I have just added the rufus scheduler gem to my application and ran it for a few minutes in development mode to find that it works.
But of course I'd like to write a spec that ensures the schedules are set up correctly. For example, typos could slip into the interval strings or some other gremlin might prevent.
My initial idea was to look at Scheduler#jobs but that can become tricky quite quickly: if there are, for example, two jobs with the same interval, I cannot see a straightforward way to identify the one to test.
Apart from that, it should be possible to set up some expectations, run the block and check whether the expected methods were called.
Do you have recommendations on how to test for correctness of job schedules at a given point in the application lifecycle?
You can place tags on jobs:
https://github.com/jmettraux/rufus-scheduler#tags
It helps identifying them. It's also useful to look them up:
https://github.com/jmettraux/rufus-scheduler#schedulerjobstag--tags--x
Related
I have a single application , maintained on two different nodes on cloud. I have a scheduler in the application which triggers every 5 minutes, which perform some update operation in database. How can I avoid the two operations to cause anomaly in database. Is there a way one application may know, that other instance is already been triggered or any sort of inter node communication that may happen in cloud foundry.
Many Thanks
A couple options come to mind for Cloud Foundry:
Create a distributed "lock" with your database. This could be as simple as a table or record in the DB that the scheduler checks out first before it does anything else. Once it has the lock, the scheduler can work. If it fails to obtain the lock, it goes back to sleep. Then when it's done, it returns the lock.
If you have lots of work to do, you could divide it into sections and have locks for each section, that way you could spread the work out across your different instances. This gets more complicated though, so you'd have to weigh the advantages against the extra complication to see if it's worth it for your use case.
Only run the scheduler on the first node. You can determine the first node by looking at your application instance number. Either the env variable CF_INSTANCE_INDEX or VCAP_APPLICATION, which contains JSON and has an instance_index property. For either option, the value will be 0 for the first instance. If it's 0, the scheduler runs. If it's greater than zero, the scheduler doesn't run.
Hope that helps!
I want to execute a specific step only once before each cucumber feature files. A cucumber feature files can have multiple scenarios. I don't want Background steps here which executes before each scenario. Every feature file can have a step (which is different in each feature) which will execute only once. So i can't use that step into before hook as i have a specific step for every 20 features. Sample Gherkin shows below:
Scenario: This will execute only once before all scenario in this current feature
When Navigate to the Page URL
Scenario: scenario 1
When Some Action
Then Some Verification
Scenario: scenario 2
When Some Action
Then Some Verification
Scenario: scenario 3
When Some Action
Then Some Verification
I hope you guys understand my Question. I am using Ruby Capybara Cucumber in my framework.
Cucumber doesn't really support what you are asking about. A way to implement this with cucumber hooks would be to use these two pieces of doc:
https://github.com/cucumber/cucumber/wiki/Hooks#tagged-hooks
https://github.com/cucumber/cucumber/wiki/Hooks#running-a-before-hook-only-once
You would tag all your feature files appropriately and you can implement tagged Before hooks that execute once on a per feature tag basis.
It's not beautiful but it accomplishes what you want without waiting on a feature request (or using a different tool).
This can be achieved by associating a Before, After, Around or AfterStep hook with one or more tags. Examples:
Before('#cucumis, #sativus') do
# This will only run before scenarios tagged
# with #cucumis OR #sativus.
end
This must be in the top 5 most frequent questions on the Cucumber mailing list. You can do what you want with hooks. However you almost certainly should not do what you want. The execution time you save by taking this approach is totally outweighed by the amount of time and effort it will take to debug the intermittent failures that such an approach generally leads to.
One of the foundations of creating automated tests is to start from a consistent place. When you have code that setups key things in scenarios, but that is not run for every scenario you have to do the following:
Ensure your setup code creates a consistent base to start from (this is easy)
Ensure that every scenario that uses this base, does not modify the base in any way at all (this is very very difficult)
In your example you'd have to ensure that every action in every scenario ends up on your original page URL. If just one scenario fails to do that, then you will end up with intermittent failures, and you will have to go through every scenario to find your culprit.
In general it is much easier and more effective to put your effort into making your setup code FAST enough so that you are not worried about running it before each scenario.
Yes, This can be done by passing the actual value in you feature file and using "(\\d+)" in you java file. Look at below shown code for better understanding.
Scenario: some test scenario
Given whenever a value is 50
In myFile.java, write the step definition as shown below
#Given("whenever a value is (\\d+)$")
public void testValueInVariable(int value) throws Throwable {
assertEqual(value, 50);
}
you can also have a look at below link to get more clear picture:
https://thomassundberg.wordpress.com/2014/05/29/cucumber-jvm-hello-world/
Some suggestions have been given, especially the one quoting the official documentation which uses a global variable to store whether or not initial setup has been run.
For my case, where multiple features were executed one after another, I had to reset the variable again by checking whether scenario.feature.name has changed:
$feature_name ||= ''
$is_setup ||= false
Before do |scenario|
current_feature_name = scenario.feature.name rescue nil
if current_feature_name != $feature_name
$feature_name = current_feature_name
$is_setup = false
end
end
$is_setup can then be used in steps to determine whether any initial setup needs to be done.
I have a script that must run at a certain hour for the amount of time I specify.
I'm looking at the clockwork gem (https://github.com/tomykaira/clockwork) which seems to be the closest piece of software I might eventually use to accomplish this, unfortunately it doesn't seem to give the ability to set a duration (start at 3PM stop 5PM), meaning I have to split the feature in 2, starting the script is going to be clockwork's job, stopping it is in the script itself with a custom solution.
Very suboptimal and messy.
How does people do this in Ruby? TIA
There is great gem called whenever for same job. With it you can set exact time for your task, like:
every 1.day, :at => '4:30 am' do
runner "MyModel.task_to_run_at_four_thirty_in_the_morning"
end
But you'll have to have two stages, one for starting one for stopping your job, which seems to be more natural than job which kills itself at some time by my opinion.
Somewhat janky, but there is another solution. I'm not sure what you are using to host your app, but on Heroku you can set up a scheduler to run every 10 minutes, on the hour, or daily. Then inside the method that the scheduler calls, you can determine the current time. Say you only want to run it between 3pm and 5pm, you would just wrap your code inside an if statement that verifies the current time is between 3pm and 5pm (watch out for time conversions with UTC).
Hope this helps.
I am designing a cloud app and need a worker process which scours my database looking for work, and then performs it.
Most of the info I seem to find on the subject of background tasks in the cloud involves some kind of scheduler and/or queuing system.
What I have doesn't quite fit into the "run this task every 5 minutes" or "add this to the queue to be executed later" models. I think the main difference to my problem is that the workers themselves find work to do, rather than being assigned it by a periodic scheduler or an external process that generates work.
What I have is basically a giant table where each entry has three fields:
job: a small task to be performed, lets say it gets the last message from a twitter account and stores it in the database
the interval at which to perform that job: say every 5 minutes, N.B. the interval is arbitrary and different for each entry in the table
the last date when the job was performed
The way I would implement this is to have a worker which has an infinite loop. When it enters the loop, it scours the database a)looking for items whose date + interval < currentTime, b)when it finds one, it sets date = currentTime, and c)then executes the job. If there is no work ATM, it sleep for a few seconds, then tries again.
I will have many parallel workers scouring the database simultaneously, which is why I do b) first and then c) in the paragraph above. Since there are parallel workers, action a) and b) are atomic operations on the database to prevent work being duplicated. If the worker crashes after a) and b), but before it manages to finish the work, it's no big deal, and the workers can just do it at the next interval; reason for this is that the work is not performed in a time-invariant system so a backlog scenario of failed jobs has no benefit as the tasks have to be performed at their exact intervals, so it's better to skip 1 interval than to have uneven intervals between which the tasks were executed.
My question is whether that is a reasonable implementation strategy? If so, how do I bring this process to life on the cloud (I am using Heroku, but may switch to EC2 in the future)? I still haven't written any code so I would welcome other suggestions (maybe I misunderstood the use cases/applications for queue systems).
This sounds so close to using something like a scheduled job that you might as well tread the well beaten path and do it the more conventional way. There's no reason why you can't schedule a job to run once every few seconds.
However, this idea of looking for work sounds dodgy. What happens if two workers find the same task to run at the same time for instance? Also, are there not triggers in the application which can indicate that work needs doing? It seems strange that you have code 'looking for work'.
You can go a very long way with simple periodic background tasks, so I would exhaust all possibilities in that area before rolling your own.
I would like to do a cron job every 10 minutes, but my system only does 1 hour. So I'm looking for a method to do this. I've seen Timer and sleep but I'm not sure how to do this or even better yet a resource for achieving this.
Take a look at http://rufus.rubyforge.org/rufus-scheduler/
rufus-scheduler is a Ruby gem for scheduling pieces of code (jobs). It understands running a job AT a certain time, IN a certain time, EVERY x time or simply via a CRON statement.
rufus-scheduler is no replacement for cron/at since it runs inside of Ruby.
To do this reliably, invest in a VPS and create the 10-minute cron job as desired. Trying to emulate cron all on your own is very likely to fail in unforeseen ways.
Creating a sleeping process is not the way to go about this; if your server doesn't give you the freedom to make your own cron as you like it, you probably can't create your own background process for this sort of thing, either. You might be able to, on each request, take a look and see how many of the jobs need done (if it was 25 minutes since last request, you might have to do two), and go back and do them retroactively.
But, seriously. You need your own server to do this dependably.