I have a few processes on my machine that I would like to have constantly running. I like however, how Jenkins organizes the jobs logging and I can go and see a build executing and see its STDOUT in realtime.
Would it be an issue to have a job that never finishes? I've heard after time there would be interruptions. Is there a better tool for something like this? Would basically love to be able to see the output from a web based perspective of the tool (and add hooks on failures)
For example if I were hosting a Node.js site, and wanted to be able to see the output of people connecting to the website or whatever is logged by the site. Ideally as long as you want to run the server, the process would be running constantly
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I want to send email batch at specific time like CRON.
I think whenever gem (https://github.com/javan/whenever) is not to fit in Cloud Foundry Environment. Because Cloud Foundry can't use crontab.
Please inform me what options are available to me.
There's a node.js app here that you could use to schedule a specific rake task.
I haven't worked with cloudfare so I'm not sure if it'll serve your needs, but you can also try some of the batch job processing tools rails has available: Delayed job and sidekiq. Those store data for recurring jobs either on your database (DJ) or in a separate redis database (Sidekiq) and both need keeping extra processes up and running, so review them deeply and the changes you'd need for your deployment process before using each one. There's also resque, and here's a tutorial to use it with rails for scheduling tasks.
There are multiple solutions here, but the short answer is that whatever you end up doing needs to implement its own scheduler. This is because there is no cron service available to your application when it runs on CF. This means there is nothing to trigger or schedule your actions. Any project or solution that depends on cron will not work when deploying to CF. Any project that implements it's own scheduler should work fine.
Some specific things I've seen people do successfully:
Use a web service that sends HTTP requests to your app on predefined intervals. The requests trigger your action. It's the services responsibility to let you define when to trigger and to send the HTTP requests. I'm intentionally avoiding mentioning any specific services, but you can find them by searching for "cron http service" or something like that.
Importing a library that has cron like functionality. I'm not familiar with Ruby, so I don't know the landscape there. #mlabarca has mentioned a couple that you might try out. Again, look to see that they implement the scheduling functionality and do not depend on cron. I'm more familiar with Java where you have Quartz and Spring, which has some scheduling functionality too.
Implement a "clock" process or scheduler. This would generally be a second app that you deploy on CF. It would be lightweight and probably not have a web interface. It could be as simple as do something, sleep, loop for ever repeating those two steps. It really depends on your needs. You could even get fancy and implement something like the first option above where you're sending some sort of request to your other apps to trigger the actual events.
There are probably other solutions as well, those are just some examples to get you started.
Probably also worth mentioning that the Cloud Controller v3 API will have first class features to run tasks. In this case, the "task" is some job that runs in a finite amount of time and exits (like a batch job). This is opposed to the standard "app" that when run on CF should continue executing forever (i.e. if it exits, it's cause of a crash). That said, I do not believe it will include a scheduler so you'd still need something to trigger the task.
I have a requirement in my MVC app.
I had an export to excel functionality that is taking 3 mins of time (user clicks on a export button and waits on).
This export downloads an excel that has multiple worksheets after applying certain rules on the data.
These rules are datamanipulations plus applying colors on the cells belonging to certain columns.
Inorder to avoid the wait time, I was asked to develop a code with in the MVC app that can run like a scheduled job.
This job has to export the excel to a dedicated folder with in the network on the scheduled time (daily once).
Also i was asked to develop a web page within the app which has links to download these excels.
Quesions here (Any help would be appreciated) :
I have chosen Quartz.NET to implement this requirement. This is an open source (to my little knowledge) that can
provide the facility to schedule a job (class developed in .NET). Is it the right choice or would there be any implications in future?
Is it really needed to develop a job like code or any other way of coding can address this?
I'm not very familiar with Quartz.net, but I do know that trying to run background/scheduled tasks from within the same process as the MVC application can be problematic.
Ref 1: http://haacked.com/archive/2011/10/16/the-dangers-of-implementing-recurring-background-tasks-in-asp-net.aspx/
Ref 2: http://www.hanselman.com/blog/HowToRunBackgroundTasksInASPNET.aspx
Essentially, you can't guarantee that the process will complete correctly when running it due to how IIS handles app pools (which is where you MVC process runs: assuming hosting on IIS anyway).
You mention running a scheduled task within your MVC app. Again, this is incorrect. Why can't you just slap a console app project into the solution and drive the code from there, then put it on the server and use the Windows Task Scheduler?
In terms of background tasks, the "correct" way to do this is to send a command from your MVC app to some sort of message queue, which can then ensure that the command doesn't get dropped. I've used RabbitMQ in the past (a middleware message broker). Perhaps this is the aim of Quartz.net.
This setup typically involves another app (for me, usually a console app run on the server) that receives the command message from the message queue and runs in it's own process, entirely separate from MVC and thus the issues inherent with IIS AppPools and background tasks.
A lot of work, really... one would think it'd be easier, but that's the surefire way to do it and maintain the integrity of the task to be run.
I'm getting the following error in the recent jobs I'm trying to submit:
2015-01-07T15:51:56.404Z: (893c24e7fd2fd6de): Workflow failed.
Causes: (893c24e7fd2fd601):
There was a problem creating the GCE VMs or starting Dataflow on the VMs so no data was processed. Possible causes:
1. A failure in user code on in the worker.
2. A failure in the Dataflow code.
Next Steps:
1. Check the GCE serial console for possible errors in the logs.
2. Look for similar issues on http://stackoverflow.com/questions/tagged/google-cloud-dataflow.
There are no other errors.
What does this error mean?
Sorry for the trouble.
The Dataflow starts up VM instances and then launches an agent on those VMs. Those agents then do the heavy lifting of executing your code (e.g. ParDo's, reading and writing) your Data.
The error indicates the job failed because no agents were requesting work. As a result, the service marked the job as a failure because it wasn't making any progress and never would since there weren't any agents to process your data.
So we need to figure out where in the agent startup process things failed.
The first thing to check is whether the VMs actually started. When you run your job do you see any VMs created in your project? It might take a minute or two for the VMs to startup but they should appear shortly after the runner prints out the message "Starting worker pool setup". The VMs should be named something like
<PREFIX-OF-JOB-NAME>-<TIMESTAMP>-<random hexadecimal number>-<instance number>
Only a prefix of the job name is used to ensure we don't exceed GCE name limits.
If the VMs startup the next thing to do is to inspect the worker logs to look for errors indicating problems in launching the agent.
The easiest way to access the logs is using the UI. Go to the Google Cloud Console and then select the Dataflow option in the left hand frame. You should see a list of your jobs. You can click on the job in question. This should show you a graph of your job. On the right side you should see a button "view logs". Please click that. You should then see a UI for navigating the logs and you can look for errors.
The second option is to look for the logs on GCS. The location to look for is:
gs://PATH TO YOUR STAGING DIRECTORY/logs/JOB-ID/VM-ID/LOG-FILE
You might see multiple log files. The one we are most interested in is the one that starts with "start_java_worker". If that log file doesn't exist then the worker didn't make enough progress to actually upload the file; or else there might have been a permission problem uploading the log file.
In that case the best thing to do is to try to ssh into one of the VMs before it gets torn down. You should have about 15 minutes before the job fails and the VMs are deleted.
Once you login to the VM you can find all the logs in
/var/log/dataflow/...
The log we care most about at this point is:
/var/log/dataflow/taskrunner/harness/start_java_worker-SOME ID.log
If there is a problem starting the code that runs on the VM that log should tell us. That log and the other logs should also tell us if there is a permission problem that prevents the code running on the worker from being able to access Dataflow.
Please take a look and let us know if you find anything.
Apart from Jeremy Lewi's great answer, I would like to add that I've seen this error appear when you don't enable the proper Google APIs in the Developers Console, as mentioned here, which leads to a permission issue, like Jeremy said.
I'm connecting to Twitter's streaming API to get a stream of updates to my Rails app, adding them to the db, etc, etc.
What's the best way to do this on Heroku? Right now, I'm using the delayed_job gem - problem is that the job (connecting to the Twitter Streaming API) expires after hours.
Is there a way to make the job run forever, or a better way to do this?
Thanks
I wouldn't make a job "run forever" as that would mean loading the CPU forever too.
The way this is usually handled is by using a cron job which starts the specific script at specific intervals (every minute, every hour, every few days, etc.).
Almost every webhost provides an easy interface to setup such cron jobs via their backend (eg: CPanel).
In case you're running your own server, you probably already know how to configure such jobs. If you don't, you'll have to lookup the individual setup guide which fits the operating system you're running on your server… there's always a way to run "jobs" at specific intervals (even on MS Windows servers — via scheduling).
And for a more detailed description and better insight into what "cron" is, you might want to check the "cron" article at Wikipedia , which also provides some pretty good examples.
While I'm interested in Jenkins as a means to provide continuous build functionality, I'm really even more interested in Jenkins as a means to exercise my application in its prod environment against unexpected changes in infrastructure beyond my control that may effect my application. I can't find a ton of information on using Jenkins in this way, but I was wondering if there are others out there doing this? Essentially I have a project that runs maven test parametized with my prod url, but for these projects I don't actually do any building. Are there other tools besides Jenkins I should be considering to do this? If so, why?
If you've got your tests set up to run via Maven already, I think Jenkins would be a good option. You could set up email, IM or SMS alerts using Jenkins plugins, and keep a record of the results within Jenkins.
The only down sides I can think of are:
You'll probably want to run your monitoring a lot more frequently than a regular CI job, so you might want to keep more build records than the default of 10.
If you already have a system like Nagios or OpenView to monitor system resources, it might be better to integrate app monitoring into that rather than having another source of truth.
Jenkins Provides a plugin called Status Monitor Plugin
We have ours set to check a specific URL every 5 mins and email us when something fails. Our problem is that it won't sent emails to cell phone carrier email addresses. However, if regular email will suffice, the setup time for a plugin is less than a half hour and it is reliable as long as the Jenkins server stays up.