Add watch option for bluechi status

This PR will add watch option for 'bluechi status'.
I added monitor for the units that are requested to be watch.
And every time the status of the service changed the screen is cleared
and every the new status is printed .

Related: eclipse-bluechi#706
Signed-off-by: Artiom Divak <adivak@redhat.com>

src/client/client.h

@@ -7,6 +7,7 @@
 
 #include "libbluechi/bus/utils.h"
 #include "libbluechi/common/common.h"
+#include "libbluechi/service/shutdown.h"
 
 #include "types.h"
 

src/client/method-status.c

@@ -11,6 +11,7 @@
 #include "libbluechi/common/opt.h"
 #include "libbluechi/common/time-util.h"
 
+
 typedef struct unit_info_t {
         const char *id;
         const char *load_state;
@@ -25,6 +26,25 @@ struct bus_properties_map {
         size_t offset;
 };
 
+typedef struct MethodStatusChange MethodStatusChange;
+
+struct MethodStatusChange {
+        Client *client;
+        char **units;
+        char *node_name;
+        size_t units_count;
+        size_t max_len;
+};
+
+void free_method_status_change(MethodStatusChange *s) {
+        free(s);
+}
+
+void clear_screen() {
+        printf("\033[2J");
+        printf("\033[%d;%dH", 0, 0);
+}
+
 static const struct bus_properties_map property_map[] = {
         { "Id", offsetof(unit_info_t, id) },
         { "LoadState", offsetof(unit_info_t, load_state) },
@@ -277,10 +297,48 @@ static int get_status_unit_on(Client *client, char *node_name, char *unit_name,
         return 0;
 }
 
-static int method_status_unit_on(Client *client, char *node_name, char **units, size_t units_count) {
+
+static int on_unit_status_changed(UNUSED sd_bus_message *m, UNUSED void *userdata, UNUSED sd_bus_error *error) {
+        MethodStatusChange *s = (MethodStatusChange *) userdata;
+
+        char **units = s->units;
+        char *node_name = s->node_name;
+        Client *client = s->client;
+        size_t units_count = s->units_count;
+        size_t max_len = s->max_len;
+
+        clear_screen();
+        print_info_header(max_len);
+        for (unsigned i = 0; i < units_count; i++) {
+                int r = get_status_unit_on(client, node_name, units[i], max_len);
+                if (r < 0) {
+                        fprintf(stderr,
+                                "Failed to get status of unit %s on node %s - %s",
+                                units[i],
+                                node_name,
+                                strerror(-r));
+                        return r;
+                }
+        }
+
+        return 1;
+}
+
+
+static int method_status_unit_on(
+                Client *client, char *node_name, char **units, size_t units_count, bool do_watch) {
         unsigned i = 0;
 
         size_t max_name_len = get_max_name_len(units, units_count);
+        _cleanup_free_ MethodStatusChange *s = malloc0(sizeof(MethodStatusChange));
+        if (s == NULL) {
+                return 0;
+        }
+        s->client = client;
+        s->max_len = max_name_len;
+        s->node_name = node_name;
+        s->units = units;
+        s->units_count = units_count;
 
         print_info_header(max_name_len);
         for (i = 0; i < units_count; i++) {
@@ -293,9 +351,72 @@ static int method_status_unit_on(Client *client, char *node_name, char **units,
                                 strerror(-r));
                         return r;
                 }
+                if (do_watch) {
+                        _cleanup_sd_bus_error_ sd_bus_error error = SD_BUS_ERROR_NULL;
+                        _cleanup_sd_bus_message_ sd_bus_message *reply = NULL;
+                        char *monitor_path = NULL;
+                        int r = 0;
+
+                        r = sd_bus_call_method(
+                                        client->api_bus,
+                                        BC_INTERFACE_BASE_NAME,
+                                        BC_OBJECT_PATH,
+                                        CONTROLLER_INTERFACE,
+                                        "CreateMonitor",
+                                        &error,
+                                        &reply,
+                                        "");
+                        if (r < 0) {
+                                fprintf(stderr, "Failed to create monitor: %s\n", error.message);
+                                return r;
+                        }
+
+                        r = sd_bus_message_read(reply, "o", &monitor_path);
+                        if (r < 0) {
+                                fprintf(stderr,
+                                        "Failed to parse create monitor response message: %s\n",
+                                        strerror(-r));
+                                return r;
+                        }
+                        r = sd_bus_match_signal(
+                                        client->api_bus,
+                                        NULL,
+                                        BC_INTERFACE_BASE_NAME,
+                                        monitor_path,
+                                        MONITOR_INTERFACE,
+                                        "UnitStateChanged",
+                                        on_unit_status_changed,
+                                        s);
+                        if (r < 0) {
+                                fprintf(stderr,
+                                        "Failed to create callback for UnitStateChanged: %s\n",
+                                        strerror(-r));
+                                return r;
+                        }
+
+                        _cleanup_sd_bus_message_ sd_bus_message *m = NULL;
+                        r = sd_bus_message_new_method_call(
+                                        client->api_bus,
+                                        &m,
+                                        BC_INTERFACE_BASE_NAME,
+                                        monitor_path,
+                                        MONITOR_INTERFACE,
+                                        "Subscribe");
+                        if (r < 0) {
+                                fprintf(stderr, "Failed creating subscription call: %s\n", strerror(-r));
+                                return r;
+                        }
+                        sd_bus_message_append(m, "ss", node_name, units[i]);
+                        _cleanup_sd_bus_message_ sd_bus_message *subscription_reply = NULL;
+                        r = sd_bus_call(client->api_bus, m, BC_DEFAULT_DBUS_TIMEOUT, &error, &subscription_reply);
+                        if (r < 0) {
+                                fprintf(stderr, "Failed to subscribe to monitor: %s\n", error.message);
+                                return r;
+                        }
+                }
         }
 
-        return 0;
+        return do_watch ? client_start_event_loop(client) : 0;
 }
 
 /***************************************************************
@@ -660,6 +781,10 @@ int method_status(Command *command, void *userdata) {
                                 userdata, command->opargv[0], command_flag_exists(command, ARG_WATCH_SHORT));
         default:
                 return method_status_unit_on(
-                                userdata, command->opargv[0], &command->opargv[1], command->opargc - 1);
+                                userdata,
+                                command->opargv[0],
+                                &command->opargv[1],
+                                command->opargc - 1,
+                                command_flag_exists(command, ARG_WATCH_SHORT));
         }
 }

tests/tests/tier0/bluechictl-status-watch-service/main.fmf

@@ -0,0 +1,2 @@
+summary: Test client watch option by running in the controller container "bluechictl status" of a spasific node in the agent container and watching the status change when the service is down and up
+id: bb9d4394-bd53-4d36-b8ba-ee91697c4810

tests/tests/tier0/bluechictl-status-watch-service/python/bluechictl_status_watch.py

@@ -0,0 +1,50 @@
+#
+# Copyright Contributors to the Eclipse BlueChi project
+#
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
+import logging
+import re
+import unittest
+
+from bluechi_machine_lib.bluechictl import BackgroundRunner, SimpleEventEvaluator
+from dasbus.error import DBusError
+
+from bluechi.api import Node
+
+LOGGER = logging.getLogger(__name__)
+node_foo_name = "node-foo"
+simple_service = "simple.service"
+
+
+class TestBluechictlStatusWatch(unittest.TestCase):
+
+    def setUp(self) -> None:
+        service_status_active = re.compile(r"^" + simple_service + ".* active")
+        service_status_inactive = re.compile(r"^" + simple_service + ".* inactive")
+        expected_patterns = {service_status_active, service_status_inactive}
+        args = ["status", node_foo_name, simple_service, "-w"]
+        self.evaluator = SimpleEventEvaluator(expected_patterns)
+        self.bgrunner = BackgroundRunner(args, self.evaluator)
+
+    def test_bluechictl_status_watch(self):
+        self.bgrunner.start()
+
+        # stop the bluechi controller service to trigger a disconnected message in the agent
+        # hacky solution to cause a disconnect:
+        #   stop the controller service
+        # problem:
+        #   dasbus will raise a DBusError for connection timeout on v1.4, v1.7 doesn't
+        #   the command will be executed anyway, resulting in the desired shutdown of the node
+        #   therefore, the DBusError is silenced for now, but all other errors are still raised
+        node = Node(node_foo_name)
+        node.stop_unit(simple_service, "replace")
+        node.start_unit(simple_service, "replace")
+        node.stop_unit(simple_service, "replace")
+
+        self.bgrunner.stop()
+        assert self.evaluator.processing_finished()
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/tests/tier0/bluechictl-status-watch-service/test_bluechictl_status_watch_service.py

@@ -0,0 +1,44 @@
+#
+# Copyright Contributors to the Eclipse BlueChi project
+#
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
+import os
+from typing import Dict
+
+from bluechi_test.config import BluechiAgentConfig, BluechiControllerConfig
+from bluechi_test.machine import BluechiAgentMachine, BluechiControllerMachine
+from bluechi_test.service import Option, Section, SimpleRemainingService
+from bluechi_test.test import BluechiTest
+
+LOGGER = logging.getLogger(__name__)
+
+NODE_FOO = "node-foo"
+
+
+def exec(ctrl: BluechiControllerMachine, nodes: Dict[str, BluechiAgentMachine]):
+    node_foo = nodes[NODE_FOO]
+    service = SimpleRemainingService()
+    service.set_option(Section.Service, Option.ExecStart, "/bin/true")
+
+    node_foo.install_systemd_service(service)
+    ctrl.bluechictl.daemon_reload_node(NODE_FOO)
+    ctrl.bluechictl.start_unit(NODE_FOO, service.name)
+
+    result, _ = ctrl.run_python(os.path.join("python", "bluechictl_status_watch.py"))
+    assert result == 0
+
+
+def test_bluechictl_status_watch_service(
+    bluechi_test: BluechiTest,
+    bluechi_node_default_config: BluechiAgentConfig,
+    bluechi_ctrl_default_config: BluechiControllerConfig,
+):
+    node_foo_cfg = bluechi_node_default_config.deep_copy()
+    node_foo_cfg.node_name = NODE_FOO
+
+    bluechi_test.add_bluechi_agent_config(node_foo_cfg)
+
+    bluechi_ctrl_default_config.allowed_node_names = [NODE_FOO]
+    bluechi_test.set_bluechi_controller_config(bluechi_ctrl_default_config)
+    bluechi_test.run(exec)