Helm: Add extraContainers to write pods (#11319)

**Adds the extraContainers to the write pod**:

**Which issue(s) this PR fixes**:
This fix will allow my team to add a pods that makes modification to the
incoming logs before sending them to loki with minimal network transfer.

**Special notes for your reviewer**:
NONE

**Checklist**
- [x] Reviewed the
[`CONTRIBUTING.md`](https://github.com/grafana/loki/blob/main/CONTRIBUTING.md)
guide (**required**)
- [x] Documentation added
- [x] Tests updated
- [x] `CHANGELOG.md` updated
- [x] If the change is worth mentioning in the release notes, add
`add-to-release-notes` label
- [x] Changes that require user attention or interaction to upgrade are
documented in `docs/sources/setup/upgrade/_index.md`
- [x] For Helm chart changes bump the Helm chart version in
`production/helm/loki/Chart.yaml` and update
`production/helm/loki/CHANGELOG.md` and
`production/helm/loki/README.md`. [Example
PR](d10549e3ec)
- [x] If the change is deprecating or removing a configuration option,
update the `deprecated-config.yaml` and `deleted-config.yaml` files
respectively in the `tools/deprecated-config-checker` directory.
[Example
PR](0d4416a4b0)

---------

Co-authored-by: Michel Hollands <42814411+MichelHollands@users.noreply.github.com>

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 ##### Enhancements
 
+* [11319](https://github.com/grafana/loki/pull/11319) **someStrangerFromTheAbyss**: Helm: Add extraContainers to the write pods.
 * [11243](https://github.com/grafana/loki/pull/11243) **kavirajk**: Inflight-logging: Add extra metadata to inflight requests logging.
 * [11110](https://github.com/grafana/loki/pull/11003) **MichelHollands**: Change the default of the `metrics-namespace` flag to 'loki'.
 * [11086](https://github.com/grafana/loki/pull/11086) **kandrew5**: Helm: Allow topologySpreadConstraints

docs/sources/setup/install/helm/reference.md

@@ -4552,6 +4552,15 @@ null
 			<td><pre lang="json">
 []
 </pre>
+</td>
+		</tr>
+		<tr>
+			<td>write.extraContainers</td>
+			<td>list</td>
+			<td>Containers to add to the write pods</td>
+			<td><pre lang="json">
+[]
+</pre>
 </td>
 		</tr>
 		<tr>

production/helm/loki/CHANGELOG.md

@@ -13,6 +13,10 @@ Entries should include a reference to the pull request that introduced the chang
 
 [//]: # (<AUTOMATED_UPDATES_LOCATOR> : do not remove this line. This locator is used by the CI pipeline to automatically create a changelog entry for each new Loki release. Add other chart versions and respective changelog entries bellow this line.)
 
+## 5.40.0
+
+- [CHANGE] Add extraContainers parameter for the write pod
+
 ## 5.39.0
 
 - [FEATURE] Add support for adding OpenStack swift container credentials via helm chart

production/helm/loki/Chart.yaml

@@ -3,7 +3,7 @@ name: loki
 description: Helm chart for Grafana Loki in simple, scalable mode
 type: application
 appVersion: 2.9.2
-version: 5.39.0
+version: 5.40.0
 home: https://grafana.github.io/helm-charts
 sources:
   - https://github.com/grafana/loki

production/helm/loki/README.md

@@ -1,6 +1,6 @@
 # loki
 
-![Version: 5.39.0](https://img.shields.io/badge/Version-5.39.0-informational?style=flat-square) ![Type: application](https://img.shields.io/badge/Type-application-informational?style=flat-square) ![AppVersion: 2.9.2](https://img.shields.io/badge/AppVersion-2.9.2-informational?style=flat-square)
+![Version: 5.40.0](https://img.shields.io/badge/Version-5.40.0-informational?style=flat-square) ![Type: application](https://img.shields.io/badge/Type-application-informational?style=flat-square) ![AppVersion: 2.9.2](https://img.shields.io/badge/AppVersion-2.9.2-informational?style=flat-square)
 
 Helm chart for Grafana Loki in simple, scalable mode
 

production/helm/loki/templates/write/statefulset-write.yaml

@@ -138,6 +138,9 @@ spec:
             {{- end }}
           resources:
             {{- toYaml .Values.write.resources | nindent 12 }}
+        {{- with .Values.write.extraContainers }}
+        {{- toYaml . | nindent 8}}
+        {{- end }}
       {{- with .Values.write.affinity }}
       affinity:
         {{- tpl . $ | nindent 8 }}

production/helm/loki/values.yaml

@@ -800,6 +800,8 @@ write:
   # https://github.com/grafana/loki/blob/main/docs/sources/operations/storage/wal.md#how-to-scale-updown
   # -- Init containers to add to the write pods
   initContainers: []
+  # -- Containers to add to the write pods
+  extraContainers: []
   # -- Volume mounts to add to the write pods
   extraVolumeMounts: []
   # -- Volumes to add to the write pods