paperless: add db backup job

jobs/services/paperless-backup.hcl

@@ -0,0 +1,50 @@
+job "paperless-backup" {
+  datacenters = ["aperture"]
+  type        = "batch"
+
+  periodic {
+    crons            = ["0 */3 * * * *"]
+    prohibit_overlap = true
+  }
+
+  group "db-backup" {
+    task "postgres-backup" {
+      driver = "raw_exec"
+
+      config {
+        command = "/bin/bash"
+        args    = ["local/script.sh"]
+      }
+
+      template {
+        data        = <<EOH
+#!/bin/bash
+
+file=/storage/backups/nomad/paperless/postgresql-paperless-$(date +%Y-%m-%d_%H-%M-%S).sql
+
+mkdir -p /storage/backups/nomad/paperless
+
+alloc_id=$(nomad job status paperless | grep running | tail -n 1 | cut -d " " -f 1)
+
+job_name=$(echo ${NOMAD_JOB_NAME} | cut -d "/" -f 1)
+
+nomad alloc exec -task db $alloc_id pg_dumpall -U {{ key "paperless/db/user" }} > "${file}"
+
+find /storage/backups/nomad/paperless/postgresql-paperless* -ctime +3 -exec rm {} \; || true
+
+if [ -s "$file" ]; then # check if file exists and is not empty
+  echo "Backup successful"
+  exit 0
+else
+  rm $file
+  curl -H "Content-Type: application/json" -d \
+  '{"content": "<@&585512338728419341> `PostgreSQL` backup for **'"${job_name}"'** has just **FAILED**\nFile name: `'"$file"'`\nDate: `'"$(TZ=Europe/Dublin date)"'`\nTurn off this script with `nomad job stop '"${job_name}"'` \n\n## Remember to restart this backup job when fixed!!!"}' \
+  {{ key "postgres/webhook/discord" }}
+fi
+EOH
+        destination = "local/script.sh"
+      }
+    }
+  }
+}
+