fix(base-cluster/monitoring): alertmanager condition

[cwrau]

Summary by CodeRabbit

• Chores
  • Improved alertmanager configuration validation handling
  • Enhanced network policy applicability conditions to better align with monitoring enablement state

[coderabbitai]

Walkthrough

Two Alertmanager-related Helm templates in the base-cluster chart are modified. The first changes the enabled field rendering to emit true or empty string via ternary logic. The second strengthens the CiliumNetworkPolicy condition to require both alertmanager enabled and network policy type "cilium".

Changes

Cohort / File(s)	Change Summary
Alertmanager Template Logic charts/base-cluster/templates/monitoring/kube-prometheus-stack/_alertmanager-config.yaml	Wrapped non-empty receivers check with ternary expression to emit true or empty string instead of direct boolean value
Alertmanager Network Policy charts/base-cluster/templates/monitoring/kube-prometheus-stack/alertmanager-networkpolicy.yaml	Combined condition requiring both alertmanager enabled (base-cluster.prometheus-stack.alertmanager.enabled) and network policy type "cilium"; adjusted end block whitespace trimming

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

• Both changes involve straightforward template conditional refinements
• No complex business logic or structural changes
• Limited scope (2 files with focused modifications)

Possibly related PRs

• fix(base-cluster): conditions must the true, not just truthy #1738: Aligns with tightening template condition output to emit literal-true/non-empty conditions rather than truthy values
• feat(base-cluster/monitoring/alertmanager)!: add receiver and route configuration capabilities #1600: Modifies complementary Alertmanager templates affecting enabled checks and network policy rendering
• feat(base-cluster): use new networkPolicy template #1414: Related to CiliumNetworkPolicy conditional changes and network policy template refactoring

Suggested labels

base-cluster

Suggested reviewers

• tasches
• marvinWolff
• teutonet-bot

Poem

🐰 A template tale in YAML form,
Where booleans dance and conditions transform,
True or empty, the choice now precise,
Alertmanagers gated with ternary spice! 🎪

Pre-merge checks and finishing touches

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'fix(base-cluster/monitoring): alertmanager condition' directly relates to the main changes, which involve fixing alertmanager-related conditional logic in monitoring templates.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch fix/base-cluster/alertmanager-condition

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📜 Recent review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 5769237 and 8780c1a.

📒 Files selected for processing (2)

• charts/base-cluster/templates/monitoring/kube-prometheus-stack/_alertmanager-config.yaml (1 hunks)
• charts/base-cluster/templates/monitoring/kube-prometheus-stack/alertmanager-networkpolicy.yaml (2 hunks)

🧰 Additional context used

🧠 Learnings (4)

📓 Common learnings

Learnt from: cwrau
Repo: teutonet/teutonet-helm-charts PR: 1600
File: charts/base-cluster/templates/monitoring/kube-prometheus-stack/_alertmanager-config.yaml:55-61
Timestamp: 2025-07-24T13:42:05.473Z
Learning: In charts/base-cluster/templates/monitoring/kube-prometheus-stack/_alertmanager-config.yaml, the receiver-type parsing logic that splits keys by space and only handles exactly two tokens is intentional and matches the schema design. The schema pattern `^email($| \S+$)` specifically allows "email" or "email <suffix>" format, not arbitrary multi-space patterns. The current parsing implementation correctly enforces this constraint.

📚 Learning: 2025-07-24T13:42:05.473Z

Learnt from: cwrau
Repo: teutonet/teutonet-helm-charts PR: 1600
File: charts/base-cluster/templates/monitoring/kube-prometheus-stack/_alertmanager-config.yaml:55-61
Timestamp: 2025-07-24T13:42:05.473Z
Learning: In charts/base-cluster/templates/monitoring/kube-prometheus-stack/_alertmanager-config.yaml, the receiver-type parsing logic that splits keys by space and only handles exactly two tokens is intentional and matches the schema design. The schema pattern `^email($| \S+$)` specifically allows "email" or "email <suffix>" format, not arbitrary multi-space patterns. The current parsing implementation correctly enforces this constraint.

Applied to files:

• charts/base-cluster/templates/monitoring/kube-prometheus-stack/alertmanager-networkpolicy.yaml
• charts/base-cluster/templates/monitoring/kube-prometheus-stack/_alertmanager-config.yaml

📚 Learning: 2025-07-24T13:42:05.473Z

Learnt from: cwrau
Repo: teutonet/teutonet-helm-charts PR: 1600
File: charts/base-cluster/templates/monitoring/kube-prometheus-stack/_alertmanager-config.yaml:55-61
Timestamp: 2025-07-24T13:42:05.473Z
Learning: In charts/base-cluster alertmanager receivers schema, email receiver keys follow the pattern `^email($| \\S+$)`, which allows only "email" or "email <suffix>" where suffix is `\S+` (no spaces allowed in suffix). The current parsing logic correctly enforces this by only handling exactly two tokens: the receiver type and the single non-whitespace suffix that becomes the receiver name.

Applied to files:

• charts/base-cluster/templates/monitoring/kube-prometheus-stack/_alertmanager-config.yaml

📚 Learning: 2025-07-21T14:04:07.149Z

Learnt from: cwrau
Repo: teutonet/teutonet-helm-charts PR: 1600
File: charts/base-cluster/templates/monitoring/kube-prometheus-stack/_alertmanager-config.yaml:50-61
Timestamp: 2025-07-21T14:04:07.149Z
Learning: In base-cluster alertmanager configuration, the schema only supports a single PagerDuty receiver (defined as `pagerduty` object), but supports multiple email receivers via pattern properties (e.g., "email", "email prod", "email staging"). Multiple PagerDuty receivers are not supported by design.

Applied to files:

• charts/base-cluster/templates/monitoring/kube-prometheus-stack/_alertmanager-config.yaml

🪛 YAMLlint (1.37.1)

charts/base-cluster/templates/monitoring/kube-prometheus-stack/alertmanager-networkpolicy.yaml

[error] 1-1: syntax error: expected the node content, but found '-'

(syntax)

charts/base-cluster/templates/monitoring/kube-prometheus-stack/_alertmanager-config.yaml

[error] 2-2: syntax error: expected '', but found '{'

(syntax)

⏰ Context from checks skipped due to timeout of 90000ms. You can increase the timeout in your CodeRabbit configuration to a maximum of 15 minutes (900000ms). (2)

• GitHub Check: check licenses
• GitHub Check: lint helm chart (base-cluster)

🔇 Additional comments (3)

charts/base-cluster/templates/monitoring/kube-prometheus-stack/_alertmanager-config.yaml (1)

2-2: Ternary expression correctly renders enabled field based on receiver presence.

The logic chain—checking receiver emptiness, negating it, and outputting "true" or ""—ensures the alertmanager config block is only fully rendered when receivers are defined. The output works correctly in the if condition on line 17.

charts/base-cluster/templates/monitoring/kube-prometheus-stack/alertmanager-networkpolicy.yaml (2)

1-1: Condition correctly requires both alertmanager enablement and cilium policy type.

The AND logic ensures the CiliumNetworkPolicy is only rendered when alertmanager is enabled (reusing the template from _alertmanager-config.yaml) and when cilium is the active network policy type. This prevents orphaned resources and aligns policy deployment with operational intent.

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33-33: Whitespace trimming is a minor, correct adjustment.

The trailing dash in {{- end -}} removes any trailing newline, consistent with Helm best practices and other blocks in this template.

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[Copilot]

Pull Request Overview

This PR improves the alertmanager template logic to conditionally render the network policy based on whether alertmanager is enabled, preventing the creation of an unnecessary CiliumNetworkPolicy resource when alertmanager is disabled.

• Modified the base-cluster.prometheus-stack.alertmanager.enabled template to explicitly return true or empty string for proper boolean evaluation in conditional contexts
• Updated the alertmanager network policy to only be rendered when both alertmanager is enabled and the network policy type is "cilium"

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
charts/base-cluster/templates/monitoring/kube-prometheus-stack/_alertmanager-config.yaml	Modified the enabled template to use ternary for explicit boolean-like return values
charts/base-cluster/templates/monitoring/kube-prometheus-stack/alertmanager-networkpolicy.yaml	Added alertmanager enabled check to the conditional and improved whitespace control

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