PubSub Message Schema Airspace

Andi Lamprecht ·2026-05-11· 3 min read· Accepted

PubSub Message Schema - Airspace

Context

This document describes the format and metadata of a pubsub message containing Airspace Table data.

Atlas pipeline has a worker attached to Airspaces table which monitors any changes done to that table. Those changes are
then transformed to fit required PubSub message schema and published to the topic: <topic_name>

Any subscriber that listen to the topic is able to use that information to fully (or partially) reproduce Atlas Airspace
table in any storage system and keep it up to date.

PubSub Message Schema:

PubSub message contains 3 fields:

• data
• ordering_key
• attributes

data

Binary string representing row processed in each action as a struct.

It has a different format, depending on an action done.

1. Insert / Update

Airspace Schema

Altitude Schema

Schedule Schema

Example message:

Binary json is represented with new line for better readability

    {
        data: b"{
            'uuid': '241fsa-521gg-5521aaz',
            'usage': 'restricted',
            'ruleset': 'droneup-delivery',
            'kind': 'class_b_airspace'
            'metadata':{
                "faa_id":"ROW",
                "airport_name":"Roswell Air Center",
                "icao":"KROW",
                "related_airspace_class":"E",
                "airspace_global_id":"A0D4D5ED-2D58-4263-8342-437CB7174D1B"
            }
            'floor':{
               value: '400',
               unit: 'ft',
               ref: 'AGL'

            }
            'ceiling':  {
               value: '400',
               unit: 'ft',
               ref: 'AGL'

            }
            'schedule': <airspace_schedule>
            'geometry': 'POINT( 11, 12)'
        "
        ordering_key: '2'
        attributes: {
            "action": "insert",
            "commit_version": 1,
            "commit_timestamp": "2023-07-20 09:04:14.331000"
            "version": 1,
        }
    }

2. Delete

ordering_key

Type: string

String representation of an automatically generated integer ID assigned to a commit. This ID is updated whenever there

is a change in the table. A higher ID value indicates that the data is more up-to-date.

attributes

Struct of cutom atributes, that describes the change

Notes:

Field metadata is strictly related to a kind. Different kind of object may contain different metadata fields

Consequences

Atlas and it’s Airspace table consumers are coupled via PubSub topic, which allows us to evolve a schema without

interaction on each other work. Currently, Atlas pushes only the subset of row values required by its consumers.

Alternatives Considered

Delta change log contains 4 types of actions: insert/pre-update/post-update and delete, which has full row data.

Insert - new data inserted to the table

Pre-Update - how row data looked before the update

Post-Update - how row data looked after the update

Delete - full row data that has been removed

To lower the message size the decision was made to publish only uuid for delete actions and skip publishing *

pre-update* actions.