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helm-charts/urlaubsverwaltung/templates/_helpers.tpl
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jklein 4976c67ce3 Add strict values.schema.json and null-safe hardening to urlaubsverwaltung
Two changes, both about values that do not do what they promise:

1. values.schema.json (#68): additionalProperties: false on every
   chart-owned object level, so a key the chart does not read is rejected
   at render time instead of being silently ignored.

2. Null-safety for hardening, probes and resources (#99): an override
   written without children is YAML null and replaced the whole default
   sub-tree, rendering "securityContext: null" (unhardened container), a
   vanished probe or a container without resource accounting - silently.
   The defaultedDict helper from #96 is adopted so an empty block means
   "chart defaults apply", while an explicitly set value still wins,
   including false and 0.

The schema types allow null for exactly these blocks, so the two changes
agree instead of the schema rejecting what the helper is meant to absorb.

No ingress gate here: this chart already gates its Ingress correctly.

Rendering with normal values is byte-identical to the previous version.

Major bump: a schema can break existing deployments that carry dead keys.
2026-08-23 20:14:27 +02:00

271 lines
11 KiB
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{{/*
Render the body of a container "resources:" block from a values dict of the form
resources:
limitFactor: 3 # optional, default 3
requests: { cpu, memory, ephemeral-storage / ephemeralStorage, ... }
limits: { ... } # optional, every entry optional
Rules (variant B, see issue #19):
- requests are rendered as given (camelCase "ephemeralStorage" is normalized
to the Kubernetes key "ephemeral-storage").
- an explicitly set limit always wins.
- a missing memory / ephemeral-storage limit is computed as
limitFactor x the corresponding request.
- a missing cpu limit is NOT set at all (the kubelet then treats CPU as
unlimited; CPU is compressible, so this cannot kill the workload).
Usage (the values path to the resources dict varies per chart):
resources:
{{- include "urlaubsverwaltung.resources" .Values.<app>.resources | nindent 12 }}
NOTE: charts in this repo deliberately have no dependencies, so this helper is
duplicated into every chart's templates/_helpers.tpl with the chart's name as
define prefix. This file in template-chart is the reference implementation.
*/}}
{{- define "urlaubsverwaltung.resources" -}}
{{- $resources := . | default dict -}}
{{- $factor := 3.0 -}}
{{- if not (kindIs "invalid" $resources.limitFactor) -}}
{{- $factor = float64 $resources.limitFactor -}}
{{- end -}}
{{- $requests := dict -}}
{{- range $key, $value := ($resources.requests | default dict) -}}
{{- if not (kindIs "invalid" $value) -}}
{{- $_ := set $requests (include "urlaubsverwaltung.resourceKey" $key) $value -}}
{{- end -}}
{{- end -}}
{{- $limits := dict -}}
{{- range $key, $value := ($resources.limits | default dict) -}}
{{- if not (kindIs "invalid" $value) -}}
{{- $_ := set $limits (include "urlaubsverwaltung.resourceKey" $key) $value -}}
{{- end -}}
{{- end -}}
{{- range $key, $request := $requests -}}
{{- if and (ne $key "cpu") (not (hasKey $limits $key)) -}}
{{- $_ := set $limits $key (include "urlaubsverwaltung.multiplyQuantity" (dict "quantity" $request "factor" $factor)) -}}
{{- end -}}
{{- end -}}
{{- $out := dict -}}
{{- with $requests }}{{- $_ := set $out "requests" . }}{{- end -}}
{{- with $limits }}{{- $_ := set $out "limits" . }}{{- end -}}
{{- toYaml $out -}}
{{- end -}}
{{/*
Normalize a resource name from values to its Kubernetes key.
*/}}
{{- define "urlaubsverwaltung.resourceKey" -}}
{{- if eq . "ephemeralStorage" -}}ephemeral-storage{{- else -}}{{ . }}{{- end -}}
{{- end -}}
{{/*
Multiply a Kubernetes quantity by a factor, keeping its suffix.
Input: dict "quantity" <string|number> "factor" <float64>.
Handles plain numbers ("2", "0.5", 1073741824), decimal ("1.5Gi"), binary
("512Mi", "1Gi", "10Ki") and milli/SI suffixes ("100m", "500M"). Integer
results are printed without a decimal point.
*/}}
{{- define "urlaubsverwaltung.multiplyQuantity" -}}
{{- $quantity := printf "%v" .quantity -}}
{{- $number := regexFind "^[0-9]+(\\.[0-9]+)?" $quantity -}}
{{- if not $number -}}
{{- fail (printf "cannot parse resource quantity %q" $quantity) -}}
{{- end -}}
{{- $suffix := trimPrefix $number $quantity -}}
{{- if not (regexMatch "^(m|k|M|G|T|P|E|Ki|Mi|Gi|Ti|Pi|Ei)?$" $suffix) -}}
{{- fail (printf "unsupported resource quantity suffix %q in %q" $suffix $quantity) -}}
{{- end -}}
{{- $product := mulf (float64 $number) .factor -}}
{{- if eq $product (floor $product) -}}
{{- printf "%d%s" (int64 $product) $suffix -}}
{{- else -}}
{{- printf "%v%s" $product $suffix -}}
{{- end -}}
{{- end -}}
{{/*
Render the replica count for a Deployment/StatefulSet.
Input: dict
"scaleDown" the chart-global .Values.scaleDown flag (may be nil)
"replicas" the workload's replicas value (may be nil)
Rules (issue #25):
- scaleDown: true takes precedence and always yields 0.
- otherwise an explicitly set replicas value is used as given, including an
explicit 0 — Helm's "default" would swallow 0, hence the explicit
kindIs "invalid" nil check.
- a missing replicas value defaults to 1.
Usage (the values path to the workload's replicas varies per chart):
replicas: {{ include "urlaubsverwaltung.replicas" (dict "scaleDown" .Values.scaleDown "replicas" .Values.<app>.replicas) }}
NOTE: like the resources helper above, this is duplicated into every chart's
templates/_helpers.tpl with the chart's name as define prefix. This file in
template-chart is the reference implementation.
*/}}
{{- define "urlaubsverwaltung.replicas" -}}
{{- if .scaleDown -}}
0
{{- else if not (kindIs "invalid" .replicas) -}}
{{- .replicas -}}
{{- else -}}
1
{{- end -}}
{{- end -}}
{{/*
Merge a user-supplied values sub-tree onto a dict of chart defaults so that a
null / empty override falls back to the defaults instead of erasing them.
Input: dict "defaults" <dict> "given" <dict|nil> "path" <string, optional
values path used in error messages>. Output: YAML of the merged dict (consume
it with fromYaml).
Why this exists (issue #99): Helm merges values maps recursively, but an
override key written without children — e.g. a leftover
securityContext:
after deleting its last remaining sub-key — is YAML null and replaces the
whole default sub-tree. The container then renders with "securityContext:
null": no readOnlyRootFilesystem, no dropped capabilities, no
allowPrivilegeEscalation: false. The workload starts and reports healthy while
being unhardened, so nothing points at the mistake. The same shape erases a
probe (it disappears) or the resources block (no requests, no computed
limits). This helper defines the opposite semantics: an empty block means
"chart defaults apply".
Rules:
- a nil "given" is treated as an empty dict (all defaults apply).
- a key whose override value is null keeps the default (nulls never delete).
- a key present in both as a map is merged recursively, so a partially
filled block only overrides the keys it actually sets.
- a scalar override for a key the defaults define as a map is rejected with
a message naming the values path, instead of failing later with a template
field error.
- any other set value wins as given, including an explicit false or 0 —
Helm's "default" and sprig's "mergeOverwrite" would both swallow those
zero values, hence the explicit kindIs "invalid" nil check.
- keys only present in the override are passed through unchanged.
NOTE: like the helpers above, this is duplicated into every chart's
templates/_helpers.tpl with the chart's name as define prefix, because charts
in this repo deliberately have no dependencies.
*/}}
{{- define "urlaubsverwaltung.defaultedDict" -}}
{{- $defaults := .defaults | default dict -}}
{{- $given := .given -}}
{{- $path := .path | default "value" -}}
{{- if kindIs "invalid" $given -}}
{{- $given = dict -}}
{{- end -}}
{{- if not (kindIs "map" $given) -}}
{{- fail (printf "%s must be a mapping or null, got %s (%v)" $path (kindOf $given) $given) -}}
{{- end -}}
{{- $out := deepCopy $defaults -}}
{{- range $key, $value := $given -}}
{{- if not (kindIs "invalid" $value) -}}
{{- $default := index $defaults $key -}}
{{- if and (kindIs "map" $value) (kindIs "map" $default) -}}
{{- $_ := set $out $key (fromYaml (include "urlaubsverwaltung.defaultedDict" (dict "defaults" $default "given" $value "path" (printf "%s.%s" $path $key)))) -}}
{{- else if kindIs "map" $default -}}
{{- fail (printf "%s.%s must be a mapping or null, got %s (%v)" $path $key (kindOf $value) $value) -}}
{{- else -}}
{{- $_ := set $out $key $value -}}
{{- end -}}
{{- end -}}
{{- end -}}
{{- toYaml $out -}}
{{- end -}}
{{/*
Pick one sub-block out of a values block that may itself be null.
Input: dict "block" <dict|nil> "key" <string> "path" <string>.
Returns YAML of dict "value" <the sub-block, may be nil>, after rejecting a
non-mapping block with a message that names the values path. Needed because
".Values.<app>.securityContext" can itself be erased, and indexing into nil
inside a template is not an error but silently yields nothing.
*/}}
{{- define "urlaubsverwaltung.subBlock" -}}
{{- $block := .block -}}
{{- if kindIs "invalid" $block -}}
{{- $block = dict -}}
{{- end -}}
{{- if not (kindIs "map" $block) -}}
{{- fail (printf "%s must be a mapping or null, got %s (%v)" .path (kindOf $block) $block) -}}
{{- end -}}
{{- toYaml (dict "value" (index $block .key)) -}}
{{- end -}}
{{/*
The effective pod / container security contexts, probes and resources
(issue #99).
The defaults below MUST stay in sync with the corresponding blocks in
values.yaml, which stays the documented, user-facing place for them; this copy
is only the fallback for the case where an override has erased the block.
*/}}
{{- define "urlaubsverwaltung.podSecurityContext" -}}
{{- $given := (fromYaml (include "urlaubsverwaltung.subBlock" (dict "block" . "key" "pod" "path" "urlaubsverwaltung.securityContext"))).value -}}
{{- $defaults := dict
"runAsNonRoot" true
"runAsUser" 1002
"runAsGroup" 1001 -}}
{{- include "urlaubsverwaltung.defaultedDict" (dict "defaults" $defaults "given" $given "path" "urlaubsverwaltung.securityContext.pod") -}}
{{- end -}}
{{- define "urlaubsverwaltung.containerSecurityContext" -}}
{{- $given := (fromYaml (include "urlaubsverwaltung.subBlock" (dict "block" . "key" "container" "path" "urlaubsverwaltung.securityContext"))).value -}}
{{- $defaults := dict
"allowPrivilegeEscalation" false
"readOnlyRootFilesystem" true
"runAsNonRoot" true
"capabilities" (dict "drop" (list "ALL")) -}}
{{- include "urlaubsverwaltung.defaultedDict" (dict "defaults" $defaults "given" $given "path" "urlaubsverwaltung.securityContext.container") -}}
{{- end -}}
{{- define "urlaubsverwaltung.livenessProbe" -}}
{{- $defaults := dict
"httpGet" (dict "port" 8080 "path" "/actuator/health/liveness")
"periodSeconds" 10
"failureThreshold" 3
"successThreshold" 1
"timeoutSeconds" 5 -}}
{{- include "urlaubsverwaltung.defaultedDict" (dict "defaults" $defaults "given" . "path" "urlaubsverwaltung.livenessProbe") -}}
{{- end -}}
{{- define "urlaubsverwaltung.readinessProbe" -}}
{{- $defaults := dict
"httpGet" (dict "port" 8080 "path" "/actuator/health/readiness")
"periodSeconds" 5
"failureThreshold" 3
"successThreshold" 1
"timeoutSeconds" 5 -}}
{{- include "urlaubsverwaltung.defaultedDict" (dict "defaults" $defaults "given" . "path" "urlaubsverwaltung.readinessProbe") -}}
{{- end -}}
{{- define "urlaubsverwaltung.startupProbe" -}}
{{- $defaults := dict
"httpGet" (dict "port" 8080 "path" "/actuator/health/liveness")
"periodSeconds" 10
"failureThreshold" 30
"timeoutSeconds" 5 -}}
{{- include "urlaubsverwaltung.defaultedDict" (dict "defaults" $defaults "given" . "path" "urlaubsverwaltung.startupProbe") -}}
{{- end -}}
{{/*
The effective resources block, fed into the resources helper above so that an
erased "resources:" still yields the chart's requests and computed limits
instead of a container without any resource accounting.
*/}}
{{- define "urlaubsverwaltung.effectiveResources" -}}
{{- $defaults := dict
"limitFactor" 3
"requests" (dict "cpu" 0.1 "memory" "768Mi" "ephemeralStorage" "10Mi") -}}
{{- $merged := fromYaml (include "urlaubsverwaltung.defaultedDict" (dict "defaults" $defaults "given" . "path" "urlaubsverwaltung.resources")) -}}
{{- include "urlaubsverwaltung.resources" $merged -}}
{{- end -}}