[stable/redis-ha]: added ability to specify exporter lua script (#20695)

* feat: redis-ha: added ability to specify exporter lua script

Signed-off-by: jwenz723 <jwenz723@gmail.com>

* Update stable/redis-ha/README.md

Co-Authored-By: Aaron Layfield <Aaron.Layfield@gmail.com>
Signed-off-by: jwenz723 <jwenz723@gmail.com>

* updated exporter script configuration to create the cm

Signed-off-by: jwenz723 <jwenz723@gmail.com>

Co-authored-by: Aaron Layfield <Aaron.Layfield@gmail.com>

stable/redis-ha/Chart.yaml

@@ -6,7 +6,7 @@ keywords:
 - redis
 - keyvalue
 - database
-version: 4.3.3
+version: 4.3.4
 appVersion: 5.0.6
 description: Highly available Kubernetes implementation of Redis
 icon: https://upload.wikimedia.org/wikipedia/en/thumb/6/6b/Redis_Logo.svg/1200px-Redis_Logo.svg.png

stable/redis-ha/README.md

@@ -93,6 +93,7 @@ The following table lists the configurable parameters of the Redis chart and the
 | `exporter.port`           | Exporter port                                                                                                                                                                                            | `9121`                                                                                     |
 | `exporter.annotations`    | Prometheus scrape annotations                                                                                                                                                                            | `{prometheus.io/path: /metrics, prometheus.io/port: "9121", prometheus.io/scrape: "true"}` |
 | `exporter.extraArgs`      | Additional args for the exporter                                                                                                                                                                         | `{}`                                                                                       |
+| `exporter.script`         | A custom custom Lua script that will be mounted to exporter for collection of custom metrics. Creates a ConfigMap and sets env var `REDIS_EXPORTER_SCRIPT`.                                                 |                                                                                            |
 | `exporter.serviceMonitor.enabled`       | Use servicemonitor from prometheus operator                                                                                                                                                | `false`                                                                                    |
 | `exporter.serviceMonitor.namespace`     | Namespace the service monitor is created in                                                                                                                                                | `default`                                                                                  |
 | `exporter.serviceMonitor.interval`      | Scrape interval, If not set, the Prometheus default scrape interval is used                                                                                                                | `nil`                                                                                      |

stable/redis-ha/templates/redis-ha-exporter-script-configmap.yaml

@@ -0,0 +1,11 @@
+{{- if .Values.exporter.script }}
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: {{ template "redis-ha.fullname" . }}-exporter-script-configmap
+  namespace: {{ .Release.Namespace }}
+  labels:
+{{ include "labels.standard" . | indent 4 }}
+data:
+  script: {{ toYaml .Values.exporter.script | indent 2 }}
+{{- end }}

stable/redis-ha/templates/redis-ha-statefulset.yaml

@@ -237,6 +237,10 @@ spec:
               {{- end }}
                 key: {{ .Values.authKey }}
         {{- end }}
+        {{- if .Values.exporter.script }}
+          - name: REDIS_EXPORTER_SCRIPT
+            value: /script/script.lua
+        {{- end }}
         livenessProbe:
           httpGet:
             path: {{ .Values.exporter.scrapePath }}
@@ -249,6 +253,11 @@ spec:
         ports:
           - name: exporter-port
             containerPort: {{ .Values.exporter.port }}
+        {{- if .Values.exporter.script }}
+        volumeMounts:
+          - mountPath: /script
+            name: script-mount
+        {{- end }}
 {{- end }}
 {{- if .Values.priorityClassName }}
       priorityClassName: {{ .Values.priorityClassName }}
@@ -262,6 +271,14 @@ spec:
         hostPath:
           path: /sys
       {{- end }}
+      {{- if .Values.exporter.script }}
+      - name: script-mount
+        configMap:
+          name: {{ template "redis-ha.fullname" . }}-exporter-script-configmap
+          items:
+            - key: script
+              path: script.lua
+      {{- end }}
 {{- if .Values.persistentVolume.enabled }}
   volumeClaimTemplates:
   - metadata:

stable/redis-ha/values.yaml

@@ -259,6 +259,31 @@ exporter:
   # Additional args for redis exporter
   extraArgs: {}
 
+  # Used to mount a LUA-Script via config map and use it for metrics-collection
+  # script: |
+  #   -- Example script copied from: https://github.com/oliver006/redis_exporter/blob/master/contrib/sample_collect_script.lua
+  #   -- Example collect script for -script option
+  #   -- This returns a Lua table with alternating keys and values.
+  #   -- Both keys and values must be strings, similar to a HGETALL result.
+  #   -- More info about Redis Lua scripting: https://redis.io/commands/eval
+  #
+  #   local result = {}
+  #
+  #   -- Add all keys and values from some hash in db 5
+  #   redis.call("SELECT", 5)
+  #   local r = redis.call("HGETALL", "some-hash-with-stats")
+  #   if r ~= nil then
+  #   for _,v in ipairs(r) do
+  #   table.insert(result, v) -- alternating keys and values
+  #   end
+  #   end
+  #
+  #   -- Set foo to 42
+  #   table.insert(result, "foo")
+  #   table.insert(result, "42") -- note the string, use tostring() if needed
+  #
+  #   return result
+
   serviceMonitor:
     # When set true then use a ServiceMonitor to configure scraping
     enabled: false