resolvectl: implement log-level with varlink methods

src/resolve/resolvectl.c

@@ -3171,16 +3171,31 @@ static int verb_revert_link(int argc, char *argv[], uintptr_t _data, void *userd
 VERB(verb_log_level, "log-level", "[LEVEL]", VERB_ANY, 2, 0,
      "Get/set logging threshold for systemd-resolved");
 static int verb_log_level(int argc, char *argv[], uintptr_t _data, void *userdata) {
-        _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
         int r;
 
-        r = acquire_bus(&bus);
+        _cleanup_(sd_varlink_unrefp) sd_varlink *vl = NULL;
+        r = sd_varlink_connect_address(&vl, "/run/systemd/resolve/io.systemd.Resolve");
         if (r < 0)
-                return r;
+                return log_error_errno(r, "Failed to connect to /run/systemd/resolve/io.systemd.Resolve: %m");
 
-        assert(IN_SET(argc, 1, 2));
+        if (argc == 1) {
+                /* Show current log level */
+                _cleanup_free_ char *level_str = NULL;
+                r = varlink_get_log_level_string(vl, &level_str);
+                if (r < 0)
+                        return r;
 
-        return verb_log_control_common(bus, "org.freedesktop.resolve1", argv[0], argc == 2 ? argv[1] : NULL);
+                puts(level_str);
+
+        } else if (argc == 2) {
+                /* Set new log level */
+                r = varlink_set_log_level_string(vl, argv[1]);
+                if (r < 0)
+                        return r;
+        } else
+                assert_not_reached();
+
+        return 0;
 }
 
 static int parse_protocol(const char *arg) {

test/units/TEST-75-RESOLVED.sh

@@ -336,6 +336,11 @@ manual_testcase_01_resolvectl() {
     assert_in '_localdnsstub' "$(dig @127.0.0.53 -x 127.0.0.53)"
     assert_in '127.0.0.54' "$(dig @127.0.0.53 _localdnsproxy)"
     assert_in '_localdnsproxy' "$(dig @127.0.0.53 -x 127.0.0.54)"
+
+    resolvectl log-level warning
+    assert_eq "$(resolvectl log-level)" "warning"
+    resolvectl log-level debug
+    assert_eq "$(resolvectl log-level)" "debug"
 }
 
 # Tests for mDNS and LLMNR settings