Imapsync boot failure due to Mail agent not ready

[DavidePrincipi]

Boot race condition: Imapsync fails if Mail agent is not ready (404 error on reveal-master-credentials).

Steps to reproduce

• Stop Mail module/agent (simulate a not-ready state at boot)
• Restart Imapsync service

Expected behavior

Imapsync (or agent.tasks.run()) should wait for Mail agent readiness or implement a retry before aborting the reveal-master-credentials helper script. If the helper fails, Imapsync can still start with the previous password.

Actual behavior

At boot, Imapsync reveal-master-credentials helper immediately executes a Mail task to get the Dovecot master password. If Mail is not started yet, api-server returns 404 and Imapsync startup aborts with error. Rare event but can occur. Example log evidence:

2026-03-01T06:20:23+01:00 [1:imapsync1:systemd] Starting imapsync server...
2026-03-01T06:20:24+01:00 [1:imapsync1:runagent] Traceback (most recent call last):
2026-03-01T06:20:24+01:00 [1:imapsync1:runagent]   File "/home/imapsync1/.config/bin/reveal-master-secret", line 20, in <module>
2026-03-01T06:20:24+01:00 [1:imapsync1:runagent]     response = agent.tasks.run(f"module/{mail_id}", action='reveal-master-credentials')
2026-03-01T06:20:24+01:00 [1:imapsync1:runagent]   File "/usr/local/agent/pypkg/agent/tasks/run.py", line 39, in run
...
2026-03-01T06:20:25+01:00 [1:imapsync1:runagent] aiohttp.client_exceptions.ClientResponseError: 404, message='Not Found', url='http://cluster-leader:9311/api/module/mail1/tasks'
2026-03-01T06:20:25+01:00 [1:imapsync1:systemd] imapsync.service: Control process exited, code=exited, status=1/FAILURE

Additional context

Ideas:

1. Fixing the core layer. The retry logic should be implemented by agent.tasks Python library itself. Also api-server 404 response does not describe the situation, we'd consider returning a temporary error code, like 503.
2. Fixing Imapsync. If the secret can't be obtained, start the service with the old password (and retry later).

Components

• Core 3.17.1
• Imapsync 1.2.2
• Mail (Dovecot) 1.7.5

See also

• https://community.nethserver.org/t/imapsync-not-starting-correctly-after-unexpected-reboot-of-server/27004

[DavidePrincipi]

In Testing 1.2.3-dev.1

Test case

Check the bug is not reproducible

[mrmarkuz]

Test case verified