I want to create a website application, that will allow our members to get text message/email alerts every day 1 hour before their lesson (a reminder).
My server-side language background is strictly in PHP (although I've tampered some c++ back in the day). For this to work, obviously, I'll needs to somehow run a program constantly on my server.
Can this be accomplished in PHP?
If yes, is php efficient at this?
If not, how can I do this?
Or, maybe, this an entirely wrong approach, and there's a better way of creating such a service.
yes, u can consider make PHP as a daemon
or check this out php execute a background process
or simply use cron - http://en.wikipedia.org/wiki/Cron
but you should NOT create a web service/application just to run background PHP processes, it should cater for complex job
Sure, you can use PHP as a scripting language on the server. It's just as capable as any other.
Write a PHP script that checks your database for what members need to be alerted, then sends the message. Add a crontab to run this script every minute/hour/whatever. To run a php script from the command line, you run the php interpreter and give it the script name to run.
$ php /path/to/script.php
You would have to start a service on the server itself or create a CRON job to run at any given interval. If you don't have admin privileges you will have to do a CRON job, which can usually be setup in your host's cpanel.
For instance, you could create a small PHP script that
1) Searched for all lessons that start in the hour proceeding the current hour. So if the script is run at 5pm it would search for lessons that start between 6pm and 6:59.
2) Send an email to those members.
It wouldn't be exactly 1 hour though.
Related
Me and my team are using a shared hosting service with a limited linux container (without root and privileged user) and we need to develop a new feature that involves long running tasks (> 600ms).
We thought of two possible solutions:
Breaking apart the task, and via the frontend, make one separate http request to the server.
Use bash screen to run a bash script with a infinite loop calling php artisan schedule:run (mimicking cronjob)
I don't feel very confortable with the first solution, moving server logic to the browser seens wrong in my opinion.
The second solution is only a supposition (not tested), we are not sure if the bash screen would randomly stop at any time.
What would be the least unstable way to achive our goal? Thx
Assuming you already explored this because you mention that a CRON would not be an option, but even unprivileged users can setup a CRON, which is the simplest solution in combination with the Laravel scheduler.
If an actual CRON using the scheduler is really out of the question I do think making an HTTP endpoint you could call from the browser is the next best thing. Just don't think an endpoint you can call from a browser that you can only call it from a browser ;)
Take for example https://www.easycron.com/ (no affiliation but the first Google result). You can setup a CRON job there to call a URL to trigger those tasks on a CRON interval. Internally at my company called the "poor mans CRON" :)
I would agree that running a "screen" session is the most unreliable since on a server reboot those are not started again and if you "infinite loop" crashes it will not automatically restart.
If you go that route (or any CRON route) you can add some monitoring using for example https://healthchecks.io/ (again no affiliation, Google). This allows you to define a CRON schedule and gives you a URL to call after the CRON finishes, if your CRON does not call that URL according to the CRON schedule you will be notified. Good to have as insurance.
I want to create an application that runs in the background in Linux (daemon) that will basically at set times (5 times) play a music file or any sound given every single day. I want this daemon to start when the computer is started in terminal mode (non-GUI). I want to know if this is possible and if so, What considerations, tools, and programming language would be the most efficient in doing so? This will be a dedicated computer that will only be executing this task, so if any recommendations on how I can maximize efficiency while disabling other features that are not required for this task will be appreciated. Also, could you please explain how processes and tasks work in terminal (non-GUI)? I always thought terminal was something like CMD in Windows and can only run tasks one at a time.
EDIT: I need the sound to run at variable times, I'll be fetching these times from a website. Any suggestions regarding how to achieve this?
Thanks for the help and sorry for any shortcoming in the questions or my research.
Look at using cron to run your tasks. cron is a very flexible scheduling utility built in to most Linux distributions.
Basically, with cron you specify a task to run (your main program, or maybe just a sound-playing program), all of its arguments, and when it runs. cron takes care of running it, and will even send you "mail" if the job produces any output (such as errors).
You can make processes fork into a subprocess of your terminal, i.e. you are able to run more than one task at a time by putting a & after your terminal command:
> cmd&
> [you can type other commands here but the "cmd" program is still running]
However, for services you generally don't have to worry about starting it as a subprocess because the system already knows to do this. Here's a good question from Super User that has an example of a working service. Simply place your service as a shell script in the /etc/init.d and it will be automatically started as a service.
I'm a webhosting owner, I don't know why currently, but I have some php scripts that are launched for many hours (as personnaly known customers), so I think there is a bug somewhere.
These scripts are eating the RAM AND the swap... So I'm looking for a way to list processes, find the execution time, kill them 1 by 1 if the execution exceed 10 or 20 minutes.
I'm not a bash master, but I know bash and pipes. The only thing I don't know, is how to list the processes (with execution time AND complete command line with arguments). Actually, even in top (then c) there is no arguments in php :/
Thanks for your help.
If you are running Apache with mod_php, you will not see a separate PHP process since the script is actually running inside an Apache process. If you are running as FastCGI, you also might not see a distinguishable PHP process for the actual script execution, though I have no experience with PHP/FastCGI and might be wrong on this.
You can set the max_execution_time option, but it is overridable at run time by calling set_time_limit() unless you run in Safe Mode. Safe mode, however, has been deprecated in PHP 5.3 and removed in 5.4, so you cannot rely on it if you are on 5.4 or plan to upgrade.
If you can manage it with your existing customers (since in some cases it requires non-trivial changes to PHP code), running PHP as CGI should allow you to monitor the actual script execution, as each CGI request will spawn a separate PHP interpreter process and you should be able to distinguish between the scripts they are executing. Note, however, that CGI is the least effective setup (the others being mod_php and FastCGI).
You can use the ps -aux command to list the processes with some detailed information.
You can also check out the ps man page.
This might also be of some help.
We are using a dedicated Amazon Ubuntu ec2 instance as Cron server, which executed 16 cron jobs at different time intervals i.e, 10 cron jobs in morning 4:15 - 7:15 and the rest # 23:00 - 23:50. I get the results via email. I want to configure something, which shoots email message at the end of they day listing the cron jobs that are executed successfully and the one that failed.
I have a jenkins configured ubuntu instance for auto-building Dev, Beta, Staging & Live environments. Can i add these cron jobs(shell scripts) as external jobs in the jenkins and monitor them. Is it possible?
Definitely possible! You can monitor external cron jobs as described here:
https://wiki.jenkins-ci.org/display/JENKINS/Monitoring+external+jobs
You can also add cron job (-like behavior) to Jenkins by creating a freestyle software project and add "Execute shell" as build process.
It's a bit more convenient since you can also trigger the execution via Jenkins ("Build now").
You might be able to combine the Jenkins monitor external job project type with a matrix project. At the very least the former will enable you to monitor the cron jobs individually.
Alternatively you could have the last monitored cron job of the day trigger building a project that checks the status of all the cron jobs (for example by retrieving and comparing the build numbers of the last and the last successful builds) and sends an email accordingly. The email plugin might be useful for the latter.
Check the CPAN or do some web digging for shell or perl script for managing cron jobs and extend its behaviour to do some reporting which you can render using HTML. Alternatively write a servlet and a some function calls to do just that.
This becomes your own standalone monitor application, which can sit in jenkins or deployed independently. If you choose to add it to jenkins, then add the reporting HTML file and its scripts to the container holding deployed web files for jenkins, word of advice place your files and script in a separate container.
Add a hyperlink to jenkins index html which will load your reporter. Now reboot tomcat and go from there.
Another option could be to take a look at Cronitor (https://cronitor.io). It basically boils down to being a tracking beacon that uses http requests to ping when a cron job/scheduled task starts and ends.
You'll be notified if your job doesn't run on schedule, or if it runs for too long/too short, etc. You can also configure it to send alerts to you via email, sms, but also Slack, Hipchat, Pagerduty and others.
Is there a limit excution time when I run a PHP Script by Cron Jobs?
For example, I need to backup my big database file through a PHP Script. I set a cronjobs which automatically run everyday.
My question, will the php script run until everything is ok?
ini_set("max_execution_time", "0");
ini_set("max_input_time", "0");
set_time_limit(0);
How I usually set up my cron job scripts is to simply printing everything (especially errors or exceptions) to standard out. To my experience most cron systems will then email the output of the script to whatever local user is running the script. I then have that mail forwarded to my work account to notify me that the script ran and if there were any errors. For basic maintenance scripts that run daily or weekly I've found this to be a quick, effective way to keep me updated on their status.