service: add new RestartMode option

rphibel · rphibel · commit e568fea9fcd2 · 2023-07-06T14:33:52.000+02:00
When this option is set to direct, the service restarts without entering a failed
state. Dependent units are not notified of transitory failure.

This is useful for the following use case:

We have a target with Requires=my-service, After=my-service.
my-service.service is a oneshot service and has Restart=on-failure in
its definition.

my-service.service can get stuck for various reasons and time out, in
which case it is restarted. Currently, when it fails the first time, the
target fails, even though my-service is restarted.

The behavior we're looking for is that until my-service is not restarted
anymore, the target stays pending waiting for my-service.service to
start successfully or fail without being restarted anymore.
diff --git a/man/org.freedesktop.systemd1.xml b/man/org.freedesktop.systemd1.xml
@@ -2588,6 +2588,8 @@ node /org/freedesktop/systemd1/unit/avahi_2ddaemon_2eservice {
       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
       readonly s Restart = '...';
       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
+      readonly s RestartMode = '...';
+      @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
       readonly s PIDFile = '...';
       readonly s NotifyAccess = '...';
       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
@@ -3233,6 +3235,8 @@ node /org/freedesktop/systemd1/unit/avahi_2ddaemon_2eservice {
 
     <!--property Restart is not documented!-->
 
+    <!--property RestartMode is not documented!-->
+
     <!--property PIDFile is not documented!-->
 
     <!--property NotifyAccess is not documented!-->
@@ -3813,6 +3817,8 @@ node /org/freedesktop/systemd1/unit/avahi_2ddaemon_2eservice {
 
     <variablelist class="dbus-property" generated="True" extra-ref="Restart"/>
 
+    <variablelist class="dbus-property" generated="True" extra-ref="RestartMode"/>
+
     <variablelist class="dbus-property" generated="True" extra-ref="PIDFile"/>
 
     <variablelist class="dbus-property" generated="True" extra-ref="NotifyAccess"/>
diff --git a/man/systemd.service.xml b/man/systemd.service.xml
@@ -897,6 +897,28 @@
         </listitem>
       </varlistentry>
 
+      <varlistentry>
+        <term><varname>RestartMode=</varname></term>
+
+        <listitem>
+          <para>Takes a string value that specifies how a service should restart:
+            <itemizedlist>
+              <listitem><para>If set to <option>normal</option> (the default), the service restarts by
+              going through a failed/inactive state.</para></listitem>
+
+              <listitem><para>If set to <option>direct</option>, the service transitions to the activating
+              state directly during auto-restart, skipping failed/inactive state.
+              <varname>ExecStopPost=</varname> is invoked.
+              <varname>OnSuccess=</varname> and <varname>OnFailure=</varname> are skipped.</para></listitem>
+            </itemizedlist>
+          </para>
+
+          <para>This option is useful in cases where a dependency can fail temporarily
+          but we don't want these temporary failures to make the dependent units fail.
+          When this option is set to <option>direct</option>, dependent units are not notified of these temporary failures.</para>
+        </listitem>
+      </varlistentry>
+
       <varlistentry>
         <term><varname>SuccessExitStatus=</varname></term>
 
diff --git a/src/core/dbus-service.c b/src/core/dbus-service.c
@@ -33,6 +33,7 @@ static BUS_DEFINE_PROPERTY_GET_ENUM(property_get_type, service_type, ServiceType
 static BUS_DEFINE_PROPERTY_GET_ENUM(property_get_exit_type, service_exit_type, ServiceExitType);
 static BUS_DEFINE_PROPERTY_GET_ENUM(property_get_result, service_result, ServiceResult);
 static BUS_DEFINE_PROPERTY_GET_ENUM(property_get_restart, service_restart, ServiceRestart);
+static BUS_DEFINE_PROPERTY_GET_ENUM(property_get_restart_mode, service_restart_mode, ServiceRestartMode);
 static BUS_DEFINE_PROPERTY_GET_ENUM(property_get_emergency_action, emergency_action, EmergencyAction);
 static BUS_DEFINE_PROPERTY_GET2(property_get_notify_access, "s", Service, service_get_notify_access, notify_access_to_string);
 static BUS_DEFINE_PROPERTY_GET(property_get_restart_usec_next, "t", Service, service_restart_usec_next);
@@ -322,6 +323,7 @@ const sd_bus_vtable bus_service_vtable[] = {
         SD_BUS_PROPERTY("Type", "s", property_get_type, offsetof(Service, type), SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("ExitType", "s", property_get_exit_type, offsetof(Service, exit_type), SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("Restart", "s", property_get_restart, offsetof(Service, restart), SD_BUS_VTABLE_PROPERTY_CONST),
+        SD_BUS_PROPERTY("RestartMode", "s", property_get_restart_mode, offsetof(Service, restart_mode), SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("PIDFile", "s", NULL, offsetof(Service, pid_file), SD_BUS_VTABLE_PROPERTY_CONST),
         SD_BUS_PROPERTY("NotifyAccess", "s", property_get_notify_access, 0, SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
         SD_BUS_PROPERTY("RestartUSec", "t", bus_property_get_usec, offsetof(Service, restart_usec), SD_BUS_VTABLE_PROPERTY_CONST),
@@ -512,6 +514,7 @@ static BUS_DEFINE_SET_TRANSIENT_PARSE(notify_access, NotifyAccess, notify_access
 static BUS_DEFINE_SET_TRANSIENT_PARSE(service_type, ServiceType, service_type_from_string);
 static BUS_DEFINE_SET_TRANSIENT_PARSE(service_exit_type, ServiceExitType, service_exit_type_from_string);
 static BUS_DEFINE_SET_TRANSIENT_PARSE(service_restart, ServiceRestart, service_restart_from_string);
+static BUS_DEFINE_SET_TRANSIENT_PARSE(service_restart_mode, ServiceRestartMode, service_restart_mode_from_string);
 static BUS_DEFINE_SET_TRANSIENT_PARSE(oom_policy, OOMPolicy, oom_policy_from_string);
 static BUS_DEFINE_SET_TRANSIENT_STRING_WITH_CHECK(bus_name, sd_bus_service_name_is_valid);
 static BUS_DEFINE_SET_TRANSIENT_PARSE(timeout_failure_mode, ServiceTimeoutFailureMode, service_timeout_failure_mode_from_string);
@@ -660,6 +663,9 @@ static int bus_service_set_transient_property(
         if (streq(name, "Restart"))
                 return bus_set_transient_service_restart(u, name, &s->restart, message, flags, error);
 
+        if (streq(name, "RestartMode"))
+                return bus_set_transient_service_restart_mode(u, name, &s->restart_mode, message, flags, error);
+
         if (streq(name, "RestartPreventExitStatus"))
                 return bus_set_transient_exit_status(u, name, &s->restart_prevent_status, message, flags, error);
 
diff --git a/src/core/load-fragment-gperf.gperf.in b/src/core/load-fragment-gperf.gperf.in
@@ -427,6 +427,7 @@ Service.RebootArgument,                  config_parse_unit_string_printf,
 Service.Type,                            config_parse_service_type,                   0,                                  offsetof(Service, type)
 Service.ExitType,                        config_parse_service_exit_type,              0,                                  offsetof(Service, exit_type)
 Service.Restart,                         config_parse_service_restart,                0,                                  offsetof(Service, restart)
+Service.RestartMode,                     config_parse_service_restart_mode,           0,                                  offsetof(Service, restart_mode)
 Service.PermissionsStartOnly,            config_parse_bool,                           0,                                  offsetof(Service, permissions_start_only)
 Service.RootDirectoryStartOnly,          config_parse_bool,                           0,                                  offsetof(Service, root_directory_start_only)
 Service.RemainAfterExit,                 config_parse_bool,                           0,                                  offsetof(Service, remain_after_exit)
diff --git a/src/core/load-fragment.c b/src/core/load-fragment.c
@@ -142,6 +142,7 @@ DEFINE_CONFIG_PARSE_ENUM(config_parse_exec_preserve_mode, exec_preserve_mode, Ex
 DEFINE_CONFIG_PARSE_ENUM(config_parse_service_type, service_type, ServiceType, "Failed to parse service type");
 DEFINE_CONFIG_PARSE_ENUM(config_parse_service_exit_type, service_exit_type, ServiceExitType, "Failed to parse service exit type");
 DEFINE_CONFIG_PARSE_ENUM(config_parse_service_restart, service_restart, ServiceRestart, "Failed to parse service restart specifier");
+DEFINE_CONFIG_PARSE_ENUM(config_parse_service_restart_mode, service_restart_mode, ServiceRestartMode, "Failed to parse service restart mode");
 DEFINE_CONFIG_PARSE_ENUM(config_parse_service_timeout_failure_mode, service_timeout_failure_mode, ServiceTimeoutFailureMode, "Failed to parse timeout failure mode");
 DEFINE_CONFIG_PARSE_ENUM(config_parse_socket_bind, socket_address_bind_ipv6_only_or_bool, SocketAddressBindIPv6Only, "Failed to parse bind IPv6 only value");
 DEFINE_CONFIG_PARSE_ENUM(config_parse_oom_policy, oom_policy, OOMPolicy, "Failed to parse OOM policy");
@@ -6299,6 +6300,7 @@ void unit_dump_config_items(FILE *f) {
                 { config_parse_service_type,          "SERVICETYPE" },
                 { config_parse_service_exit_type,     "SERVICEEXITTYPE" },
                 { config_parse_service_restart,       "SERVICERESTART" },
+                { config_parse_service_restart_mode,  "SERVICERESTARTMODE" },
                 { config_parse_service_timeout_failure_mode, "TIMEOUTMODE" },
                 { config_parse_kill_mode,             "KILLMODE" },
                 { config_parse_signal,                "SIGNAL" },
diff --git a/src/core/load-fragment.h b/src/core/load-fragment.h
@@ -41,6 +41,7 @@ CONFIG_PARSER_PROTOTYPE(config_parse_service_timeout_failure_mode);
 CONFIG_PARSER_PROTOTYPE(config_parse_service_type);
 CONFIG_PARSER_PROTOTYPE(config_parse_service_exit_type);
 CONFIG_PARSER_PROTOTYPE(config_parse_service_restart);
+CONFIG_PARSER_PROTOTYPE(config_parse_service_restart_mode);
 CONFIG_PARSER_PROTOTYPE(config_parse_socket_bindtodevice);
 CONFIG_PARSER_PROTOTYPE(config_parse_exec_output);
 CONFIG_PARSER_PROTOTYPE(config_parse_exec_input);
diff --git a/src/core/service.c b/src/core/service.c
@@ -2011,7 +2011,8 @@ static void service_enter_dead(Service *s, ServiceResult f, bool allow_restart)
                  * are only transitionary and followed by an automatic restart. We have fine-grained
                  * low-level states for this though so that software can distinguish the permanent UNIT_INACTIVE
                  * state from this transitionary UNIT_INACTIVE state by looking at the low-level states. */
-                service_set_state(s, restart_state);
+                if (s->restart_mode != SERVICE_RESTART_MODE_DIRECT)
+                        service_set_state(s, restart_state);
 
                 r = service_arm_timer(s, /* relative= */ true, service_restart_usec_next(s));
                 if (r < 0)
@@ -5009,6 +5010,13 @@ static const char* const service_restart_table[_SERVICE_RESTART_MAX] = {
 
 DEFINE_STRING_TABLE_LOOKUP(service_restart, ServiceRestart);
 
+static const char* const service_restart_mode_table[_SERVICE_RESTART_MODE_MAX] = {
+        [SERVICE_RESTART_MODE_NORMAL] = "normal",
+        [SERVICE_RESTART_MODE_DIRECT]  = "direct",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(service_restart_mode, ServiceRestartMode);
+
 static const char* const service_type_table[_SERVICE_TYPE_MAX] = {
         [SERVICE_SIMPLE]        = "simple",
         [SERVICE_FORKING]       = "forking",
diff --git a/src/core/service.h b/src/core/service.h
@@ -91,6 +91,13 @@ typedef enum ServiceTimeoutFailureMode {
         _SERVICE_TIMEOUT_FAILURE_MODE_INVALID = -EINVAL,
 } ServiceTimeoutFailureMode;
 
+typedef enum ServiceRestartMode {
+        SERVICE_RESTART_MODE_NORMAL,
+        SERVICE_RESTART_MODE_DIRECT,
+        _SERVICE_RESTART_MODE_MAX,
+        _SERVICE_RESTART_MODE_INVALID = -EINVAL,
+} ServiceRestartMode;
+
 struct ServiceFDStore {
         Service *service;
 
@@ -108,6 +115,7 @@ struct Service {
         ServiceType type;
         ServiceExitType exit_type;
         ServiceRestart restart;
+        ServiceRestartMode restart_mode;
         ExitStatusSet restart_prevent_status;
         ExitStatusSet restart_force_status;
         ExitStatusSet success_status;
@@ -249,6 +257,9 @@ usec_t service_restart_usec_next(Service *s);
 const char* service_restart_to_string(ServiceRestart i) _const_;
 ServiceRestart service_restart_from_string(const char *s) _pure_;
 
+const char* service_restart_mode_to_string(ServiceRestartMode i) _const_;
+ServiceRestartMode service_restart_mode_from_string(const char *s) _pure_;
+
 const char* service_type_to_string(ServiceType i) _const_;
 ServiceType service_type_from_string(const char *s) _pure_;
 
diff --git a/src/shared/bus-unit-util.c b/src/shared/bus-unit-util.c
@@ -2206,6 +2206,7 @@ static int bus_append_service_property(sd_bus_message *m, const char *field, con
                               "Type",
                               "ExitType",
                               "Restart",
+                              "RestartMode",
                               "BusName",
                               "NotifyAccess",
                               "USBFunctionDescriptors",
diff --git a/src/test/test-tables.c b/src/test/test-tables.c
@@ -95,6 +95,7 @@ int main(int argc, char **argv) {
         test_table(scope_state, SCOPE_STATE);
         test_table(service_exec_command, SERVICE_EXEC_COMMAND);
         test_table(service_restart, SERVICE_RESTART);
+        test_table(service_restart_mode, SERVICE_RESTART_MODE);
         test_table(service_result, SERVICE_RESULT);
         test_table(service_state, SERVICE_STATE);
         test_table(service_type, SERVICE_TYPE);
diff --git a/test/testsuite-03.units/fails-on-restart-restartdirect.service b/test/testsuite-03.units/fails-on-restart-restartdirect.service
@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+[Unit]
+Description=Fail on restart
+StartLimitIntervalSec=1m
+StartLimitBurst=3
+
+[Service]
+Type=oneshot
+ExecStart=false
+Restart=on-failure
+RestartMode=direct
diff --git a/test/testsuite-03.units/fails-on-restart-restartdirect.target b/test/testsuite-03.units/fails-on-restart-restartdirect.target
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+[Unit]
+Requires=fails-on-restart-restartdirect.service
diff --git a/test/testsuite-03.units/fails-on-restart.service b/test/testsuite-03.units/fails-on-restart.service
@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+[Unit]
+Description=Fail on restart
+StartLimitIntervalSec=1m
+StartLimitBurst=3
+
+[Service]
+Type=oneshot
+ExecStart=false
+Restart=on-failure
+RestartMode=normal
diff --git a/test/testsuite-03.units/fails-on-restart.target b/test/testsuite-03.units/fails-on-restart.target
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+[Unit]
+Requires=fails-on-restart.service
diff --git a/test/testsuite-03.units/succeeds-on-restart-restartdirect.service b/test/testsuite-03.units/succeeds-on-restart-restartdirect.service
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+[Service]
+Type=oneshot
+ExecStart=/usr/lib/systemd/tests/testdata/testsuite-03.units/succeeds-on-restart.sh
+Restart=on-failure
+RestartMode=direct
diff --git a/test/testsuite-03.units/succeeds-on-restart-restartdirect.target b/test/testsuite-03.units/succeeds-on-restart-restartdirect.target
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+[Unit]
+Requires=succeeds-on-restart-restartdirect.service
diff --git a/test/testsuite-03.units/succeeds-on-restart.service b/test/testsuite-03.units/succeeds-on-restart.service
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+[Service]
+Type=oneshot
+ExecStart=/usr/lib/systemd/tests/testdata/testsuite-03.units/succeeds-on-restart.sh
+Restart=on-failure
+RestartMode=normal
diff --git a/test/testsuite-03.units/succeeds-on-restart.sh b/test/testsuite-03.units/succeeds-on-restart.sh
@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+# SPDX-License-Identifier: LGPL-2.1-or-later
+if [[ ! -f "/succeeds-on-restart.ko" ]]
+then
+    touch "/succeeds-on-restart.ko"
+    exit 1
+else
+    rm "/succeeds-on-restart.ko"
+    exit 0
+fi
diff --git a/test/testsuite-03.units/succeeds-on-restart.target b/test/testsuite-03.units/succeeds-on-restart.target
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+[Unit]
+Requires=succeeds-on-restart.service
diff --git a/test/units/testsuite-03.sh b/test/units/testsuite-03.sh
@@ -153,4 +153,17 @@ systemctl restart propagatestopto-indirect.target
 assert_rc 3 systemctl --quiet is-active propagatestopto-and-pullin.target
 assert_rc 3 systemctl --quiet is-active sleep-infinity-simple.service
 
+# Test restart mode direct
+systemctl start succeeds-on-restart-restartdirect.target
+assert_rc 0 systemctl --quiet is-active succeeds-on-restart-restartdirect.target
+
+systemctl start fails-on-restart-restartdirect.target || :
+assert_rc 3 systemctl --quiet is-active fails-on-restart-restartdirect.target
+
+systemctl start succeeds-on-restart.target || :
+assert_rc 3 systemctl --quiet is-active succeeds-on-restart.target
+
+systemctl start fails-on-restart.target || :
+assert_rc 3 systemctl --quiet is-active fails-on-restart.target
+
 touch /testok
