From fb9f78901a19f2e53fe4dbb9c8d2ef692752c60a Mon Sep 17 00:00:00 2001
From: Samuel Alfageme <samuel@alfage.me>
Date: Thu, 17 Sep 2020 15:03:33 +0200
Subject: [PATCH] useStatefulSet switch in revad for stateful workloads

This is specially useful when running into sharded scenarios as
e.g. different storage providers to map users with different
rules. Ref. https://github.com/cs3org/reva/pull/1142

This commit contains a preliminary version, where the "real"
uniqueness of each replica in the set (in terms of config) is yet
to be implemented. First version will simply rely on the hostname
as selector inside the 'configFiles' value for a user-provided
toml file.
---
 revad/README.md                 |  6 +++++
 revad/templates/deployment.yaml | 39 +++++++++++++++++++++++++++------
 revad/templates/service.yaml    |  4 ++++
 revad/values.yaml               |  2 ++
 4 files changed, 44 insertions(+), 7 deletions(-)

diff --git a/revad/README.md b/revad/README.md
index e39630f..dee56e7 100644
--- a/revad/README.md
+++ b/revad/README.md
@@ -41,6 +41,7 @@ The following configurations may be set. It is recommended to use `values.yaml`
 | `extraVolumeMounts`                               | Array of additional volume mounts.                                                                           | `[]`                                                                                                                      |
 | `extraVolumes`                                    | Array of additional volumes.                                                                                 | `[]`                                                                                                                      |
 | `emptyDir.sizeLimit`                              | `emptyDir` `sizeLimit` if a Persistent Volume is not used                                                    | `""`                                                                                                                      |
+| `useStatefulSet`                                  | If true, Revad will be deployed using a `StatefulSet` rather than the usual `Deployment`.                    | `false`                                                                                                                   |
 | `persistentVolume.enabled`                        | If true, Revad will create a Persistent Volume Claim.                                                        | `false`                                                                                                                   |
 | `persistentVolume.accessModes`                    | Revad data Persistent Volume access modes.                                                                   | `[ReadWriteOnce]`                                                                                                         |
 | `persistentVolume.annotations`                    | Revad data Persistent Volume annotations.                                                                    | `{}`                                                                                                                      |
@@ -71,3 +72,8 @@ The following configurations may be set. It is recommended to use `values.yaml`
 $ helm install custom-reva cs3org/revad \
   --set-file configFiles.revad\\.toml=custom-config.toml
 ```
+
+### Stateful deployment
+
+```console
+```
diff --git a/revad/templates/deployment.yaml b/revad/templates/deployment.yaml
index d412c7e..ebf6ff9 100644
--- a/revad/templates/deployment.yaml
+++ b/revad/templates/deployment.yaml
@@ -1,10 +1,13 @@
 apiVersion: apps/v1
-kind: Deployment
+kind: {{ if .Values.useStatefulSet }}{{ "StatefulSet" }}{{- else }}{{ "Deployment" }}{{- end }}
 metadata:
   name: {{ include "revad.fullname" . }}
   labels:
     {{- include "revad.labels" . | nindent 4 }}
 spec:
+  {{- if .Values.useStatefulSet }}
+  serviceName: {{ include "revad.fullname" . }}
+  {{- end }}
   replicas: {{ .Values.replicaCount }}
   selector:
     matchLabels:
@@ -61,18 +64,40 @@ spec:
         - name: {{ include "revad.fullname" . }}-configfiles
           configMap:
             name: {{ template "revad.fullname" . }}-config
+      {{- if .Values.extraVolumes }}
+        {{ toYaml .Values.extraVolumes | nindent 8 }}
+      {{- end }}
+    {{- if .Values.persistentVolume.enabled }}
+      {{- if .Values.useStatefulSet }}
+  volumeClaimTemplates:
+    - metadata:
+        name: {{ include "revad.fullname" . }}-datadir
+        {{- if .Values.persistentVolume.annotations }}
+        annotations:
+          {{- toYaml .Values.persistentVolume.annotations | indent 10 }}
+        {{- end }}
+      spec:
+        accessModes:
+          {{- toYaml .Values.persistentVolume.accessModes | indent 10 }}
+        resources:
+          requests: 
+            storage: "{{ .Values.persistentVolume.size }}"
+          {{- if (eq "-" .Values.persistentVolume.storageClass) }}
+            storageClassName: ""
+          {{- else }}
+            storageClassName: "{{ .Values.persistentVolume.storageClass }}"
+          {{- end }}
+      {{- else }}
         - name: {{ include "revad.fullname" . }}-datadir
-        {{- if .Values.persistentVolume.enabled }}
           persistentVolumeClaim:
             claimName: {{ if .Values.persistentVolume.existingClaim }}{{ .Values.persistentVolume.existingClaim }}{{- else }}{{ template "revad.fullname" . }}{{- end }}
-        {{- else }}
+      {{- end }}
+    {{- else }}
+        - name: {{ include "revad.fullname" . }}-datadir
           emptyDir:
           {{- if .Values.emptyDir.sizeLimit }}
             sizeLimit: {{ .Values.emptyDir.sizeLimit }}
           {{- else }}
             {}
           {{- end -}}
-        {{- end -}}
-        {{- if .Values.extraVolumes }}
-          {{ toYaml .Values.extraVolumes | nindent 8 }}
-        {{- end }}
+    {{- end }}
diff --git a/revad/templates/service.yaml b/revad/templates/service.yaml
index 5fba114..7616ea2 100644
--- a/revad/templates/service.yaml
+++ b/revad/templates/service.yaml
@@ -5,7 +5,11 @@ metadata:
   labels:
     {{- include "revad.labels" . | nindent 4 }}
 spec:
+  {{- if .Values.useStatefulSet }}
+  clusterIP: None
+  {{- else }}
   type: {{ .Values.service.type }}
+  {{- end }}
   ports:
     {{- if .Values.service.http }}
     - port: {{ .Values.service.http.port }}
diff --git a/revad/values.yaml b/revad/values.yaml
index 2fa54a6..51d771b 100644
--- a/revad/values.yaml
+++ b/revad/values.yaml
@@ -18,6 +18,8 @@ extraVolumes: []
 emptyDir:
   sizeLimit: ""
 
+useStatefulSet: false
+
 persistentVolume:
   ## If true, revad will create/use a Persistent Volume Claim
   ## If false, use emptyDir