| Author: | Jesús Arias Fisteus |
|---|
Ztreamy is a middleware for publishing streams of semantically-described events on the Web. It is implemented on top of the Tornado Web Server. This guide describes how to install the software, start a simple stream and consume its events.
This guide describes how to install Ztreamy in Linux systems. It should work also in Windows, but we have not yet tested it.
In order to install Ztreamy, you need an installation of Python 2.6 or Python 2.7. Python 3 is not backwards compatible and is not supported yet. Python is installed by default in many Linux distributions. Therefore, it is probably already installed in your system.
You can install Ztreamy globally in your Linux installation, or in a local directory, using virtualenv. The latter is probably better if you just want to try Ztreamy, because this way it can be safely removed just by removing the virtualenv directory.
First, install the virtualenv package using the package manager of your Linux distribution. For example, in Debian and Ubuntu:
sudo apt-get install python-virtualenv
Ztreamy requires the libcurl library and its development files to be installed in your system. In Debian and Ubuntu they are packaged as libcurl3 and libcurl-dev:
sudo apt-get install curl libcurl3 libcurl4-openssl-dev
Now, somewhere in your user account, create the virtualenv directory in which Ztreamy will be installed. For example, if you call the directory venv:
virtualenv venv . venv/bin/activate
The first command creates the virtual environment and installs Python inside it. The second command makes this virtual environment the default in the current terminal. The second command has to be executed every time a new terminal is opened for using Ztreamy.
Finally, you have to download Ztreamy and install it. Download the file ztreamy-<version>.tar.gz (where <version> represents the version number of the release of Ztreamy) from the downloads page of Ztreamy. Then, install it with easy_install. For example, if you downloaded ztreamy-0.1.1.tar.gz you would install it with:
easy_install ztreamy-0.1.1.tar.gz
The easy_install command will install Ztreamy inside the virtual environment. In addition, it will also download and install all the other python packages required by Ztreamy.
In order to try your installation of Ztreamy, you can create a stream, send events to it from an event source and run a client to see what is transmitted through the stream:
python -m ztreamy.server --port=9000
This command launches an HTTP server in the port 9000 of your computer, and serves an event stream from it.
In another command window, launch a client to listen to that stream:
python -m ztreamy.client http://localhost:9000/events/stream
Finally, you need an event source that sends events to the server in order to be published in the stream. Ztreamy integrates a tool that creates events for testing purposes:
python -m ztreamy.tools.event_source --distribution="exp[3]" http://localhost:9000/events/publish
It will create and send events to the server. The time between events follows an exponential distribution with an average of 3 seconds. You should see the events arriving at the terminal in which the client is running.
In order to stop the framework, type control-c in the terminals of the event source and the server. The client will stop automatically when the server is finished.