Plugin: Sage Job Queue (SJQ) v3

[ohpleaseno]

this is from the mailcheck.log. i don't think it tells anything useful though

2010-02-15 20:36:56,710  INFO [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:585) - Servlet POST request completed [0ms]
2010-02-15 20:37:06,726  WARN [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:135) - All client connections are being accepted and processed, please consider setting up client restrictions in SJQ settings
2010-02-15 20:37:06,726  INFO [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:585) - Servlet POST request completed [0ms]
2010-02-15 20:37:16,710  WARN [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:135) - All client connections are being accepted and processed, please consider setting up client restrictions in SJQ settings
2010-02-15 20:37:16,710  INFO [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:585) - Servlet POST request completed [0ms]
2010-02-15 20:37:19,351  INFO [SJQ-InternalTaskClnt] com.google.code.sagetvaddons.sjq.server.InternalTaskClient (InternalTaskClient.java:67) - Run completed [0ms]
2010-02-15 20:37:22,398  INFO [SJQ-SystemMessageQueueLoader] com.google.code.sagetvaddons.sjq.server.SystemMessageQueueLoader (SystemMessageQueueLoader.java:70) - Run completed [344ms]
2010-02-15 20:37:26,710  WARN [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:135) - All client connections are being accepted and processed, please consider setting up client restrictions in SJQ settings
2010-02-15 20:37:26,710  INFO [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:585) - Servlet POST request completed [0ms]
2010-02-15 20:37:36,726  WARN [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:135) - All client connections are being accepted and processed, please consider setting up client restrictions in SJQ settings
2010-02-15 20:37:36,742  INFO [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:585) - Servlet POST request completed [16ms]
2010-02-15 20:37:46,710  WARN [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:135) - All client connections are being accepted and processed, please consider setting up client restrictions in SJQ settings
2010-02-15 20:37:46,710  INFO [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:585) - Servlet POST request completed [0ms]
2010-02-15 20:37:56,710  WARN [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:135) - All client connections are being accepted and processed, please consider setting up client restrictions in SJQ settings
2010-02-15 20:37:56,710  INFO [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:585) - Servlet POST request completed [0ms]
2010-02-15 20:37:59,992  INFO [Thread-25] com.google.code.sagetvaddons.sre.server.SageRecordingExtender (SageRecordingExtender.java:149) - Found 1 active recordings.
2010-02-15 20:37:59,992  INFO [Thread-25] com.google.code.sagetvaddons.sre.server.SageRecordingExtender (SageRecordingExtender.java:165) - 	XXI Winter Olympics: Figure Skating, Speed Skating, Snowboarding --> Too early to check status
2010-02-15 20:38:03,132  WARN [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:135) - All client connections are being accepted and processed, please consider setting up client restrictions in SJQ settings
2010-02-15 20:38:03,132  INFO [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:593) - Checking client '192.168.3.104': 100 resources free.
2010-02-15 20:38:03,132  INFO [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:585) - Servlet POST request completed [0ms]
2010-02-15 20:38:06,710  WARN [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:135) - All client connections are being accepted and processed, please consider setting up client restrictions in SJQ settings
2010-02-15 20:38:06,710  INFO [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:585) - Servlet POST request completed [0ms]
2010-02-15 20:38:16,710  WARN [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:135) - All client connections are being accepted and processed, please consider setting up client restrictions in SJQ settings
2010-02-15 20:38:16,710  INFO [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:585) - Servlet POST request completed [0ms]
2010-02-15 20:38:20,913  WARN [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:135) - All client connections are being accepted and processed, please consider setting up client restrictions in SJQ settings
2010-02-15 20:38:20,913  INFO [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:585) - Servlet POST request completed [0ms]
2010-02-15 20:38:22,867  INFO [SJQ-SystemMessageQueueLoader] com.google.code.sagetvaddons.sjq.server.SystemMessageQueueLoader (SystemMessageQueueLoader.java:70) - Run completed [204ms]
2010-02-15 20:38:26,726  WARN [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:135) - All client connections are being accepted and processed, please consider setting up client restrictions in SJQ settings
2010-02-15 20:38:26,726  INFO [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:585) - Servlet POST request completed [0ms]
2010-02-15 20:38:36,726  WARN [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:135) - All client connections are being accepted and processed, please consider setting up client restrictions in SJQ settings
2010-02-15 20:38:36,726  INFO [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:585) - Servlet POST request completed [0ms]
2010-02-15 20:38:46,710  WARN [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:135) - All client connections are being accepted and processed, please consider setting up client restrictions in SJQ settings
2010-02-15 20:38:46,710  INFO [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:585) - Servlet POST request completed [0ms]
2010-02-15 20:38:56,710  WARN [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:135) - All client connections are being accepted and processed, please consider setting up client restrictions in SJQ settings
2010-02-15 20:38:56,710  INFO [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:585) - Servlet POST request completed [0ms]
2010-02-15 20:39:06,726  WARN [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:135) - All client connections are being accepted and processed, please consider setting up client restrictions in SJQ settings
2010-02-15 20:39:06,726  INFO [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:585) - Servlet POST request completed [0ms]
2010-02-15 20:39:16,710  WARN [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:135) - All client connections are being accepted and processed, please consider setting up client restrictions in SJQ settings
2010-02-15 20:39:16,710  INFO [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:585) - Servlet POST request completed [0ms]
2010-02-15 20:39:19,351  INFO [SJQ-InternalTaskClnt] com.google.code.sagetvaddons.sjq.server.InternalTaskClient (InternalTaskClient.java:67) - Run completed [0ms]
2010-02-15 20:39:22,960  INFO [SJQ-SystemMessageQueueLoader] com.google.code.sagetvaddons.sjq.server.SystemMessageQueueLoader (SystemMessageQueueLoader.java:70) - Run completed [15ms]
2010-02-15 20:39:26,726  WARN [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:135) - All client connections are being accepted and processed, please consider setting up client restrictions in SJQ settings
2010-02-15 20:39:26,726  INFO [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:585) - Servlet POST request completed [0ms]
2010-02-15 20:39:36,726  WARN [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:135) - All client connections are being accepted and processed, please consider setting up client restrictions in SJQ settings
2010-02-15 20:39:36,726  INFO [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:585) - Servlet POST request completed [0ms]
2010-02-15 20:39:46,710  WARN [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:135) - All client connections are being accepted and processed, please consider setting up client restrictions in SJQ settings
2010-02-15 20:39:46,710  INFO [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:585) - Servlet POST request completed [0ms]
2010-02-15 20:39:56,710  WARN [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:135) - All client connections are being accepted and processed, please consider setting up client restrictions in SJQ settings
2010-02-15 20:39:56,710  INFO [26999190@qtp-2634125-5] com.google.code.sagetvaddons.sjq.server.SJQServlet (SJQServlet.java:585) - Servlet POST request completed [0ms]

EDIT: Went into services on the client machine and changed it to use "Local System Account". It immediately threw up this log in SJQ

Date: Mon Feb 15 20:51:18 EST 2010







HTTP ERROR 500


Problem accessing /sjq/SJQ. Reason:

    Unexpected ':' encountered on line 17
Caused by:

java.lang.RuntimeException: Unexpected ':' encountered on line 17
	at com.google.code.sagetvaddons.sjq.server.ClientParser.readTask(ClientParser.java:399)
	at com.google.code.sagetvaddons.sjq.server.ClientParser.<init>(ClientParser.java:244)
	at com.google.code.sagetvaddons.sjq.server.SJQServlet.doPost(SJQServlet.java:185)
	at com.google.code.sagetvaddons.sjq.server.SJQServlet.doGet(SJQServlet.java:100)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
	at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:502)
	at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:389)
	at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
	at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
	at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
	at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:417)
	at org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:230)
	at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
	at org.mortbay.jetty.handler.rewrite.RewriteHandler.handle(RewriteHandler.java:230)
	at org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.java:114)
	at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
	at org.mortbay.jetty.Server.handle(Server.java:326)
	at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:534)
	at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:864)
	at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:539)
	at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
	at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
	at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
	at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:520)

[Slugger]

Nope, nothing there. What I tend to do when I hit these kinds of problems is to scrap what's there and add it back block by block until the error is encountered then study the block causing the error. Like I said, I don't see a problem, but obviously the code does so you're going to have to find out exactly what block is causing it (the reported line number isn't always the actual cause).

So figure out which block is causing the error, then when you do that, figure out which exact line of the block is causing the error then when you have that hopefully you can see the problem or if not then let me know which line it is and maybe I can spot it.

Also, if it is an uncaught exception causing this then you may have to enable debug logging in both SageTV and Jetty in order for the exception to be logged somewhere. If it is an uncaught exception then enabling the debug logging will be the only way to get output of the error such that I can fix it.

[Slugger]

Are you sure the copy/paste is right from before because I don't even see a colon on line 17 of the config you pasted in before?

[ohpleaseno]

Here it is again

:MAPDIR "\\\\localhost\\recorded tv" "\\\\server\\recorded tv"

COMSKIP {
   :MAX 2
   :RESOURCES 25
   :RETURNCODE 1
   "D:/shares/Software/sagetv/comskip80_027/comskip.exe \"--ini=D:/shares/Software/sagetv/comskip80_027/comskip.ini\" \"%c%\""
}

# Run at most 1 mediashink job from 2am - 10am Monday - Friday  :OFFHOUR "0-2, 14-23"

MEDIASHRINKHQ 
{
   :CPU "LOW"
   :MAX 1
   :RESOURCES 50
   "C:\\encoding\\mediashrink\\mediaEngine.exe \"%c%\" /inPlace /mediaShrink /batch /saveLog /defaultProfile autoEncode /onepass /findFileRegEx \"avi|mpg|mkv|mp4|mpeg|VIDEO_TS|ts|ogm|divx|mpts|dvr-ms\" /centralworkfolder "c:\\encoding\\workfolder""

[Slugger]

Try replacing line 17 with this:

"C:\\encoding\\mediashrink\\mediaEngine.exe \"%c%\" /inPlace /mediaShrink /batch /saveLog /defaultProfile autoEncode /onepass /findFileRegEx \"avi|mpg|mkv|mp4|mpeg|VIDEO_TS|ts|ogm|divx|mpts|dvr-ms\" /centralworkfolder \"c:\\encoding\\workfolder\""

What's different? You didn't escape the double quotes on the last argument.

[ChaOConnor]

Slugger, I have Jetty debugging enabled. What am I looking for in the Sagetv_0.txt? It's a big damn file... lol

[Slugger]

Look for exception dumps from sjq. Searching for sjq in the log should be enough. You may have to enable Jetty debug logging as well in order for the exceptions to show up in the logs.

[razrsharpe]

Originally Posted by Slugger

SJQ should be calling the task multiple times, once for each file segment. So if a recording was split into 2 parts, SJQ should pass file-0.mpg to the first command then run the command again with file-1.mpg. If it's not, it's a regression (this definitely used to work like this). Note that if the task failed for an earlier segment then the remaining segments will not be processed, but instead the task is just halted and marked as failed.

Questions about this... I have seen this scenario:
-SJQ starts a job shortly after a recording is started (comskip)
-that recording becomes a multi segment file at some point during the show (after SJQ starts the job)
-SJQ only processes the first segment (ie the segment that existed when the job was started)

It would be great if SJQ (at the completion of the job it was passed) checked for segments and then add those segments to the queue... Maybe it does this and my problem came from a 2 min gap where the first segment finished and then the second segment began... So presumably the job could have finished entirely before the second segment even began...

[razrsharpe]

I also have another feature request: Add a third object type that sjq can process that really isnt an object type at all but rather combines generic scheduling and all the SJQ rule processing, resource allocation, etc... so we could have a parameter like frequency (x hrs, days, etc) so then we can do things like reboot the server if it hasnt been done in x time, and isnt doing anything (recording, comskipping, etc).... or you can handle the defrag scenario someone brought up a while ago...

[Slugger]

Originally Posted by razrsharpe

Questions about this... I have seen this scenario:
-SJQ starts a job shortly after a recording is started (comskip)
-that recording becomes a multi segment file at some point during the show (after SJQ starts the job)
-SJQ only processes the first segment (ie the segment that existed when the job was started)

It would be great if SJQ (at the completion of the job it was passed) checked for segments and then add those segments to the queue... Maybe it does this and my problem came from a 2 min gap where the first segment finished and then the second segment began... So presumably the job could have finished entirely before the second segment even began...

Never thought of this scenario. As it stands, you'd have to process tasks after each recording instead of when one starts in order to ensure all segments are processed. I'd suggest an issue ticket to have me investigate alternative solutions to this problem.

Originally Posted by razrsharpe

I also have another feature request: Add a third object type that sjq can process that really isnt an object type at all but rather combines generic scheduling and all the SJQ rule processing, resource allocation, etc... so we could have a parameter like frequency (x hrs, days, etc) so then we can do things like reboot the server if it hasnt been done in x time, and isnt doing anything (recording, comskipping, etc).... or you can handle the defrag scenario someone brought up a while ago...

Hmm... yeah, I never really designed things to work in this type of scenario, but you might want to add an issue ticket for this as well. I could envision a possible "time of day" or "date" object that could be processed. Not sure though, just thinking out loud. Definitely will want to add an issue ticket if you want me to think about it further.

[razrsharpe]

thanks issue tickets submitted....

I just thought of a possible workaround to make sjq behave like a traditional file scheduler when needed... write some code to create sage system messages (from the commandline using the sagex remote apis), use windows to schedule an event that would run the code and create a sagetv system message, sjq processes that system message.. and along with your other ruleset constraints would get processed correctly... of course having another object type would be easiest... but i think that this would work... any reason why it shouldn't?

[Slugger]

Should work fine, as long as you don't mind generating a bunch of sys msgs that are going to popup in your STV on your tv...

[razrsharpe]

Originally Posted by Slugger

Should work fine, as long as you don't mind generating a bunch of sys msgs that are going to popup in your STV on your tv...

ya good point... maybe i'll request a forth sys msg type from sage that doesnt change the alert level, or popup on the stv... mmmm

[bikesquid]

There's this weird little mouse thing I'm wondering about. When selecting a task in any of the task windows (active, completed, failed) a little pop-up window comes up (which is great), but it's sorta runs around the screen just out of reach of the mouse... unless I move it just right. Is there a setting somewhere I can change so it stays put?

Also could there be an added option to 'move to complete' or 'ignore' or some such to simply bypass a file for now and forever... rather than delete which as far as I can tell allows it to return next task run?

[Slugger]

Originally Posted by bikesquid

There's this weird little mouse thing I'm wondering about. When selecting a task in any of the task windows (active, completed, failed) a little pop-up window comes up (which is great), but it's sorta runs around the screen just out of reach of the mouse... unless I move it just right. Is there a setting somewhere I can change so it stays put?

There's no setting to fix this, it would require a code change. Open an issue ticket to remind me to have a look at it.

Also could there be an added option to 'move to complete' or 'ignore' or some such to simply bypass a file for now and forever... rather than delete which as far as I can tell allows it to return next task run?

No. The way you have certain files ignored is to tweak your rule set such that the file is ignored (i.e. the file is never added to the queue in the first place).

[bikesquid]

Originally Posted by Slugger

There's no setting to fix this, it would require a code change. Open an issue ticket to remind me to have a look at it.

Will do.

Originally Posted by Slugger

No. The way you have certain files ignored is to tweak your rule set such that the file is ignored (i.e. the file is never added to the queue in the first place).

Yes, but for one off recordings I don't think of till I see them in the task list it would be nice to not have to create a rule exception, delete the file from the task list, and rerun hoping I got the rule right (I'm retarded). Just thought I'd ask, thanks.

[patja]

Hi, I'm a newb when it comes to SJQ, just got it fired up today.

I am having a little glitch with getting files queued up for comskip using the usual rule built around $.IsFileCurrentlyRecording{} == false. I am seeing files incorrectly identified by the Media Debugger as having $.IsFileCurrentlyRecording{} as true when they are not in fact currently recording

So as a workaround I switched to $.IsCompleteRecording{} which seems to be accurate so far.

What's the difference between these two booleans? Does CompleteRecording mean it is not a partial aborted recording?

And is there a suggestion of how to troubleshoot why my finished recordings are being flagged as IsFileCurrentlyRecording ?

Thank!

[Slugger]

Originally Posted by patja

Hi, I'm a newb when it comes to SJQ, just got it fired up today.

I am having a little glitch with getting files queued up for comskip using the usual rule built around $.IsFileCurrentlyRecording{} == false. I am seeing files incorrectly identified by the Media Debugger as having $.IsFileCurrentlyRecording{} as true when they are not in fact currently recording

So as a workaround I switched to $.IsCompleteRecording{} which seems to be accurate so far.

That's weird. It sounds like a bug with SageTV since all SJQ does it make the Sage API call under the hood. However, to confirm that, you should load the expression evaluator in Studio and make the IsFileCurrentlyRecording() call in there for files that SJQ is messing up on. If you get the same results in Studio then it's a Sage bug that should be reported to Sage ASAP. If you don't get the same results then it would point to an SJQ bug, but one that will be tough to track down because, as I say, I literally just parse the function name and make the corresponding API call and return the result. And if it is an SJQ bug then it's one of those bugs that if I can't reproduce it locally and I don't have access to a system/environment where I can reproduce it then there's very little chance of me actually tracking it down and fixing it. First, I'll need to know what you discover from the Studio test.

What's the difference between these two booleans? Does CompleteRecording mean it is not a partial aborted recording?

And is there a suggestion of how to troubleshoot why my finished recordings are being flagged as IsFileCurrentlyRecording ?

Thank!

The meanings of all of these object methods can be found in the SageTV API docs, since SJQ just exposes the Sage API underneath the hood (for object based method calls).

IsCompleteRecording()

IsFileCurrentlyRecording()

The docs for IsCompleteRecording() say that the determination is complex. Doesn't seem like I'd use it as a substitute for IsFileCurrentlyRecording(). I would do the tests in Studio as I suggest to try and figure out where the problem lies with the IsFileCurrentlyRecording() test.

[patja]

Originally Posted by Slugger

That's weird. It sounds like a bug with SageTV since all SJQ does it make the Sage API call under the hood. However, to confirm that, you should load the expression evaluator in Studio and make the IsFileCurrentlyRecording() call in there for files that SJQ is messing up on.

Never having cracked Studio open before, I've just spent about 30 minutes googling "expression evaluator sagetv" and other variants looking for some examples of how to structure the relevant expression to plug into the expression evaluator, and come up dry. Can you give me an example of what to put in there to call the IsFileCurrentlyRecording() method on a given file by airingID or file path?

[Slugger]

Originally Posted by patja

Never having cracked Studio open before, I've just spent about 30 minutes googling "expression evaluator sagetv" and other variants looking for some examples of how to structure the relevant expression to plug into the expression evaluator, and come up dry. Can you give me an example of what to put in there to call the IsFileCurrentlyRecording() method on a given file by airingID or file path?

Something like this should work:

IsFileCurrentlyRecording(GetMediaFileForID("12345"))

Just replace the number with the actual media file id for the media file you want to test. Where do you get the media id? Use the web server and get it from the recording details page. Be sure to use double quotes around the id number.