Running

Running from a cloned git repository

A single instance of a provisioner may be invoked as a twisted plugin:

$ cd /project/folder
$ export PYTHONPATH=.
$ twistd -n provisioner

Running from installed software

Warning

The author hasn’t gotten around to writing proper Python install scripts as of yet. Once he does, the recommended way to install the software will be with pip. Once that happens, you won’t need to worry about your current working folder or your PYTHONPATH.

$ twistd -n provisioner

Other options for the provisioner plugin or the twistd program itself are available. Notably, the -n option used in the above commands runs the program in the foreground. See the OS Service Integration examples for an example of additional options being used. Also, use the –help option for more information.

Note

In the architecture for the txamqpprovisioner system an AMQP message exchange forms a backbone that connects event sources to provisioners. As such, there isn’t a single run command for the entire system. Instead, individual services can be stopped and started.

OS Service Integration examples

RHEL6 Upstart

The following is an example of a simple Upstart script to daemonize an LDAP subject provisioner service.

description "Twisted LDAP Subject Provisioner"
author "Carl <waldbiec@lafayette.edu>"

start on runlevel [2345]
stop on runlevel [016]

kill timeout 60
respawn
respawn limit 10 5

script
/usr/bin/sudo -u grouper /bin/bash <<START
cd /opt/txamqpprovisioner/
. ./pyenv/bin/activate
export LD_LIBRARY_PATH=/usr/local/lib64
export PYTHONPATH=.
twistd -n --syslog --prefix ldapsubj --pidfile /var/run/txamqpprovisioner/ldapsubj.pid  provisioner -c /etc/grouper/provisioners/ldapsubj.cfg
START
end script

The majority of the configuration is the Upstart boilerplate. The actual script block is a shell HERE document from lines 13-16. The script is run as the grouper user on the system using the sudo command.

On line 13, the current directory is changed to the software installation folder. On line 14, the Python virtual environment for the software is activated. Line 15 sets up an environment variable- in this case the LD_LIBRARY_PATH variable lets the operating system know that it needs to look in a non-standard location for a shared library the software depends on.

Line 16 is where the service is finally invoked. In this case, the -n option is used to run the service in the foreground. The Upstart machinery will take care of running the process as a background service. Other options are provided to log to syslog using a particular prefix, choose a file to use for tracking the process PID, and specifying an individual configuration file.