Docs on flow label `telemetry` flag inconsistent with implementation

[krdln]

All flow labels have the telemetry flag steering whether flow label should be included in [ARC] telemetry.

https://github.com/fluxninja/aperture/blob/71957f6293e4d5cff0cd81ce4f92f2962e1e95c8/pkg/policies/flowcontrol/label/flow-label.go#L14-L18

This is togglable for classifier-created flow labels and also, we set this flag for builtin flow labels: https://github.com/fluxninja/aperture/blob/71957f6293e4d5cff0cd81ce4f92f2962e1e95c8/pkg/policies/flowcontrol/service/checkhttp/checkhttp-labels.go#L30-L65

The implementation though ignores this flag and behaves as if all flow labels (classifier-created and builtin) had telemetry: true.

https://github.com/fluxninja/aperture/blob/71957f6293e4d5cff0cd81ce4f92f2962e1e95c8/pkg/policies/flowcontrol/service/checkhttp/checkhttp.go#L163

https://github.com/fluxninja/aperture/blob/71957f6293e4d5cff0cd81ce4f92f2962e1e95c8/pkg/policies/flowcontrol/service/checkhttp/checkhttp.go#L176

(note the ToPlainMap – it drops the telemetry flag). https://github.com/fluxninja/aperture/blob/71957f6293e4d5cff0cd81ce4f92f2962e1e95c8/pkg/policies/flowcontrol/label/flow-label.go#L33

Either docs are outdated or impl wrong.

[krdln]

Either docs are outdated or impl wrong.

• Regarding Telemetry flag on Rule the consensus is that impl is wrong (so Telemetry: false should be respected in the code)
• Regarding sending out headers, I think we should stop sending them from now. If we decide we do want to send all headers by default, we will just flip the flag https://github.com/fluxninja/aperture/blob/71957f6293e4d5cff0cd81ce4f92f2962e1e95c8/pkg/policies/flowcontrol/service/checkhttp/checkhttp-labels.go#L64.

Note: There's some code duplication between checkhttp & authz, make sure to handle both places!

[krdln]

Update: The consensus is that we should stop sending header values. In other words: the Telemetry: false should always be respected.