Allow for custom Containerfile adding

src/lib.rs

@@ -1,9 +1,13 @@
-use std::{fs, path::PathBuf};
+use std::{
+    collections::HashMap,
+    fs::{self, read_to_string},
+    path::PathBuf,
+};
 
 use anyhow::Result;
 use clap::{Parser, Subcommand};
 use recipe::Recipe;
-use tera::{Context, Tera};
+use tera::{from_value, Context, Function, Tera};
 
 pub const DEFAULT_CONTAINERFILE: &'static str =
     include_str!("../templates/starting_point.template");
@@ -37,6 +41,22 @@ pub enum CommandArgs {
     },
 }
 
+fn print_containerfile() -> impl Function {
+    Box::new(
+        |args: &HashMap<String, tera::Value>| -> tera::Result<tera::Value> {
+            match args.get("containerfile") {
+                Some(v) => match from_value::<String>(v.clone()) {
+                    Ok(containerfile) => {
+                        Ok(read_to_string(format!("containerfiles/{containerfile}"))?.into())
+                    }
+                    Err(_) => Err("Arg containerfile wasn't a string".into()),
+                },
+                None => Err("Needs the argument 'containerfile'".into()),
+            }
+        },
+    )
+}
+
 pub fn setup_tera(recipe: String) -> Result<(Tera, Context)> {
     let recipe_de =
         serde_yaml::from_str::<Recipe>(fs::read_to_string(PathBuf::from(&recipe))?.as_str())?
@@ -47,6 +67,7 @@ pub fn setup_tera(recipe: String) -> Result<(Tera, Context)> {
 
     let mut tera = Tera::default();
     tera.add_raw_template("Containerfile", DEFAULT_CONTAINERFILE)?;
+    tera.register_function("print_containerfile", print_containerfile());
 
     Ok((tera, context))
 }