset m 3 1

All in all, I'm very happy with the latest Ubuntu release!

Setting up Logback with nice default appender

I spent some time looking for a solution to make Logback log everything to console in development environment and still have easy setup for logging into file in production environment.

So, my goal was that if I execute my application without any extra Logback configuration, everything goes to console. And in case configuration file exists in the environment, Logback would use that and forget the default configuration.

The default console logging configuration is in the root of classpath and is named as logback.xml (the file Logback looks for by default). Here's the contents the file.

<?xml version="1.0" encoding="UTF-8"?>
<configuration scan="true" scanPeriod="30 seconds">

  <define name="INCLUDED_FILE_EXISTS" class="ch.qos.logback.core.property.FileExistsPropertyDefiner">
    <path>${configpath}/included-logback.xml</path>
  </define>
  
  <if condition='property("INCLUDED_FILE_EXISTS").equals("true")'>
    <then>
      <!-- this configuration is used in other than development environments i.e. custom config per environment -->
      <include file="${configpath}/included-logback.xml"/>
    </then>
    <else>
      <!-- This configuration is used only in development enviroment -->
      <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
        <encoder>
          <pattern>%d{HH:mm:ss.SSS} %-5level %logger{35} - %msg%n</pattern>
        </encoder>
      </appender>
      <root level="WARN">
        <appender-ref ref="STDOUT" />
      </root>
      <logger name="fi.foo.bar.package" level="DEBUG"/>
    </else>
  </if> 
</configuration>

This configuration has two important sections. First one is the use of FileExistsPropertyDefiner. It checks the existence of the given file in file system and sets value of property INCLUDED_FILE_EXISTS to true or false. If you want, you can also check existence of a file on classpath by using ResourceExistsPropertyDefiner. The variable configpath is defined in system properties.  Second interesting section is where the INCLUDED_FILE_EXISTS property is used to include the external file. If the file was found, its configuration is used and default configuration is discarded completely.

Here is example of the included file. The file has name included-logback.xml.

<included scan="true">
  <!-- This file is scanned so you can update it while application is running -->
  <appender name="FILELOG" class="ch.qos.logback.core.rolling.RollingFileAppender">
    <file>${configpath}/logs/application.log</file>
    <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
      <fileNamePattern>${configpath}/logs/application-%d{yyyy-MM-dd}.log.gz</fileNamePattern>
    </rollingPolicy>
    <encoder>
      <pattern>%d{HH:mm:ss.SSS} %-5level %logger{35} - %msg%n</pattern>
    </encoder>
  </appender>

  <root level="INFO">
    <appender-ref ref="FILELOG" />
  </root>
</included>