feat: [Policy Assistant] walkthrough mode and a README (KubeCon demo PR 2/2)

[huntergregory]

• Finally adding a good README for the project.
• Walkthrough mode is as seen at KubeCon, but the code is no longer as hacky.
• Probe mode is working too.
• Files used for the demo are included in examples/demos/.

A followup PR can leverage #227 to specify traffic for the walkthrough (traffic is hard-coded right now). Also, #239 will give us the power to read policies from file/cluster.

Outputs

walkthrough

$ ./cyclonus analyze --policy-path examples/demos/kubecon-eu-2024 --mode walkthrough             
verdict walkthrough:
+---------------------------------------+---------+-------------------------------------------------------------+------------------------------+
|                TRAFFIC                | VERDICT |                     INGRESS WALKTHROUGH                     |      EGRESS WALKTHROUGH      |
+---------------------------------------+---------+-------------------------------------------------------------+------------------------------+
| demo/[pod=a] -> demo/[pod=b]:80 (TCP) | Allowed | [ANP] Allow (allow-80)                                      | no policies targeting egress |
+---------------------------------------+---------+-------------------------------------------------------------+                              +
| demo/[pod=a] -> demo/[pod=b]:81 (TCP) | Denied  | [ANP] Pass (pass-81) -> [BANP] Deny (baseline-deny)         |                              |
+---------------------------------------+---------+-------------------------------------------------------------+                              +
| demo/[pod=b] -> demo/[pod=a]:80 (TCP) | Allowed | [ANP] Allow (allow-80)                                      |                              |
+---------------------------------------+---------+-------------------------------------------------------------+                              +
| demo/[pod=b] -> demo/[pod=a]:81 (TCP) | Denied  | [ANP] Pass (pass-81) -> [NPv1] Dropped (demo/deny-to-pod-a) |                              |
+---------------------------------------+---------+-------------------------------------------------------------+------------------------------+

probe

$ ./cyclonus analyze --policy-path examples/demos/kubecon-eu-2024 --mode probe --probe-path examples/demos/kubecon-eu-2024/demo-probe.json
simulated connectivity:
INFO[2024-08-07T17:26:28-07:00] probe on port 80, protocol TCP               
Ingress:
+--------+--------+--------+
|        | DEMO/A | DEMO/B |
+--------+--------+--------+
| demo/a | #      | .      |
| demo/b | X      | #      |
+--------+--------+--------+

Egress:
+--------+--------+--------+
|        | DEMO/A | DEMO/B |
+--------+--------+--------+
| demo/a | #      | .      |
| demo/b | .      | #      |
+--------+--------+--------+

Combined:
+--------+--------+--------+
|        | DEMO/A | DEMO/B |
+--------+--------+--------+
| demo/a | #      | .      |
| demo/b | X      | #      |
+--------+--------+--------+

INFO[2024-08-07T17:26:28-07:00] probe on port 81, protocol TCP               
Ingress:
+--------+--------+--------+
|        | DEMO/A | DEMO/B |
+--------+--------+--------+
| demo/a | #      | .      |
| demo/b | X      | #      |
+--------+--------+--------+

Egress:
+--------+--------+--------+
|        | DEMO/A | DEMO/B |
+--------+--------+--------+
| demo/a | #      | .      |
| demo/b | .      | #      |
+--------+--------+--------+

Combined:
+--------+--------+--------+
|        | DEMO/A | DEMO/B |
+--------+--------+--------+
| demo/a | #      | .      |
| demo/b | X      | #      |
+--------+--------+--------+

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: huntergregory

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[huntergregory]

Also, https://github.com/kubernetes-sigs/network-policy-api/pull/239 will give us the power to read policies from file/cluster.

I have a local hack imitating #239 to produce outputs using --policy-path

[k8s-ci-robot]

PR needs rebase.

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