Support envoy "safe retry on reset" policy value

[geomacy]

Envoy v1.31.0 introduced a new safe retry on reset setting reset-before-request . This release was included in Contour v1.30.1.

We want to use retries but want to avoid where possible the risk of retrying API operations that it would be unsafe to retry.

This issue proposes an update to the Contour validation enum for retryPolicy RetryOn to include the new policy value so that HTTPProxies can take advantage of this new, safer, behaviour.

From:

// RetryOn is a string type alias with validation to ensure that the value is valid.
// +kubebuilder:validation:Enum="5xx";gateway-error;reset;connect-failure;retriable-4xx;refused-stream;retriable-status-codes;retriable-headers;cancelled;deadline-exceeded;internal;resource-exhausted;unavailable
type RetryOn string

to

// RetryOn is a string type alias with validation to ensure that the value is valid.
// +kubebuilder:validation:Enum="5xx";gateway-error;reset;reset-before-request;connect-failure;retriable-4xx;refused-stream;retriable-status-codes;retriable-headers;cancelled;deadline-exceeded;internal;resource-exhausted;unavailable
type RetryOn string

[github-actions]

Hey @geomacy! Thanks for opening your first issue. We appreciate your contribution and welcome you to our community! We are glad to have you here and to have your input on Contour. You can also join us on our mailing list and in our channel in the Kubernetes Slack Workspace

[tsaarni]

Thanks for spotting this @geomacy! I opened a PR #6772.

[geomacy]

Many thanks @tsaarni!