Routing script tutorial

Revision as of 09:42, 9 December 2009

Introduction

Working with scripts requires you to define a class that will help you select one of your previously created routes. There are 3 mandatory things to define for your script to work:

1. Define your new script routing class, which can contain one or many of these methods (route_order,route_match,route_remap)
2. The 'init_routes' method
3. The 'route' method

For more information about the parameters that can be used within a method, please see the mini development guide

Script routing class

The scripting class is used to define on which call/NAP parameters the call needs to match the route or to remap the call parameter. You also need to define all new methods required by your script routing class. It is highly recommended to derive your new class for the 'base_routing' class, because it provides you with more functionality.

What I need to define a script routing class

There are 3 methods that can be used:

1. route_order
2. route_match
3. route_remap

Please note that 'route_order' will be called before 'route_match', both of which will be called before 'route_remap'.

'route_order' method

'route_order' allows to order routes using one of 3 possible arguments. It is only possible to call 'route_order' once.

1.  :route_field_name - The field name of the route to order with. The value of the route field should be an integer so that it can be compared.
2.  :proc - A user-supplied proc to call instead of trying to order internally. It should accept two arguments (route list, nap list) and return the sorted route list.
3.  :method - A user-supplied method to call instead of trying to order internally. It should accept two arguments (route list, nap list) and return the sorted route list.

base_routing pre-implemented ordering method:

• 'order_by_asr', this method will order the routes according to the asr(average success rate). This method requires adding a custom NAP parameter called ':asr_type'. Its value can be: global, last_24h, current_hour, last_hour. It can be used in your custom class like this:

 route_order :method => :order_by_asr

'route_match' method

'route_match' allows to match a call to one route using one of 4 possible arguments. It is possible to call 'route_match' multiple times to reduce the number of matching routes. Since 'route_match' will return the first matching route it find, there is a possibility that there is more than one route match, therefore it is important to order the routes or prioritize them using 'route_order'.

1.  :call_field_name - The field name of the call to try to match
2.  :route_field_name - The field name of the route to try to match with. The default is to use the call field name. If the value of the field is empty, the match is considered positive. The value of the route field can be a regular expression. (e.g., /555000./ )
3.  :proc - A user-supplied proc to call instead of trying to do the match internally. It should accept three arguments (route, call, nap list) and return a boolean to indicate the match
4.  :method - A user-supplied method to call instead of trying to do the match internally. It should accept three arguments (route, call, nap list) and return a boolean to indicate the match

base_routing pre-implemented matching method:

• 'match_nap_availability', this method will verify the availability through the nap status.

 route_match :method => :match_nap_availability

• 'match_asr_threshhold', this method will verify will match any route who's destination NAP has a higher asr than the threshold stored for that nap. This method requires adding 2 custom NAP parameters called. The first custom parameter is 'asr_threshhold_type'. Its values can be: global, last_24h, current_hour, last_hour. The second custom parameter is 'asr_threshhold'. Its value needs to be an integer between 0 and 100.

 route_match :method => :match_asr_threshhold

'route_remap' method

'route_remap' allows to remap the parameter of the route or the call using one of the 4 possible arguments. There are actually 3 types of remapping that can be performed: via the :call_field_name/:route_field_name arguments; the :proc argument; and/or the :method argument.

1.  :call_field_name - The field name of the call to remap
2.  :route_field_name - The field name of the route to remap with. The default is to use the call field name. If the value of the field is empty, the incoming call's attribute is used. The value of the route field can be a regular expression remap. (e.g., /(555000.)/001\1/ )
3.  :proc - A user supplied proc to call instead of trying to do the remap internally. It should accept four arguments (route, call, nap list, remapped fields) and return a hash of remapped fields
4.  :method - A user supplied method to call instead of trying to do the match internally. It should accept four arguments (route, call, nap list, remapped fields) and return a hash of remapped fields

'init_routes' method

The 'init_routes' is a mandatory method that is call every time the script is loaded (i.e., think loading the configuration). It may be to your advantage to perform some pre-processing such as ordering your routes; that way the routes will not be re-ordered at every call that comes in.

'route' method

The 'route' is a mandatory method that is call at every call that comes in. This is where you can perform the dynamic routing part.

Route retry

As soon as more than one route matches an incoming call, route retry apply the following way:

• An outgoing call will be made based on the first matching route
• If that outgoing call fails while there are other matching routes left, another outgoing call attempt is made using next matching route
• Outgoing call is considered failed if terminated with an error before being answered, or if not alerted within defined timeout (5 seconds by default).

Route retry timeout can be configured in the Gateway application configuration page of the Toolpack Web Portal configuration pages:

• Go to the Gateway->Configuration menu.
• Click on the Edit link of the configuration you wish modify.
• Expand the 'Advanced' section
• Change the value 'Route retry alerting timeout'

What else?

There are numerous possibilities:

• Add new methods for route selection
• Add new columns in the NAP or route
• Create scripts that include other scripts to help make the routing more modular

Examples and tutorials

• script routing class tutorial
• 'route_order' tutorial
• 'route_match' tutorial
• 'route_remap' tutorial
• Pre-built routing scripts are also available through the Web Portal in the script routing menu

Back to the Scriptable Routing Engine page.