circuit-maintenance-parser

circuit-maintenance-parser is a Python library that parses circuit maintenance notifications from Network Service Providers (NSPs), converting heterogeneous formats to a well-defined structured format.

Context

Every network depends on external circuits provided by NSPs who interconnect them to the Internet, to office branches or to external service providers such as Public Clouds.

Obviously, these services occasionally require operation windows to upgrade or to fix related issues, and usually they happen in the form of circuit maintenance periods. NSPs generally notify customers of these upcoming events so that customers can take actions to minimize the impact on the regular usage of the related circuits.

The challenge faced by many customers is that mostly every NSP defines its own maintenance notification format, even though in the end the relevant information is mostly the same across NSPs. This library is built to parse notification formats from several providers and to return always the same object struct that will make it easier to process them afterwards.

The format of this output is following the BCOP defined during a NANOG meeting that aimed to promote the usage of the iCalendar format. Indeed, if the NSP is using the proposed iCalendar format, the parser is straight-forward and there is no need to define custom logic, but this library enables supporting other providers that are not using this proposed practice, getting the same outcome.

You can leverage this library in your automation framework to process circuit maintenance notifications, and use the standardized Maintenance model to handle your received circuit maintenance notifications in a simple way. Every Maintenance object contains the following attributes:

• provider: identifies the provider of the service that is the subject of the maintenance notification.
• account: identifies an account associated with the service that is the subject of the maintenance notification.
• maintenance_id: contains text that uniquely identifies (at least within the context of a specific provider) the maintenance that is the subject of the notification.
• circuits: list of circuits affected by the maintenance notification and their specific impact.
• start: timestamp that defines the starting date/time of the maintenance in GMT.
• end: timestamp that defines the ending date/time of the maintenance in GMT.
• stamp: timestamp that defines the update date/time of the maintenance in GMT.
• organizer: defines the contact information included in the original notification.
• status: defines the overall status or confirmation for the maintenance.¹
• summary: human-readable details about this maintenance notification. May be an empty string.
• sequence: a sequence number for notifications involving this maintenance window. In practice this is generally redundant with the stamp field, and will be defaulted to 1 for most non-iCalendar parsed notifications.²
• uid: a unique (?) identifer for a thread of related notifications. In practice this is generally redundant with the maintenance_id field, and will be defaulted to 0 for most non-iCalendar parsed notifications.

Please, refer to the BCOP to more details about the standardized meaning of these attributes.

¹ Per the BCOP, status (X-MAINTNOTE_STATUS) is an optional field in iCalendar notifications. However, a Maintenance object will always contain a status value; in the case where an iCalendar notification omits this field, the status will be set to "NO-CHANGE", and it's up to the consumer of this library to determine how to appropriately handle this case. Parsers of other notification formats are responsible for setting an appropriate value for this field based on the notification contents, and may or may not include "NO-CHANGE" as one of the possible reported values.

² Per the BCOP, sequence is a mandatory field in iCalendar notifications. However, some NSPs have been seen to send notifications which, while otherwise consistent with the BCOP, omit the SEQUENCE field; in such cases, this library will report a sequence number of -1.

Workflow

1. We instantiate a Provider, directly or via the init_provider method, that depending on the selected type will return the corresponding instance.
2. Get an instance of the NotificationData class. This instance groups together DataParts which each contain some content and a specific type (that will match a specific Parser). For example, a NotificationData might describe a received email message, with DataParts corresponding to the subject line and body of the email. There are factory methods to initialize a NotificationData describing a single chunk of binary data, as well as others to initialize one directly from a raw email message or email.message.EmailMessage instance.
3. Each Provider uses one or more Processors that will be used to build Maintenances when the Provider.get_maintenances(data) method is called.
4. Each Processor class uses one or more Parsers to process each type of data that it handles. It can have custom logic to combine the parsed data from multiple Parsers to create the final Maintenance object.
5. Each Parser class supports one or a set of related data types, and implements the Parser.parse() method used to retrieve a Dict with the relevant keys/values.

By default, there is a GenericProvider that support a SimpleProcessor using the standard ICal Parser, being the easiest path to start using the library in case the provider uses the reference iCalendar standard.

Supported Providers

Supported providers using the BCOP standard

• EuNetworks
• NTT
• PacketFabric
• Telia
• Telstra

Supported providers based on other parsers

• AWS
• AquaComms
• Cogent
• Colt
• Equinix
• EXA (formerly GTT)
• HGC
• Lumen
• Megaport
• Momentum
• Seaborn
• Sparkle
• Telstra
• Turkcell
• Verizon
• Zayo

Note: Because these providers do not support the BCOP standard natively, maybe there are some gaps on the implemented parser that will be refined with new test cases. We encourage you to report related issues!

Installation

The library is available as a Python package in pypi and can be installed with pip: pip install circuit-maintenance-parser

How to use it?

The library requires two things:

• The notificationdata: this is the data that the library will check to extract the maintenance notifications. It can be simple (only one data type and content, such as an iCalendar notification) or more complex (with multiple data parts of different types, such as from an email).
• The provider identifier: used to select the proper Provider which contains the processor logic to take the proper Parsers and use the data that they extract. By default, the GenericProvider (used when no other provider type is defined) will support parsing of iCalendar notifications using the recommended format.

Python Library

First step is to define the Provider that we will use to parse the notifications. As commented, there is a GenericProvider that implements the gold standard format and can be reused for any notification matching the expectations.

from circuit_maintenance_parser import init_provider

generic_provider = init_provider()

type(generic_provider)
<class 'circuit_maintenance_parser.provider.GenericProvider'>

However, usually some Providers don't fully implement the standard and maybe some information is missing, for example the organizer email or maybe a custom logic to combine information is required, so we allow custom Providers:

ntt_provider = init_provider("ntt")

type(ntt_provider)
<class 'circuit_maintenance_parser.provider.NTT'>

Once we have the Provider ready, we need to initialize the data to process, we call it NotificationData and can be initialized from a simple content and type or from more complex structures, such as an email.

from circuit_maintenance_parser import NotificationData

raw_data = b"""BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Maint Note//https://github.com/maint-notification//
BEGIN:VEVENT
SUMMARY:Maint Note Example
DTSTART;VALUE=DATE-TIME:20151010T080000Z
DTEND;VALUE=DATE-TIME:20151010T100000Z
DTSTAMP;VALUE=DATE-TIME:20151010T001000Z
UID:42
SEQUENCE:1
X-MAINTNOTE-PROVIDER:example.com
X-MAINTNOTE-ACCOUNT:137.035999173
X-MAINTNOTE-MAINTENANCE-ID:WorkOrder-31415
X-MAINTNOTE-IMPACT:OUTAGE
X-MAINTNOTE-OBJECT-ID;X-MAINTNOTE-OBJECT-IMPACT=NO-IMPACT:acme-widgets-as-a-service
X-MAINTNOTE-OBJECT-ID;X-MAINTNOTE-OBJECT-IMPACT=OUTAGE:acme-widgets-as-a-service-2
X-MAINTNOTE-STATUS:TENTATIVE
ORGANIZER;CN="Example NOC":mailto:[email protected]
END:VEVENT
END:VCALENDAR
"""

data_to_process = NotificationData.init_from_raw("ical", raw_data)

type(data_to_process)
<class 'circuit_maintenance_parser.data.NotificationData'>

Finally, with we retrieve the maintenances (it is a List because a notification can contain multiple maintenances) from the data calling the get_maintenances method from the Provider instance:

maintenances = generic_provider.get_maintenances(data_to_process)

print(maintenances[0].to_json())
{
"account": "137.035999173",
"circuits": [
{
"circuit_id": "acme-widgets-as-a-service",
"impact": "NO-IMPACT"
},
{
"circuit_id": "acme-widgets-as-a-service-2",
"impact": "OUTAGE"
}
],
"end": 1444471200,
"maintenance_id": "WorkOrder-31415",
"organizer": "mailto:[email protected]",
"provider": "example.com",
"sequence": 1,
"stamp": 1444435800,
"start": 1444464000,
"status": "TENTATIVE",
"summary": "Maint Note Example",
"uid": "42"
}

Notice that, either with the GenericProvider or NTT provider, we get the same result from the same data, because they are using exactly the same Processor and Parser. The only difference is that NTT notifications come without organizer and provider in the notification, and this info is fulfilled with some default values for the Provider, but in this case the original notification contains all the necessary information, so the defaults are not used.

ntt_maintenances = ntt_provider.get_maintenances(data_to_process)
assert maintenances_ntt == maintenances

CLI

There is also a cli entrypoint circuit-maintenance-parser which offers easy access to the library using few arguments:

• data-file: file storing the notification.
• data-type: ical, html or email, depending on the data type.
• provider-type: to choose the right Provider. If empty, the GenericProvider is used.

circuit-maintenance-parser --data-file "/tmp/___ZAYO TTN-00000000 Planned MAINTENANCE NOTIFICATION___.eml" --data-type email --provider-type zayo
Circuit Maintenance Notification #0
{
  "account": "some account",
  "circuits": [
    {
      "circuit_id": "/OGYX/000000/ /ZYO /",
      "impact": "OUTAGE"
    }
  ],
  "end": 1601035200,
  "maintenance_id": "TTN-00000000",
  "organizer": "[email protected]",
  "provider": "zayo",
  "sequence": 1,
  "stamp": 1599436800,
  "start": 1601017200,
  "status": "CONFIRMED",
  "summary": "Zayo will implement planned maintenance to troubleshoot and restore degraded span",
  "uid": "0"
}

How to Extend the Library?

Even though the library aims to include support for as many providers as possible, it's likely that not all the thousands of NSP are supported and you may need to add support for some new one. Adding a new Provider is quite straightforward, and in the following example we are adding support for an imaginary provider, ABCDE, that uses HTML notifications.

First step is creating a new file: circuit_maintenance_parser/parsers/abcde.py. This file will contain all the custom parsers needed for the provider and it will import the base classes for each parser type from circuit_maintenance_parser.parser. In the example, we only need to import Html and in the child class implement the methods required by the class, in this case parse_html() which will return a dict with all the data that this Parser can extract. In this case we have to helper methods, _parse_bs and _parse_tables that implement the logic to navigate the notification data.

from typing import Dict
import bs4  # type: ignore
from bs4.element import ResultSet  # type: ignore
from circuit_maintenance_parser.parser import Html

class HtmlParserABCDE1(Html):
    def parse_html(self, soup: ResultSet) -> Dict:
        data = {}
        self._parse_bs(soup.find_all("b"), data)
        self._parse_tables(soup.find_all("table"), data)
        return [data]

    def _parse_bs(self, btags: ResultSet, data: Dict):
      ...

    def _parse_tables(self, tables: ResultSet, data: Dict):
      ...

Next step is to create the new Provider by defining a new class in circuit_maintenance_parser/provider.py. This class that inherits from GenericProvider only needs to define two attributes:

• _processors: is a list of Processor instances that uses several data Parsers. In this example, we don't need to create a new custom Processor because the combined logic serves well (the most likely case), and we only need to use the new defined HtmlParserABCDE1 and also the generic EmailDateParser that extract the email date. Also notice that you could have multiple Processors with different Parsers in this list, supporting several formats.
• _default_organizer: this is a default helper to fill the organizer attribute in the Maintenance if the information is not part of the original notification.

class ABCDE(GenericProvider):
    _processors: List[GenericProcessor] = [
        CombinedProcessor(data_parsers=[EmailDateParser, HtmlParserABCDE1]),
    ]
    _default_organizer = "[email protected]"

And expose the new Provider in circuit_maintenance_parser/__init__.py:

from .provider import (
    GenericProvider,
    ABCDE,
    ...
)

SUPPORTED_PROVIDERS = (
    GenericProvider,
    ABCDE,
    ...
)

Last, but not least, you should update the tests!

• Test the new Parser in tests/unit/test_parsers.py
• Test the new Provider logic in tests/unit/test_e2e.py

... adding the necessary data samples in tests/unit/data/abcde/.

Contributing

Pull requests are welcomed and automatically built and tested against multiple versions of Python through Travis CI.

The project is following Network to Code software development guidelines and is leveraging:

• Black, Pylint, Mypy, Bandit and pydocstyle for Python linting and formatting.
• Unit and integration tests to ensure the library is working properly.

Local Development

Requirements

• Install poetry
• Install dependencies and library locally: poetry install
• Run CI tests locally: invoke tests --local

How to add a new Circuit Maintenance provider?

1. Define the Parsers(inheriting from some of the generic Parsers or a new one) that will extract the data from the notification, that could contain itself multiple DataParts. The data_type of the Parser and the DataPart have to match. The custom Parsers will be placed in the parsers folder.
2. Update the unit/test_parsers.py with the new parsers, providing some data to test and validate the extracted data.
3. Define a new Provider inheriting from the GenericProvider, defining the Processors and the respective Parsers to be used. Maybe you can reuse some of the generic Processors or maybe you will need to create a custom one. If this is the case, place it in the processors folder.
   • The Provider also supports the definition of a _include_filter and a _exclude_filter to limit the notifications that are actually processed, avoiding false positive errors for notification that are not relevant.
4. Update the unit/test_e2e.py with the new provider, providing some data to test and validate the final Maintenances created.
5. Expose the new Provider class updating the map SUPPORTED_PROVIDERS in circuit_maintenance_parser/__init__.py to officially expose the Provider.

Questions

For any questions or comments, please check the FAQ first and feel free to swing by the Network to Code slack channel (channel #networktocode). Sign up here

License notes

This library uses a Basic World Cities Database by Pareto Software, LLC, the owner of Simplemaps.com: The Provider offers a Basic World Cities Database free of charge. This database is licensed under the Creative Commons Attribution 4.0 license as described at: https://creativecommons.org/licenses/by/4.0/.