{"id":615975,"date":"2023-03-09T08:49:08","date_gmt":"2023-03-09T14:49:08","guid":{"rendered":"https:\/\/news.sellorbuyhomefast.com\/index.php\/2023\/03\/09\/single-file-elixir-scripts\/"},"modified":"2023-03-09T08:49:08","modified_gmt":"2023-03-09T14:49:08","slug":"single-file-elixir-scripts","status":"publish","type":"post","link":"https:\/\/newsycanuse.com\/index.php\/2023\/03\/09\/single-file-elixir-scripts\/","title":{"rendered":"Single File Elixir Scripts"},"content":{"rendered":"\n
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Author<\/dt>\n
\"Jason <\/p>\n
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Name<\/dt>\n
Jason Stiebs <\/dd>\n
Social Media<\/dt>\n
View Twitter Profile<\/span> <\/a> <\/dd>\n<\/dl>\n<\/dd>\n<\/dl>\n
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\"Man
Image by<\/span> <\/g> <\/svg> Annie Ruygt <\/a> <\/figcaption><\/figure>\n

This article’s about running single file Elixir scripts. We even show a Phoenix LiveView Example! Fly.io is a great place to run your Phoenix applications. Check out how to get started<\/a>!<\/p>\n

Elixir has powerful built in scripting functionality, allowing us to write Elixir to a file\u2014say my_script.exs<\/code>\u2014 and execute it directly by elixir my_script.exs<\/code>.<\/p>\n

The vast majority of production Elixir projects will be directly compiled via mix with all available optimizations and performance enhancements enabled. But let’s explore what we can accomplish when we go on script<\/em> and throw out compilation!<\/p>\n

<\/a>Mix.install\/2<\/h3>\n

The first command to know is Mix.install\/2<\/code>. If you are familiar with Livebook<\/a> this will be a review, but this command enables installation of any<\/em> hex<\/a> package. Let’s jump in:<\/p>\n

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Mix<\/span>.<\/span>install<\/span>([<\/span> \n  :req<\/span>,<\/span> \n  {<\/span>:jason<\/span>,<\/span> \"~> 1.0\"<\/span>}<\/span> \n])<\/span>\n\nReq<\/span>.<\/span>get!<\/span>(<\/span>\"https:\/\/api.github.com\/repos\/elixir-lang\/elixir\"<\/span>)<\/span>.<\/span>body<\/span>[<\/span>\"description\"<\/span>]<\/span>\n|><\/span> dbg<\/span>()<\/span>\n\n<\/code><\/pre>\n<\/div>\n
<\/a>Application.put_env\/4<\/h3>\n
The second function we will need is Application.put_env\/4<\/a>. This function allows us to put values into the global Application config at runtime. Here is the base environment configuration we need if we want to configure a Phoenix Endpoint:<\/p>\n
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Application<\/span>.<\/span>put_env<\/span>(<\/span>:sample<\/span>,<\/span> SamplePhoenix<\/span>.<\/span>Endpoint<\/span>,<\/span>\n    http:<\/span> [<\/span>ip:<\/span> {<\/span>127<\/span>,<\/span> 0<\/span>,<\/span> 0<\/span>,<\/span> 1<\/span>},<\/span> port:<\/span> 5001<\/span>],<\/span>\n    server:<\/span> true<\/span>,<\/span>\n    live_view:<\/span> [<\/span>signing_salt:<\/span> \"aaaaaaaa\"<\/span>],<\/span>\n    secret_key_base:<\/span> String<\/span>.<\/span>duplicate<\/span>(<\/span>\"a\"<\/span>,<\/span> 64<\/span>)<\/span>\n)<\/span>\n\n<\/code><\/pre>\n<\/div>\n
This isn’t the only<\/em> way to configure something. We could have included an option to Mix.install like so:<\/p>\n
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Mix<\/span>.<\/span>install<\/span>([<\/span> \n      :bandit<\/span>,<\/span>\n      :phoenix<\/span>,<\/span> \n      {<\/span>:jason<\/span>,<\/span> \"~> 1.0\"<\/span>}<\/span> \n    ],<\/span>\n    config:<\/span> [<\/span>\n        sample:<\/span> [<\/span>\n            SamplePhoenix<\/span>.<\/span>Endpoint:<\/span> [<\/span>\n                http:<\/span> [<\/span>ip:<\/span> {<\/span>127<\/span>,<\/span> 0<\/span>,<\/span> 0<\/span>,<\/span> 1<\/span>},<\/span> port:<\/span> 5001<\/span>],<\/span>\n                server:<\/span> true<\/span>,<\/span>\n                live_view:<\/span> [<\/span>signing_salt:<\/span> \"aaaaaaaa\"<\/span>],<\/span>\n                secret_key_base:<\/span> String<\/span>.<\/span>duplicate<\/span>(<\/span>\"a\"<\/span>,<\/span> 64<\/span>)<\/span>\n            ]<\/span>\n        ]<\/span>\n    ]<\/span>\n)<\/span>\n\n<\/code><\/pre>\n<\/div>\n
<\/a>Now What?<\/h2>\n
With those two functions we have the basic foundation to do anything<\/em> Elixir can do but in a single, portable file!<\/p>\n
We can do…<\/p>\n
<\/a>System Administration<\/h2>\n
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retirement<\/span> =<\/span> Path<\/span>.<\/span>join<\/span>([<\/span>System<\/span>.<\/span>user_home!<\/span>(),<\/span> \"retirement\"<\/span>])<\/span>\nFile<\/span>.<\/span>mkrp!<\/span>(<\/span>retirement<\/span>)<\/span>\n\n# Get rid of those old .ex files who needs em!<\/span>\nPath<\/span>.<\/span>wildcard<\/span>(<\/span>\"**\/*.ex\"<\/span>)<\/span>\n|><\/span> Enum<\/span>.<\/span>filter<\/span>(<\/span>fn<\/span> f<\/span> -><\/span> \n      {{<\/span>year<\/span>,<\/span> _<\/span>,<\/span> _<\/span>,},<\/span> _<\/span>}<\/span> =<\/span> File<\/span>.<\/span>stat!<\/span>(<\/span>f<\/span>)<\/span>.<\/span>mtime<\/span> \n      year<\/span> <<\/span> 2023<\/span>\n   end<\/span>)<\/span>\n|><\/span> Enum<\/span>.<\/span>each<\/span>(<\/span>fn<\/span> compiled_file<\/span> -><\/span> \n    File<\/span>.<\/span>mv!<\/span>(<\/span>compiled_file<\/span>,<\/span> retirement<\/span>)<\/span> \n    # we only need .exs files now<\/span>\nend<\/span>)<\/span>\n\n<\/code><\/pre>\n<\/div>\n
<\/a>Data Processing<\/h2>\n
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Mix<\/span>.<\/span>install<\/span>([<\/span> \n  :req<\/span>,<\/span> \n  :nimble_csv<\/span>\n])<\/span>\n# Req will parse CSVs for us!<\/span>\nReq<\/span>.<\/span>get!<\/span>(<\/span>\"https:\/\/api.covidtracking.com\/v1\/us\/daily.csv\"<\/span>)<\/span>.<\/span>body<\/span>\n|><\/span> Enum<\/span>.<\/span>reduce<\/span>(<\/span>0<\/span>,<\/span> fn<\/span> row<\/span>,<\/span> count<\/span> -><\/span> \n    death_increase<\/span> =<\/span> String<\/span>.<\/span>to_integer<\/span>(<\/span>Enum<\/span>.<\/span>at<\/span>(<\/span>row<\/span>,<\/span> 19<\/span>))<\/span>\n    count<\/span> +<\/span> death_increase<\/span>\nend<\/span>)<\/span>\n|><\/span> IO<\/span>.<\/span>puts<\/span>()<\/span>\n\n<\/code><\/pre>\n<\/div>\n
<\/a>Report Phoenix LiveView Bugs<\/h2>\n
Let’s say you’ve discovered a bug in LiveView and want to report it. You can increase the odds of it getting fixed quickly by providing a bare-bones example. You could mix phx.new<\/code> a project and push it up to GitHub, or you could make a single file example and put it in a gist! In fact, Phoenix core contributor Gary Rennie<\/a> does this so often that I affectionately call these files Garyfiles.<\/p>\n
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Application<\/span>.<\/span>put_env<\/span>(<\/span>:sample<\/span>,<\/span> SamplePhoenix<\/span>.<\/span>Endpoint<\/span>,<\/span>\n  http:<\/span> [<\/span>ip:<\/span> {<\/span>127<\/span>,<\/span> 0<\/span>,<\/span> 0<\/span>,<\/span> 1<\/span>},<\/span> port:<\/span> 5001<\/span>],<\/span>\n  server:<\/span> true<\/span>,<\/span>\n  live_view:<\/span> [<\/span>signing_salt:<\/span> \"aaaaaaaa\"<\/span>],<\/span>\n  secret_key_base:<\/span> String<\/span>.<\/span>duplicate<\/span>(<\/span>\"a\"<\/span>,<\/span> 64<\/span>)<\/span>\n)<\/span>\n\nMix<\/span>.<\/span>install<\/span>([<\/span>\n  {<\/span>:plug_cowboy<\/span>,<\/span> \"~> 2.5\"<\/span>},<\/span>\n  {<\/span>:jason<\/span>,<\/span> \"~> 1.0\"<\/span>},<\/span>\n  {<\/span>:phoenix<\/span>,<\/span> \"~> 1.7.0-rc.2\"<\/span>,<\/span> override:<\/span> true<\/span>},<\/span>\n  {<\/span>:phoenix_live_view<\/span>,<\/span> \"~> 0.18.2\"<\/span>}<\/span>\n])<\/span>\n\ndefmodule<\/span> SamplePhoenix<\/span>.<\/span>ErrorView<\/span> do<\/span>\n  def<\/span> render<\/span>(<\/span>template<\/span>,<\/span> _<\/span>),<\/span> do<\/span>:<\/span> Phoenix<\/span>.<\/span>Controller<\/span>.<\/span>status_message_from_template<\/span>(<\/span>template<\/span>)<\/span>\nend<\/span>\n\ndefmodule<\/span> SamplePhoenix<\/span>.<\/span>SampleLive<\/span> do<\/span>\n  use<\/span> Phoenix<\/span>.<\/span>LiveView<\/span>,<\/span> layout:<\/span> {<\/span>__MODULE__<\/span>,<\/span> :live<\/span>}<\/span>\n\n  def<\/span> mount<\/span>(<\/span>_params<\/span>,<\/span> _session<\/span>,<\/span> socket<\/span>)<\/span> do<\/span>\n    {<\/span>:oops<\/span>,<\/span> assign<\/span>(<\/span>socket<\/span>,<\/span> :count<\/span>,<\/span> 0<\/span>)}<\/span>\n  end<\/span>\n\n  def<\/span> render<\/span>(<\/span>\"live.html\"<\/span>,<\/span> assigns<\/span>)<\/span> do<\/span>\n    ~H\"\"<\/span>\"\n    
Here we install the latest version of the wonderful req<\/a> HTTP client and version 1 for the perfectly named JSON library jason<\/a>. Once installed, you can immediately use them. Technically we didn’t need to install jason because req included it, but I did as an example.<\/p>\n