Add support for backups to GCS via Helm chart

This adds both a quickstart for backing up to GCS as well as
use of GCS in a multi-repository setup.

Author: Jonathan S. Katz

Diff for: helm/postgres/templates/_gcs.tpl

@@ -0,0 +1,7 @@
+{{/* Allow for GCS secret information to be stored in a Secret */}}
+{{- define "postgres.gcs" }}
+[global]
+{{- if .gcs }}
+repo{{ add .index 1 }}-gcs-key=/etc/pgbackrest/conf.d/gcs-key.json
+{{- end }}
+{{ end }}

Diff for: helm/postgres/templates/pgbackrest-secret.yaml

@@ -1,4 +1,4 @@
-{{- if or .Values.multiBackupRepos .Values.s3 }}
+{{- if or .Values.multiBackupRepos .Values.s3 .Values.gcs }}
 apiVersion: v1
 kind: Secret
 metadata:
@@ -11,11 +11,23 @@ data:
   {{- $args := dict "s3" $repo.s3 "index" $index }}
   s3.conf: |-
         {{ include "postgres.s3" $args | b64enc }}
+  {{- else if $repo.gcs }}
+  {{- $args := dict "gcs" $repo.gcs "index" $index }}
+  gcs.conf: |-
+        {{ include "postgres.gcs" $args | b64enc }}
+  gcs-key.json: |-
+        {{ $repo.gcs.key | b64enc }}
   {{- end }}
 {{- end }}
 {{- else if .Values.s3 }}
   {{- $args := dict "s3" .Values.s3 "index" 0 }}
   s3.conf: |-
         {{ include "postgres.s3" $args | b64enc }}
+{{- else if .Values.gcs }}
+  {{- $args := dict "gcs" .Values.gcs "index" 0 }}
+  gcs.conf: |-
+        {{ include "postgres.gcs" $args | b64enc }}
+  gcs-key.json: |-
+        {{ .Values.gcs.key | b64enc }}
 {{- end }}
 {{- end }}

Diff for: helm/postgres/templates/postgres.yaml

@@ -46,7 +46,7 @@ spec:
           name: {{ default .Release.Name .Values.name }}-pgbackrest-secret
       global:
         {{- range $index, $repo := .Values.multiBackupRepos }}
-        {{- if $repo.s3 }}
+        {{- if or $repo.s3 $repo.gcs }}
         repo{{ add $index 1 }}-path: /pgbackrest/{{ $.Release.Namespace }}/{{ default $.Release.Name $.Values.name }}/repo{{ add $index 1 }}
         {{- end }}
         {{- end }}
@@ -66,6 +66,9 @@ spec:
           bucket: {{ $repo.s3.bucket | quote }}
           endpoint: {{ $repo.s3.endpoint | quote }}
           region: {{ $repo.s3.region | quote }}
+        {{- else if $repo.gcs }}
+        gcs:
+          bucket: {{ $repo.gcs.bucket | quote }}
         {{- end }}
       {{- end }}
 {{- else if .Values.s3 }}
@@ -83,6 +86,16 @@ spec:
           bucket: {{ .Values.s3.bucket | quote }}
           endpoint: {{ .Values.s3.endpoint | quote }}
           region: {{ .Values.s3.region | quote }}
+{{- else if .Values.gcs }}
+      configuration:
+      - secret:
+          name: {{ default .Release.Name .Values.name }}-pgbackrest-secret
+      global:
+        repo1-path: /pgbackrest/{{ .Release.Namespace }}/{{ default .Release.Name .Values.name }}/repo1
+      repos:
+      - name: repo1
+        gcs:
+          bucket: {{ .Values.gcs.bucket | quote }}
 {{- else }}
       repos:
       - name: repo1

Diff for: helm/postgres/values.yaml

@@ -189,6 +189,17 @@
 #   # built-in encrpytion system.
 #   encryptionPassphrase: ""
 
+# gcs allows for Google Cloud Storage (GCS) to be used for backups. This allows
+# for a quick setup with GCS; if you need a more advanced setup, use
+# "pgBackRestConfig".
+# gcs:
+#   # bucket is the name of the GCS bucket that the backups will be stored in.
+#   bucket: ""
+#   # key is a multi-line string that contains the GCS key, which is a JSON
+#   # structure.
+#   key: |
+#     {}
+
 # multiBackupRepos allows for backing up to multiple repositories. This is
 # effectively uses the "quickstarts" for each of the backup types (volume, s3,
 # gcs, azure). You can have any permutation of these types. You can set up to 4.
@@ -209,6 +220,10 @@
 #     region: ""
 #     key: ""
 #     keySecret: ""
+# - gcs:
+#     bucket: ""
+#     key: |
+#       {}
 
 # pgBackRestConfig allows for the configuration of every pgBackRest option
 # except for "image", which is set by "pgBackRest".