fix: better elixir docs and defaults

docs/pages/docs/providers/elixir.md

@@ -11,17 +11,27 @@ Elixir is detected if a `mix.exs` file is found.
 The following Elixir versions are available
 
 - `latest` (Default)
+- `1.17`
+- `1.16`
+- `1.15`
+- `1.14`
+- `1.13`
 - `1.12`
 - `1.11`
 - `1.10`
 - `1.9`
 
 The version can be overridden by
 
+- Elixir version is extracted from the `mix.exs` file automatically
 - Setting the `NIXPACKS_ELIXIR_VERSION` environment variable
 - Setting the version in a `.elixir-version` file
 
-```
+The OTP version is automatically set and cannot currently be customized.
+
+The default install script is:
+
+```shell
 MIX_ENV=prod
 
 mix local.hex --force
@@ -31,13 +41,26 @@ mix deps.get --only prod
 
 ## Build
 
-```
+```shell
 mix compile
 mix assets.deploy
+mix ecto.deploy # if available
 ```
 
+If you are building outside of a live environment, you may want to omit `ecto.deploy` (which can sometimes rely on a
+database connection) which you can do by overriding the build command.
+
 ## Start
 
-```
+```shell
 mix phx.server
 ```
+
+## Environment Variables
+
+The following environment variables are set by default:
+
+```shell
+MIX_ENV=prod
+ELIXIR_ERL_OPTIONS="+fnu"
+```

src/providers/elixir.rs

@@ -11,7 +11,7 @@
 use anyhow::Result;
 use regex::{Match, Regex};
 const DEFAULT_ELIXIR_PKG_NAME: &str = "elixir";
-const ELIXIR_NIXPKGS_ARCHIVE: &str = "ef99fa5c5ed624460217c31ac4271cfb5cb2502c";
+const ELIXIR_NIXPKGS_ARCHIVE: &str = "c5702bd28cbde41a191a9c2a00501f18941efbd0";
 
 pub struct ElixirProvider {}
 
@@ -25,17 +25,11 @@
     }
 
     fn get_build_plan(&self, app: &App, env: &Environment) -> Result<Option<BuildPlan>> {
-        let mut plan = BuildPlan::default();
-
-        plan.add_variables(EnvironmentVariables::from([(
-            "MIX_ENV".to_string(),
-            "prod".to_string(),
-        )]));
+        let setup = self.setup(app, env)?.unwrap_or_default();
 
-        let elixir_pkg = ElixirProvider::get_nix_elixir_package(app, env)?;
-        let mut setup_phase = Phase::setup(Some(vec![elixir_pkg]));
-        setup_phase.set_nix_archive(ELIXIR_NIXPKGS_ARCHIVE.to_string());
-        plan.add_phase(setup_phase);
+        let mut plan = BuildPlan::default();
+        plan.add_variables(ElixirProvider::default_elixir_environment_variables());
+        plan.add_phase(setup);
 
         // Install Phase
         let mut install_phase = Phase::install(Some("mix local.hex --force".to_string()));
@@ -51,9 +45,6 @@
             build_phase.add_cmd("mix assets.deploy".to_string());
         }
 
-        if mix_exs_content.contains("postgrex") && mix_exs_content.contains("ecto") {
-            build_phase.add_cmd("mix ecto.setup");
-        }
         plan.add_phase(build_phase);
 
         // Start Phase
@@ -65,6 +56,36 @@
 }
 
 impl ElixirProvider {
+    fn setup(&self, app: &App, env: &Environment) -> Result<Option<Phase>> {
+        let elixir_pkg = ElixirProvider::get_nix_elixir_package(app, env)?;
+        // TODO should try to extract and optionally set the OTP version
+        let mut setup = Phase::setup(Some(vec![elixir_pkg]));
+        setup.set_nix_archive(ELIXIR_NIXPKGS_ARCHIVE.to_string());
+
+        // Many Elixir packages need some C headers to be available
+        setup.add_pkgs_libs(vec!["stdenv.cc.cc.lib".to_string()]);
+        setup.add_nix_pkgs(&[Pkg::new("gcc")]);
+
+        return Ok(Some(setup));
+    }
+
+    fn default_elixir_environment_variables() -> EnvironmentVariables {
+        let var_map = vec![
+            ("MIX_ENV", "prod"),
+            // required to avoid the following error:
+            // warning: the VM is running with native name encoding of latin1 which may cause Elixir to malfunction as it expects utf8. Please ensure your locale is set to UTF-8 (which can be verified by running "locale" in your shell) or set the ELIXIR_ERL_OPTIONS="+fnu" environment variable
+            ("ELIXIR_ERL_OPTIONS", "+fnu"),
+        ];
+
+        let mut env_vars = EnvironmentVariables::new();
+
+        for (key, value) in var_map {
+            env_vars.insert(key.to_owned(), value.to_owned());
+        }
+
+        env_vars
+    }
+
     fn get_nix_elixir_package(app: &App, env: &Environment) -> Result<Pkg> {
         fn as_default(v: Option<Match>) -> &str {
             match v {
@@ -89,6 +110,8 @@
                 .map(|c| c.get(2).unwrap().as_str().to_owned())
         };
 
+        // TODO next, let's try .tool-version
+
         // If it's still none, return default
         if custom_version.is_none() {
             return Ok(Pkg::new(DEFAULT_ELIXIR_PKG_NAME));
@@ -116,8 +139,10 @@
             ("1", "11") => Ok(Pkg::new("elixir_1_11")),
             ("1", "12") => Ok(Pkg::new("elixir_1_12")),
             ("1", "13") => Ok(Pkg::new("elixir_1_13")),
-            ("1", "14") => Ok(Pkg::new("elixir")),
+            ("1", "14") => Ok(Pkg::new("elixir_1_14")),
             ("1", "15") => Ok(Pkg::new("elixir_1_15")),
+            ("1", "16") => Ok(Pkg::new("elixir_1_16")),
+            ("1", "17") => Ok(Pkg::new("elixir_1_17")),
             _ => Ok(Pkg::new(DEFAULT_ELIXIR_PKG_NAME)),
         }
     }