Package: trython
TrythonThe main use for this package is when making requests with the requests module.
Sometimes the network might be unavailable, Or the server (the endpiont) might be temporarily down,
We don't want our script to quit just because of that (although we can put everything in a loop and catch error's, We don't want to do that because that will still lose the progress of the previous loop, and is a bit messy).This is wheretrythoncomes in, it gives you two very approachable techniques to solve this.From here on I'll be usingrequests.getas the function we want to add error handling to.Installationpip3 install trythonApproach 1Replacingrequests.getwith an alternitave error handled one.importrequestsimporttrythonrequests.get=trython.wrap(requests.get)Now when you callrequests.getand it throws an error, we will catch that and try to run the request again - without you even knowing.Approach 2Decorating your own function.importrequestsimporttrython@trython.wrap()defrequests_get(url):returnrequests.get(url)Now when you callrequests_getthe same logic will be applied.Approach 3Creating a temporary function with a context manager.importrequestsimporttrythonimporttrython_validatorswithtrython.context_wrap(requests.get,validator=trython_validators.requests_json_validator,time_to_sleep=1)asget:response=get('https://jsonplaceholder.typicode.com/posts').json()withtrython.context_wrap(requests.get,validator=trython_validators.requests_xml_validator,time_to_sleep=1)asget:response=get('https://www.cs.utexas.edu/~mitra/csFall2015/cs329/lectures/xml/xslplanes.1.xml.txt').textThis is very usefull if you want to have diffrent validators for the same function, as shown above.OptionsThe wrap function takes in a couple of arguments:func: (callable) This is the function that we are adding error handling to.number_of_attempts: (int)default=5The number of times you want to retry before finally raising the error.time_to_sleep: (int)default=30Time to sleep between retries.errors_to_catch: (tuple)default=(Exception, )Which errors you want to handle.validator: (callable)default=NoneA function that will validate if the return of the function is valid, if the function throws an error or returns false - it will be treated as if thefuncthew an error.on_exception_callback: (callable)default=NoneA function to be called every time there's an exception raised byfunc, use this if you would like to not retry some errors - based on the error message.on_raise_callback: (callable)default=NoneA function to be called when we finaly raise the error, this function should take the exception as an argument.More about validtatorsLet's take another look at validators, because without them this whole thing is useless.First you need to install it, to install run:pipinstalltrython-validatorsA very common reason that a script will quit is when you are hitting a api endpiont, and you expect a certain data type, and you go ahead and call some function and that data that will give you an error when it doesn't understand that data it got, without validators there's no way for us to know that.That's when we create a validator - when we expect the result of a given function to be something, but might a times be something else entirely.
We create a function that takes in the func's return value and we check if it satisfies us, And if the validator function returns false or throws an error, then we retry, otherwise - we know we got the right data.I have included some predefined validators which you can import like this:import trython_validators.
Feel free to make pr with some other helpful validators.