missing
Fixes#6625
When an SNS topic subscription was created with TF and then removed via
the AWS Console, Terraform threw an error:
```
* aws_sns_topic_subscription.testme: NotFound: Subscription does not
* exist
status code: 404, request id: a22e7ed7-3630-5a8a-b767-317ac1440e24
```
This PR will remove the topic subscription from state on a NotFound and
will then readd the subscripton
Change the `RetryFunc` from a plain `error` return type to a
specialized `RetryError` which must decide whether it is
retryable or not.
Add `RetryableError` / `NonRetryableError` factory functions that
callers are meant to use to build up these errors.
This makes it eminently clear whether or not a given error is
retryable from inside the client code.
Goal here is to _not_ change any behavior, simply reflect the
existing behavior with the new, clearer, API.
http and https SNS topic subscription endpoints require confirmation to set a valid arn otherwise
arn would be set to "pending confirmation". If the endpoints auto confirm then arn is set
asynchronously but if we try to create another subscription with same parameters then api returns
"pending subscription" as arn but does not create another a duplicate subscription. In order to
solve this we should be fetching the subscription list for the topic and identify the subscription
with same parameters i.e., protocol, topic_arn, endpoint and extract the subscription arn.
Following changes were made to support the http/https endpoints that auto confirms
1. Added 3 extra parameters i.e.,
1. endpoint_auto_confirms -> boolean indicates if end points auto confirms
2. max_fetch_retries -> number of times to fetch subscription list for the topic to get the subscription arn
3. fetch_retry_delay -> delay b/w fetch subscription list call as the confirmation is done asynchronously.
With these parameters help added support http and https protocol based endpoints that auto confirm.
2. Update website doc appropriately
Paul Stack