Note: This blog post is from 2006. Some content may be outdated--though not necessarily. Same with links and subsequent comments from myself or others. Corrections are welcome, in the comments. And I may revise the content as necessary.
If you've ever needed to know how long your CFMX instance has been running, did you know there's an incredibly simple solution? It's not really obvious, and in fact it may not work on trial editions of ColdFusion (for reasons explained below), but it's worked on the Enterprise and Developer editions that I and others have tested it.
Some may have noticed that there is a server.coldfusion.expiration variable (one of many read-only variables in the server scope, within the coldfusion structure). According to the docs, it's supposed to represent the date on which a trial edition of CFMX will expire.
But some have found (and I've confirmed) that on non-trial editions it instead reports the time that the server started. Try it youself:
<cfoutput>#server.coldfusion.expiration#</cfoutput>
It'll be a date, but is it in the future? or the past? Assuming it's the past, and you're not running on a trial edition, then it's likely the time your server had started. If you could restart your server and test again, you'll know for sure. :-)
Better formatting of the result
Now, if you want to easily determine how long the server has been up, just use the datediff function to report how many minutes there are between the time reported and the current time:
<cfoutput>#datediff("n",server.coldfusion.expiration,now())#</cfoutput>
Now, that number will be in the thousands after only one day. If you just want to better format the number of minutes, you could use the numberformat function which (without any formatstring) simply adds commas where they would be appropriate:
<cfset uptime = datediff("n",server.coldfusion.expiration,now())>
<cfoutput>#numberformat(uptime)#</cfoutput>
But even better, you could use one of the nifty functions available at the cflib.org that could help present the result minutes in terms of days, hours, and minutes (duration()). Assuming you included the latter in your page, you could then output the value as:
<!--- assuming you have included or pasted the duration UDF --->
<cfset uptime = duration(server.coldfusion.expiration,now())><br>
<cfoutput>#uptime.days# Day(s) #uptime.hours# Hour(s) #uptime.minutes# Minute(s)
<br>Server started on #dateformat(server.coldfusion.expiration)# at #timeformat(server.coldfusion.expiration)#
</cfoutput>
I may put together a UDF to submit to the cflib to pull all this together, and which also checks if indeed the server being checked is a trial edition, etc. But I'll look forward to hearing people's feedback first.
Other options
Of course, it's worth pointing out that there are of course many tools that will monitor a server's uptime by watching it externally. It may also be possible to ask the operating system to report how long a given process or service has been running. I'll leave that for others to investigate.
Finally, I'll point out that there is indeed a tag in the Adobe Developers Exchange, CF_UpTimeMonger, that purports to help detect server uptime and says it works even for CF 4 and CF5. I have not explored it.
