CLI: Generate BundleDiff From Status

[weyfonk]

The Fleet CLI should include a command to generate bundle diffs from a resource (bundle or bundle deployment) status. The resource status already contains the needed patch.

EDIT
Implement output of patches in a format that can be directly inserted into fleet.yaml files and uses the comparePatches structure.

[thardeck]

QA Template:

Test Cases

Test 1: Standard Output (Default)

Objective: Verify default bundlediff output shows human-readable diff information

Steps:

1. Deploy a bundle with a modified resource (e.g., ConfigMap with extra annotation)
2. Run: fleet bundlediff --bundle-deployment <name> -n <namespace>
3. Verify output shows bundle deployment name, bundle name, and modified resources with their patches

Expected Result:

BundleDeployment: cluster-fleet-local-abc123/my-bundle-deployment
Bundle: my-bundle

Modified Resources:
  ConfigMap.v1 default/my-config
    Status: Modified
    Patch: {"metadata":{"annotations":{"timestamp":"2024-01-15T10:30:00Z"}}}

---

Test 2: JSON Output

Objective: Verify --json flag produces valid JSON output

Steps:

1. Deploy a bundle with a modified resource
2. Run: fleet bundlediff --bundle-deployment <name> -n <namespace> --json
3. Verify output is valid JSON: fleet bundlediff --bundle-deployment <name> -n <namespace> --json | jq .

Expected Result:

• Output is valid JSON that can be parsed by jq
• Contains bundleDeploymentName, bundleName, namespace, and modifiedResources array

---

Test 3: Fleet YAML Output

Objective: Verify --fleet-yaml flag produces valid YAML with comparePatches format

Steps:

1. Deploy a bundle with a modified resource
2. Run: fleet bundlediff --bundle-deployment <name> -n <namespace> --fleet-yaml
3. Verify output contains:
   • diff: section
   • comparePatches: list
   • Resource metadata (apiVersion, kind, name, namespace)
   • Operations with op: remove and correct path

Expected Result:

diff:
  comparePatches:
  - apiVersion: v1
    kind: ConfigMap
    name: my-config
    namespace: default
    operations:
    - op: remove
      path: /metadata/annotations/timestamp

---

Test 4: GitOps Drift Acceptance Workflow

Objective: Verify that comparePatches can be added to a GitRepo to accept drift

Steps:

1. Deploy a GitRepo that creates resources in a cluster
2. Modify a deployed resource to create drift
3. Verify bundle shows as "Modified": kubectl get bundle <name> -n fleet-local
4. Generate fleet.yaml snippet:

   fleet bundlediff --bundle-deployment <name> -n <namespace> --fleet-yaml > patches.yaml

5. Add the diff section from patches.yaml to your fleet.yaml in Git
6. Commit and push to Git
7. Wait for Fleet to reconcile (~30-60 seconds)
8. Verify bundle is no longer "Modified": kubectl get bundle <name> -n fleet-local
9. Verify the resource still contains the modified value (comparePatches accept drift, don't revert it)

Expected Result:

• Bundle transitions from "Modified" to "Ready" state
• The manually modified field remains unchanged
• Fleet accepts the drift instead of reverting it