yEd Module

N2G yEd Module supports producing graphml XML structured text files that can be opened by yWorsk yEd Graph Editor or yEd web application.

Quick start

Nodes and links can be added one by one using add_node and add_link methods

from N2G import yed_diagram

diagram = yed_diagram()
diagram.add_node('R1', top_label='Core', bottom_label='ASR1004')
diagram.add_node('R2', top_label='Edge', bottom_label='MX240')
diagram.add_link('R1', 'R2', label='DF', src_label='Gi0/1', trgt_label='ge-0/1/2')
diagram.layout(algo="kk")
diagram.dump_file(filename="Sample_graph.graphml", folder="./Output/")

After opening and editing diagram, it might look like this:

R1 Core ASR1004 R2 Edge MX240 DF Gi0/1 ge-0/1/2

Adding SVG nodes

By default N2G uses shape nodes, but svg image can be sourced from directory on your system and used as node image instead. However, svg images as nodes can support only one label attribute, that label will be displayed above svg picture.

from N2G import yed_diagram

diagram = yed_diagram()
diagram.add_node('R1', pic="router.svg", pic_path="./Pics/")
diagram.add_node('R2', pic="router_edge.svg", pic_path="./Pics/")
diagram.add_link('R1', 'R2', label='DF', src_label='Gi0/1', trgt_label='ge-0/1/2')
diagram.layout(algo="kk")
diagram.dump_file(filename="Sample_graph.graphml", folder="./Output/")

After opening and editing diagram, it might look like this:

_images/svg_nodes_example.png

Loading graph from dictionary

Diagram elements can be loaded from dictionary structure. That dictionary may contain nodes, links and edges keys, these keys should contain list of dictionaries where each dictionary item will contain elements attributes such as id, labels, description etc.

from N2G import yed_diagram

diagram = yed_diagram()
sample_graph={
'nodes': [
    {'id': 'a', 'pic': 'router.svg', 'label': 'R1' },
    {'id': 'R2', 'bottom_label':'CE12800', 'top_label':'1.1.1.1'},
    {'id': 'c', 'label': 'R3', 'bottom_label':'FI', 'top_label':'fns751', 'description': 'role: access'},
    {'id': 'd', 'pic':'firewall.svg', 'label': 'FW1', 'description': 'location: US'},
    {'id': 'R4', 'pic': 'router'}
],
'links': [
    {'source': 'a', 'src_label': 'Gig0/0\nUP', 'label': 'DF', 'target': 'R2', 'trgt_label': 'Gig0/1', 'description': 'role: uplink'},
    {'source': 'R2', 'src_label': 'Gig0/0', 'label': 'Copper', 'target': 'c', 'trgt_label': 'Gig0/2'},
    {'source': 'c', 'src_label': 'Gig0/0', 'label': 'ZR', 'target': 'a', 'trgt_label': 'Gig0/3'},
    {'source': 'd', 'src_label': 'Gig0/10', 'label': 'LR', 'target': 'c', 'trgt_label': 'Gig0/8'},
    {'source': 'd', 'src_label': 'Gig0/11', 'target': 'R4', 'trgt_label': 'Gig0/18'}
]}
diagram.from_dict(sample_graph)
diagram.layout(algo="kk")
diagram.dump_file(filename="Sample_graph.graphml", folder="./Output/")

After opening and editing diagram, it might look like this:

R1 R2 1.1.1.1 CE12800 R3 fns751 FI FW1 R4 DF Gig0/0 UP Gig0/1 Copper Gig0/0 Gig0/2 ZR Gig0/0 Gig0/3 LR Gig0/10 Gig0/8 Gig0/11 Gig0/18 role: access location: US role: uplink

Loading graph from list

From list method allows to load graph from list of dictionaries, generally containing link details like source, target, labels. Additionally source and target can be defined using dictionaries as well, containing nodes details.

Note

Non-existing node will be automatically added on first encounter, by default later occurrences of same node will not lead to node attributes change, that behavior can be changed setting node_duplicates yed_diagram attribute equal to update value.

from N2G import yed_diagram

diagram = yed_diagram()
sample_list_graph = [
    {'source': {'id': 'SW1', 'top_label': 'CORE', 'bottom_label': '1,1,1,1'}, 'src_label': 'Gig0/0', 'target': 'R1', 'trgt_label': 'Gig0/1'},
    {'source': {'id': 'R2', 'top_label': 'DC-PE'}, 'src_label': 'Gig0/0', 'target': 'SW1', 'trgt_label': 'Gig0/2'},
    {'source': {'id':'R3', 'bottom_label': '1.1.1.3'}, 'src_label': 'Gig0/0', 'target': 'SW1', 'trgt_label': 'Gig0/3'},
    {'source': 'SW1', 'src_label': 'Gig0/4', 'target': 'R4', 'trgt_label': 'Gig0/1'},
    {'source': 'SW1', 'src_label': 'Gig0/5', 'target': 'R5', 'trgt_label': 'Gig0/7'},
    {'source': 'SW1', 'src_label': 'Gig0/6', 'target': 'R6', 'trgt_label': 'Gig0/11'}
]
diagram.from_list(sample_list_graph)
diagram.dump_file(filename="Sample_graph.graphml", folder="./Output/")

After opening and editing diagram, it might look like this:

_images/from_list_example.png

Loading graph from csv

Similar to from_dict or from_list methods, from_csv method can take csv data with elements details and add them to diagram. Two types of csv table should be provided - one for nodes, another for links.

from N2G import yed_diagram

diagram = yed_diagram()
csv_links_data = """"source","src_label","label","target","trgt_label","description"
"a","Gig0/0\nUP","DF","R1","Gig0/1","vlans_trunked: 1,2,3\nstate: up"
"R1","Gig0/0","Copper","c","Gig0/2",
"R1","Gig0/0","Copper","e","Gig0/2",
d,Gig0/21,FW,e,Gig0/23,
"""
csv_nodes_data=""""id","pic","label","bottom_label","top_label","description"
a,router,"R12",,,
"R1",,,"SGD1378","servers",
"c",,"R3","SGE3412","servers","1.1.1.1"
"d","firewall.svg","FW1",,,"2.2.2.2"
"e","router","R11",,,
"""
diagram.from_csv(csv_nodes_data)
diagram.from_csv(csv_links_data)
diagram.dump_file(filename="Sample_graph.graphml", folder="./Output/")

After opening and editing diagram, it might look like this:

R12 R1 servers SGD1378 R3 servers SGE3412 FW1 R11 DF Gig0/0 UP Gig0/1 Copper Gig0/0 Gig0/2 Copper Gig0/0 Gig0/2 FW Gig0/21 Gig0/23 1.1.1.1 2.2.2.2 vlans_trunked: 1,2,3 state: up

Loading existing diagrams

N2G yEd module uses custom nmetadata and emetadata attributes to store original node and link id. For nodes, nmetadata contains node id in a format {'id': 'node_id_value'}, for links emetadata contains source and target node ids as well as link id, e.g. {"sid": "SW1", "tid": "R6", "id": "8e96ade0d90d33c3308721dc2a53b391"}, where link id calculated using rules described in API reference section.

nmetadata and emetadata custom attributes used to properly load previously produced diagrams for modification, as a result:

Warning

currently, N2G yEd module can properly load only diagrams that were created by this module in the first place or diagrams that had manually added nmetadata and emetadata attributes.

N2G yEd module provides from_file and from_text methods to load existing diagram content, to load diagram from file one can use this as example:

from N2G import yed_diagram

diagram = yed_diagram()
diagram.from_file("./source/diagram_old.graphml")

After diagram loaded it can be modified or updated using add_x, from_x, delete_x or compare methods.

Diagram layout

To arrange diagram nodes in certain way one can use layout method that relies on igraph library to calculate node coordinates in accordance with certain algorithm. List of supported layout algorithms and their details can be found here together with brief description in API Reference section.

Sample code to layout diagram:

from N2G import yed_diagram

diagram = yed_diagram()
diagram.from_file("./source/diagram_old.graphml")
diagram.layout(algo="drl", width=500, height=500)
diagram.dump_file(filename="Sample_graph.graphml", folder="./Output/")

Comparing diagrams

Comparing diagrams can be useful to spot changes in your system. N2G compare method allow to calculate differences between old and new graphs and produce resulting diagram highlighting changes.

from N2G import yed_diagram

diagram = yed_diagram()
old_graph = {
'nodes': [
    {'id': 'R1'}, {'id': 'R2'}, {'id': 'R3'},
    ],
'edges': [
    {'source': 'R1', 'target': 'R2'},
    {'source': 'R2', 'target': 'R3'},
    {'source': 'R3', 'target': 'R1'}
]}
new_graph = {
'nodes': [
    {'id': 'R1'}, {'id': 'R2'}, {'id': 'R4'},
    ],
'edges': [
    {'source': 'R1', 'target': 'R2'},
    {'source': 'R2', 'target': 'R4'}
]}
diagram.from_dict(old_graph)
diagram.compare(new_graph)
diagram.layout(algo="kk", width=500, height=500)
diagram.dump_file(filename="Sample_graph.graphml", folder="./Output/")

Original and after diagrams:

_images/compare_example.png

R3 and its links are missing - highlighted in gray, but R4 and its link is new - highlighted in green.

API reference

API reference for N2G yEd module.