Back up every store: the restic module holds node-backup, the stores contribute their dumps

ADR 0214 / to-be 43. restic keeps one repository per machine and takes a nightly snapshot per
module — 14 daily, 8 weekly, 6 monthly — and restores beside the live data, never over it. postgres,
mssql and mongodb contribute a consistent dump; minio, influxdb, the vault, mailu, gitea and
nextcloud the directories that hold their data.

modules/mssql/module.json

@@ -65,6 +65,13 @@
       "mode": "0700",
       "owner": "10001:0"
     },
+    {
+      "id": "dumps",
+      "type": "directory",
+      "path": "${dir:data}/backup",
+      "mode": "0700",
+      "owner": "10001:0"
+    },
     {
       "id": "net",
       "type": "network",
@@ -86,6 +93,13 @@
         "${dir:data}:/var/opt/mssql"
       ],
       "secrets-in-environment": "the image documents only MSSQL_SA_PASSWORD, no _FILE and no configuration field; not convertible without a wrapper entrypoint"
+    },
+    {
+      "id": "backup-sql",
+      "type": "file",
+      "path": "${dir:state}/backup.sql",
+      "mode": "0600",
+      "content": "SET NOCOUNT ON;\nDECLARE @n sysname, @s nvarchar(max);\nDECLARE c CURSOR LOCAL FAST_FORWARD FOR\n  SELECT name FROM sys.databases WHERE database_id > 4 AND state = 0 AND source_database_id IS NULL;\nOPEN c;\nFETCH NEXT FROM c INTO @n;\nWHILE @@FETCH_STATUS = 0\nBEGIN\n  SET @s = N'BACKUP DATABASE ' + QUOTENAME(@n) + N' TO DISK = N''/var/opt/mssql/backup/' + REPLACE(@n, N'''', N'''''') + N'.bak'' WITH INIT, COPY_ONLY, CHECKSUM';\n  EXEC (@s);\n  FETCH NEXT FROM c INTO @n;\nEND\nCLOSE c;\nDEALLOCATE c;\n"
     }
   ],
   "build": {
@@ -112,5 +126,12 @@
         }
       }
     ]
-  }
+  },
+  "contributions": [
+    {
+      "seat": "node-backup",
+      "kind": "backup",
+      "content": "run { cat ${dir:state}/sa.secret; echo; cat ${dir:state}/backup.sql; } | docker exec -i mssql sh -c 'read -r p; SQLCMDPASSWORD=\"$p\" exec /opt/mssql-tools18/bin/sqlcmd -C -b -S localhost -U sa -i /dev/stdin'\npath ${dir:dumps}\n"
+    }
+  ]
 }