Netdiff is a simple abstraction layer for parsing network topology data of open source dynamic routing protocols or any other networking software which has knowledge about the topology of a network.
Its goal is to allow applications like openwisp-network-topology to collect, visualize and monitor network topology data without having to deal with the details of each networking software from which the data is retrieved.
Features:
- parse different formats
- detect changes in two topologies
- return consistent NetJSON output
- uses the popular networkx library under the hood
Table of Contents:
Install from pypi:
pip install netdiffInstall tarball:
pip install https://github.com/openwisp/netdiff/tarball/masterAlternatively you can install via pip using git:
pip install -e git+git://github.com/openwisp/netdiff#egg=netdiffIf you want to contribute, install your cloned fork:
git clone [email protected]:<your_fork>/netdiff.git
cd netdiff
python setup.py developCalculate diff of an OLSR 0.6.x topology:
from netdiff import OlsrParser
from netdiff import diff
old = OlsrParser(file='./stored-olsr.json')
new = OlsrParser(url='http://127.0.0.1:9090')
diff(old, new)In alternative, you may also use the subtraction operator:
from netdiff import OlsrParser
from netdiff import diff
old = OlsrParser(file='./stored-olsr.json')
new = OlsrParser(url='http://127.0.0.1:9090')
old - newThe output will be an ordered dictionary with three keys:
- added
- removed
- changed
Each key will contain a dict compatible with the NetJSON NetworkGraph format representing respectively:
- the nodes and links that have been added to the topology
- the nodes and links that have been removed from the topology
- the nodes and links that are present in both topologies but their attributes have changed
If no changes are present, keys will contain None.
So if between old and new there are no changes, the result will be:
{
"added": None
"removed": None,
"changed": None
}While if there are changes, the result will look like:
{
"added": {
"type": "NetworkGraph",
"protocol": "OLSR",
"version": "0.6.6",
"revision": "5031a799fcbe17f61d57e387bc3806de",
"metric": "ETX",
"nodes": [
{
"id": "10.150.0.7",
"label": "Node A",
"local_addresses": [],
"properties": {}
},
{
"id": "10.150.0.6",
"label": "Node B",
"local_addresses": ["10.56.2.1"],
"properties": {
"hostname": "nodeb.lan"
}
}
],
"links": [
{
"source": "10.150.0.3",
"target": "10.150.0.7",
"cost": 1.50390625,
"cost_text", "",
"properties": {}
},
{
"source": "10.150.0.3",
"target": "10.150.0.6",
"cost": 1.0
"cost_text", "",
"properties": {}
}
]
},
"removed": {
"type": "NetworkGraph",
"protocol": "OLSR",
"version": "0.6.6",
"revision": "5031a799fcbe17f61d57e387bc3806de",
"metric": "ETX",
"nodes": [
{
"id": "10.150.0.8",
"label": "Node C",
"local_addresses": [],
"properties": {}
}
],
"links": [
{
"source": "10.150.0.7",
"target": "10.150.0.8",
"cost": 1.0
"cost_text", "",
"properties": {}
}
]
},
"changed": {
"type": "NetworkGraph",
"protocol": "OLSR",
"version": "0.6.6",
"revision": "5031a799fcbe17f61d57e387bc3806de",
"metric": "ETX",
"nodes": [],
"links": [
{
"source": "10.150.0.3",
"target": "10.150.0.2",
"cost": 1.0
"cost_text", "",
"properties": {}
}
]
}
}Parsers are classes that extend netdiff.base.BaseParser and implement a parse method which is in charge of converting a python data structure into networkx.Graph object and return the result.
Parsers also have a json method which returns valid NetJSON output.
The available parsers are:
netdiff.OlsrParser: parser for the olsrd jsoninfo plugin or the older txtinfo pluginnetdiff.BatmanParser: parser for the batman-advanced alfred tool (supports also the legacy txtinfo format inherited from olsrd)netdiff.Bmx6Parser: parser for the BMX6 b6m toolnetdiff.CnmlParser: parser for CNML 0.1netdiff.NetJsonParser: parser for the NetJSON NetworkGraph formatnetdiff.OpenvpnParser: parser for the OpenVPN status filenetdiff.WireguardParser: parser for the Wireguard VPN (the command to use iswg show all dump)netdiff.ZeroTierParser: parser for ZeroTier VPN (the command to use iszerotier-cli peers -jor access the peers information through the ZeroTier Service API)
Data can be supplied in 3 different ways, in the following order of precedence:
data:dictorstrrepresenting the topology/graphurl: URL to fetch data fromfile: file path to retrieve data from
Other available arguments:
- timeout: integer representing timeout in seconds for HTTP or telnet requests, defaults to
None - verify: boolean indicating to the request library whether to do SSL certificate verification or not
- directed: boolean that enables the use of a directed graph (
networkx.DiGraph), defaults toFalse
Local file example:
from netdiff import BatmanParser
BatmanParser(file='./my-stored-topology.json')HTTP example:
from netdiff import NetJsonParser
url = 'https://raw.githubusercontent.com/interop-dev/netjson/master/examples/network-graph.json'
NetJsonParser(url=url)Telnet example with timeout:
from netdiff import OlsrParser
OlsrParser(url='telnet://127.0.1', timeout=5)HTTPS example with self-signed SSL certificate using verify=False:
from netdiff import NetJsonParser
OlsrParser(url='https://myserver.mydomain.com/topology.json', verify=False)Netdiff parsers can return a valid NetJSON NetworkGraph object:
from netdiff import OlsrParser
olsr = OlsrParser(url='telnet://127.0.0.1:9090')
# will return a dict
olsr.json(dict=True)
# will return a JSON formatted string
print(olsr.json(indent=4))Output:
{
"type": "NetworkGraph",
"protocol": "OLSR",
"version": "0.6.6",
"revision": "5031a799fcbe17f61d57e387bc3806de",
"metric": "ETX",
"nodes": [
{
"id": "10.150.0.3"
},
{
"id": "10.150.0.2"
},
{
"id": "10.150.0.4"
}
],
"links": [
{
"source": "10.150.0.3",
"target": "10.150.0.2",
"cost": 2.4
},
{
"source": "10.150.0.3",
"target": "10.150.0.4",
"cost": 1.0
}
]
}All the exceptions are subclasses of netdiff.exceptions.NetdiffException.
netdiff.exceptions.ConversionException
Raised when netdiff can't recognize the format passed to the parser.
Not necessarily an error, should be caught and managed in order to support additional formats.
The data which was retrieved from network/storage can be accessed via the "data" attribute, eg:
def to_python(self, data):
try:
return super().to_python(data)
except ConversionException as e:
return self._txtinfo_to_jsoninfo(e.data)netdiff.exceptions.ParserError
Raised when the format is recognized but the data is invalid.
netdiff.exceptions.NetJsonError
Raised when the json method of netdiff.parsers.BaseParser does not have enough data to be compliant with the NetJSON NetworkGraph specification.
netdiff.exceptions.TopologyRetrievalError
Raised when it is not possible to retrieve the topology data (eg: the URL might be temporary unreachable).
By default, the OpenVPN parser uses the common name to identify a client, this was chosen because if the public IP address is used, the same client will not be recognized if it connects with a different IP address (very probable since many ISPs use dynamic public IP addresses).
This does not work when the vpn server configuration allows different clients to use the same common name (which is generally not recommended anyway).
If you need to support legacy systems which are configured with the OpenVPN duplicate-cn feature enabled, you can pass duplicate_cn=True during the initialization of OpenvpnParser. This will change the behavior of the parser so that each client is identified by their common name and IP address (and additionally the port used if there are multiple clients with same common name and IP).
If you get a similar error when performing a request to the jsoninfo plugin of olsrd (version 0.6 to 0.9) chances are high that http headers are disabled.
To fix it turn on http headers in your olsrd configuration file, eg:
LoadPlugin "olsrd_jsoninfo.so.0.0"
{
PlParam "httpheaders" "yes" # add this line
PlParam "Port" "9090"
PlParam "accept" "0.0.0.0"
}Install your forked repo:
git clone git://github.com/<your_fork>/netdiff
cd netdiff/
python setup.py developInstall test requirements:
pip install -r requirements-test.txtRun tests with:
./runtests.py
./run-qa-checksAlternatively, you can use the nose2 command (which has a ton of available options):
nose2
nose2 tests.test_olsr # run only olsr related tests
nose2 tests/test_olsr.py # variant form of the previous command
nose2 tests.test_olsr:TestOlsrParser # variant form of the previous command
nose2 tests.test_olsr:TestOlsrParser.test_parse # run specific testSee test coverage with:
coverage run --source=netdiff runtests.py && coverage reportPlease refer to the OpenWISP contributing guidelines.
See OpenWISP Support Channels.
See CHANGES.
See LICENSE.
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