vCO and defensive scripting – practical experience

In the last couple of weeks I did a lot of Customer vCO Workshops to enable the Customers to create their own solutions. During the workshops I noticed some recurrent errors which were made from the  teams.

On some point of our Workflow, we will work with Userinputs. These Inputs can be direct Inputs from the users or maybe also Lines which are read from a file (CSV as example). Mostly these Inputs are compared to other Information’s . In this example I will use the ESX Hostname.

As you can see I have a VC with an cluster and one ESX Host with the name vmware01.example.com

Now we want to check if a Host with a specific name. So we use a really simple workflow.

In the scripting element I use this code:

for (i = 0; i < allHostsofVC.length; i++) {

if (HosttoCheck == allHostsofVC[i].name)

{

System.log("Yeah, we found the Host. Input is " + HosttoCheck + " Value from allHostsofVC[i].name is: " +  allHostsofVC[i].name);

}

else

{

System.log("oh no......no host found.Input is " + HosttoCheck + " Value from allHostsofVC[i].name is: " +  allHostsofVC[i].name);

}

}

So, now let’s make a first run

As we can see the search string and the hostname are identical.

Now let’s see what happens when the user write the hostname in Uppercase.

As we can see the name isn’t resolved. This leads to wrong results. The easiest way to avoid this is to change everything into LowerCase. So let’s modify our scripting element:

for (i = 0; i < allHostsofVC.length; i++) {

if (HosttoCheck.toLowerCase() == allHostsofVC[i].name.toLowerCase())

{

System.log("Yeah, we found the Host. Input is " + HosttoCheck + " Value from allHostsofVC[i].name is: " +  allHostsofVC[i].name);

}

else

{

System.log("oh no......no host found.Input is " + HosttoCheck + " Value from allHostsofVC[i].name is: " +  allHostsofVC[i].name);

}

}

Let’s start the last run again:

Also the User Input and the return string are different, we got the correct match.

This example leads us to another problem when we have to catch a user input regarding the hostnames. Most users tend to write only the name as shortname.

We can check it with the code we used before.

As we can see we didn’t catch the server. Why can we see in the vCenter Server MOB Browser. The Server is registered with the FQDN and from VMware API sight the shortname isn’t available.

How can we solve this problem? It is quite easy……. We just split the name at the dot and compare it with the name.

for (i = 0; i < allHostsofVC.length; i++){

var HostShortName = new Array()

HostShortName = allHostsofVC[i].name.toLowerCase().split(".")

if (HosttoCheck.toLowerCase() == allHostsofVC[i].name.toLowerCase() || HosttoCheck.toLowerCase() == HostShortName[0])

{

System.log("Yeah, we found the Host. Input is " + HosttoCheck + " Value from allHostsofVC[i].name is: " +  allHostsofVC[i].name);

}

else

{

System.log("oh no......no host found.Input is " + HosttoCheck + " Value from allHostsofVC[i].name is: " +  allHostsofVC[i].name);

}

}

Then we get our Hostname also when it is insert as shortname.

So, hope this help some to get their workflow created without to big problems. Have fun and Orchestrate the world 😉