[Helm] Add the ability to add extraObjects (#8004)

**What this PR does / why we need it**:

Add the ability to create extraObjects in helm chart. This'll allow
users to inject a configmap of loki rules or secrets for object
storages. Also, the `extraObjects` is also a common fields for helm
charts (i.e.
https://github.com/grafana/helm-charts/blob/main/charts/grafana/values.yaml#L1148)

docs/sources/installation/helm/reference.md

@@ -470,6 +470,15 @@ false
 			<td><pre lang="json">
 "v1.6.0"
 </pre>
+</td>
+		</tr>
+		<tr>
+			<td>extraObjects</td>
+			<td>list</td>
+			<td></td>
+			<td><pre lang="json">
+[]
+</pre>
 </td>
 		</tr>
 		<tr>

production/helm/loki/CHANGELOG.md

@@ -11,6 +11,10 @@ Entries should be ordered as follows:
 
 Entries should include a reference to the pull request that introduced the change.
 
+## 3.8.2
+
+- [FEATURE] Added `extraObjects` helm values to extra manifests.
+
 ## 3.8.1
 
 - [ENHANCEMENT] Add the ability to specify container lifecycle

production/helm/loki/Chart.yaml

@@ -4,7 +4,7 @@ name: loki
 description: Helm chart for Grafana Loki in simple, scalable mode
 type: application
 appVersion: 2.7.0
-version: 3.8.1
+version: 3.8.2
 home: https://grafana.github.io/helm-charts
 sources:
   - https://github.com/grafana/loki

production/helm/loki/README.md

@@ -1,6 +1,6 @@
 # loki
 
-![Version: 3.8.1](https://img.shields.io/badge/Version-3.8.1-informational?style=flat-square) ![Type: application](https://img.shields.io/badge/Type-application-informational?style=flat-square) ![AppVersion: 2.7.0](https://img.shields.io/badge/AppVersion-2.7.0-informational?style=flat-square)
+![Version: 3.8.2](https://img.shields.io/badge/Version-3.8.2-informational?style=flat-square) ![Type: application](https://img.shields.io/badge/Type-application-informational?style=flat-square) ![AppVersion: 2.7.0](https://img.shields.io/badge/AppVersion-2.7.0-informational?style=flat-square)
 
 Helm chart for Grafana Loki in simple, scalable mode
 

production/helm/loki/templates/extra-manifests.yaml

@@ -0,0 +1,4 @@
+{{ range .Values.extraObjects }}
+---
+{{ tpl (toYaml .) $ }}
+{{ end }}

production/helm/loki/values.yaml

@@ -1304,3 +1304,24 @@ minio:
     requests:
       cpu: 100m
       memory: 128Mi
+
+# Create extra manifests via values. Would be passed through `tpl` for templating
+extraObjects: []
+# - apiVersion: v1
+#   kind: ConfigMap
+#   metadata:
+#     name: loki-alerting-rules
+#   data:
+#     loki-alerting-rules.yaml: |-
+#       groups:
+#         - name: example
+#           rules:
+#           - alert: example
+#             expr: |
+#               sum(count_over_time({app="loki"} |~ "error")) > 0
+#             for: 3m
+#             labels:
+#               severity: warning
+#               category: logs
+#             annotations:
+#               message: "loki has encountered errors"