Oh my goodness. I never thought that I will need to ask you this. But unfortunately yes, I need to!
I have a PHP written script of my own that uses ffmpeg-php. And ffmpeg-php is a bastard. For some input it works ok, but for some it crashes my whole PHP and server throws Internal Server Error 500. I've tried several times to update ffmpeg-php, ffmpeg itself and so on, but when for some input it works in version 0.5 in 0.6 it wont work. And what i need is be sure that rest of the script will be processed correctly. And now it does not, because when it comes to run toGDImage() on movie frame I have Internal Server Error 500 and no feedback why from any source.
So for peace of mind of my users I decided that I need to isolate this part of script that messes with ffmpeg-php. I need a way to assure that if something will go terribly wrong in this part, it rest will go on.
Try catch does not work because this is not a warning, nor a fatal error, it is a horrible server-disaster. So what are your suggestions?
I think about putting this script into another file called ffmpeg-php-process.php and call it via HTTP and read result, if it is Internal Server Error 500 - I will know that it was not ok.
Or are there any other, more neat ways to isolate disaster scripts in PHP?
Ps. Don't write that I need to diagnose or debug or find the source of the error. I'm not a damn beginner and I'm not a ffmpeg dev to mess in it's code, I need to make my users safe now, and it's everything that i care now.
If you're getting a 500 error, it's because an exception of some sort is being thrown at a level lower than that of PHP itself. Unless your code is spinning into some kind of infinite loop or hitting a recursion limit (and especially since it worked with version 0.5), there's a good chance that ffmpeg or ffmpeg-php is crashing and taking the instance of PHP that launched it down with it.
Frankly, there's nothing you can do from PHP.
Your best bet would be, since you've already got access to the server, to write the script in question using a language like Python. There's a ton of ffmpeg python plugins, so you shouldn't have a difficult time setting that up at all. Call your Python script from PHP and pull in the output from a file. What this will do is isolate PHP from your script failing. It'll also get you away from ffmpeg-php (which, at least to me, seems like an unholy combination).
If you're dead-set on using PHP (which I don't recommend), you can launch another PHP script using php-cli from your outward-facing PHP script and do the work from there (as you would with Python). Again, I highly recommend that you avoid this.
Hope this helps!
You could spawn a new process containing your php-ffmpeg script. There are some functions to do that: proc_open() as instance.
The documentation has a not bad example about it:
http://php.net/proc_open
I have something similar going with a convoluted, large, bulky legacy php-email system I support. When it got apparent that the email system was becoming it's own beast, we split it off as its own virtual server entirely. There's no separation like PHYSICAL separation. And hey, virtual servers are cheap....
On the plus side, you can start, restart, and generally destroy the separate server with little affect on the rest of your code. It may also have improved backup implications (isolate media and logic) Since going this route, we've not ever taken the main application server down.
However, it does create a connection challenge as now rather than working local you're going to have your server talking to another separated by at the very least a bit of wire in the same cabinet (hopefully)
Related
I recently started web development. The course I took was to install WAMP and start developing right away. I used an atom text editor, this -combined with wamp- proved to be a very fast way to write client-side code(HTML, CSS, Javascript).
But when I started to write serverside PHP things got a little messy. I should probably explain my site's structure here.
I keep separate PHP, CSS, javascript files for every page on the client side, for the server side a have 2 different types of PHP files:
Files that only perform a specific operation on the database(For example returning "5 more answers"). These are always called by AJAX requests.
Files that load the page for the first time. These are only used when the user opens the page for the first time, they do necessary database queries and return the page. Later requests always go to the 1st type of PHP files.
Now regarding my problem. I debugged until now by printing variables to the screen with var_dump() or echoing. But this started to become too slow as the data I work with grew. I wonder if there is a way of debugging which will let me but a breakpoint in one of my PHP files. Then, when I open it on the browser, on the localhost I created using WAMP, will let me go through the PHP file step by step.
I have been dealing with this issue for 3 days, I tried to make it work with Eclipse IDE but couldn't find a way. Also, there seems to be no tutorials or Q&A on the internet regarding the issue.
Breakpoint debugging opens a whole new world, and is the natural step after var_dump() debugging. Not only does it speed up development, but it provides much more information about your code, as you can step through each line and see what values have been set at each step, and how they evolve as your program executes its code. This means you can track the entirety of the values at different stages with one run - imagine tracking all variables at each point using var_dump()!
Although choosing an IDE is a personal decision based on personal taste, i strongly recommend you try out PhpStorm. If you can get a student licence go for it.
PhpStorm has extensive documentation & tutorials on all features in the IDE, debugging is no exception:
https://www.jetbrains.com/help/phpstorm/configuring-xdebug.html
https://www.youtube.com/watch?v=GokeXqI93x8
I don't know of a specific solution to your issue. I'm not exactly sure what you're doing but as a quick tip, I find add the following snippet to the top of the file useful as it will highly error more easily rather than browser just say nope.
error_reporting(E_ALL);
ini_set('display_errors', 'On');
Hope this help you a bit.
I tried out what's recommended in comments and answers. I first tried Netbeans. To be fair it disappointed me. Download kept getting stuck at 100%, even for different versions. When I stopped downloading and went ahead to create a php project, there was missing parts I guess. I couldn't even manage to create a php project. But that might just be me not being able to do it.
Then I followed #leuquim's answer and #Alex Howansky's comment and downloaded PHPStorm. And I got it to work in no more than 20 minutes. I downloaded it with a student's licence. For people who want to use PHPStorm with WAMP here's a Youtube tutorial:
https://www.youtube.com/watch?v=CxX4vnZFbZU
One thing to note in the video is that, maker of the video chooses PHP Web Application in the Run Configurations. That has been changed to PHP Web Page.
I'm a self taught programmer and I consider PHP one of my strongest languages. There are undoubtedly some things I don't do correctly though, since I'm not in the field and I've never had anyone leaning over my shoulder telling me about better ways.
The most cumbersome thing to me about php is debugging code. It's not too bad when I'm writing a script called with AJAX or php code inside of a webpage, because I can simply output values directly to the page. When I'm writing code without a client side though, I currently resort to outputting my debug info to the error_log. I have to navigate to it (which sometimes is a task in itself, refreshing directories to make it show up, etc), check whatever value I outputted to it, then open up my script and start working again.
I feel like there might be a better way, so I thought I'd ask. Is there a trade secret that can shave some seconds off whenever I need to know how many rows a query returns or if a path has been constructed correctly?
My development environments are Coda on my MacBook and Zend on my PC. I work on everything remotely. Nearly all my code requires the server environment to run correctly.
Update
After writing this, I just realized I could actually make a webpage using WebSockets that acted as an output window. Then import a file into each script with a function that pushed output to the webpage. Hmm... I really like this idea actually.
I guess this pretty vague question could be classified as a programming one. I did consider whether it belonged in the Ask Ubuntu / WordPress Development / Linux Administration communities- but of course I don't like to spam either. Apologies up front if I made a huge mistake and caused you to have a bad day.
Take a linux server, it has a number of WordPress sites on it, and we can already guess that the dominant interpreted language is PHP when you consider the above scenario.
These are not live sites, they are simply sites copied from a production server.
I want to simulate random traffic to all of them at once to see if the server can handle the load. Perhaps a PHP script run from the command line can do this?
Just looking for ideas at this stage.
I have tried https://www.blitz.io/ - works wonderfully, however just one site at a time as far as I'm aware.
http://jmeter.apache.org/ will do the job but need way more time to configure than blitz.io
Oke, i've been busting my head on this one.
I'm gonna try and keep things short, however, if you need more info, don't hesitate to ask.
I've written an import repo for an external firm, so we can import their data into our service.
quick overview of implemented logic?
ftp, grab xml file, parse it with simple_xml and do db stuff using laravel eloquent component.
on my dev machine,
every run gets parsed fully and all data is inserted correctly into the database.
problem
when i try the same thing on my production server.
I'm receiving a duplicate entry error, always on the same exact record. (unless i'm using another file)
pre script setup to help detect the error
on each run i do the following:
make sure i'm using the exact same files on both dev and prod
environment... (i've disabled the ftpgrab and uploaded manually to
the correct location)
truncate all the related tables so i'm always
starting with empty! tables.
i've manually triple-zillion checked for duplicates in the xml, but they're not in there.... and the fact that
my dev machine parses the file correctly confirms this.
what i tried
at this point, i've got no more clues as to how i'm supposed to debug this properly.
by now, i've checked so many things (most of them i can't even remember), all of which seemed pretty unrelated to me, but i had to try them.
those things include:
automatic disconnects due to browser
mysql wait timeouts
php script timeouts
memory settings
none of them seem to help (which was exactly what i was expecting)
another fact
my php version on my dev is 5.4.4 and the version on the production server is 5.3.2 (i know this is bad practise, but i'm not using any new features, it's really dead easy code, though it has quite a few lines :-) )
i've been suspecting this to be the cause, but
i've now switched to 5.3.14 on my dev... still the import runs without an issue
the changes from 5.3.2 to 5.3.14 are probably pretty minor
i've tried to manually compile the exact same php version, but i'm to inexperienced to properly do this. moreover, it probably wouldn't have the exact same specs anyway (i think it's pretty impossibly to ./configure exactly the same, considering the use of MacOs vs Ubuntu? especially for a noob like me)
So i've abandoned this path.
I've tried to find the differences in the php versions, but i can't seem to stumble upon anything that might be the cause to all this.
there was a change related to non-numeric keys in arrays (or strings for that matter) in version 5.4.4 (i think) but since i've now come to the conclusion that 5.3.14 also works, this definitely is not the issue. --- looking around insecurely hoping not having said anything downright stupid ---
quick thought while writing this:
the thing is, even though i'm getting the duplicate error statement.
The record did get inserted into the database.
moreover, the error gets triggered when having processed about 2700 (of total 6000) records.
the bound data to the query is actually the data of the second record in the xml file.)
I'm sincerely hoping anyone could put me on the right track for this issue :(
If you made it this far, but don't have a clue about what's going on, thx for reading and sticking to it.
If you might have clue, please enlighten me!
I have been tasked with setting up a website on various environments for different stages of evaluation (dev/test/staging/etc).
On our staging environment however, it seems there is some difference preventing the PHP script from finishing, so the page is never delivered to the browser.
I'm wondering if there is a way I can output to log some sort of stack trace or backtrace upon cutting the connection, or is there some other method to find out what exactly PHP is doing at any given point in the script's life cycle?
It's a Drupal site, so it involves a lot of code I'm not familiar with, and could take hours to sprinkle die; commands throughout to see where the script is loading to.
I understand I should probably be looking at the differences in environments, however all should have very similar configuration (Ubuntu 11.04) and the staging environment seems entirely happy to serve other PHP sites whilst this particular site is refusing to finish. If anything this staging site has more resources available that other environments which are not having problems.
UPDATE: Sorry all, found the problem in the end. The staging environment was on a VLAN that was not permitted to access itself via public IP, and for whatever reason (still confused about this) it was trying to access itself as part of the page load and never completing the request. Setting a hosts file entry for 127.0.0.1 fixed the issue.
Debugging an issue like this step-by-step using a tool like xDebug is an option, but will probably take a long time -- finding where to put the breakpoints is going to be on about the same level as working out where to put die statements around the code. The debugger option is a better way of doing it, but won't save much in comparison, when you have a problem like this where you have an unknown blocker somewhere in large amounts of unknown code.
But xDebug also has a profiler tool which can show you what functions were called during the program run, how long they took, and highlight where the bottlenecks are. This will probably be a better place to start. Just configure xDebug to generate a profiler trace, and then use kCacheGrind to view the trace in a graphical environment.
If your program is getting stuck in a loop or something specific is taking a long time to complete, this will pinpoint the problem almost straight away; you'll be able to see exactly which function is taking the time, and what the call chain looks like to get to it.
It's quite possible that once you've seen that, you'll be able to find the problem just by looking at the relevant code. But if you can't, you can then use xDebug's step-thru debugger to analyse the function as it runs and see what the variables are set to to see why it's looping.
xDebug can be found here: http://www.xdebug.org/
Use xDebug.
Its very easy to install and use.
it has few options like breakpoints and step by step to track status of PHP script before finishes loading
and you can download xDebug from here http://www.xdebug.org/
step by step tutoril for set up xdebug is availble at sachithsays.blogspot.com/