Do not send config to Kong Gateway when no changes occurred

[programmer04]

Is there an existing issue for this?

• I have searched the existing issues

Does this enhancement require public documentation?

• I have added an Acceptance Criteria item for adding and/or adjusting public documentation (if applicable)

Problem Statement

Method

kubernetes-ingress-controller/internal/dataplane/kong_client.go

Line 393 in cf2efda

func (c *KongClient) Update(ctx context.Context) error {

can use optimization that for now is reserved for Fallback configuration

• feat: use TakeSnapshotIfChanged to avoid taking redundant snapshot #6092

in its main path to avoid redundant submissions of config to Kong Gateway

Proposed Solution

• move the configuration change check to the main code path

Additional information

There is a flag mysterious flag

kubernetes-ingress-controller/internal/manager/config.go

Line 181 in cf2efda

flagSet.BoolVar(&c.EnableReverseSync, "enable-reverse-sync", false, `Send configuration to Kong even if the configuration checksum has not changed since previous update.`)

that seems to be pretty similar. Decide what about it. See also internal/dataplane/sendconfig/config_change_detector.go which suppose to do the same, but in later stage of sending a config.

Acceptance Criteria

• In case of the same configuration method Update returns without sending configuration to Kong
• Decision about flag --enable-reverse-sync is made