Welcome to botocore — botocore 1.16.0 documentation

Upgrading to 1.12.0

What Changed

The botocore event system was changed to emit events based on the service id rather than the endpoint prefix or service name.

Why Was The Change Was Made

This was done to handle several issues that were becoming increasingly problematic:

• Services changing their endpoint prefix would cause some registered events to no longer fire (but not all).
• New services that launch using an endpoint that another service is using won't be able to be uniquely selected. There are a number of cases of this already.
• Services whose client name and endpoint prefix differed would require two different strings if you want to register against all events.

How Do I Know If I'm Impacted

Any users relying on registering an event against one service impacting other services are impacted. You can consult the following table to see if you are impacted. If you are registering an event using one of the event parts in the leftmost column with the intention of impacting an unintended target service in the rightmost column, then you are impacted and will need to update.

For example, if you are registering an event againstbefore-call.elasticloadbalancing expecting it to run when making calls with an elbv2 client, you will be impacted.

If you are registering an event against one of the services in the Unintended Targets column, you may be impacted if you were relying on those events not firing.

If you are registering events using * in the service place, or are registering against any service not in this table, you will not need a code change. In many cases the actual event name will have changed, but for services without shared endpoints we do the work of translating the event name at registration and emission time. In future versions of botocore we will remove this translation, so you may wish to update your code anyway.

How Do I Update My Code

You will need to look at the events you are registering against and determine which services you wish to impact with your handler. If you only wish to impact the intended target service (as defined in the above table), then you don't need to change the event. If you wish to impact another service in addition to the intended target service, you will need to register a new event using that service's event name. Similarly, if you wish to impact another service instead you will simply need to change the event you are registered against.

To get the new event name, consult this table:

Additionally, you can get the new event name in code like so:

from botocore.session import Sessionsession = Session()client = session.create_client('elbv2')service_event_name = client.meta.service_model.service_id.hyphenize()

Armed with the service event name, simply replace the old service name in the handler with the new service event name. If you were registering an event against before-call.autoscaling intending to impact autoscaling-plansfor example, you would instead register againstbefore-call.auto-scaling-plans.

If you are registering an event against one of the services in the Unintended Targets column, you will now see those events getting fired where previously they were not. While this is enabling that expected behavior, this still represents a change in actual behavior. You should not need to update your code, but you should test to ensure that you are seeing the behavior you want.