use new QMPClient code

[qemu-server.git] / PVE / QMPClient.pm

package PVE::QMPClient;

use strict;
#use PVE::SafeSyslog;
use PVE::QemuServer;
use IO::Multiplex;
use JSON;
use Data::Dumper;

# Qemu Monitor Protocol (QMP) client.
#
# This implementation uses IO::Multiplex (libio-multiplex-perl) and
# allows you to issue qmp commands to different VMs in parallel.

# Note: kvm can onyl handle 1 connection, so we close connections asap

sub new {
    my ($class, $eventcb) = @_;

    my $mux = new IO::Multiplex;

    my $self = bless {
        mux => $mux,
        fhs => {}, # $vmid => fh
        fhs_lookup => {}, # $fh => $vmid
        queue => {},
        current => {},
        errors => {},
    }, $class;

    $self->{eventcb} = $eventcb if $eventcb;

    $mux->set_callback_object($self);

    return $self;
}

# add a single command to the queue for later execution 
# with queue_execute()
sub queue_cmd {
    my ($self, $vmid, $callback, $execute, %params) = @_;

    my $cmd = {};
    $cmd->{execute} = $execute;
    $cmd->{arguments} = \%params;
    $cmd->{callback} = $callback;

    push @{$self->{queue}->{$vmid}}, $cmd;
}

# execute a single command
sub cmd {
    my ($self, $vmid, $cmd) = @_;

    my $result;

    my $callback = sub {
        my ($vmid, $resp) = @_;
        $result = $resp->{'return'};
    };

    $cmd->{callback} = $callback;
    $cmd->{arguments} = {} if !defined($cmd->{arguments});

    $self->{queue}->{$vmid} = [ $cmd ];

    $self->queue_execute();

    my $cmdstr = $cmd->{execute} || '';
    die "VM $vmid qmp command '$cmdstr' failed - $self->{errors}->{$vmid}"
        if defined($self->{errors}->{$vmid});    

    return $result;
};

my $cmdid_seq = 0;
my $next_cmdid = sub {
    $cmdid_seq++;
    return "$$:$cmdid_seq";
};

my $close_connection = sub {
    my ($self, $vmid) = @_;
            
    my $fh = $self->{fhs}->{$vmid};
    return if !$fh;
 
    delete $self->{fhs}->{$vmid};
    delete $self->{fhs_lookup}->{$fh};

    $self->{mux}->close($fh);
};

my $open_connection = sub {
    my ($self, $vmid) = @_;

    my $sname = PVE::QemuServer::qmp_socket($vmid);

    my $fh = IO::Socket::UNIX->new(Peer => $sname, Blocking => 0, Timeout => 1) ||
        die "unable to connect to VM $vmid socket - $!\n";

    $self->{fhs}->{$vmid} = $fh;
    $self->{fhs_lookup}->{$fh} = $vmid;
    $self->{mux}->add($fh);
 
    return $fh;
};

my $check_queue = sub {
    my ($self) = @_;

    my $running = 0;
        
    foreach my $vmid (keys %{$self->{queue}}) {
        my $fh = $self->{fhs}->{$vmid};
        next if !$fh;

        if ($self->{errors}->{$vmid}) {
            &$close_connection($self, $vmid);
            next;
        }

        if ($self->{current}->{$vmid}) { # command running, waiting for response
            $running++;
            next;
        }

        if (!scalar(@{$self->{queue}->{$vmid}})) { # no more commands for the VM
            &$close_connection($self, $vmid);
            next;
        }

        eval {

            my $cmd = $self->{current}->{$vmid} = shift @{$self->{queue}->{$vmid}};
            $cmd->{id} = &$next_cmdid();

            my $qmpcmd = to_json({
                execute => $cmd->{execute},
                arguments => $cmd->{arguments},
                id => $cmd->{id}});

            $self->{mux}->write($fh, $qmpcmd);
        };
        if (my $err = $@) {
            $self->{errors}->{$vmid} = $err;
        } else {
            $running++;
        }
    }

    $self->{mux}->endloop() if !$running;

    return $running;
};

# execute all queued command
sub queue_execute {
    my ($self, $timeout) = @_;

    $timeout = 3 if !$timeout;

    $self->{current} = {};
    $self->{errors} = {};

    # open all necessary connections
    foreach my $vmid (keys %{$self->{queue}}) {
        next if !scalar(@{$self->{queue}->{$vmid}}); # no commands for the VM

        eval {
            my $fh = &$open_connection($self, $vmid);
            my $cmd = { execute => 'qmp_capabilities', arguments => {} };
            unshift @{$self->{queue}->{$vmid}}, $cmd;
            $self->{mux}->set_timeout($fh, $timeout);
        };
        if (my $err = $@) {
            warn $err;
            $self->{errors}->{$vmid} = $err;
        }
    }

    my $running;

    for (;;) {

        $running = &$check_queue($self);

        last if !$running;

        $self->{mux}->loop;
    }

    # make sure we close everything
    foreach my $vmid (keys %{$self->{fhs}}) {
        &$close_connection($self, $vmid);
    }

    $self->{queue} = $self->{current} = $self->{fhs} = $self->{fhs_lookup} = {};
}

# mux_input is called when input is available on one of
# the descriptors.
sub mux_input {
    my ($self, $mux, $fh, $input) = @_;

    return if $$input !~ m/}\r\n$/;

    my $raw = $$input;

    # Remove the input from the input buffer.
    $$input = '';

    my $vmid = $self->{fhs_lookup}->{$fh};
    if (!$vmid) {
        warn "internal error - unable to lookup vmid";
        return;
    }

    eval {
        my @jsons = split("\n", $raw);

        foreach my $json (@jsons) {
            my $obj = from_json($json);
            next if defined($obj->{QMP}); # skip monitor greeting

            if (exists($obj->{error}->{desc})) {
                my $desc = $obj->{error}->{desc};
                chomp $desc;
                die "$desc\n" if $desc !~ m/Connection can not be completed immediately/;
                next;
            }

            if (defined($obj->{event})) {
                if (my $eventcb = $self->{eventcb}) {
                    &$eventcb($obj);
                }
                next;
            }

            my $cmdid = $obj->{id};
            die "received responsed without command id\n" if !$cmdid;

            my $curcmd = $self->{current}->{$vmid};
            die "unable to lookup current command for VM $vmid\n" if !$curcmd;

            delete $self->{current}->{$vmid};
            
            if ($curcmd->{id} ne $cmdid) {
                die "got wrong command id '$cmdid' (expected $curcmd->{id})\n";
            }

            if (my $callback = $curcmd->{callback}) {
                &$callback($vmid, $obj);
            }
        }
    };
    if (my $err = $@) {
        $self->{errors}->{$vmid} = $err;
    }

    &$check_queue($self);
}

# This gets called every second to update player info, etc...
sub mux_timeout {
    my ($self, $mux, $fh) = @_;

    if (my $vmid = $self->{fhs_lookup}->{$fh}) {
        $self->{errors}->{$vmid} = "got timeout\n";
    }

    &$check_queue($self);
}

1;