[PATCH qemu-server] fix #2062: agent: add timeout parameter to guest cmd

["Janusz Waluś" <janwalus@gmail.com>]

This adds timeout parameter to QGA commands, allowing override of the hardcoded 3-second limit.
Timeout applies for initial checking if QGA is working as well as the actual command.
This resolves timeout false positives in environments with high I/O load.

Suggested-by: Tim Marx
Signed-off-by: Janusz Waluś <janwalus@gmail.com>
Buglink: https://bugzilla.proxmox.com/show_bug.cgi?id=2062
---
 src/PVE/API2/Qemu/Agent.pm  | 18 +++++++++++++++---
 src/PVE/QemuServer/Agent.pm |  8 ++++----
 2 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/src/PVE/API2/Qemu/Agent.pm b/src/PVE/API2/Qemu/Agent.pm
index f826fc27..7fbc2791 100644
--- a/src/PVE/API2/Qemu/Agent.pm
+++ b/src/PVE/API2/Qemu/Agent.pm
@@ -201,6 +201,14 @@ sub register_command {
                 description => "The QGA command.",
                 enum => [sort keys %$guest_agent_commands],
             },
+            timeout => {
+                type => 'integer',
+                description =>
+                    "Timeout for the command in seconds. If not specified, the default"
+                        . " timeout for each command is used.",
+                minimum => 1,
+                optional => 1,
+            },
         },
     };
 
@@ -233,10 +241,14 @@ sub register_command {
 
             my $conf = PVE::QemuConfig->load_config($vmid); # check if VM exists
 
-            PVE::QemuServer::Agent::assert_agent_available($vmid, $conf);
-
             my $cmd = $param->{command} // $command;
-            my $res = mon_cmd($vmid, "guest-$cmd");
+            my $timeout = $param->{timeout} // 3;
+            PVE::QemuServer::Agent::assert_agent_available($vmid, $conf, $timeout);
+
+            my %cmd_params;
+            $cmd_params{timeout} = $param->{timeout} if defined($param->{timeout});
+
+            my $res = mon_cmd($vmid, "guest-$cmd", %cmd_params);
 
             return { result => $res };
         },
diff --git a/src/PVE/QemuServer/Agent.pm b/src/PVE/QemuServer/Agent.pm
index be6df443..08288d00 100644
--- a/src/PVE/QemuServer/Agent.pm
+++ b/src/PVE/QemuServer/Agent.pm
@@ -79,8 +79,8 @@ sub get_qga_key($conf, $key) {
     return $agent->{$key};
 }
 
-sub qga_check_running($vmid, $nowarn = 0) {
-    eval { PVE::QemuServer::Monitor::mon_cmd($vmid, "guest-ping", timeout => 3); };
+sub qga_check_running($vmid, $nowarn = 0, $timeout = 3) {
+    eval { PVE::QemuServer::Monitor::mon_cmd($vmid, "guest-ping", timeout => $timeout); };
     if ($@) {
         warn "QEMU Guest Agent is not running - $@" if !$nowarn;
         return 0;
@@ -106,10 +106,10 @@ sub check_agent_error($result, $errmsg, $noerr = 0) {
     return 1;
 }
 
-sub assert_agent_available($vmid, $conf) {
+sub assert_agent_available($vmid, $conf, $timeout = 3) {
     die "No QEMU guest agent configured\n" if !defined($conf->{agent});
     die "VM $vmid is not running\n" if !PVE::QemuServer::Helpers::vm_running_locally($vmid);
-    die "QEMU guest agent is not running\n" if !qga_check_running($vmid, 1);
+    die "QEMU guest agent is not running\n" if !qga_check_running($vmid, 1, $timeout);
 }
 
 # loads config, checks if available, executes command, checks for errors
-- 
Hi everyone,

This is my first patch to Proxmox project. Please let me know if any adjustments are needed regarding code and submittion process itself.

Best regards,
Janusz