Honour continuousScanning.matchingRules.namespaces

[arpitjain099]

Closes #397.

MatchingRules.Namespaces is declared and unmarshalled (continuousscanning/loader.go:24) and then never read. LoadGVRs takes .APIResources and nothing else, and LoadGVRs was the entire TargetLoader interface, so the namespace list had nowhere to go. NewDynamicWatch then hardcoded Namespace(""), so continuous scanning watched every GVR across the whole cluster regardless of what was configured.

That matters because the Helm chart ships a namespaces list in its defaults and documents it as functional:

continuousScanning:
  matchingRules:
    match:
      - apiGroups: ["apps"]
        apiVersions: ["v1"]
        resources: ["deployments"]
    namespaces:
      - default

so it reads as namespace scoping that quietly does nothing. The only namespace filtering that actually happened is cfg.SkipNamespace in service.go:47, which is the unrelated global exclude list.

The change adds LoadNamespaces to TargetLoader, threads it from service.listen into NewWatchPool, and builds one watch per GVR per namespace. Two things kept deliberately unchanged:

• Cluster-scoped resources still ignore the namespace, via the existing k8sinterface.IsNamespaceScope branch, since there is nothing to scope.
• An empty or absent list still means every namespace, so any rule set that omits the field behaves exactly as it does now. That is the case the no namespaces keeps one watch per gvr test pins.

Tests: TestNewWatchPoolNamespaces covers both the empty case and the fan-out (2 GVRs by 2 namespaces gives 4 watches, one per pair), TestNewDynamicWatch gains a case asserting the namespace reaches the recorded watch action on the fake client, and TestTargetLoaderLoadNamespaces covers the loader in both shapes. assertWatchAction now checks the namespace as well as the GVR, which is what makes the first of those meaningful.

go build ./continuousscanning/..., go vet ./continuousscanning/... and go test ./continuousscanning/... are clean. A whole-repo go build ./... does not complete on macOS: inspektor-gadget/pkg/utils/host is Linux-only and excluded by build constraints here. That is pre-existing and unrelated to this change, but it does mean I have not built the packages that depend on it, so CI is the real check for those.

Summary by CodeRabbit

• New Features
  • Added namespace-aware continuous scanning for supported resources.
  • Scans can now target specific namespaces or retain cluster-wide coverage when none are configured.
  • Watch pools create separate watches for each configured namespace.
  • Cluster-scoped resources continue to be monitored independently of namespace settings.

[coderabbitai]

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• continuousscanning/watchbuilder.go
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---

📝 Walkthrough

Walkthrough

Continuous scanning now loads namespaces from matching rules and applies them to dynamic and self-healing watches. Empty namespaces preserve cluster-wide behavior. Cluster-scoped resources use one cluster-wide watch.

Changes

Namespace scoping

Layer / File(s)	Summary
Namespace loading contract continuousscanning/loader.go, continuousscanning/loader_test.go	TargetLoader exposes LoadNamespaces. The loader returns configured namespaces and returns nil when rules are missing or namespaces are unspecified.
Watch pool wiring continuousscanning/service.go	listen loads namespaces, logs them with the GVRs, and passes them to NewWatchPool.
Namespace-aware watch creation continuousscanning/watchbuilder.go, continuousscanning/watchbuilder_test.go	Dynamic and self-healing watches accept namespaces. NewWatchPool creates one watch per namespace for namespaced GVRs and one cluster-wide watch for each cluster-scoped GVR. Tests verify namespace propagation and watch fan-out.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Merge Risk: ⚪ Minimal · up to ab9bc

The change makes configured namespace scoping functional while preserving existing behavior when no namespaces are configured, with targeted validation reported as passing; no actionable merge-blocking risk remains.

Sequence Diagram(s)

sequenceDiagram
  participant listen
  participant targetLoader
  participant NewWatchPool
  participant NewDynamicWatch
  listen->>targetLoader: LoadNamespaces(ctx)
  targetLoader-->>listen: configured namespaces
  listen->>NewWatchPool: pass GVRs and namespaces
  NewWatchPool->>NewDynamicWatch: create watches by GVR and namespace
  NewDynamicWatch-->>NewWatchPool: namespace-scoped or cluster-wide watch

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🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the primary change: applying configured continuous scanning namespaces.
Linked Issues check	✅ Passed	The changes satisfy issue #397 by propagating namespaces to watches while preserving all-namespace and cluster-scoped behavior.
Out of Scope Changes check	✅ Passed	The implementation and tests remain focused on honoring namespace scoping in continuous scanning.
Docstring Coverage	✅ Passed	Docstring check was indeterminate for this PR — some files could not be analyzed in time. Not blocking.

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

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Inline comments:
In `@continuousscanning/watchbuilder.go`:
- Around line 130-134: Update the watch construction loop around
NewSelfHealingWatch so cluster-scoped GVRs iterate over []string{""} and create
exactly one watch, while namespaced GVRs continue using the configured
namespaces. Extend TestNewWatchPoolNamespaces with a cluster-scoped case such as
ClusterRole to verify this behavior.

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📒 Files selected for processing (5)

• continuousscanning/loader.go
• continuousscanning/loader_test.go
• continuousscanning/service.go
• continuousscanning/watchbuilder.go
• continuousscanning/watchbuilder_test.go

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[matthyx]

Solid fix for the underlying issue (#397) — the loader/service/watchbuilder wiring and the empty-namespaces-means-all-namespaces fallback all look right, and the new tests cover the intended fan-out.

One blocker before merge: cluster-scoped resources get a duplicate watch per configured namespace (see inline comment on watchbuilder.go), since the per-namespace fan-out in NewWatchPool doesn't special-case IsNamespaceScope. That means duplicate events into the scan channel whenever a matching-rule set mixes cluster-scoped and namespace-scoped resources with a non-empty namespaces list — plausible given the shipped Helm defaults. CodeRabbit's automated review flagged the same thing independently.

Not requesting changes beyond that — will re-review once the fan-out is scoped to namespaced GVRs only (or namespaces default to [""] per-GVR rather than globally) and a cluster-scoped case is added to TestNewWatchPoolNamespaces.

[matthyx]

Blocker: this fans out one watch per (GVR, namespace) pair unconditionally, including for cluster-scoped GVRs. NewDynamicWatch/IsNamespaceScope correctly ignores namespace for a cluster-scoped resource, but that just means the same cluster-wide watch gets created once per configured namespace — e.g. with namespaces: [default, kube-system] and a cluster-scoped resource in APIResources (nodes, clusterroles, etc.), you get 2 identical SelfHealingWatches both streaming every event for that resource into the same channel. That's duplicate events feeding the scanner, not just wasted watches.

Fix: skip the per-namespace fan-out for cluster-scoped GVRs and create exactly one watch for them (e.g. check k8sinterface.IsNamespaceScope(&gvr) here, or default namespaces to [""] per-GVR instead of once globally). TestNewWatchPoolNamespaces only uses namespaced GVRs (deployments, pods), so it doesn't catch this — worth adding a cluster-scoped case (e.g. clusterroles) asserting exactly one watch regardless of how many namespaces are configured.

[arpitjain099]

You are right, and the consequence is worse than wasted watches as you say: the duplicates all write into the same resourceEventsCh, so the scanner sees each event once per configured namespace.

Fixed in ab9bc9c. The namespace list is now chosen per GVR rather than once for the pool:

watchNamespaces := namespaces
if !k8sinterface.IsNamespaceScope(&gvr) {
    watchNamespaces = clusterScoped
}

I confirmed IsNamespaceScope actually resolves these offline before relying on it in a test, since it would be an easy thing to assume:

apps/v1, Resource=deployments                  IsNamespaceScope=true
/v1, Resource=pods                             IsNamespaceScope=true
rbac.authorization.k8s.io/v1, Resource=clusterroles IsNamespaceScope=false
/v1, Resource=nodes                            IsNamespaceScope=false

TestNewWatchPoolClusterScopedGVRs covers three cases: two cluster-scoped GVRs against three namespaces, the mixed set you described, and a cluster-scoped GVR with no namespaces configured. Without the change the first two fail with exactly the duplication you predicted:

expected: map[string]int{"":2}
actual  : map[string]int{"default":2, "kube-system":2, "kubescape":2}

expected: map[string]int{"":1, "default":1, "kube-system":1}

so six watches where two were wanted. The mixed case asserts the exact namespace distribution rather than just the count, so a fix that under-fans the namespaced GVR would not pass either.

I left TestNewWatchPoolNamespaces alone since it still covers the namespaced fan-out on its own terms.

go build, go vet and go test ./continuousscanning/... are clean. As before, a whole-repo go build ./... does not complete on macOS because inspektor-gadget/pkg/utils/host is Linux-only, so CI is the check for the packages that depend on it.