Allow hostname override

Relates to #679

hw_diag/utilities/network.py

@@ -54,6 +54,7 @@ def setup_hostname():
     # This runs before the Flask app is really fully running, so we do not have the
     # global "g" object with the db session, so we must spawn our own.
     db = get_db_session()
+    INITIAL_HOSTNAME_OVERRIDE = os.getenv('INITIAL_HOSTNAME_OVERRIDE', 'false')
     HOSTNAME_SET_KEY = "hostname_set"
     try:
         try:
@@ -74,7 +75,12 @@ def setup_hostname():
             # Set hostname via Balena supervisor...
             default_password = generate_default_password()
             hostname_suffix = default_password[6:]
-            hostname = "nebra-%s.local" % hostname_suffix
+
+            if INITIAL_HOSTNAME_OVERRIDE != "false":
+                hostname = INITIAL_HOSTNAME_OVERRIDE
+            else:
+                hostname = "nebra-%s.local" % hostname_suffix
+
             balena_supervisor = BalenaSupervisor.new_from_env()
             balena_supervisor.set_hostname(hostname)
             hostname_set_row.value = "true"