Merge pull request #119 from jk-cluster/feat/values-schema-mcrouter

minecraft-router: strict values.schema.json + Null-Absicherung (Welle 2, #68/#99)

minecraft-router/Chart.yaml

@@ -5,7 +5,7 @@ icon: https://avatars.githubusercontent.com/u/988985
 
 type: application
 
-version: 2.0.0+up1.46.4
+version: 3.0.0+up1.46.4
 appVersion: "1.46.4"
 
 maintainers:

minecraft-router/templates/_helpers.tpl

@@ -114,3 +114,170 @@ template-chart is the reference implementation.
 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. Where the chart
+defines a default, Helm treats that null as a deletion of the default; the
+template then renders "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 "minecraft-router.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 "minecraft-router.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.server.securityContext" can itself be erased.
+*/}}
+{{- define "minecraft-router.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 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.
+
+Two things a rebuilt default probe must not lose:
+  - the API port is addressed by NAME ("api-port"), not by number, so the probe
+    keeps working if server.apiPort is overridden.
+  - mc-router has no /health endpoint even in 1.46.4, so GET /routes is the
+    health signal, and the "Accept: application/json" header belongs to it (it
+    was mandatory in 1.25.1 and is the correct request for a JSON endpoint).
+
+The pod context deliberately pins uid/gid 10000 even though the image declares
+USER 65532 since 1.46.0, so the runtime identity does not silently change with
+the base image.
+*/}}
+{{- define "minecraft-router.podSecurityContext" -}}
+{{- $given := (fromYaml (include "minecraft-router.subBlock" (dict "block" . "key" "pod" "path" "server.securityContext"))).value -}}
+{{- $defaults := dict
+      "runAsNonRoot" true
+      "runAsUser" 10000
+      "runAsGroup" 10000
+      "fsGroup" 10000
+      "fsGroupChangePolicy" "Always" -}}
+{{- include "minecraft-router.defaultedDict" (dict "defaults" $defaults "given" $given "path" "server.securityContext.pod") -}}
+{{- end -}}
+
+{{- define "minecraft-router.containerSecurityContext" -}}
+{{- $given := (fromYaml (include "minecraft-router.subBlock" (dict "block" . "key" "container" "path" "server.securityContext"))).value -}}
+{{- $defaults := dict
+      "allowPrivilegeEscalation" false
+      "readOnlyRootFilesystem" true
+      "runAsNonRoot" true
+      "capabilities" (dict "drop" (list "ALL") "add" (list)) -}}
+{{- include "minecraft-router.defaultedDict" (dict "defaults" $defaults "given" $given "path" "server.securityContext.container") -}}
+{{- end -}}
+
+{{- define "minecraft-router.probeHttpGet" -}}
+{{- dict "path" "/routes" "port" "api-port" "httpHeaders" (list (dict "name" "Accept" "value" "application/json")) | toYaml -}}
+{{- end -}}
+
+{{- define "minecraft-router.livenessProbe" -}}
+{{- $defaults := dict
+      "httpGet" (fromYaml (include "minecraft-router.probeHttpGet" .))
+      "periodSeconds" 10
+      "timeoutSeconds" 5
+      "failureThreshold" 3 -}}
+{{- include "minecraft-router.defaultedDict" (dict "defaults" $defaults "given" . "path" "server.livenessProbe") -}}
+{{- end -}}
+
+{{- define "minecraft-router.readinessProbe" -}}
+{{- $defaults := dict
+      "httpGet" (fromYaml (include "minecraft-router.probeHttpGet" .))
+      "periodSeconds" 10
+      "timeoutSeconds" 5
+      "failureThreshold" 3 -}}
+{{- include "minecraft-router.defaultedDict" (dict "defaults" $defaults "given" . "path" "server.readinessProbe") -}}
+{{- end -}}
+
+{{- define "minecraft-router.startupProbe" -}}
+{{- $defaults := dict
+      "httpGet" (fromYaml (include "minecraft-router.probeHttpGet" .))
+      "periodSeconds" 2
+      "timeoutSeconds" 5
+      "failureThreshold" 15 -}}
+{{- include "minecraft-router.defaultedDict" (dict "defaults" $defaults "given" . "path" "server.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 "minecraft-router.effectiveResources" -}}
+{{- $defaults := dict
+      "limitFactor" 3
+      "requests" (dict "cpu" "100m" "memory" "50Mi" "ephemeral-storage" "50Mi") -}}
+{{- $merged := fromYaml (include "minecraft-router.defaultedDict" (dict "defaults" $defaults "given" . "path" "server.resources")) -}}
+{{- include "minecraft-router.resources" $merged -}}
+{{- end -}}

minecraft-router/templates/minecraft-router.deployment.yaml

@@ -24,7 +24,7 @@ spec:
     spec:
       automountServiceAccountToken: false
       securityContext:
-        {{- toYaml .Values.server.securityContext.pod | nindent 8 }}
+        {{- include "minecraft-router.podSecurityContext" .Values.server.securityContext | nindent 8 }}
       containers:
         - name: {{ .Release.Name }}-{{ .Chart.Name }}-deployment
           image: "itzg/mc-router:{{ .Chart.AppVersion }}"
@@ -65,15 +65,15 @@ spec:
               protocol: TCP
               containerPort: {{ .Values.server.apiPort }}
           livenessProbe:
-            {{- toYaml .Values.server.livenessProbe | nindent 12 }}
+            {{- include "minecraft-router.livenessProbe" .Values.server.livenessProbe | nindent 12 }}
           readinessProbe:
-            {{- toYaml .Values.server.readinessProbe | nindent 12 }}
+            {{- include "minecraft-router.readinessProbe" .Values.server.readinessProbe | nindent 12 }}
           startupProbe:
-            {{- toYaml .Values.server.startupProbe | nindent 12 }}
+            {{- include "minecraft-router.startupProbe" .Values.server.startupProbe | nindent 12 }}
           resources:
-            {{- include "minecraft-router.resources" .Values.server.resources | nindent 12 }}
+            {{- include "minecraft-router.effectiveResources" .Values.server.resources | nindent 12 }}
           securityContext:
-            {{- toYaml .Values.server.securityContext.container | nindent 12 }}
+            {{- include "minecraft-router.containerSecurityContext" .Values.server.securityContext | nindent 12 }}
           volumeMounts:
             - name: config-mount
               mountPath: /data/custom-routing-config.json

minecraft-router/values.schema.json

@@ -0,0 +1,189 @@
+{
+  "$schema": "https://json-schema.org/draft-07/schema#",
+  "title": "minecraft-router values",
+  "description": "Strict values schema (issue #68). additionalProperties is false on every chart-owned object level, so a key that the chart does not read is rejected at render time instead of being silently ignored. The only objects that stay open are the ones passed verbatim into the Kubernetes pod spec (probes, security contexts, global) - the chart does not interpret their contents, so it cannot judge which keys are meaningful. The hardening, probe and resources blocks additionally accept null, because an erased block falls back to the chart defaults (issue #99).",
+  "type": "object",
+  "additionalProperties": false,
+  "properties": {
+    "global": {
+      "description": "Helm's conventional cross-chart values. Unused by this chart, kept open so an umbrella install cannot break on it.",
+      "type": "object"
+    },
+    "scaleDown": {
+      "type": "boolean"
+    },
+    "mappings": {
+      "description": "Routing table: which client-facing hostname is proxied to which backend. Required and must not be empty - the chart fails loudly on a missing or empty list, so this block is deliberately NOT null-safe (issue #99 covers only the silent class). A change here rolls the router pod via the checksum/config annotation.",
+      "type": ["array", "null"],
+      "items": {
+        "type": "object",
+        "additionalProperties": false,
+        "required": ["domain", "internalUrl"],
+        "properties": {
+          "domain": {
+            "description": "Client-facing hostname the Minecraft client connects to.",
+            "type": ["string", "null"]
+          },
+          "internalUrl": {
+            "description": "Cluster-internal address of the backend server.",
+            "type": ["string", "null"]
+          },
+          "port": {
+            "description": "Overrides server.backendPort for this single backend.",
+            "type": ["integer", "null"],
+            "minimum": 1,
+            "maximum": 65535
+          }
+        }
+      }
+    },
+    "server": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "replicas": {
+          "type": "integer",
+          "minimum": 0
+        },
+        "outwardPort": {
+          "description": "nodePort of the router Service. 25565 is deliberately outside the Kubernetes default node-port range - the cluster runs an extended --service-node-port-range, and Minecraft clients connect to this exact port.",
+          "type": ["integer", "null"],
+          "minimum": 1,
+          "maximum": 65535
+        },
+        "port": {
+          "type": ["integer", "null"],
+          "minimum": 1,
+          "maximum": 65535
+        },
+        "backendPort": {
+          "type": ["integer", "null"],
+          "minimum": 1,
+          "maximum": 65535
+        },
+        "apiPort": {
+          "description": "Port of the mc-router HTTP API. Not exposed by the Service; only the probes talk to it.",
+          "type": ["integer", "null"],
+          "minimum": 1,
+          "maximum": 65535
+        },
+        "resources": {
+          "$ref": "#/definitions/resources"
+        },
+        "livenessProbe": {
+          "$ref": "#/definitions/probe"
+        },
+        "readinessProbe": {
+          "$ref": "#/definitions/probe"
+        },
+        "startupProbe": {
+          "$ref": "#/definitions/probe"
+        },
+        "securityContext": {
+          "$ref": "#/definitions/securityContext"
+        },
+        "env": {
+          "description": "Extra environment variables. This is also how every mc-router option the chart does not model explicitly is set: mc-router parses its flags with go-flagsfiller, so \"--some-flag\" is settable as \"SOME_FLAG\".",
+          "$ref": "#/definitions/env"
+        }
+      }
+    }
+  },
+  "definitions": {
+    "resources": {
+      "description": "May be null / empty: the chart then falls back to its default requests and computed limits (issue #99) instead of rendering a container without resource accounting.",
+      "type": ["object", "null"],
+      "additionalProperties": false,
+      "properties": {
+        "limitFactor": {
+          "type": "number",
+          "exclusiveMinimum": 0
+        },
+        "requests": {
+          "$ref": "#/definitions/resourceList"
+        },
+        "limits": {
+          "$ref": "#/definitions/resourceList"
+        }
+      }
+    },
+    "resourceList": {
+      "type": ["object", "null"],
+      "additionalProperties": false,
+      "properties": {
+        "cpu": {
+          "type": ["string", "number", "null"]
+        },
+        "memory": {
+          "type": ["string", "number", "null"]
+        },
+        "ephemeral-storage": {
+          "type": ["string", "number", "null"]
+        },
+        "ephemeralStorage": {
+          "type": ["string", "number", "null"]
+        }
+      }
+    },
+    "env": {
+      "type": "array",
+      "items": {
+        "type": "object",
+        "additionalProperties": false,
+        "required": ["name"],
+        "properties": {
+          "name": {
+            "type": "string"
+          },
+          "value": {
+            "type": "string"
+          },
+          "valueFrom": {
+            "type": "object",
+            "additionalProperties": false,
+            "properties": {
+              "secretKeyRef": {
+                "$ref": "#/definitions/keyRef"
+              },
+              "configMapKeyRef": {
+                "$ref": "#/definitions/keyRef"
+              }
+            }
+          }
+        }
+      }
+    },
+    "keyRef": {
+      "type": "object",
+      "additionalProperties": false,
+      "required": ["name", "key"],
+      "properties": {
+        "name": {
+          "type": "string"
+        },
+        "key": {
+          "type": "string"
+        }
+      }
+    },
+    "securityContext": {
+      "description": "May be null / empty at any level: the chart then falls back to its hardening defaults (issue #99) instead of rendering an unhardened workload.",
+      "type": ["object", "null"],
+      "additionalProperties": false,
+      "properties": {
+        "pod": {
+          "description": "Merged onto the chart's pod hardening defaults and rendered as the pod's securityContext; kept open because the chart does not interpret the individual fields.",
+          "type": ["object", "null"]
+        },
+        "container": {
+          "description": "Merged onto the chart's container hardening defaults and rendered as the container's securityContext; kept open because the chart does not interpret the individual fields.",
+          "type": ["object", "null"]
+        }
+      }
+    },
+    "probe": {
+      "description": "Merged onto the chart's probe defaults and rendered as a container probe; kept open because the chart does not interpret the individual fields. May be null / empty, which means the defaults apply (issue #99) rather than the probe disappearing.",
+      "type": ["object", "null"]
+    }
+  }
+}