Using notify service type instead of simple to allow handling startup errors by systemd

Author: svpcom

scripts/systemd/[email protected]

@@ -4,7 +4,7 @@ Requires=wifibroadcast.service
 ReloadPropagatedFrom=wifibroadcast.service
 
 [Service]
-Type=simple
+Type=notify
 # common environment
 EnvironmentFile=/etc/default/wifibroadcast
 # per-profile environment

wfb_ng/protocols.py

@@ -27,11 +27,11 @@
 from copy import deepcopy
 from twisted.python import log, failure
 from twisted.internet import reactor, defer, threads, task
-from twisted.internet.protocol import ProcessProtocol, Factory
+from twisted.internet.protocol import ProcessProtocol, Factory, ConnectedDatagramProtocol
 from twisted.protocols.basic import LineReceiver, Int32StringReceiver
 
 from .conf import settings
-
+from .common import fatal_error
 
 class BadTelemetry(Exception):
     pass
@@ -667,3 +667,25 @@ def start(self):
                                  childFDs={0: "w", 1: "r", 2: "r"})
 
         return df.addCallback(lambda _: self.df)
+
+
+class SDNotifier(ConnectedDatagramProtocol):
+    def startProtocol(self):
+        log.msg("Sending notification to systemd")
+        self.transport.write(b'READY=1')
+        self.transport.stopListening()
+
+    def connectionFailed(self, reason):
+        log.msg("Connection to systemd failed: %s" % (reason.value,), isError=1)
+        fatal_error()
+
+
+def notify_ready():
+    sock = os.getenv('NOTIFY_SOCKET')
+    if sock is None :
+        return
+
+    if sock[0] == '@':
+        sock = '\0' + sock[1:]
+
+    return reactor.connectUNIXDatagram(sock.encode(), SDNotifier())

wfb_ng/server.py

@@ -33,7 +33,7 @@
 
 from . import _log_msg, ConsoleObserver, ErrorSafeLogFile, call_and_check_rc, ExecError, version_msg
 from .common import abort_on_crash, exit_status, df_sleep, search_attr
-from .protocols import AntStatsAndSelector, RFTempMeter, SSHClientProtocol, MsgPackAPIFactory, JSONAPIFactory
+from .protocols import AntStatsAndSelector, RFTempMeter, SSHClientProtocol, MsgPackAPIFactory, JSONAPIFactory, notify_ready
 from .services import parse_services, init_udp_direct_tx, init_udp_direct_rx, init_mavlink, init_tunnel, init_udp_proxy, hash_link_domain, bandwidth_map
 from .cluster import parse_cluster_services, gen_cluster_scripts
 from .conf import settings, cfg_files
@@ -271,6 +271,8 @@ def _cleanup(x):
                                           srv_cfg.udp_peers_auto if is_cluster else wlans,
                                           link_id, ant_sel_f, is_cluster, rx_only_wlan_ids))
 
+
+    notify_ready()
     yield defer.gatherResults(dl, consumeErrors=True).addBoth(_cleanup).addErrback(lambda f: f.trap(defer.FirstError) and f.value.subFailure)