Elixir Wizards

In this episode of the podcast we are joined by Chris Keathley to continue our exploration of Elixir internals as he tells us about two very popular libraries that he developed, Wallaby and Raft. We start off with some background and his initial experiences with Elixir and open source projects before diving into Wallaby and some of the biggest lessons that Chris learned during and after his work on the library. Chris does a great job of explaining concurrent tests and the Sandbox and some of the reasons he has pretty much stopped working on the front end of projects. From there we move onto another one of Chris' exciting projects, Raft! In order to introduce the library, Chris explains more about consensus algorithms, Leslie Lamport and his groundbreaking work on Paxos. Raft is, in some ways, a simplified, more accessible version of Paxos for Elixir and Chris goes on to give a brief rundown of its inner workings. For this great conversation with a great guest, join us today! Key Points From This Episode: Chris' background, history with Elixir and his current employment. How Chris got started with open source work. Why Chris has moved away from front end work in the last while. The major lessons Chris learned while building Wallaby. How the concurrent tests work on Wallaby and the Sandbox. Why Chris is still excited about Raft, even though he hasn't touched it in a while. Explaining Raft, consensus algorithms and Paxos. How the Raft library actually works; building Raft systems and processes. Where to find and connect with Chris online! And much more! Links Mentioned in Today’s Episode: SmartLogic — https://www.smartlogic.io/ Chris Keathley — https://keathley.io/ Chris Keathley on github — https://github.com/keathley Bleacher Report — https://bleacherreport.com/ Wallaby — https://hexdocs.pm/wallaby/Wallaby.html Raft — https://raft.github.io/ Erlang — https://www.erlang.org/ Slack — https://slack.com/ Leslie Lamport — http://www.lamport.org/ Paxos Made Live — https://blog.acolyer.org/2015/03/05/paxos-made-live/ Elixir Outlaws Podcast — https://elixiroutlaws.com/Special Guest: Chris Keathley.

Welcome back to the SmartLogic Podcast where we talk about the latest developments and best practices in the web and mobile software industry. In continuing with our theme of Elixir Internals, we’re having a conversation about the inner workings of one of the most popular Elixir libraries, Credo, and we are joined by the author René Föhring. René shares the story of how he was introduced to Elixir while doing his PhD and looking for a new programming language and then shares the philosophy and inspiration Credo was developed on. Wanting Credo to be a less rule-based, authoritative code analysis tool and more user friendly, René focused on creating it to act as a type of digital mentor to the many developers out there who do not have a human mentor. He also shares about some of the launching hiccups, what he would have done differently had he been given another opportunity and some of the most important lessons that he has learned working in the open source community. Be sure to join us for all the inside info! Key Points from This Episode: More about René’s job as head of product development at 5 Minds and what they do. What he does in his free time: open source maintenance and conference speaking. How he got started with Elixir and wanting to learn a new programming language. What Credo is all about, why you’d want to use it and what makes it different. The inspiration behind writing Credo and wanting a more positive, less dogmatic tool. Starting off building on Dogma but then pivoting and going in an independent direction. The hiccups René experienced when first releasing Credo and what he’d do differently. The different checks in Credo and how they function and respond to issues. How Elixir 1.6 impacted the development of Credo. What’s new with the Credo 1.1 release? René’s experience working with open source and the first library he contributed to. Important lessons he has learned by being part of the open source community. And much more! Links Mentioned in Today’s Episode: Elixir — https://elixir-lang.org/ Credo — http://credo-ci.org/ René Föhring on Twitter — https://twitter.com/rrrene?lang=en 5 Minds IT – Solutions — https://www.5minds.de/ GitHub — https://github.com/ Ruby — https://www.ruby-lang.org/en/ Go — https://golang.org/ Cplusplus — http://www.cplusplus.com/ StyleCop — https://github.com/StyleCop/StyleCop Dogma — https://github.com/lpil/dogma Hex — https://hex.pm/ Learn more about how SmartLogic uses Phoenix and Elixir.Special Guest: René Föhring.

Today on the show we continue our series on the inner workings of several different Elixir libraries and are happy to be joined by Meryl Dakin, Software Engineer at the Flatiron School and author of Token Alchemist. In this episode, we discover how Meryl got started with Elixir and what the process was like for her transitioning from Ruby to Elixir. We learn more about the internal functions of Token Alchemist within the school context and discuss the unique opportunities Meryl has discovered in Elixir, as well as the trickier language features that programmers are likely to experience in their learning process. Meryl also shares the challenges that Token Alchemist attempts to overcome – delving deeper into LTI, the Learn.co platform, OAuth and JSON. For all this and more, be sure to click play! Key Points From This Episode: Discover why Meryl first got started with Elixir. Learn more about the Flatiron Bootcamp for coders. Meryl’s experience in transitioning from Ruby to Elixir. The opportunities for concurrency and fault tolerance in Elixir. Discover the top three tricky language features in Elixir. The benefits of going back to the basics of Elixir. Find out the problems that Token Alchemist attempts to solve. Meryl explains LTI and the Learn.co platform for students. Learn more about custom parameters in Token Alchemist. The process of learning OAuth in Token Alchemist. What to consider when using LTI in Elixir. The benefits of resource link history ID’s in the LTI spec. Opportunities for you with Token Alchemist. And much more! Links Mentioned in Today’s Episode: We Work — https://www.wework.com/ Flatiron School — https://flatironschool.com/ Elixir — https://elixir-lang.org/ Ruby — https://www.ruby-lang.org/en/ Learn.co — https://learn.co/ Meryl on LinkedIn — https://www.linkedin.com/in/meryldakin/ Meryl on Twitter — https://twitter.com/meryldakin Meryl on GitHub — https://github.com/meryldakin Token Alchemist on GitHub — https://github.com/meryldakin/token_alchemist Learn more about how SmartLogic uses Phoenix and Elixir.Special Guest: Meryl Dakin.

Welcome back to show everyone and today in our exploration of Elixir libraries we are talking to Paul Schoenfelder! He is here to unpack Distillery, his own creation from the world of Elixir and tell us about how it works. We also discuss how Paul made the transition from bigger corporations into the startup world, his early experiences of different coding languages and the initial steps he took in writing Distillery. Paul is very honest about the unclear future of the library and he shares his hopes for it for the short term as well as clarifying its key concepts and functions. He gives great advice and directions for learning more about the resource and how you can help him and his projects out if you use them. For all this and then some, be sure to join us today for the show! Key Points From This Episode: Paul's work background, language history and the last few years working Elixir. The first library that Paul contributed to and created on his own! What brought about the creation of Distillery. Clarifying releases, compiling, generating, deployment and more. Where to learn more and find out details about the library. The first steps Paul took when writing this latest version of the Distillery. Looking to the future of Distillery and its current best use cases. Hot upgrades and who they can be useful to when it comes to Elixir. Let Paul know if you are using or want to contribute to a project of his! And much more! Links Mentioned in Today’s Episode: Smartlogic — https://www.smartlogic.io/ Paul Schoenfelder — https://github.com/bitwalker Bitwalker — http://bitwalker.org/ Distillery — https://hex.pm/packages/distillery DockYard — https://dockyard.com/ Erlang — https://www.erlang.org/ Phoenix — https://phoenixframework.org/ Learn more about how SmartLogic uses Phoenix and Elixir.Special Guest: Paul Schoenfelder.

Today on the show we continue our series on the inner workings and various libraries of Elixir and are very happy to welcome Bryan Joseph of Revelry to talk about his very own ElixirScript. ElixirScript is essentially an Elixir to JavaScript compiler, allowing users to run Elixir online more easily. We ask Bryan what inspired this project and about some of the major challenges that have faced it. We also talk about the role of his company, Revelry in his career and work in open source. Bryan tells us about his very own conference, The Big Elixir and why you should be traveling to New Orleans to check it out! Other topics covered include the architecture of ElixirScript, binary pattern matching, Bryan's other experiences of libraries and his hopes for ElixirScript's future. For all this and then some, be sure to listen in today! Key Points From This Episode: Some background on Bryan, his work and how he got started with Elixir. What is ElixirScript? What does it do? How Brian got the idea! ElixirScript's architecture; the inner workings of the compiler. The major problems and challenges that face this task with JavaScript. Step one in the process; the conversion of concepts. Binary pattern matching and the implementation of strings. The things Bryan would do differently looking back on the product. Bryan's other experiences of libraries, contributions and fixes. Marketing, posting and getting the word out on ElixirScript. The current state of the project and hopes for the future. A little bit about The Big Elixir and what sets it apart from other conferences. And much more! Links Mentioned in Today’s Episode: Smartlogic — https://www.smartlogic.io/ ElixirScript — https://elixirscript.github.io/ Bryan Joseph — https://github.com/bryanjos Revelry — https://revelry.co/ The Big Elixir— https://www.thebigelixir.com/ Metaprogramming Elixir — https://www.amazon.com/Metaprogramming-Elixir-Write-Less-Code/dp/1680500414 Chris McCord — http://chrismccord.com/ Erlang — https://www.erlang.org/ ElixirCon — https://www.elixirlabs.net/events/elixircon-2018 Lonestar Elixir — https://www.lonestarelixir.com/ Operation Spark — https://operationspark.org/ Flatiron — https://flatironschool.com/ Learn more about how SmartLogic uses Phoenix and Elixir.Special Guest: Bryan Joseph.

Hey everybody and welcome back to Season 2 of the podcast! This season we will be talking about Elixir internals, libraries and the inner workings of the language. In our first episode we are very happy to be joined by Brooklyn Zelenka to start off our journey on the subject with an exploration of her very own Witchcraft. In this episode we talk to Brooklyn about her history with Elixir, how she got started and what attracts her to it. Brooklyn explains the influence that open source philosophy has had on her career in developing and from there she gives a pretty comprehensive introduction to what Witchcraft is, expanding its key concepts. Although this is quite a high level discussion about Elixir and Witchcraft, we are confident that with Brooklyn's expert help even our most uninitiated listener can get some benefit from our conversation. We also talk about type systems, property-based checking and Dialyzer, so for all of this and more make sure to join us as we kick things off for Season 2! Key Points From This Episode: A quick introduction to Brooklyn, where she works and how she got started with Elixir. The influence of open source and library contributions on Brooklyn's development. Getting to grips with Witchcraft; defining monads and functors. Why some of these scary terms do not need to frighten you. A few little things that differentiate Witchcraft and some surprising elements. The convenient guarantees that Witchcraft provides around your data structure. Why there is no type system baked into Elixir; overheads, inputs and outputs. Property-based checking and compile times in Witchcraft. Merging of Elixir and Dialyzer; benefits and problems. Getting in touch with Brooklyn and getting involved with Witchcraft and Elixir. And much more! Links Mentioned in Today’s Episode: Smartlogic — https://www.smartlogic.io/ Brooklyn Zelenka — https://github.com/expede Brooklyn Zelenka on Twitter — https://twitter.com/expede Brooklyn Zelenka Email — hello@brooklynzelenka.com Fission — https://fission.codes/ Elixir — https://elixir-lang.org/ Witchcraft — https://hex.pm/packages/witchcraft Dialyzer — https://github.com/jeremyjh/dialyxir Learn more about how SmartLogic uses Phoenix and Elixir.Special Guest: Brooklyn Zelenka.

We’re excited to announce our season two topic, Elixir Internals. In this season we talk with developers behind some of the most popular Elixir libraries, including Witchcraft, ElixirScript, Distillery, Ecto, and more!

With this season over, we bring Dan Ivovich back to talk about what we learned. Dan Ivovich - Director of Development Operations @ SmartLogic 00:43 - Why are you using Elixir in production? 01:20 - Advantages / disadvantages of Elixir 02:38 - How do you deploy? 03:48 - Zero downtime deploys 05:40 - Clustering 06:56 - Elixir App performance 09:00 - Background task processing 10:36 - Common Libraries 14:40 - 3rd Party Services 16:16 - Do you have a story where Elixir saved the day in production? 17:56 - OTP features 18:31 - Tip to developers Learn more about how SmartLogic uses Phoenix and Elixir.Special Guest: Dan Ivovich.

We talk with Jeffrey Matthias from Community about their current and past Elixir projects and how they are deployed. Jeffrey Matthias - Community Find Jeffrey elsewhere online: http://github.com/idlehands https://twitter.com/idlehands 0:47 - Give us a quick overview of the Elixir projects you have in production. 3:29 - Why are you using Elixir in production? 6:04 - What are some of the high level advantages / disadvantages of Elixir, from your perspective? 10:14 - What do you use to host your Elixir app? Linode, AWS, DO Heroku Enmesos mesos How do you deploy your application? Ansible Deploy scripts Distillery 14:19 - Are you able to get zero downtime deploys? If so, how? 17:06 - Do you cluster the application? If so, how? 22:53 - How does your Elixir App perform compared to others in your environment? Response time Throughput Jobs/hr 25:01 - How are you solving background task processing? 29:17 - What libraries are you using? Phoenix 33:53 - Third party apps 37:28 - Do you have a story where Elixir saved the day in production? 40:42 - If you could give one tip to developers out there who are or may soon be running Elixir in production, what would it be? Learn more about how SmartLogic uses Phoenix and Elixir.Special Guest: Jeffrey Matthias.Links:EnbalaWeedmapsDocker: Up & RunningAsync APIRabbitMQAMQP Elixir ClienterlcassErlang in Anger

We talk with Jay Ashe from Cava about their current and past Elixir projects and how they are deployed. Jay Ashe - Cava Find Jay elsewhere online: https://twitter.com/jgashe 0:40 - Give us a quick overview of the Elixir projects you have in production. CAVA is a fast-casual mediterranean restaurant chain with 75 stores across the US. Elixir and phoenix power CAVA’s online ordering platform (order.cava.com and the CAVA app). We’ve got a REST (and websockets) api sitting behind react and our mobile apps, and we use phoenix templates for some of our back of house systems. 1:11 - Why are you using Elixir in production? We have from the start! The application was originally implemented by Chris Bell and his team at madebymany. Chris, by the way, has a fantastic talk from ElixirConf 2016 that goes into our architecture and how we use elixir and OTP constructs to model our business logic. Chris will occasionally talk about the CAVA project on his Elixir podcast, ElixirTalk. Chris’ Talk - https://www.youtube.com/watch?v=fkDhU-2NWJ8 1:58 - What are some of the high level advantages / disadvantages of Elixir, from your perspective? Advantages: Elixir and Phoenix gives you rails-esque productivity/developer experience that scales. I think phoenix channels are a great example of this. Build a channel with complex real-time functionality and let it scale effortlessly. Disadvantages: Hiring and onboarding, depending on your mindset, can be difficult. If you’re used to hiring for experience in  your stack, its just going to be more difficult. Lately we’ve started doing one-hour weekly knowledge shares that cover elixir basics and are closely tied to our usage of them. So, here’s a test case, and here are all of the test helpers that we have set up that will help you write that test. We also just sent a new Elixir dev to lonestar elixir 3:59 - What do you use to host your Elixir app? Heroku How do you deploy your application? Heroku-buildpack-elixir https://github.com/HashNuke/heroku-buildpack-elixir 4:44 - Are you able to get zero downtime deploys? As close as possible! We get that out of the box with heroku. When we deploy, heroku won’t point traffic to the new dyno until the app is healthy. We make extensive use of Phoenix channels over websockets, and our clients will reconnect automatically and transparently. 5:10 - Do you cluster the application? Nope. 5:52 - How does your Elixir App perform compared to others in your environment? I can’t really talk about numbers here, but Elixir is not at all our bottleneck. We don’t have other production applications 6:25 - How are you solving background task processing? Quantum for cron jobs, genservers for everything else. We’re running a single elixir application that handles all synchronous and async processing 7:07 - What libraries are you using? Phoenix Phoenix_swagger for API documentation that integrates with controller tests https://github.com/xerions/phoenix_swagger Ex_rated for rate limiting calls to our integrations https://github.com/grempe/ex_rated Timex and calendar for datetime support with timezones https://github.com/bitwalker/timex A combination of httpotion and httpoison for HTTP clients, but im interested in trying Mint https://github.com/ericmj/minthttps://github.com/appcues/mojito Bamboo for transactional emails, like order confirmations etc https://github.com/thoughtbot/bamboo 8:59 - 3rd Party Services (i.e. Email, Payment Processing, etc) Sendgrid for email, Google for geocoding, slack for some internal alerting of application health, LevelUp for payments. https://www.thelevelup.com/ 10:07 - Do you have a story where Elixir saved the day in production? Yes and no. So I could tell this story by explaining the issue we saw and the underlying cause at the same time, but I think it would be more fun to tell it like our team experienced it. One day at lunch our application started going down. Lots of 500 errors. Red lights flashing. Panic ensuing. Lunch is our busiest time of day, so 1) we thought it was load related and 2) we really needed to fix it None of our traditional resources (database, cpu, memory) were constrained and our integrations that were synchronous were fine. Our logs were littered with errors from an analytics integration that ran asynchronously on genservers, but it didn’t seem related because we could see the error logs at times when our application was otherwise healthy. The team that used the analytics didn’t have a pressing need for them, and we deprioritized fixing the issue because the bug we were working on was so much more important (that’s foreshadowing). I spent a little time looking at websockets, but I was easily able to match the load of the websocket portion of our application on my local machine with no degradations in performance (thanks, phoenix), so that was out. At this point the issue was going on every day at lunch and I was getting annoyed at seeing the logs from the analytics integration when debugging, so I spent like 15 minutes finding and fixing the issue (a bad API key, basically) Voila, issue gone. Time to grab some lunch. We spent a while coming up with an explanation for this. Eventually we learned about max_restarts on a supervisor. By default, if a process crashes 3 times in 5 seconds, the process won’t be restarted again. So if another process (like the one handling a web request) tries to call that process that wasn’t restarted, the caller would crash, and we’d start to get 500 errors, customers couldn’t log in, mass confusion. So there are a few takeaways from this story: For a while, elixir saved the day in production. - A supervision tree prevented failures from the analytics process from affecting customers, until the scale of our failures exceeded the max_restart level. - Our supervision tree needed some love though, clearly. - Monitor your resources. CPU is a resource, but calls to another API are also a resource and can get unhealthy too. 15:00 - Are you using any cool OTP features? GenServers, definitely. There’s lots we can do asynchronously especially in terms of our integrations. One process per store is a cool model that scales well and keeps issues isolated to a single store. 15:50 - If you could give one tip to developers out there who are or may soon be running Elixir in production, what would it be? If you’re on a small team, Heroku or a similar provider might give you a lot of value in terms of infrastructure you can set up and forget. Learn more about how SmartLogic uses Phoenix and Elixir.Special Guest: Jay Ashe.Links:ElixirConf 2016 - Selling Food With Elixir by Chris BellHeroku-buildpack-elixirPhoenix SwaggerEx_ratedTimexMintMojitoLevelUp