CODEWITHSUNDEEP
pythonopen-sourcecommand-line-arguments
Srijan
Srijan

Reputation: 1284

Passing own arguments to ryu proxy app

I am developing ryu app. The app is basically a python script. The ryu apps are invoked by ryu-manager like this

ryu-manager {filename}

There are certain parameters that are taken by ryu-manager. I want to know if there is a way i could pass arguments to my file?

argparse module of python to parse command line options is there but am not sure it will work as all arguments I provide are used by ryu-manager not my script.

Any help would be appreciated.

Upvotes: 3

Views: 2169

Answers (3)

S Mayer
S Mayer

Reputation: 92

Doing so is a 4-step process. I'll show an example where you read parameters and then print them, but you could assign them to variables or do whatever you would like to by referencing this process.

  1. Create a .conf file (e.g. params.conf)

    #Example Conf File

[DEFAULT]

param1_int = 42
param2_str = "You read my data :)"
param3_list = 1,2,3
param4_float = 3.14

  2. Add the following code to your __init__ method. I did this to the simple_switch_13.py which comes with ryu:

    from ryu import cfg
:
:
class SimpleSwitch13(app_manager.RyuApp):
    def __init__(self, *args, **kwargs):
        super(SimpleSwitch13, self).__init__(*args, **kwargs)
           :
        CONF = cfg.CONF
        CONF.register_opts([
            cfg.IntOpt('param1_int', default=0, help = ('The ultimate answer')),
            cfg.StrOpt('param2_str', default='default', help = ('A string')),
            cfg.ListOpt('param3_list', default = None, help = ('A list of numbers')),
            cfg.FloatOpt('param4_float', default = 0.0, help = ('Pi? Yummy.'))])

        print 'param1_int = {}'.format(CONF.param1_int))
        print 'param2_str = {}'.format(CONF.param2_str))
        print 'param3_list = {}'.format(CONF.param3_list))
        print 'param4_float = {}'.format(CONF.param4_float))

  3. Run Script

    ryu-manager paramtest.py --config-file [PATH/TO/FILE/params.conf]

  4. Profit

I referenced the following when putting together my answer, they can provide more detail (such as the oslo.config stuff, which I had never heard of prior to running into this issue).

More info on oslo.config: http://www.giantflyingsaucer.com/blog/?p=4822

Ryu email chain on this issue: https://sourceforge.net/p/ryu/mailman/message/33410077/

Upvotes: 2

Zachary Miller
Zachary Miller

Reputation: 189

I have not found a way to pass arguments to a ryu controller. One way that I have used to get around this is to pass arguments as an environment variable. For example, I have a program which invokes ryu-manager and needs to pass a parameter to the app. I do this as follows: ARG=value ryu-manager app.py

Upvotes: 0

Glenn
Glenn

Reputation: 555

I haven't tried this, but:

"Ryu currently uses oslo.config.cfg for command-line parsing. (ryu/contrib/oslo/config). There are several examples in the tree. ryu/app/tunnel_port_updater.py"

from http://comments.gmane.org/gmane.network.ryu.devel/2709

see also https://github.com/osrg/ryu/blob/master/ryu/app/tunnel_port_updater.py

The Ryu 'getting started' page simply suggests:

ryu-manager [--flagfile <path to configuration file>] [generic/application specific options…]

http://www.osrg.net/ryu/_sources/getting_started.txt

Upvotes: 3

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