Support to "tail" the watchdog

Anyone available to test and review code?

I tested with success.

EDIT: I suggest to catch CTRL+C (or other) and finalize the code run by normal way instead of aborting execution. It will present problems to #543550: Drush interactive mode :)

neilnz: Yes, what I would like is to return to the shell upon `watchdog tail` abortion. I have no preference for ctrl-c or just `q` or another. I think drush does nothing with catching ctrl-c, and I've not thunk about the possibility of catching ctrl-c from the interactive shell for aborting a command.

Btw, there's no ETA for the interactive mode. I just code some lines time by time. Still in a kind of 'proof of concept' phase.

This is pretty nifty. I'm not too versed with catching CTRL-C and the like. I suppose thats only a nice to have at this point.

Patch no longer applies. Would be great to get a reroll.

Looks like you need to add a handler to catch SIGINT with http://php.oregonstate.edu/manual/en/function.pcntl-signal.php

I think this could probably be installed globally (perhaps trigger a drush hook, similar to hook_shutdown) - I guess this could be used to rollback any changes (e.g. half completed updates). Anyone want to take a shot?

That said, I am not sure I see any issue with just killing php/drush in the middle of tailing watchdog - were there some specific concerns here?

pcntl is not available on most binary distributions of php

looked at this a bit and then discovered the 'watch' command in unix. i has to get it via macports.

`watch -n1 "drush ws"` is working for me.

Very nice work, I like this. I have only one issue with the way this works: the watchdog history is backward.

 Date              Severi  Type  Message                        User      
                   ty                                                     
 2010-01-30 11:45  notice  cron  Cron run completed.            Anonymous 
 2010-01-30 10:39  notice  cron  Cron run completed.            Anonymous 
 2010-01-30 09:35  notice  cron  Cron run completed.            Anonymous 
 2010-01-30 07:27  notice  cron  Cron run completed.            Anonymous 
 2010-01-30 06:23  notice  cron  Cron run completed.            Anonymous 
 2010-01-30 12:27  notice  user  Session closed for anarcat.  Anonymous 
                                                                        
 2010-01-30 12:27  notice  user  Session opened for anarcat.  Anonymous 
                                                                        

Column alignment issues aside (that's not your fault), I think that the order should be the exact opposite: more recent events should be at the bottom of the log, not at top. Notice how the "session" stuff looks out of order: the reason it's like this is because those entries were added after the tail was started, so those are in proper order.

It also seem like there's an extra newline on the stuff that appears after tail has been started.

@moshe - this is really not like "watch": watch will fire up drush every second and hit the whole bootstrap code everytime, very inefficient: the above patch will keep drush running indefinitely, using only limited resources (an SQL query from time to time and resident memory).

The messed up columns may be my usage of drush which involves bypassing the bash script and running drush.php directly. At least I *guess* that is the issue. (In my opinion, the columns detection stuff should be done in PHP, but then this is not the place to discuss that.)

I don't know if DESC/ASC changed recently, however i feel it's necessary for the SQL request to be ASC for the LIMIT to work the way it is now. I haven't crunched enough cycles to figure out a better way so I didn't improve your patch, but that's the key trick, I think.

I'd like to make this issue dependant on #170583: watchdog fixes and improvements as both work on the same code and #170583 is a major refactor that will allow a cleaner patch for wd-tail.

#170583: watchdog fixes and improvements has landed. feel fee to proceed here.

Patch attached.

* wd-show remains the same: recent events at the top.
* wd-tail: recent events at the bottom.
* uses a trick around Console_Table for the display.
* Ctrl-C to abort (no catch).

Works well; I like it.

I'll mention the two thoughts I did have. 'watchdog-tail' could also just be 'watchdog-show --tail'; fewer commands that way, but I don't mind it the way it is, either.

It also might be nice to be able to specify the value to pass to sleep via an option, to give more control over load vs. responsiveness. Since 'tail' is less likely to be run on a production site, load probably isn't much of an issue, though, so I think this could be committed as-is.

I also like 'watchdog-show --tail'. Changed in the first patch attached.

Also attached an alternative patch that allows for --tail=3 and this is the argument for sleep(); if --tail the value is 1. I'm not specially interested in this, just to play.

--tail=3 isn't a good option; people who want to set it will likely put $options['sleep-delay'] = 3; in a config file. If you overload the sleep delay to also mean 'tail', then you can't do this without disabling watchdog-show.

Here is a patch with support for sleep-delay. I've also added some comments to the code. Feel free to correct my poor english in the options description.

There's also an error with `theme('username' (array)$result)` I will address in a new issue.

committed. thanks.