system-config/doc/source/firehose_schema.rst

title

Firehose Schema

Firehose Schema

This attempts to document the topic and payload schema for all the services reporting to the firehose. However since much of what is reported to firehose is dynamically generated it is possible this document misses a case.

Gerrit

Messages on firehose for gerrit are generated using the germqtt project. For the most part these are basically identical to what gerrit returns on it's native event stream except over MQTT.

Topics

The topics for gerrit are generated dynamically. However, they follow a fairly straightforward pattern. The basic formula for this is:

gerrit/<git namespace>/<repo name>/<gerrit event>

So for example a typical topic would be:

gerrit/openstack/nova/comment-added

The git namespace and repo name are pretty self explanatory and are just from the git repository the change in gerrit is for. The event is defined in the gerrit event stream. You can see the full reference for topics in the Gerrit docs for Gerrit events. However, for simplicity the possible values are:

• change-abandoned
• change-merged
• change-restored
• comment-added
• draft-published
• hashtags-changed
• merge-failed
• patchset-created
• ref-updated
• reviewer-added
• topic-changed

Payload

The payload for gerrit messages are basically the same JSON that gets returned by gerrit's event stream command. Instead of repeating the entire gerrit schema doc here just refer to gerrit's docs on the JSON payload which documents the contents of each JSON object and refer to the doc on Gerrit events for which JSON objects are included with which event type.

Launchpad

The messages sent to firehose for launchpad are generated using lpmqtt

Topics

The topics for lpmqtt follow a pretty simple formula:

launchpad/<project>/<event type>/<bug number>

the project is the launchpad project name, event type will always be "bug" (or not present). The intent of this was to be "bug" or "blueprint", but due to limitations in launchpad getting notifications from blueprints is not possible. The flexibility was left in the schema just in case this ever changes. The bug number is obviously the bug number from launchpad.

It's also worth noting that only the base topic is a guaranteed field. Depending on the notification email from launchpad some of the other fields may not be present. In those cases the topic will be populated left to right until a missing field is encountered.

Payload

The payload of messages is dynamically generated and dependent on the notification recieved from launchpad, and launchpad isn't always consistent in what fields are present in those notifications.

However, for bug event types there is a standard format. The fields which are always present for bugs (which should normally be the only message for firehose) are:

• commenters
• bug-reporter
• bug-modifier
• bug-number
• event-type

The remaining fields are dynamic and depend on launchpad. An example message payload (with the body trimmed) for a bug is:

{
  "status": "Triaged",
  "project": "octavia",
  "assignee": "email@fakedomain.com",
  "bug-reporter": "Full name (username)",
  "event-type": "bug",
  "bug-number": "1680938",
  "commenters": ["username"]
  "tags": ["rfe"],
  "importance": "Medium",
  "bug-modifier": "Full Name (username)",
  "body": "notification body, often is just bug comment or summary",
}