Symfony Project sfservermon Post 6 - Update server status.

Updating the Server status.

The previous post allow us to create a new updater class and run it from the command line:

[johnr@sentos4 webserver]$ app/console servermon:update

It also talked about the initialisation of the ServerUpdate class using dependency injection as a Symfony service.

This post documents the actual update process, and involves 2 classes:

• ServerUpdate - which uses the UpdaterStatus class to check the status for all required servers.
• UpdaterStatus - updates a status for one particular server, it also provides a notify method to do the required notification.

At first thought much of the ServerUpdate code could be included in the UpdateCommand class - however the Symfony documentation for the console class reccommends that the command class do very little other than check any required parameters - for this application at least this is a very good reason - as an update can be initiated from the update action in the default Controller.

Much of this code is a straight port (read copy and paste) from the excellent code in phpServerMon application.

ServerUpdate Class.

This class has an update method: called from the updateCommand or the updateAction:

$serverUpdate =  $this->container = 
     $this->getApplication()->getKernel()->getContainer()->get('server_update');
$serverUpdate->update($serverLabel);

It does the following:

1. Creates an array $servers[] of the required servers to update
2. Reads the application configuration.
3. Creates a Monitor log class.
4. Creates a new updaterStatus class.
5. Loops through each server: 

Reading the Required Servers:

If a server label is specified read that one or read all active servers:

if ($serverLabel) {
$servers = $this->em->getRepository('JMPRServerMonBundle:MonitorServers')->findByLabel($serverLabel);
} else {
$servers = $this->em->getRepository('JMPRServerMonBundle:MonitorServers')->findByActive('yes');
}

Getting the Configuration and Creating the required Classes.

//get Configuration.
$configuration = $this->em->getRepository('JMPRServerMonBundle:MonitorConfig')->getConfig();

$monitorLog = $this->em->getRepository('JMPRServerMonBundle:MonitorLog');

$updater = new UpdaterStatus($this->em, $configuration, $monitorLog);

The configuration data requires helper class in its repository: - getConfig.

The configuration is stored (persisted) as a series of database records - 1 record for each configuration setting, but is used throughout the application as an associative array:

public function getConfig() {
$configArray=array();
$configs = $this->findAll();
foreach($configs as $config) {
$configArray[$config->getKey()] = $config->getValue();
}
return $configArray;
}

Main Server loop:

This is where the work happens:

1. Saving the old status
2. Calling UpdateStatus to updating it
3. Notifying and
4. Updating the server entity

(1) $status_org = $server->getStatus();

// remove the old status from the array to avoid confusion between the new and old status
$server->setStatus('unknown');

(2) $updater->setServer($server, $status_org);

//check server status
$status_new = $updater->getStatus();

(3) //notify the nerds of applicable
$updater->notify();

//update server status
(4) $server->setLastCheck(new \DateTime('now'));
$server->setStatus($status_new);
$server->setError($updater->getError());
$server->setRtime($updater->getRtime());

if ($status_new = 'on') {
$server->setLastOnline($server->getLastCheck());
}
$this->em->persist($server);
$this->em->flush();

The next post goes into details on the Updater Status class.