cosmos-sajal

// assume getData to be an API call
console.log("Getting Data1");
var data1 = getData('123');
console.log("Data is:", data1);

console.log("Getting Data2");
var data2 = getData('456');
console.log("Data is:", data2);

var sum = 1 + 2;

cosmos-sajal

console.log("Getting Data1");
getData('123', function(data1) {
  console.log("Data is:", data1);
});

console.log("Getting Data2");
getData('456', function(data1) {
  console.log("Data is:", data1);
});

cosmos-sajal

sudo apt-get install percona-toolkit
pt-online-schema-change --alter
"Add column <new_column> varchar(60) NOT NULL default <default_value>"
--user=root D=<database_name>,t=<table_name> --execute

cosmos-sajal

    /**
     * @return Integer
     */
    public function getProcessId()
    {
        return getmypid();
    }

cosmos-sajal

    /**
     * @return boolean
     */
    public function isProcessRunning($pid)
    {
            if (file_exists("/proc/".$pid)) {
                return true;
            } else {
                return false;
            }

cosmos-sajal

    /**
     * @param Integer $pid
     *
     * @return boolean
     */
    public function isProcessRunning($pid)
    {
            if (file_exists("/proc/".$pid)) {
                return true;
            } else {

cosmos-sajal

    /**
     * @param Integer $pid
     *
     * @return boolean
     */
    public function isProcessRunning($pid)
    {
         if (file_exists("/proc/".$pid)) {
             return true;
         }

cosmos-sajal

/**
 * Class LockHandlerUtil
 */
class LockHandlerUtil
{
    /**
     * @param String $fileName
     * @param String $rootDir
     */
    public function __construct($fileName, $rootDir)

cosmos-sajal

        $this->lockHandlerUtil = new LockHandlerUtil(
            $this->getName(),
            $this->getContainer()->get('kernel')->getRootDir()
        );
        
        // $this->getName() will return the current file name
        // of the Command (Cron) in Symfony framework.

cosmos-sajal

if ($this->lockHandlerUtil->isDuplicateInstanceRunning()) {
  // trigger some kind of alert
  return;
}

/*
  actual cron code
  ....
  ....
*/