feat: enable flagd probes

[Kavindu-Dodan]

This PR

Relates to #408

Introduce flagd Liveness and Readiness probes for side-car deployed through OFO. Default is enabled (probes are enabled).

Behavior can be controlled through FlagSourceConfiguration CRD field probesEnabled .

probesEnabled: true, false

How to test

Consider the following FlagSourceConfiguration CRD configurations,

Probes enabled (default),

apiVersion: core.openfeature.dev/v1alpha3
kind: FlagSourceConfiguration
metadata:
  name: myappfs
spec:
  sources:
  - source: flags/flags
    provider: kubernetes

Probes disabled,

apiVersion: core.openfeature.dev/v1alpha3
kind: FlagSourceConfiguration
metadata:
  name: myappfs
spec:
  probesEnabled: false #probes disabled
  sources:
  - source: flags/flags
    provider: kubernetes

Alternatively, it is possible to configure the behavior from OFO Helm deployment. For this, helm value sidecarConfiguration.probesEnabled can be used. This internally maps to OFO manager env var SIDECAR_PROBES_ENABLED.

Helm value based overriding is desired if probes need to be disabled by default and be enabled by overriding through FlagSourceConfiguration CRD definition.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (main@dd34801). Click here to learn what that means.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #390   +/-   ##
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  Coverage        ?   71.29%           
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  Files           ?       11           
  Lines           ?      836           
  Branches        ?        0           
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  Hits            ?      596           
  Misses          ?      213           
  Partials        ?       27           

Impacted Files	Coverage Δ
...pis/core/v1alpha2/flagsourceconfiguration_types.go	100.00% <ø> (ø)
...pis/core/v1alpha3/flagsourceconfiguration_types.go	100.00% <ø> (ø)
...ore/v1alpha2/flagsourceconfiguration_conversion.go	100.00% <100.00%> (ø)
...ore/v1alpha3/flagsourceconfiguration_conversion.go	100.00% <100.00%> (ø)
webhooks/pod_webhook.go	83.93% <100.00%> (ø)

Flag	Coverage Δ
component-tests	64.91% <100.00%> (?)
unit-tests	21.05% <18.18%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

[beeme1mr]

Hey @Kavindu-Dodan, could you please update the Artifact Hub readme with the new information?

https://github.com/open-feature/open-feature-operator/blob/main/chart/open-feature-operator/README.md#sidecar-configuration

[Kavindu-Dodan]

Hey @Kavindu-Dodan, could you please update the Artifact Hub readme with the new information?

https://github.com/open-feature/open-feature-operator/blob/main/chart/open-feature-operator/README.md#sidecar-configuration

Thanks, I updated (along with formatting improvement) the readme. Also, your review helped to validate Helm configurations which I missed :)

[beeme1mr]

Looks good from a feature and documentation perspective. Nice job with the PR description by the way!