nextcloud: add promise to check if nextcloud is installed

This promise check if nextcloud app was correctly deployed, it ensure that slapos instance will deploy until nextcloud install succeed.

/reviewed-on nexedi/slapos!676

software/nextcloud/buildout.hash.cfg

@@ -26,4 +26,4 @@ md5sum = fbc5eacda192cb02c8d9861cb628fe6f
 
 [template-nextcloud-instance]
 filename = nextcloud-instance.cfg.in
-md5sum = 426df55e81725cd7faa408d3cd93558e
+md5sum = 28f9a64176e86360a3398742d5ad8470

software/nextcloud/nextcloud-instance.cfg.in

@@ -96,6 +96,23 @@ depends =
   ${nextcloud-backup-cron:recipe}
   ${nextcloud-news-updater:recipe}
   ${nextcloud-config-update:recipe}
+  ${nextcloud-install-promise:name}
+
+[nextcloud-install-promise]
+<= monitor-promise-base
+module = check_command_execute
+name = check-nextcloud-install.py
+config-command = ${nc-install-wrapper:output}
+
+[nc-install-wrapper]
+recipe = collective.recipe.template
+input = inline:#!/bin/bash
+  if [ -f "${instance-parameter:nextcloud}/config/CAN_INSTALL" ]; then
+    echo "Nextcloud is not installed.";
+    exit 1;
+  fi
+output = ${directory:bin}/check-nc-install
+mode = 744
 
 [nextcloud-apache-httpd]
 recipe = slapos.recipe.template:jinja2