Table Of Contents

Working with Mediator Framework

Framework Overview

Configurable Nodes

Configuring Nodes

configure()

configuration()

Starting and Stopping Nodes

start()

stop()

Getting and Setting Attributes

getattr()

setattr()

hasattr()

Composite Nodes

About Composite Nodes

Working with Node Children

has_child()

get_child()

children_nodes()

children_names()

Getting and Setting Node Values

get()

set()

Working with Mediator Framework

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This chapter describes the Mediator framework and includes the following sections:

•Framework Overview

•Configurable Nodes

•Composite Nodes

•Getting and Setting Node Values

Framework Overview

Mediator framework is the software application that provides the core function of the Mediator. The framework gives the Mediator its multiprotocol exchange capabilities, including the following:

•Assembling a running system from configuration data.

•Getting and setting values.

•Processing raw data.

•Presenting data from disparate sources in a uniform format.

•Making data easily available to end users.

•Providing services such as data logging and HTTP services.

•Providing an environment for custom system configuration.

•Providing an environment for developing custom solutions.

There are two types of framework nodes:

•Configurable Nodes

•Composite Nodes

All nodes inherit framework from one of two base node types. The composite node may hold child nodes; configurable nodes, on the other hand, are leaf nodes in the hierarchy. The composite node data type is an extension to the configurable node, so all the methods discussed for configurable nodes apply to composite nodes as well.

For more information on the framework, see the Cisco Network Building Mediator Release 3.x.x User Guide.

Configurable Nodes

This section explains the operations that you can perform with the configurable nodes and includes the following topics:

•Starting and Stopping Nodes

•Getting and Setting Attributes

Configuring Nodes

This section lists the standard APIs used for configurable nodes and includes the following topics:

•configure()

•configuration()

configure()

This API function allows the client to configure those parameters or attributes of the node that have been specified as configurable.

Inputs

Requires a single hash map type parameter providing name/value pairs for configurable attributes of the node. The values are usually primitive type, and the appropriate conversions are applied internally. Certain parameters will require explicit values, whereas others may have default values. The proper mechanism for configuring a parent node and name is via this method.

Outputs

No return value.

---

Note Invocations of configure() which modify the configuration of a node in the framework are never persisted. Each time the framework starts or restarts, only the configuration information specified in the Broadway XML configuration file is used.

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Examples

>>> a=as_node('services/network/http_server')

>>> a.configure({'name': 'http_server', 'parent': '/services/network', 'thread_c': '3', 
'ip': '', '__node_id__': '471', 'enabled': '0', 'maintenance_interval': '25', 
'zombie_timeout': '600', 'authentication': 'form', 'debug': '0', 'port': '80', 
'user_manager': '/services/User%20Manager'}) 

configuration()

This API function allows the client to query a node for configured attributes.

Inputs

Accepts no parameters.

Outputs

Returns a hash map analogous to the hash map with which the node was configured.

Examples

>>> a=as_node('/services/time/local/second')

>>> a.configuration()

{'debug': '0', 'enabled': '1', 'name': 'second', 'parent': '/services/time/local'}

Starting and Stopping Nodes

This section lists the standard APIs used for starting and stopping nodes and includes the following topics:

•start()

•stop()

start()

This API function allows the client to perform node-specific implementation to initialized configured nodes.

Inputs

Accepts no parameters.

Outputs

No return value.

Examples

a.start()

stop()

This API function allows the client to perform node-specific implementation to clean up node resources, stop associated processes, and scheduled entries.

Inputs

Accepts no parameters.

Outputs

No return value.

Examples

a.stop()

Getting and Setting Attributes

This section lists the standard APIs used for getting and setting attributes and includes the following topics:

•getattr()

•setattr()

•hasattr()

getattr()

This API function provides the client with a method-based mechanism for retrieving arbitrary named attributes of a node.

Inputs

Requires single parameter naming attribute to retrieve.

Outputs

Returns value of attribute if it exists.

Examples

>>> a=as_node('services/network/http_server')

>>> a.getattr('enabled')

0

setattr()

This API function provides the client with a method-based mechanism for setting the value of arbitrarily named attributes of a node.

Inputs

Requires two parameters: name of attribute to be set, and the value it should be set to.

Outputs

No return value.

Examples

>>> a=as_node('services/network/http_server')

>>> a.setattr('enabled',1)

hasattr()

This API function provides the client with a method-based mechanism for querying the node about the existence of attributes.

Inputs

Requires single parameter: name of attribute to check on.

Outputs

Returns Boolean value indicating whether the attribute exists.

Examples

>>> a=as_node('services/network/http_server')

>>> a.hasattr('enabled')

True

Composite Nodes

This section describes the extended operations that you can perform with the composite nodes and includes the following topics:

•About Composite Nodes

•Working with Node Children

About Composite Nodes

Composite Node extends the actions of the configurable nodes such that their invocation propagates to all the node descendants. Starting or stopping a parent node automatically starts and stops each of the child nodes in the parent also.

Working with Node Children

This section lists the standard APIs used for manipulating node children and includes the following topics:

•has_child()

•get_child()

•children_nodes()

•children_names()

has_child()

This API function allows the client to query the node for existence of a child node based on the node name.

Inputs

Requires on parameter: name of child node to check for.

Outputs

Returns Boolean value indicating whether child with specified name exists.

Examples

>>> a=as_node('services/time/local')

>>> a.has_child('second')

True

get_child()

This API function allows the client to query the node for a child node reference by name.

Inputs

Requires one parameter: the name of the child node to get.

Outputs

Returns child node instance if one exists.

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Note Although this method is part of the composite node API, invoking it remotely over XML-RPC will result in an error. It is described here for completeness.

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children_nodes()

This API function allows the client to query the node for a list of child nodes.

Inputs

Accepts no parameters.

Outputs

Returns list of child node instances.

---

Note Although this method is part of the composite node API, invoking it remotely over XML-RPC will result in an error. It is described here for completeness.

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Examples

children_nodes()

>>> a=as_node('services/time/local')

>>> a.children_nodes()

[<mpx.service.time.time_attribute.TimeAttribute object at 0x1062abb0>, 
<mpx.service.time.time_attribute.TimeAttribute object at 0x1062ab70>, 
<mpx.service.time.time_attribute.TimeAttribute object at 0x1062ac10>, 
<mpx.service.time.time_attribute.MilliSeconds object at 0x1062ab30>, 
<mpx.service.time.time_attribute.TimeAttribute object at 0x1062abf0>, 
<mpx.service.time.time_attribute.TimeAttribute object at 0x1062ab50>, 
<mpx.service.schedule.scheduler.Schedules object at 0x10d7af70>, 
<mpx.service.time.time_attribute.TimeAttribute object at 0x1062ab90>, 
<mpx.service.time.time_attribute.TimeAttribute object at 0x1062abd0>]

children_names()

This API function allows the client to query the node for a list of child node names.

Inputs

Accepts no parameter.

Outputs

Returns list of child node names.

Examples

children_names()

>>> a=as_node('services/time/local')

>>> a.children_names()

['hour', 'month', 'second', 'milliseconds', 'weekday', 'year', 'time_schedules_1', 'day', 
'minute']

Getting and Setting Node Values

This section lists the additional API functions that you can perform with the composite nodes, these functions are not defined by the base classes. This section includes the following topics:

•get()

•set()

get()

This API allows the client to get the current value of a point node.

Inputs

Accepts no parameters.

Outputs

Returns current value of node.

Examples

get()

>>> a=as_node('interfaces/relay1')

>>> a.get()

0

set()

This API allows the client to set the current value of a point node.

Inputs

Requires single parameter: new value of node.

Outputs

No return value.

Examples

set()

>>> a=as_node('interfaces/relay1')

>>> a.set(1)