Use this rule to control that the YAML documents do contain a required key (parameter required-key-name). Parameters can be defined as a regular expression.

Because not all documents are certainly expected to contain the indicated key, an initial "filter" key/value (the parameters parent-key-name and parent-key-value) is used to identify the documents that must be checked. Use the parameter parent-key-name-root to tell where this so-called parent key must be located in the document. The location of the key can also be defined with two ancestor regular expressions.

Parameters

parent-key-name
Regular expression that matches the required parent-key-name. Leave empty for no parent checking.
parent-key-value
Regular expression that matches the value for the required parent-key
parent-key-name-root
Tells if the filter parent key must be located at the root level of the document (yescode>), if it must not be located at the root level of the document (not) or if it can be located anywhere in the document (anywhere)
required-key-name
Regular expression that matches the required key name
included-ancestors
Regular expression that matches against an ancestor string made of joining the parent chain of the matching key. The parents are separated by a colon (:) and always start with an implicit <root> parent. So, the ancestor string for a connectionTimeout key could be: <root>:spring:datasource:hikari. If the includedAncestors regex matches the ancestor string of the key, the key is checked. The start and end line markers ^ and $ are implicit, just like the key regex. Leave empty for no included ancestor matching.
excluded-ancestors
Regular expression that matches against the ancestor string of the matching key, just like above. However, if this regex matches, the key is *not* checked. The start and end line markers ^ and $ are implicit, just like the key regex. Leave empty for no excluded ancestor matching.

Examples

With parent-key-name = kind and parent-key-value = Pod and parent-key-name-root = yes and required-key-name = readinessProbe the following code snippet would PASS:

    apiVersion: v1
    kind: Pod
    metadata:
        labels:
            test: liveness
        name: liveness-http
    spec:
        containers:
            - name: liveness
              image: k8s.gcr.io/liveness
              args:
              - /server
              readinessProbe:
                  httpGet:
                      path: /healthz
                      port: 8080
                      httpHeaders:
                      - name: Custom-Header
                      value: Awesome
                  initialDelaySeconds: 3
                  periodSeconds: 3

the following code snippets would FAIL:

    apiVersion: v1
    kind: Pod
    metadata:
        labels:
            test: liveness
        name: liveness-http
    spec:
        containers:
            - name: liveness
              image: k8s.gcr.io/liveness
              args:
                  - /server
              initialDelaySeconds: 3
              periodSeconds: 3

With: 

    required-key-name = required.*
    parentKeyName =
    parentKeyValue =
    isParentKeyAtRoot =
    included-ancestors = .*:nesting\d
    excluded-ancestors = .*:nesting2:nesting3
the following code snippet would PASS:

other1:
    notRequired1: valueNot1

nesting8: # has required key
  required8: value

the following code snippet would FAIL:

nesting1: # has no required.* key, violation
  first2: valueF2
  #required1: value1
  nesting2:
    #requiredYes: valueYes
    nesting3:
      required3Not: valueNot3

With: 

    required-key-name = waitDurationInOpenState.*|wait-duration-in-open-state.*
    parentKeyName =
    parentKeyValue =
    isParentKeyAtRoot =
    included-ancestors = .*:circuitbreaker
    excluded-ancestors =
the following code snippet would PASS:

iov:
  circuitbreaker:
    failure-rate-threshold-percentage: 70
    wait-duration-in-open-state-millis: 1500

resilience4j:
  circuitbreaker:
    failureRateThreshold: 50
    waitDurationInOpenStateInSeconds: 60

the following code snippet would FAIL for two places:

iov:
  circuitbreaker:
    failure-rate-threshold-percentage: 70
    #wait-duration-in-open-state-millis: 1500

resilience4j:
  circuitbreaker:
    failureRateThreshold: 50