RR 312 How to Handle WTF's

How to Handle WTFsOn today’s episode of Ruby Rogues we are chatting about WTFs. On our panel we’ve got Dave Carmona, Brian Hogan and I’m Charles Max Wood. We talk a bit about some of the recent WTFs we’ve encountered and some of our tricks for handling it, including talking to a Rubber Duck. It’s a fun episode so check it out!WTF’s in Two FlavorsCharles starts out the episode inquiring to the panel about two different kinds of WTFs. The whats and the whys. WTFs that happen and developers don’t understand what the WTF is, and then on the other hand WTFs that happen and the developer doesn’t know why it’s happening.Unreadable Perl and the Rubber DuckDavid talks a bit about how hard it is sometimes to read and understand what is happening with Perl code, even if you wrote it yourself. Sometimes debugging Perl codes many years later, running into syntax errors end up being a ‘Why’ WTF. He introduces a method to use for ‘Why’ WTFs that he calls the ‘Rubber Ducky Debugging’ method. The ‘Rubber Ducky Debugging Method’ is when you place a rubber duck on your desk, and when you encounter a WTF you can simply talk through the issue to the duck to help you think through your issue. Brian and Charles add that this method works fine with real people as well and have done it many times with their wives, even for issues that don’t involve code.Blaming it on Past BrianBrain mentions that sometimes when working with someone else’s code, it’s easy to blame the previous developer. Unfortunately in his case, Brian finds that “Past Brian” has often been the culprit.Dave and Code he Doesn’t UnderstandWhen encountering classes that are really big with many different methods, find the entry point. If it doesn’t have a traditional initializer or call method for the entry point, you can look around other relevant parts of the code to try and figure it out. Sometimes if it’s obfuscated, you can go through variables and rename them to more relevant names to identify what they are doing to help understand the method at hand.Puts Debugging Aaron Patterson had written an article on his blog about ‘Puts debugging’ that turned Dave onto the the untraditional debugging method. Dave will sometimes write a separate debugger class to separate puts into a different log to keep it organized.Brian’s Version of Puts DebuggingBrian mentions that when working on a rails application he will sometimes raise the object he wants to inspect. Errors in Ruby are often something you wouldn’t expect and being able to quickly inspect the object using raise .Using raises the whole stack including the object, session, and cookies , etc.Dave’s Ruby LifesaversDave also adds that adding the gems to your development better_errors, and then en binding_of_caller are lifesavers. It allows for a more interruptive session with raised errors. Also, in Rails 4 the console feature was added, allowing you to tweak things and play around to debug. Also, Pry is really useful for loop through and investigate. Dave also notes that Pry, while being a great tool, can sometimes be a bit annoying if you have a large number of loops.Crazy Bug Story - BrianBrian talks about how in Elixir the declaring of methods is very similar to Ruby but at the end of Elixir method calls you add keyword do. If you do this in Ruby, the interpreter’s error message is unusual and doesn’t give any information that helps you find the issue, making it very hard to find the issue. This could be very time consuming for the debugger. He adds that having a second pair of eyes helps with issues like these.Crazy Bug Story - DavidDavid talks about working on a personal project late into the night. Using Rails 5.1.1, he thought that maybe his issue with the enumerators. He considered that maybe the issue was with Rails 5.1.1 being that is newer. To test to find out if he caused the error, he recreated a simple bit of code that uses enumerators and saw that it worked, then created the same project in 5.1.1 and it also worked, concluding that he created the issue. Later he found he declared the datatype for the enumerator as a string instead of an int. Brian added that creating a fresh application to test for errors is a great way to start debugging, in comparison to immediately to asking others what the problem might be. This method of checking can have a quick pay off if the code is simple. Also, creating new applications to test gives a great foundation of knowing that the problem is in your own code.Crazy Bug Story - CharlesCharles’ bug was something he encountered in his podcast feed application he created in Rails 4. Charles didn’t read the error message very well so he tried it debugging it with Puts Debugging. It’s turned out that he was using a strftime method that he had accidentally formatted the string wrong, using -’s instead of /’s.Characterizing with a TestIn issues like Charles’ you can take input that’s going into a method and then setup an integration test. Tests like this can be made fairly quickly. By copying and pasting the input parameters into a test like a Capybara test, then you can get a better idea of where the issue actually is.Creating the Error to Fix the ErrorBrain mentions that sometimes when he has a specific error, he will try to write a new set of code that reproduces the issue. Then from there he will try to ‘break’ the broken code in efforts to find a debugging solution in the original code.Making your Production Environment The Same as Your Development EnvironmentIf you’re using something like caching in your production environment, make sure it is set up in your developmental environment. Debugging caching issues can be some of the most complicated bugs to fix. If you set up your environment to be the same it helps. If you need to start the caching over during development or tests, it’s as simple as a CLI command. When you’re doing feature tests, if you do it with caching enabled, you can use timecop. Timecop allows you to essentially time travel to test timing issues without having to wait.Favorite Development ToolsSome of the panelist’s favorite tools are Pry, binding_of_caller, better_errors, Konami, and Sinatra. Google Chrome’s RailsPanel extension Works like MiniProfiler, but digs in further. By adding this gem to your development environment and running it on Chrome, it shows you all the requests that come through, the controller in action, and lists out all the parameters, as well as active record calls and errors.Favorite Production ToolsBrian suggests using any tools available to capture exceptions and error messages. Capturing these issues before the user contacts you makes recreating the issue and debugging it a lot easier. Dave mentions using New Relic to capture performance of application as well as error notification. With New Relic you can adjust the notification threshold and give it actions like sending it to a Slack channel. Then use something like Sumo Logic to concatenate and combine the logs if it’s coming from various servers.Shipping Logs Off FluentD can be used to ship off logs to analyze. In some cases management won’t be okay with shipping things off. Doing things internally can sometimes be too much and using a third party aggregation tools can be helpful.Some Tools Can Be HeavySumo Logic applet is Java based and takes up quite a bit of space. Jenkins is also a Java setup and takes many parameters to get running. In some cases with smaller applications, applets like Sumo Logic can take up more space than the application. Trying to parse multiple servers can be daunting and will definitely need a centralized logging option.Other Logging Tools Elastic.co and Logstash are other logging tools. They have integrations with tools like Docker and Kibana. If you can roll your own logging tools then great. But it’s usually time consuming and takes resources.Getting Information from People and Assume It’s WrongCharles mentions that in some cases, especially in cases where something you’re using is dated, resources can be limited to get informationBecome a supporter of this podcast: https://www.spreaker.com/podcast/ruby-rogues--6102073/support.