private void PollServer(TrackedService server)
{
bool pollOk = true;
string commandArg = null;
if (server.ServiceType == ServiceType.Block)
{
commandArg = "heartbeatB";
}
else if (server.ServiceType == ServiceType.Root)
{
commandArg = "heartbeatR";
}
else if (server.ServiceType == ServiceType.Manager)
{
commandArg = "heartbeatM";
}
else
{
tracker.log.Error(String.Format("Don't know how to poll type {0}", server.ServiceType));
pollOk = false;
}
// Send the poll command to the server,
IMessageProcessor p = connector.Connect(server.ServiceAddress, ServiceType.Block);
MessageStream outputStream = new MessageStream();
outputStream.AddMessage(new Message("poll", commandArg));
IEnumerable <Message> inputStream = p.Process(outputStream);
foreach (Message m in inputStream)
{
// Any error with the poll means no status change,
if (m.HasError)
{
pollOk = false;
}
}
// If the poll is ok, set the status of the server to UP and remove from
// the monitor list,
if (pollOk)
{
// The server status is set to 'STATUS_UP' if either the current state
// is 'DOWN CLIENT REPORT' or 'DOWN HEARTBEAT'
// Synchronize over 'servers_map' for safe alteration of the ref.
ServiceStatus oldStatus;
lock (monitoredServers) {
oldStatus = server.CurrentStatus;
if (oldStatus == ServiceStatus.DownClientReport ||
oldStatus == ServiceStatus.DownHeartbeat)
{
server.CurrentStatus = ServiceStatus.Up;
}
// Remove the server from the monitored_servers list.
monitoredServers.Remove(server);
}
if (tracker.log.IsInterestedIn(LogLevel.Information))
{
tracker.log.Info(String.Format("Poll ok. Status now UP for {0} {1}", server.ServiceAddress, server.ServiceType));
}
// Fire the event if the status changed,
try {
if (tracker.StatusChange != null)
{
tracker.StatusChange(this,
new ServiceStatusEventArgs(server.ServiceAddress, server.ServiceType, oldStatus,
ServiceStatus.Up));
}
} catch (Exception e) {
// Catch any exception generated. Log it but don't terminate the
// thread.
tracker.log.Error("Exception in listener during poll", e);
}
}
else
{
// Make sure the server status is set to 'DOWN HEARTBEAT' if the poll
// failed,
// Synchronize over 'servers_map' for safe alteration of the ref.
lock (monitoredServers) {
ServiceStatus sts = server.CurrentStatus;
if (sts == ServiceStatus.Up ||
sts == ServiceStatus.DownClientReport)
{
server.CurrentStatus = ServiceStatus.DownHeartbeat;
}
}
}
}