This is a demo project of a PubSub application using ∅mq with Google's Protocol Buffers for serializing data build with Maven.
I have a multi account system, so I have to switch to my administrator account.
su admin
Install ∅mq form source (the latest homebrew version 3.2.1-rc2 had some errors that cause jzmq unit tests to fail)
cd ~/Projects/external
git clone git://github.com/zeromq/libzmq.git
cd libzmq
./autogen.sh
./configure
make
make install
Exit to the normal user
exit
Switch to admun user
su admin
Install latest jzmq
cd ~/Projects/external
git clone git://github.com/zeromq/jzmq.git
cd jzmq
./autogen.sh
./configure
make
make install
Test the installation
cd perf
java -Djava.library.path=/usr/local/lib -classpath /usr/local/share/java/zmq.jar:../src/zmq.jar:zmq-perf.jar local_lat tcp://127.0.0.1:5555 1 100
At the first run this fails
...
Library not loaded: /usr/local/lib/libzmq.1.dylib
Referenced from: /usr/local/lib/libjzmq.0.dylib
And indeed the file does not exist, but libzmq.3.dylib does exist, so
ln -s /usr/local/lib/libzmq.3.dylib /usr/local/lib/libzmq.1.dylib
Rerun the perf test
java -Djava.library.path=/usr/local/lib -classpath /usr/local/share/java/zmq.jar:../src/zmq.jar:zmq-perf.jar local_lat tcp://127.0.0.1:5555 1 100
java -Djava.library.path=/usr/local/lib -classpath /usr/local/share/java/zmq.jar:../src/zmq.jar:zmq-perf.jar remote_lat tcp://127.0.0.1:5555 1 100
Proceed to compile the maven artifact
cd ..
export JAVA_HOME=`/usr/libexec/java_home -v 1.7`
mvn clean install -DskipTests
Exit to the normal user
exit
Although jzmq's official maven.readme advices you to add a dependency to the native artifact, I didn't work. In fact it did only work without the native library.
So just add
<dependency>
<groupId>org.zeromq</groupId>
<artifactId>jzmq</artifactId>
<version>${version.jzmq}</version>
</dependency>
to your dependencies.
I want to use Google's Protocol Buffers as the serializing mechanism
Protocol Buffers are a way of encoding structured data in an efficient yet extensible format. Google uses Protocol Buffers for almost all of its internal RPC protocols and file formats.
brew install protobuf
There is a Maven plugin to build .proto files. It's not released on Maven Central, so you have to add the plugin repository to your $M2_HOME/settings.xml. In this example I added it directly to the pom.xml though.
<pluginRepositories>
<pluginRepository>
<id>protoc-plugin</id>
<url>http://sergei-ivanov.github.com/maven-protoc-plugin/repo/releases/</url>
</pluginRepository>
</pluginRepositories>
To include the generated source in Eclipse with m2eclipse. You also have to add
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>build-helper-maven-plugin</artifactId>
<executions>
<execution>
<id>add-source</id>
<phase>generate-sources</phase>
<goals>
<goal>add-source</goal>
</goals>
<configuration>
<sources>
<source>${project.build.directory}/generated-sources/protoc</source>
</sources>
</configuration>
</execution>
</executions>
</plugin>
to your pom.xml.
Exception in thread "main" java.lang.UnsatisfiedLinkError: /usr/local/lib/libjzmq.0.dylib: dlopen(/usr/local/lib/libjzmq.0.dylib, 1): Library not loaded: /usr/local/lib/libzmq.1.dylib
Referenced from: /usr/local/lib/libjzmq.0.dylib
Reason: image not found
at java.lang.ClassLoader$NativeLibrary.load(Native Method)
at java.lang.ClassLoader.loadLibrary1(ClassLoader.java:1939)
at java.lang.ClassLoader.loadLibrary0(ClassLoader.java:1864)
at java.lang.ClassLoader.loadLibrary(ClassLoader.java:1854)
at java.lang.Runtime.loadLibrary0(Runtime.java:845)
at java.lang.System.loadLibrary(System.java:1084)
at org.zeromq.ZMQ.<clinit>(ZMQ.java:35)
at local_lat.main(local_lat.java:36)
There is a /usr/local/lib/libzmq.3.dylib but no /usr/local/lib/libzmq.3.dylib.
As a workaround I executed
ln -s /usr/local/lib/libzmq.3.dylib /usr/local/lib/libzmq.1.dylib
When trying to fix my zeromq installation I got
dyld: DYLD_ environment variables being ignored because main executable (/usr/bin/sudo) is setuid or setgid
Turned out $LD_LIBRARY_PATH was set. Unset it via
unset LD_LIBRARY_PATH
cd ~/Projects/external/jzmq
mvn clean install
fails with
Tests in error:
testDestruction(org.zeromq.ZContextTest): no jzmq in java.library.path
...
What is java.library.path
java.library.path is used for pointing to native system libraries (dll or so files). It points to a directory and calls to native code that use System.loadLibrary look in that directory for the native libs.
The project dependencies (jar files) should be specified on the application's classpath, not in this location.
from 1
As I couldn't get the tests to finish I did
mvn clean install -DskipTests
But was greeted with
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-javadoc-plugin:2.7:jar (attach-javadoc) on project jzmq: MavenReportException: Error while creating archive:Unable to find javadoc command: The environment variable JAVA_HOME is not correctly set.
Make sure JAVA_HOME is set. If you have Java 6
export JAVA_HOME=`/usr/libexec/java_home -v 1.6`
or Java 7
export JAVA_HOME=`/usr/libexec/java_home -v 1.7`
Unfortunately the Maven tests for jzmq ddidn't finish (correctly).
singleMessage(org.zeromq.ZDispatcherTest) Time elapsed: 1.01 sec <<< FAILURE!
junit.framework.AssertionFailedError: expected:<0> but was:<1>
and even worse Running org.zeromq.ZFrameTest seems to be stuck in an endless loop.
The mailing list suggested to remove homebrews latest version (3.2.1-rc2) and install libzmq from source.
This solved the problems with the tests.
The mailing list suggested to install zeromq from source
brew remove zeromq
git clone git://github.com/zeromq/libzmq.git
cd libzmq/
./autogen.sh
./configure
make
make install
Testing the installation with perf failed at first
cd perf
java -Djava.library.path=/usr/local/lib -classpath /usr/local/share/java/zmq.jar:../src/zmq.jar:zmq-perf.jar local_lat tcp://127.0.0.1:5555 1 100
...
Library not loaded: /usr/local/lib/libzmq.1.dylib
Referenced from: /usr/local/lib/libjzmq.0.dylib
So, I executed
ln -s /usr/local/lib/libzmq.3.dylib /usr/local/lib/libzmq.1.dylib
Then I recompiled jzmq
cd ../jzmq
make clean
make
make install
Now the tests successfully ran, so installed the artifact
export JAVA_HOME=`/usr/libexec/java_home -v 1.7`
mvn clean install
The code example for protocol buffers is taken from 2 and the basic pubsub example is taken from ∅mq official java examples 3, and 4