I have a php script which runs as the Apache daemon user, to first remove any existing crontabs that might be already installed by the daemon user, then adding the new crontab.
I wish to evoke this only once when my PHP Slim web application loads for the first time, ideally as part of the Apache startup.
It seems that putting it anywhere in the index.php file (either directly or via a require file) doesn't prevent the crontab script from being constantly reloaded. I've tried using $GLOBAL with an if statement, which unfortunately I haven't been able to formulate a working solution, however there must be something more rudimentary which allows me to invoke a php script just once after Apache has been restarted?
Ideally I'd rather not modify the Apache startup script since I wish to keep everything within the slim web application itself (for source control purposes).
Related
I have some CGI scripts which are used internal to the organization. Due to some standard changes, the server/system team has commented the below line from httpd.conf (apache config file) that support the CGI scripts. Because of this change, the existing CGI scripts are affected and unable to execute them on browser.
### LoadModule cgid_module modules/mod_cgid.so
Is there a way to overcome this situation and make the scripts work as is.
NOTE : The above commented line cannot be uncommented/enabled.
Ways of circumventing your company's policy, from best to worse:
Load mod_cgi anyway.
Load mod_fcgi, and convert your CGI script into a Fast CGI daemon. It's a lot of work, but you'll can get faster code out of it!
Load your own module that does exactly the same thing as mod_cgi. mod_cgi is open source, so it should be easy to just rename it.
Load mod_fcgi, and write a Fast CGI daemon that executes your script.
Install a second apache web server with mod_cgi enabled. Link to it directly or use mod_proxy on the original server.
Write your own web server. Link to it directly or use mod_proxy on the original server.
Last time you asked this question, you talked about using mod_perl instead. The standard way to run CGI program unchanged (for some value of "unchanged") under mod_perl is by using ModPerl::Registry. Did you try that? How did it go?
Another alternative would be to convert your programs to use PSGI. You could try using Plack::App::Wrap::CGI or CGI::Emulate::PSGI. Using Plack would free you from any deployment restrictions. You could run the code under mod-perl or even as a separate service behind a proxy server.
But I can't help marvelling at how ridiculous this whole situation is. Your company has CGI programs that it (presumably) relies on to run part of its business. And they've just decided to turn off support for them. You need to find out why this decision has been made and try to buy some time in order to convert to an alternative technology.
I've got a little project that uses perl cgi scripts. At this moment I use Apache to run these scripts. I have an index.html file that redirects to a cgi file.
Now I want to make my project 'portable', which means that I want to be able to move the project to another location without the need to configure apache (so not changing the cgi-bin directory in the configuration). The end product would be a script (or html file) that could be opened so that a browser would pop up, just like it would run as it would be using Apache. I actually don't really know where to start.
It's not completely clear what you're asking. But I suspect you're about to find out why PSGI/Plack is such a good idea.
If you write your application to the PSGI interface then you'll be able to just drop it in to any PSGI-enabled web environment (or set up your own lightweight web server using something like Starman).
I am running Python under WSGI on an Apache server using CentOS 6. The python script uses a wrapper for the NCAR library called PyNGL. The purpose of this library is to generate graphics from supplied data.
I am attempting to use my python script as a web service by hooking it up to web.py, but it has an entry point for direct execution as well.
Here is the weird thing:
When I run the script directly it works as intended and produces an output image in the directory of the script. However, when I attempt to invoke it through the web.py controller (with the exact same parameters) it fails.
My apache error log contains this:
warning:GKS:GCLRWK: -- cairo driver error: error opening output file
I'm guessing that this is probably a permissions problem, but I haven't the slightest idea where its trying to output.
Edit: I think I have confirmed that it is indeed a permissions error.
I attempted to create file using relative paths and got a similar error:
<type 'exceptions.IOError'> at /plot
[Errno 13] Permission denied: 'Output.txt'
This error refers to this line here:
with open("Output.txt", "w") as text_file:
text_file.write(str(self.__dict__))
Now of course I can specify an absolute path for that text file, but not for the graphical output from PyNGL. Is there a way to determine where it is trying to output, or to change the default output directory?
Usually your application would be running with the current working directory as '/'. The Apache user will not be able to write to that directory.
In any web application you should in general never rely on it being run in a specific directory as different web servers behave differently as to what the current working directory would be. If you assume it always runs in a specific directory, your application would be inherently unportable. Changing the working directory of an application to get around this is also in general bad practice because in a hosting mechanism that allows multiple application to run in the same process, they would all interfere with each other if they each tried to set their own working directory.
What you should do is always use absolute paths when reading and write files and not use relative paths. Why do you say you can't use absolute paths?
Also be aware that your application will run as a special user which would not have access to directories to create files. You would therefore need to open up access to the Apache user. Best practice would be to limit though what the Apache user can write to.
Now since you are using mod_wsgi, one viable option is to make sure you are using mod_wsgi daemon mode and when using the WSGIDaemonProcess directive set the 'home' option to override the current working directory for the single WSGI application delegated to that process. You can also set 'user' and 'group' options to have the process run as a different user that does have access to the directory.
I have an application with some cacheing backend and I want to clear the cacheing whenever the webserver is been restarted.
Is there a apache configuration directive or any other way to execute a shell script upon webserver (re)start?
Thanks,
Phil
Adding some more information, as asked by some answers already:
Base system is ofc linux based, in this exact situation: CentOs
Modifying the startup script is unfortunately no option as pointed out by one of the comments already, due to it beeing not configuration file within the respective RPM packages and therefor beeing replaced by updates. Also I think modifying the startup script would be a bad thing in general
I see, that actually linking both "restarting the webserver" and "clearing my app cache" is not exactly what should be tied together. I will consider other alternatives
My situation is as follows: I can define how the virtual host config looks like, but I can not define how the rest of the servers configuration looks like.
The application is actually PHP based (and runs on the symfony framework). Symfony pre-compiles alot of stuff into dynamic php files from what it finds in the static configuration files. We deploy our apps via RPM and after deployment, an webserver restart is actually initiated already, so I thought it might make sense to tie the cache-cleanup to it. But I think after getting all your feedback, it looks like it is better to put the cache cleanup process into the installation process itself.
You haven't provided a lot of detail here, so it's hard to give a concrete answer, but I would suggest that your best option is to write a script which handles restarting apache, and clearing your cache. It would look something like this:
#!/bin/sh
# restart apache
/etc/init.d/httpd graceful
# whatever needs to be done to clear cache
rm -rf /my/cache/dir
Ramy suggests modifying the system startup script for Apache -- this is a bad idea! If and when you update Apache on your server, there is a good chance that your change will be lost.
Dirk suggests that what you are trying to do is probably misguided, and I think he's right. You haven't told us what platform you are running, but I can think of few situations where restarting your webserver and clearing a cache actually need to happen together.
You can modify Startup script for the Apache Web Server in /etc/init.d/httpd and write your own syntax inside it.
chattr +i /etc/init.d/httpd
If you have (root) access to the server you could do this by shell scripts but I would consider if it is the best way of cache management to rely on apache restarts.
I am building a cgi application, and now I would like it to be like an application that stands and parses each connection, with this, I can have all session variables saved in memory instead of saving them to file(or anyother place) and loading them again on a new connection
I am using lamp within a linux vmware but I can't seem to find how to install the module for it to work and what to change in the httpd.conf. I tried to compile the module, but I couldn't because my apache isn't a regular instalation, its a lamp already built one, and it seems that the mod needs the apache directory to be compiled. I saw some coding examples out there, so I guess is not that hard once its runing ok with Apache
Can you help me with this please?
Thanks,
Joe
Using FastCGI just means that you spawn a number of processes which will handle requests they get from the actual webserver instead of the webserver spawning a new process whenever a request arrives.
Use something like memcached if you want to keep stuff like sessions in memory.