Python Usage of maapi_shared functions inside FASTMAP

[Maan Al Bachari]

Hi Team,

I’m trying to better understand the following:

• how to use MAAPI functions inside cb_create within service packages, how to define maapi object/session..etc with the existing parameters NCS is passing when the functions is called. I cannot seem to find an examples on that, apologies if I missed it
• how to use shared functions, such shared_copy_tree..my understanding we need to use the shared methods inside FASTMAP and not the normal ones

I get the following error  when running my code:

Error: Operation was aborted (49): Operation on: /ncs:devices/device{xr1}/config/cisco-ios-xr:class-map{af} failed because: sharedCreate() called outside fastmap

Here is the code snippet:

# -*- mode: python; python-indent: 4 -*-
import ncs
from ncs.application import Service

class ServiceCallbacks(Service):

     @Service.create
     def cb_create(self, tctx, root, service, proplist):
          self.log.info('Service create(service=', service._path, ')')
          srcPE = service.src_device
          srcGePhyPort = service.src_GigE_physint
          destPE = service.dest_device
          destPort = service.dest_interface
          currentClass = 'af'
          m = ncs.maagic.get_maapi(root)
          t = m.attach(tctx.th)
          t.shared_copy_tree('/ncs:devices/device{%s}/config/cisco-ios-xr:class-map{%s}' % (srcPE, currentClass), '/ncs:devices/device{%s}/config/cisco-ios-xr:class-map{%s}' % (destPE, currentClass))

          template = ncs.template.Template(service)
          template.apply('service-template', vars)

To me the above function is inside FASTMAP since it’s in cb_create and using the same root and session transaction handler, what am I missing?

If I pass flag 0 the error I get back is bad formatted or non-existent path, the above works fine with copy_tree but not shared, which is problematic when I want to remove or modify the service

Please excuses any obvious mistakes, my python skills are very rudimental to say the least

Thanks!

[Dan.Sullivan]

Hi Maan,

If you don't used share_copy_tree and must copy_tree does it do what you want?

-Dan

[Maan Al Bachari]

Hi Dan,

With copy_tree I can deploy the service and see the class-map in my example being copied from xr0 to xr1, however when I delete the service, it's doesn't remove the class-map from xr1. That's why I thought I need to use shared_copy_tree, as indicated in the documentation:

shared_copy_tree(*args, **kwargs)
FASTMAP version of copy_tree().

Does that make sense?

Thanks!

[Dan.Sullivan]

Hi Maan,

No, that's not really the purpose of 'shared'. In fact, shared sets are used to insure configuration changes can be handled correctly among 1 or more services which share some common configuration items. I'm not sure exactly what is going on with your service. I'll take a closer look.

-Dan

[Dan.Sullivan]

Hi Maan,

Can you post the service modifications once your service is configured?

-Dan

[Maan Al Bachari]

Hi Dan,

admin@ncs(config)# services emergency_pe_migration_mx_mx 123 src-device xr0 src-GigE-physint 0/0/0/1 dest-device xr1 dest-interface 0/0/0/1
admin@ncs(config-emergency_pe_migration_mx_mx-123)# commit dry-run                                                                                                     cli {
    local-node {
        data  devices {
                  device xr1 {
                      config {
             +            cisco-ios-xr:class-map af {
             +                prematch match-any;
             +                match {
             +                    dscp {
             +                        dscp-list ef;
             +                    }
             +                }
             +            }
                      }
                  }
              }
              services {
             +    emergency_pe_migration_mx_mx 123 {
             +        src-device xr0;
             +        src-GigE-physint 0/0/0/1;
             +        dest-device xr1;
             +        dest-interface 0/0/0/1;
             +    }
              }
    }
}
admin@ncs(config-emergency_pe_migration_mx_mx-123)# commit
Commit complete.
admin@ncs(config-emergency_pe_migration_mx_mx-123)# exit
admin@ncs(config)# no services emergency_pe_migration_mx_mx 123
admin@ncs(config)# commit dry-run
cli {
    local-node {
        data  services {
             -    emergency_pe_migration_mx_mx 123 {
             -        src-device xr0;
             -        src-GigE-physint 0/0/0/1;
             -        dest-device xr1;
             -        dest-interface 0/0/0/1;
             -    }
              }
    }
}

This is with tree_copy , pong deleting the service, the changes earlier made on xr1 is not reverted.

Thanks!

[Maan Al Bachari · Accepted solution]

Dan, thanks so much for your help! Below is how we made it work:

instead of

m = ncs.maagic.get_maapi(root)
t = m.attach(tctx)
t.shared_copy_tree('/ncs:devices/device{%s}/config/cisco-ios-xr:class-map{%s}' % (srcPE, currentClass), '/ncs:devices/device{%s}/config/cisco-ios-xr:class-map{%s}' % (destPE, currentClass))

we used

t = ncs.maagic.get_trans(root)
t.shared_copy_tree('/ncs:devices/device{%s}/config/cisco-ios-xr:class-map{%s}' % (srcPE, currentClass), '/ncs:devices/device{%s}/config/cisco-ios-xr:class-map{%s}' % (destPE, currentClass))

no need to redefine a maapi object and attaching to a transaction, just use the existing transaction by root

Thanks!