A pyang plugin to produce a JSON representation of module trees for use in graph libraries

This simplistic pyang plugin produces a JSON representation from YANG files. The output can be fed through a variety of libraries for data visualization. Development is mainly done for use with D3, e.g. using Hierarchies (d3-hierarchy).

Some libraries require certain objects, e.g. D3 expects name and children objects for structure. This may need to be adjusted in the plugin code for other libraries. Should likely be moved to options.

Example

$ pyang -f jsontree ietf-interfaces\@2014-05-08.yang
{
  "contact": "WG Web:   <http://tools.ietf.org/wg/netmod/>\nWG List:  <mailto:netmod@ietf.org>\n\nWG Chair: Thomas Nadeau\n          <mailto:tnadeau@lucidvision.com>\n\nWG Chair: Juergen Schoenwaelder\n          <mailto:j.schoenwaelder@jacobs-university.de>\n\nEditor:   Martin Bjorklund\n          <mailto:mbj@tail-f.com>",
  "name": "ietf-interfaces",
  "organization": "IETF NETMOD (NETCONF Data Modeling Language) Working Group",
  "type": "module",
  "children": [
    {
      "description": "Interface configuration parameters.",
      "type": "container",
      "name": "interfaces",
      "children": [
        {
          "description": "The list of configured interfaces on the device.\n\nThe operational state of an interface is available in the\n/interfaces-state/interface list.  If the configuration of a\nsystem-controlled interface cannot be used by the system\n(e.g., the interface hardware present does not match the\ninterface type), then the configuration is not applied to\nthe system-controlled interface shown in the\n/interfaces-state/interface list.  If the configuration\nof a user-controlled interface cannot be used by the system,\nthe configured interface is not instantiated in the\n/interfaces-state/interface list.",
          "type": "list",
          "name": "interface",
          "children": [
            {
              "description": "The name of the interface.\n\nA device MAY restrict the allowed values for this leaf,\npossibly depending on the type of the interface.\nFor system-controlled interfaces, this leaf is the\ndevice-specific name of the interface.  The 'config false'\nlist /interfaces-state/interface contains the currently\nexisting interfaces on the device.\n\nIf a client tries to create configuration for a\nsystem-controlled interface that is not present in the\n/interfaces-state/interface list, the server MAY reject\nthe request if the implementation does not support\npre-provisioning of interfaces or if the name refers to\nan interface that can never exist in the system.  A\nNETCONF server MUST reply with an rpc-error with the\nerror-tag 'invalid-value' in this case.\n\nIf the device supports pre-provisioning of interface\nconfiguration, the 'pre-provisioning' feature is\nadvertised.\n\nIf the device allows arbitrarily named user-controlled\ninterfaces, the 'arbitrary-names' feature is advertised.\n\nWhen a configured user-controlled interface is created by\nthe system, it is instantiated with the same name in the\n/interface-state/interface list.",
              "type": "leaf",
              "name": "name",
              "children": []
            }
          ]
        }
      ]
    }
   [...]
  ]
}