Dynamically generate list of rules files for prometheus

This enables the dynamic generation of the list of rules files for
prometheus, driven by the rules added in the appropriate tree under
.Values.conf.prometheus.rules. This removes the necessity of adding
the file name manually in addition to defining the rules in the
rules tree, which should reduce overhead associated with adding
new rules for prometheus to evaluate

Change-Id: Ib768a252c5ea4f2d099df534c3ffcfb2949d7481

prometheus/templates/configmap-etc.yaml

@@ -16,6 +16,18 @@ limitations under the License.
 
 {{- if .Values.manifests.configmap_etc }}
 {{- $envAll := . }}
+
+{{- if empty $envAll.Values.conf.prometheus.scrape_configs.rule_files -}}
+{{- $_ := set $envAll.Values "__rule_files" ( list ) }}
+{{- $rulesKeys := keys $envAll.Values.conf.prometheus.rules -}}
+{{- range $rule := $rulesKeys }}
+{{- $rulesFile := printf "/etc/config/rules/%s.rules" $rule }}
+{{- $__rule_files := append $envAll.Values.__rule_files $rulesFile }}
+{{- $_ := set $envAll.Values "__rule_files" $__rule_files }}
+{{ end }}
+{{- set .Values.conf.prometheus.scrape_configs "rule_files" $envAll.Values.__rule_files | quote | trunc 0 -}}
+{{- end -}}
+
 ---
 apiVersion: v1
 kind: ConfigMap

prometheus/values.yaml

@@ -200,13 +200,6 @@ conf:
       global:
         scrape_interval: 60s
         evaluation_interval: 60s
-      rule_files:
-        - /etc/config/rules/alertmanager.rules
-        - /etc/config/rules/etcd3.rules
-        - /etc/config/rules/kubernetes.rules
-        - /etc/config/rules/kube_apiserver.rules
-        - /etc/config/rules/kube_controller_manager.rules
-        - /etc/config/rules/kubelet.rules
       scrape_configs:
         - job_name: kubelet
           scheme: https