Add Haunt for Scheme as a provider (#1198)

* draft

* register provider

* simplification

* fix registration

* incorporate feedback

* start command quirk

* lint fix

* add scheme snapshot test

---------

Co-authored-by: Jake Runzer <[email protected]>

docs/pages/docs/providers/scheme.md

@@ -0,0 +1,26 @@
+---
+title: Scheme
+---
+
+# {% $markdoc.frontmatter.title %}
+
+Scheme via [Haunt](https://dthompson.us/projects/haunt.html) is detected is there is a `haunt.scm` file found.
+
+## Setup
+
+Installs the basic dependencies
+
+## Build
+
+Build the project based on your `haunt.scm`.
+
+## Start
+
+Haunt wasn't made for this, so our entrypoint is actually a Guile script.  
+Make sure it is in the root directory with your `haunt.scm`.  
+Note: This is only necessary in production. You can use the `haunt` command normally in dev.
+
+```scheme
+;; init.scm
+(system "haunt serve")
+```

docs/sidebar.ts

@@ -54,6 +54,7 @@ export const sidebarItems: ISidebarSection[] = [
       { href: "/docs/providers/python", text: "Python" },
       { href: "/docs/providers/ruby", text: "Ruby" },
       { href: "/docs/providers/rust", text: "Rust" },
+      { href: "/docs/providers/scheme", text: "Scheme" },
       { href: "/docs/providers/staticfile", text: "Staticfile" },
       { href: "/docs/providers/swift", text: "Swift" },
       { href: "/docs/providers/scala", text: "Scala" },

examples/scheme/haunt.scm

@@ -0,0 +1,14 @@
+(use-modules (haunt asset)
+             (haunt builder blog)
+             (haunt builder assets)
+             (haunt reader commonmark)
+             (haunt site))
+
+(site #:title "Built with Guile"
+      #:domain "example.com"
+      #:default-metadata
+      '((author . "John Doe")
+        (email  . "[email protected]"))
+      #:readers (list)
+      #:builders (list)
+)

examples/scheme/init.scm

@@ -0,0 +1 @@
+(display "Hello from Scheme!")

src/lib.rs

@@ -39,8 +39,8 @@ use providers::{
     fsharp::FSharpProvider, gleam::GleamProvider, go::GolangProvider,
     haskell::HaskellStackProvider, java::JavaProvider, lunatic::LunaticProvider,
     node::NodeProvider, php::PhpProvider, python::PythonProvider, ruby::RubyProvider,
-    rust::RustProvider, scala::ScalaProvider, staticfile::StaticfileProvider, swift::SwiftProvider,
-    zig::ZigProvider, Provider,
+    rust::RustProvider, scala::ScalaProvider, scheme::HauntProvider,
+    staticfile::StaticfileProvider, swift::SwiftProvider, zig::ZigProvider, Provider,
 };
 use std::process::Command;
 
@@ -62,6 +62,7 @@ pub fn get_providers() -> &'static [&'static (dyn Provider)] {
         &GleamProvider {},
         &GolangProvider {},
         &HaskellStackProvider {},
+        &HauntProvider {},
         &JavaProvider {},
         &LunaticProvider {},
         &ScalaProvider {},

src/providers/mod.rs

@@ -21,6 +21,7 @@ pub mod python;
 pub mod ruby;
 pub mod rust;
 pub mod scala;
+pub mod scheme;
 pub mod staticfile;
 pub mod swift;
 pub mod zig;

src/providers/scheme.rs

@@ -0,0 +1,36 @@
+use super::Provider;
+use crate::nixpacks::{
+    app::App,
+    environment::Environment,
+    nix::pkg::Pkg,
+    plan::{
+        phase::{Phase, StartPhase},
+        BuildPlan,
+    },
+};
+use anyhow::Result;
+
+pub struct HauntProvider {}
+
+impl Provider for HauntProvider {
+    fn name(&self) -> &str {
+        "scheme"
+    }
+
+    fn detect(&self, app: &App, _env: &Environment) -> Result<bool> {
+        Ok(app.includes_file("haunt.scm"))
+    }
+
+    fn get_build_plan(&self, _app: &App, _env: &Environment) -> Result<Option<BuildPlan>> {
+        let setup = Phase::setup(Some(vec![Pkg::new("haunt"), Pkg::new("guile")]));
+        let mut build = Phase::build(Some("haunt build".to_string()));
+        build.depends_on_phase("setup");
+        // In production, init.scm should run "haunt serve"
+        // However, "haunt serve" doesn't terminate on its own, which the tests depend on
+        // So for the example, init.scm simply logs to the console
+        let start = StartPhase::new("guile init.scm --auto-compile".to_string());
+
+        let plan = BuildPlan::new(&vec![setup, build], Some(start));
+        Ok(Some(plan))
+    }
+}

tests/docker_run_tests.rs

@@ -1480,3 +1480,9 @@ async fn test_config_toml_file() {
     let output = run_image(&name, None).await;
     assert!(output.contains("hey there"));
 }
+
+#[tokio::test]
+async fn test_scheme() {
+    let name = simple_build("./examples/scheme").await.unwrap();
+    assert!(run_image(&name, None).await.contains("Hello from Scheme!"));
+}

tests/snapshots/generate_plan_tests__scheme.snap

@@ -0,0 +1,35 @@
+---
+source: tests/generate_plan_tests.rs
+expression: plan
+---
+{
+  "providers": [],
+  "buildImage": "[build_image]",
+  "variables": {
+    "NIXPACKS_METADATA": "scheme"
+  },
+  "phases": {
+    "build": {
+      "name": "build",
+      "dependsOn": [
+        "install",
+        "setup"
+      ],
+      "cmds": [
+        "haunt build"
+      ]
+    },
+    "setup": {
+      "name": "setup",
+      "nixPkgs": [
+        "haunt",
+        "guile"
+      ],
+      "nixOverlays": [],
+      "nixpkgsArchive": "[archive]"
+    }
+  },
+  "start": {
+    "cmd": "guile init.scm --auto-compile"
+  }
+}