Geonosis

Geonosis is a Zookeeper client daemon that synchronizes Zookeeper nodes with a local file system. It uses Curator to access Zookeeper and is coded in Scala.

Zookeeper is a widely used and well tested system in the Java world but as soon as you leave the JVM, you have to rely on a module of your language binded to the Zookeeper C driver. A combination that might be far from being stable enough in all situations.

Geonosis is here to replace any (non Java) read-only system that could benefit of data kept in Zookeeper.

Usage

./sbt run

or

./sbt run [-Dconfig.file=/path_to/application.conf]

Default parameters are located in src/main/resources/application.conf

How it works?

Geonosis will connect to Zookeeper servers listed in its configuration file and synchronize configured paths.

A typical Geonosis configuration file would look like this:

zookeeper {
  servers = ["localhost:2181"]
  paths = ["/test"]
}
syncdir = "/tmp/zookeeper"
port = 9000
validate_json = false

With this configuration file, Geonosis will connect to a Zookeeper server on localhost:2181 and keep track of all children nodes under node /test. Files will be created on the local file system under /tmp/zookeeper.

For example, with the following Zookeeper nodes hierarchy:

/test
/test/test1
/test/test2
/test/test2/test21

The following files hierarchy will be created:

/tmp/zookeeper/test/test1/__data__
/tmp/zookeeper/test/test1/__metadata__
/tmp/zookeeper/test/test1/__data__
/tmp/zookeeper/test/test1/__metadata__

Data found in Zookeeper nodes are dumped into a __data__ file and metadata in a __metadata__ file formated as JSON.

Geonosis keeps track of any changes in Zookeeper watched nodes and will apply any changes to local files as soon as it gets notified by Zookeeper.

Create a Debian package

You can create a Debian package of Geonosis with:

$ ./sbt clean debian:packageBin

A Debian package will be created in ./target. After installing, the default configuration (in /etc/geonosis/application.conf) can be overridden with some configuration in /etc/geonosis/geonosis.conf.

Build & Run Geonosis

You can compile and test geonosis with:

$ ./sbt
> test
> container:start
> ~ ;copy-resources;aux-compile

~ ;copy-resources;aux-compile automatically recompile source when it changes.