Add support for automatic backups

boardgame-manager.nomad.hcl

@@ -30,13 +30,22 @@ job [[ .bgm.instance | toJSON ]] {
       ]
     }
 
-    volume "boardgame-manager" {
+    volume "data" {
       type = [[ .bgm.volumes.data.type | toJSON ]]
       source = [[ .bgm.volumes.data.source | toJSON ]]
       attachment_mode = "file-system"
       access_mode     = "single-node-writer"
     }
 
+[[ if and .bgm.backup.enabled (not (eq .bgm.backup.cron "")) -]]
+    volume "backup" {
+      type            = [[ $c.volumes.backup.type | toJSON ]]
+      source          = [[ $c.volumes.backup.source | toJSON ]]
+      attachment_mode = "file-system"
+      access_mode     = "multi-node-multi-writer"
+    }
+[[- end ]]
+
     task "boardgame-manager" {
       driver = [[ $c.nomad.driver | toJSON ]]
 
@@ -51,12 +60,54 @@ job [[ .bgm.instance | toJSON ]] {
       }
 
       volume_mount {
-        volume = "boardgame-manager"
+        volume = "data"
         destination = "/opt/bgm/databases"
       }
 
 [[ template "common/resources.tpl" .bgm.resources ]]
 
     }
+
+[[ if and .bgm.backup.enabled (not (eq .bgm.backup.cron "")) -]]
+    task "backup" {
+      driver = [[ $c.nomad.driver | toJSON ]]
+
+      lifecycle {
+        hook    = "poststart"
+        sidecar = true
+      }
+
+      config {
+        image           = [[ .bgm.backup.image | toJSON ]]
+        pids_limit      = 50
+        readonly_rootfs = true
+        command         = "supercronic"
+        args            = [
+          "/secrets/backup.cron"
+        ]
+      }
+
+      template {
+        data =<<_EOT
+[[ .bgm.backup.cron ]] dump-sqlite /data/data.db /backup
+_EOT
+        destination = "secrets/backup.cron"
+      }
+
+      # Mount the data volume readonly so we can read the DB
+      volume_mount {
+        volume      = "data"
+        destination = "/data"
+        read_only   = true
+      }
+
+      # Mount the backup volume
+      volume_mount {
+        volume      = "backup"
+        destination = "/backup"
+      }
+[[ template "common/resources.tpl" .bgm.backup.resources ]]
+    }
+[[- end ]]
   }
 }

variables.yml

@@ -17,11 +17,24 @@ bgm:
   env: {}
 
   # Boardgame manager needs a volume to store its SQLite DB
+  # And an optional volume for backups of the DB
   volumes:
     data:
       type: csi
-      source: boardgame-manager
+      source: bgm-data
+    backup:
+      type: csi
+      source: bgm-backup
+
 
   # Public URL where the app will be exposed
   public_url: https://bgm.example.org
 
+  backup:
+    enabled: false
+    image: '[[ .docker.repo ]][[ .docker.base_images.sqlite.image ]]'
+    cron: '15 19 * * *'
+    resources:
+      cpu: 10
+      memory: 32
+