In this episode of ElixirMix, Josh and Michael talk about some of the treasures hidden in the Standard Library. They discuss, ETS, DETS, Mnesia, caching strategies, and building non-web UIs with Wx and Scenic. Check it out and much more!

Podcast Episode

I put together an episode for anyone looking to get started writing tests with Elixir.

https://elixircasts.io/introduction-to-testing

When I got into Elixir, I was admiring all the awesome shiny magic it had ready for me to build things. But there’s actually less to it than you might think! - In a good way! https://medium.com/@svengehring/there-is-no-magic-in-elixir-9f61c1ec6ea4

In Part 4 of this series on Event Sourcing we’ll introduce middleware and improve our test coverage.

https://medium.com/@imanhodjaev/organising-absithe-and-ecto-errors-2a2257ccdff6

I’ve been using Absinthe in my own project for some time now and wanted to share my thoughts on the topic of organising and working with errors in general and particularly with Ecto.Changeset errors. In my opinion this topic is poorly covered though there are some guidance in the official documentation and numerous other places which I tried to unify them. Also as it is quite hard to figure out the exact common shape of possible API errors at the beginning and it comes over time once you have something in place.

Syncfusion has just published a short but dense book about Elixir and OTP. You can download it here: https://www.syncfusion.com/ebooks/elixir-succinctly

First milestone achieved: a Pi Zero running Nerves sending USB keypresses triggered by GPIO. Next: setup a keyboard matrix! https://www.youtube.com/watch?v=pTK-UYxU-YQ

• The correct home path for kiex is ~/.kiex/elixirs/elixir-VERSION/lib/elixir as that contains the true lib and bin directory, but users may select other directories by mistake, so doing the following adjustments:

• Adjust bin home path to lib/elixir.

• Adjust elixirs/elixir-VERSION home path to elixirs/elixir-VERSION/lib/elixir.

• In RubyMine, attach OTP applications as separate projects with Elixir facets instead of directly creating ELIXIR_MODULE modules in DirectoryConfigurator. This matches the manual steps of opening the OTP apps as separate directories after opening the root of the project.

  • Mark directories when adding facet
  • Sync libraries when adding facet or attaching to root project. Ensures External Libraries show up for all OTP applications.

• Convert Small IDE projects with ELIXIR_MODULEs:

  1. Remove ELIXIR_MODULE *.iml files
  2. Remove ELIXIR_MODULE entries root project’s modules.xml file.
  3. Lack of modules in project in doOpenProject will trigger DirectoryProjectConfigurators to be run, which will setup the project and run DirectoryConfigurator to attach the apps OTP apps and Elixir facets.
     • Only support automatic attaching multiple OTP apps as separate projects in Rubymine. In IntelliJ normal support for multiple Modules in one Project still works.

• Increase suspect nameSet size to 15 to support geo. geo has 13 String.Chars implementations.

• Check that HomePath has ebin paths when validation. Prevents selecting false HomePaths for kiex.

• Adding missing ESpec template. When reviewing #1410 I missed that the template wasn’t in resources. 🤦‍♂️

• Ignore targets when calculating Dep path.

• Ignore organization when calculating Dep path.

• Get view provider document in read action.

• Support rebar.config deps that are name only.

• Always use containingFile for QualifiableAlias maxScope for getReference. Prevents cache capturing maxScope, which can vary based on invocation.

• Create new project before attaching it in Small IDEs. When attaching a directory to a project during startup, saving is disallowed, so the attached directory only has a workspace.xml in its .idea when the attach is attempted. Attaching requires the .idea/*.iml Module file, so the attaching fails, saying the directory is an unsupported format.

  Experimentation showed that manually attaching the directory also did not work, but opening the directory in a separate window, then opening and attaching it again would make the directory have the full project files. To mimic this manual process:

  1. The internals of doOpenProject are copied
  2. A save of the project files is forced, bypassing the normal “startup” save blocker
  3. The project is attached to the root project. Tested to work when upgrading from 10.4.0 to 10.5.0-pre in Rubymine when no project was already open.

• Check if project can be attached instead of if RubyMine Although GoLand supports attaching projects, it doesn’t work for non-Go projects, so it is also excluded. How the support appears in each non-IntelliJ IDEA is shown below:

  IDE	Works?
  Android Studio	YES	Android Studio is built on top of IntelliJ, so it has full multi-Module support. It is not Small IDE.
  CLion	NO	No Attach to Project support to multiple module support.
  DataGrip	No	DataGrip doesn’t have a Project View and doesn’t support Attach to Project. You can still run tests if you directly open the file.
  GoLand	NO	Modules show up, but independent projects are not attached as in other Small IDEs, so disabled. In general, the Go settings, like Test Runners always win, so it is recommended to not use GoLand at all for Elixir development.
  PHPStorm	YES	The projects are listed in Directories. The Languages & Frameworks > Elixir shows all 3 projects. Right-clicking on the marked Test directory will not show the Elixir Run Configuration, Python ones win, but subdirectories and *_test.exs will show up in the context menu.
  PyCharm	YES	The root project is listed in Project. app/* projects are listed listed as Project Dependencies of the root Project. The Languages & Frameworks > Elixir shows all 3 projects. Right-clicking on the marked Test directory will not show the Elixir Run Configuration, Python ones win, but subdirectories and *_test.exs will show up in the context menu.
  Rider	No	Solution system is separate from Project system.
  Rubymine	YES	The projects are listed in Project Structure. The Languages & Frameworks > Elixir shows all 3 projects. Right-clicking on the marked Test directory will not show the Elixir Run Configuration, Python ones win, but subdirectories and *_test.exs will show up in the context menu.
  WebStorm	NO	No Attach to Project support or multiple module support.

• Don’t count Android Studio as a Small IDE. It includes Project Structure menu with multiple-language, multiple-Module per Project support from IntelliJ.

Installation Instructions

ExternalState: for when your GenServers have long running functions but other processes need to ask them quick questions. At [https://hexdocs.pm/external_state and https://github.com/sampscl/external_state

A very simple tutorial on how recursive functions work, to help those unfamiliar with them understand the concept. https://medium.com/@damonvjanis/recursive-functions-in-elixir-93a118c69db7

I just published Uribe. This is a new library to manipulate URI struct in Elixir. PRs are welcome

Phoenix serves static files with a Plug.Static defined in the endpoint. But what if we want to serve additional static files from subpaths? https://medium.com/@svengehring/serving-static-assets-on-a-subpath-in-phoenix-758f9ecb9921

I just published a new post ‘Native graph data in Elixir: Using libgraph for graph data structures‘.

This post looks at the Elixir libgraph package from Paul Schoenfelder.

After a brief introduction to building graphs using libgraph I take a quick look at how to serialize and visualize these graphs with Graphviz tools.

I then show how to create a libgraph graph from CSV data, and explore some basic graph structures.

Lastly a couple naive conversions from graph database formats (both property and RDF graphs) into native libgraph formats is attempted.

The very simple :ets wrapper simplifying cross-process :ets handling (like Agent, but :ets.)

https://hexdocs.pm/nimble_ets / https://github.com/am-kantox/nimble_ets

It seems to me that GenServers and supervision trees are emphasized a bit too much - we can build great applications without writing them ourselves: You may not need GenServers and Supervision Trees

This week the elixir outlaws discuss implicit vs. explicit api design.

https://elixiroutlaws.com/38

Recently when working on an Elixir project I ran into an interesting gotcha with Agents that caused massive amounts of resource usage. In this post I’m describing how using Agents can lead to high memory usage and how you can solve it by using a worker pool.

https://www.theguild.nl/caveats-storing-large-amounts-of-data-in-elixir-agents/

Just released KeywordValidator

This is a tiny library that validates keyword lists against a schema. Provides detailed error feedback when something is not right. Helps prevent code repetition and cryptic errors stemming from function options! Enjoy.

• Github
• Hex
• HexDocs

In my latest Phoenix LiveView tutorial we go over how to create a real-time updating todo list with Phoenix LiveView and Phoenix PubSub. Check it out and let me know what you think!

https://dennisbeatty.com/2019/04/24/how-to-create-a-todo-list-with-phoenix-liveview.html

checkout new public GitBook for Killer Elixir Books https://extips.blackode.in/