Per-application datasource not found after service restart.

Ok, I think I may have found a super hacky solution. Earier in this thread, I discovered that if I simply "touch" any value in the `this.datastructures`, some internal magical cache appears to get flushed and the application will bootstrap properly. This got me thinking about possibly doing this "touch" programmatically. What I've done now is include a timestamp when my config is cached in memory:

private struct function getConfigSettings( boolean useCacheConfig = true ) {

	var configName = "appConfig_#this.name#";

	if ( useCacheConfig && server.keyExists( configName ) ) {

		return( server[ configName ] );

	}

	var config = server[ configName ] = deserializeJson( PATH_TO_CONFIG_FILE );

	// HACK: I'm having trouble with my "this.datasources" configuration bombing-out
	// on server-start for reasons that I don't understand. Through trial-and-error,
	// I've discovered that "touching" that structure fixes this issue. As such, I'm
	// going to see if this date/time-stamp can act as a "touch" on that value.
	config.loadedAt = getTickCount();

	return( config );

}

As you can see, I'm injecting a `.loadedAt` property when this is cached in the `server` scope. Then, in my `this.datasources` struct, I now have:

this.datasources = {
	
	"bennadel": {
		username: this.config.dsn.username,
		password: this.config.dsn.password,
		driver: "MySQL",
		class: "com.mysql.jdbc.Driver",
		
		// ...... truncated .......

		// HACK: For reasons that I don't understand at all (and what is looking very
		// much like a bug in ColdFusion), the datasources configuration occasionally
		// bombs-out when the service-start up for the first time. But, I've
		// discovered that simply "touching" this structure (ie, changing any property
		// in it) appears to fix the problem (maybe by flushing some sort of cache).
		// As such, I'm going to see if including a timestamp will act as a "touch".
		// This timestamp is when the config object was cached. And, since it's cache
		// whenever the onApplicationStart() method runs, if the application fails to
		// bootstrap, the next request will get a newer timestamp.
		_loaded_at_: this.config.loadedAt
	}
};
this.datasource = "bennadel";

Once I had this code in place, I started restarting the ColdFusion service. After about 7 restarts, I finally was able to reproduce the "datasource cannot be found error." However, unlike in previous tests, where this bad state _persisted_ indefinitely, I found that the next page request lead to a working application. I'm presuming this is befcause the next request triggered a new `onApplicationStart()` call, which in turn, reloaded the config, which in turn lead to a new `config.loadedAt` date/time stamp. It seems this new timestamp was enough to "touch" the structure, which cleared whatever crazy caching is going on.

This is nuts!!! But, it seems to work 🤞

Ok, I've spent the last hour-and-a-half restarting my live site and trying to add debugging. What a pain. It only actually breaks like 1 out of every 10 CF restarts. So, here's what I did:

First, I wrapped my `this.datasources` definition in a try/catch and logged any error using `cflog()`. There were no errors to be found in this block of code, even when the application was having trouble bootstrapping.

I added this to the top of my `onError()` handler:

writeDump( getApplicationMetadata().datasource );
writeDump( getApplicationMetadata().datasources.keyList() );
writeDump( exception );
abort;

And, when the application got into a bad state, here's what it showed me:

Note that both the `this.datasource` and `this.datasources` properties are correctly defined within `getApplicationMetadata()`. 

Just bananas!!

Ok, so I just tried one more thing. I restarted the ColdFusion service, and the datasource bombed-out. Then, all I did was update a value in the `this.datasources` - I changed `interval: 420` to `interval: 421`, re-uploaded my `Application.cfc` and the site immediately came online.

To be clear, it has nothing to do with `interval`. I tried it a few more times, changing _different_ properties, and everytime I "touch" the `this.datasources` structure, the site immediately bootstraps and comes online. It's like an invalid version of the datasource is getting cached and then ColdFusion re-caches it if any of the keys change.

Ok, so I just restarted the server and the datasource bombed-out again. Here's what I discovered:

• It is never making it past the `onApplicationStart()` method because I have some query-operations being triggered inside that function (preloading some in-memory structures from the DB). Meaning, once it gets in this state, every request is calling the `onApplicationStart()` method.
• If I dumped-out the `getApplicationMetadata()` inside the `onApplicationStart()`, it shows _all the data_ that I expected, including the default `datasource` and the `datasources` configuration.
• If I comment-out the data-pre-loading inside the `onApplicationStart()`, the application bootstraps. But then it errored due to missing pre-loaded data. BUT, if I then put this in the `onRequestStart()` code:

```

applicationStop();

location( url = cgi.script_name );

```

... in order to restart the application and refresh the page, then **everything starts up fine**.

This is just so strange.

 

I'm running into a rather strange issue and I don't know how to debug it.

By @bennadel22497347

Debug suggestion:

Run the following CFM page in the same directory as the Application.cfc:

<cfscript>
	try {
		writedump(new Application());
	} 
	catch (any e) {
		writedump(var=e, label="Oops!");
	}
</cfscript>

Hi @bennadel22497347 , I only have questions. But I hope they help.

1.  Is the datasource "bennadel" already configured in the ColdFusion Administrator?
        If so, then the code you've shown will be a repetition. The correct initialization code will probably be
        
        this.datasource="bennadel";
   
   
2.   Have you ensured that all the necessary datasource attributes - and appropriate values - are included in { ... }?
         For example, might the attributes you currently use make ColdFusion to create a connection each time?
         I would provide in { ... } , as a minimum, the attributes required to create a datasource in the ColdFusion Administrator. (Mind the default values)

I don't have a good debugging suggestion either. When I run into a problem like this, I generally just go in and yank on things until they work or break in a different way.

I've never heard of setting those "this." variables in onApplicationStart, onServerStart or onSessionStart. But it seems to work for Mark when he uses onApplicationStart, so try that! In the worst case, it still won't work intermittently and you're back where you started. You might also just see if there's a minor point release to the JVM beyond what you're using. Will upgrading to that work? Who knows? But this kind of random "pushing on buttons" might solve your problem even if you never find out why. Or, you might try using CFTRY/CFCATCH or its CFSCRIPT equivalent around the code you're using here. You shouldn't need it, but again, who knows?

Dave Watts, Eidolon LLC

To add to Charlie's answer, I would also ask where are you setting this? Are you setting in onApplicationStart() (this is where I would set it). I'm convinced there's a race condition of some sort that seems to happen sometimes. I also include a function inside of onRequestStart that lets me restart the application with a long URL variable. Just in case there's some kind of weird issue that happens. But like Charlie said, in this kind of thing I go back to the basics and just start dumping out the app scope and meta data and see what CF thinks it is doing. Is it ALL the app variables not setting, just some? Ping me if you run into more issues!

Hey, Ben, and a hearty welcome to the forums. We've missed you. 🙂

First, can you do a dump of getapplicationmetadata()? I'd recommend doing it in a separate template rather than the Application.cfc itself. Do you see the datasource and ALL other this scope things you set?

If you do not, assess whether you may have any code that could affect that surrounding the setting of those vars, like a try/catch or even a cflock with perhaps throwontimeout="no".

Also, are those settings created in a method in the cfc or outside of any (what is termed the "pseudo-constructor", for the sake of other readers)?

It would be awesome if you may stick around and share your wealth of knowledge with folks here, but I realize you've got more irons in the fire than a blacksmith at a rodeo. 🙂