[ovirt-devel] Making event types backwards compatible?

[Juan Hernández]

Hello,

It has been recently requested that the API provides event types:

  [RFE] Expose event types to API
  https://bugzilla.redhat.com/1453170

Currently the API provides the event code and description, for example:

  <event href="/ovirt-engine/api/events/8021" id="8021">
    <code>19</code>
    <description>Host myhost failed to recover.</description
    ...
  </event>

There is no documentation of what is the meaning of codes, except the
source code of the engine itself. This forces some applications to add
their own code to name mapping. For example, the 'ovirt' Ruby gem used
by older versions of ManageIQ to interact with oVirt contains the following:

  https://github.com/ManageIQ/ovirt/blob/v0.17.0/lib/ovirt/event.rb#L25-L485

We could avoid this by adding to the API a new event attribute that
indicates the type:

  <event href="/ovirt-engine/api/events/8021" id="8021">
    <code>19</code>
    <type>host_recover_failure</type>
    <description>Host myhost failed to recover.</description>
    ...
  </event>

Ideally this should be defined as an enum, so that it will be
represented as an enum in the SDKs. Alternatively it could just be an
string, and we could reuse the 'name' attribute:

  <event href="/ovirt-engine/api/events/8021" id="8021">
    <code>19</code>
    <name>host_recover_failure</name>
    <description>Host myhost failed to recover.</description>
    ...
  </event>

However, the key point to making this useful would be to keep the types
(or names) backwards compatible, so that users of the API can rely on
their values and meanings.

So this is my question to you: can we commit to keep the names and
meanings of the backend event types backwards compatible?

Regards,
Juan Hernandez