feat: activate stats when flag is on in audit, webhook

[acpana]

We merged #2686 (yay! 😀 ) but forgot to actually "activate" the driver options when the flags are true. 🤦🏼

This PR leverages the flags to pass in as driver opts for stats gathering.

Here's what the stats look like:

• audit

{
  "level": "info",
  "ts": 1683670170.7345476,
  "logger": "controller",
  "msg": "audit review request stats",
  "process": "audit",
  "audit_id": "2023-05-09T22:09:29Z",
  "execution_stats": [
    {
      "scope": "template",
      "statsFor": "K8sRequiredLabels",
      "stats": [
        {
          "name": "templateRunTimeNS",
          "value": 229701,
          "source": {
            "type": "engine",
            "value": "Rego"
          },
          "description": "the number of nanoseconds it took to evaluate all constraints for a template"
        },
        {
          "name": "constraintCount",
          "value": 1,
          "source": {
            "type": "engine",
            "value": "Rego"
          },
          "description": "the number of constraints that were evaluated for the given constraint kind"
        }
      ],
      "labels": [
        {
          "name": "TracingEnabled",
          "value": false
        },
        {
          "name": "PrintEnabled",
          "value": false
        },
        {
          "name": "target",
          "value": "admission.k8s.gatekeeper.sh"
        }
      ]
    }
  ]
}

• audit from cache

{
  "level": "info",
  "ts": 1683671032.5509458,
  "logger": "controller",
  "msg": "audit from cache review request stats",
  "process": "audit",
  "audit_id": "2023-05-09T22:23:52Z",
  "execution_stats": [
    {
      "scope": "template",
      "statsFor": "K8sRequiredLabels",
      "stats": [
        {
          "name": "templateRunTimeNS",
          "value": 240380,
          "source": {
            "type": "engine",
            "value": "Rego"
          },
          "description": "the number of nanoseconds it took to evaluate all constraints for a template"
        },
        {
          "name": "constraintCount",
          "value": 1,
          "source": {
            "type": "engine",
            "value": "Rego"
          },
          "description": "the number of constraints that were evaluated for the given constraint kind"
        }
      ],
      "labels": [
        {
          "name": "TracingEnabled",
          "value": false
        },
        {
          "name": "PrintEnabled",
          "value": false
        },
        {
          "name": "target",
          "value": "admission.k8s.gatekeeper.sh"
        }
      ]
    }
  ]
}

• webhook

{
  "level": "info",
  "ts": 1683692576.9093642,
  "logger": "webhook",
  "msg": "admission review request stats",
  "hookType": "validation",
  "process": "admission",
  "event_type": "review_response_stats",
  "resource_group": "",
  "resource_api_version": "v1",
  "resource_kind": "Namespace",
  "resource_namespace": "",
  "request_username": "kubernetes-admin",
  "execution_stats": [
    {
      "scope": "template",
      "statsFor": "K8sRequiredLabels",
      "stats": [
        {
          "name": "templateRunTimeNS",
          "value": 762561,
          "source": {
            "type": "engine",
            "value": "Rego"
          },
          "description": "the number of nanoseconds it took to evaluate all constraints for a template"
        },
        {
          "name": "constraintCount",
          "value": 1,
          "source": {
            "type": "engine",
            "value": "Rego"
          },
          "description": "the number of constraints that were evaluated for the given constraint kind"
        }
      ],
      "labels": [
        {
          "name": "TracingEnabled",
          "value": false
        },
        {
          "name": "PrintEnabled",
          "value": false
        },
        {
          "name": "target",
          "value": "admission.k8s.gatekeeper.sh"
        }
      ]
    }
  ]
}

[codecov-commenter]

Codecov Report

Patch coverage: 20.00% and project coverage change: +0.03 🎉

Comparison is base (e59ae18) 53.17% compared to head (dc33fa5) 53.21%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2749      +/-   ##
==========================================
+ Coverage   53.17%   53.21%   +0.03%     
==========================================
  Files         126      126              
  Lines       11294    11295       +1     
==========================================
+ Hits         6006     6011       +5     
+ Misses       4814     4812       -2     
+ Partials      474      472       -2     

Flag	Coverage Δ
unittests	53.21% <20.00%> (+0.03%)	⬆️

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

Impacted Files	Coverage Δ
pkg/audit/manager.go	10.05% <0.00%> (-0.02%)	⬇️
pkg/webhook/policy.go	36.53% <100.00%> (ø)

... and 3 files with indirect coverage changes

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[sozercan]

LGTM

[maxsmythe]

LGTM, adding an event_type tag/value to the log output could also make these lines more filterable.

[acpana]

@maxsmythe there is an event type on the webhook "event_type": "review_response_stats", but not on the audit log lines. I can add those in a follow up or with the docs.