Add config option to derive macro so we can specify config file location

3 files changed, 17 insertions, 3 deletions

diff --git a/askama_shared/src/generator.rs b/askama_shared/src/generator.rs
index a09631c..9aec1d6 100644
--- a/askama_shared/src/generator.rs
+++ b/askama_shared/src/generator.rs
@@ -29,7 +29,7 @@ pub fn derive_template(input: TokenStream) -> TokenStream {
 /// value as passed to the `template()` attribute.
 fn build_template(ast: &syn::DeriveInput) -> Result<String, CompileError> {
     let template_args = TemplateArgs::new(ast)?;
-    let config_toml = read_config_file()?;
+    let config_toml = read_config_file(&template_args.config_path)?;
     let config = Config::new(&config_toml)?;
     let input = TemplateInput::new(ast, &config, template_args)?;
     let source: String = match input.source {
@@ -82,6 +82,7 @@ pub(crate) struct TemplateArgs {
     pub(crate) escaping: Option<String>,
     pub(crate) ext: Option<String>,
     pub(crate) syntax: Option<String>,
+    pub(crate) config_path: Option<String>,
 }
 
 impl TemplateArgs {
@@ -174,6 +175,12 @@ impl TemplateArgs {
                 } else {
                     return Err("syntax value must be string literal".into());
                 }
+            } else if ident == "config" {
+                if let syn::Lit::Str(ref s) = pair.lit {
+                    args.config_path = Some(s.value())
+                } else {
+                    return Err("config value must be string literal".into());
+                }
             } else {
                 return Err(format!("unsupported attribute key {:?} found", ident).into());
             }
diff --git a/askama_shared/src/input.rs b/askama_shared/src/input.rs
index 6c49156..350fc01 100644
--- a/askama_shared/src/input.rs
+++ b/askama_shared/src/input.rs
@@ -35,6 +35,7 @@ impl TemplateInput<'_> {
             escaping,
             ext,
             syntax,
+            ..
         } = args;
 
         // Validate the `source` and `ext` value together, since they are
diff --git a/askama_shared/src/lib.rs b/askama_shared/src/lib.rs
index 2aa7114..07331bc 100644
--- a/askama_shared/src/lib.rs
+++ b/askama_shared/src/lib.rs
@@ -327,12 +327,18 @@ struct RawEscaper<'a> {
     extensions: Vec<&'a str>,
 }
 
-fn read_config_file() -> std::result::Result<String, CompileError> {
+fn read_config_file(config_path: &Option<String>) -> std::result::Result<String, CompileError> {
     let root = PathBuf::from(env::var("CARGO_MANIFEST_DIR").unwrap());
-    let filename = root.join(CONFIG_FILE_NAME);
+    let filename = match config_path {
+        Some(config_path) => root.join(config_path),
+        None => root.join(CONFIG_FILE_NAME),
+    };
+
     if filename.exists() {
         fs::read_to_string(&filename)
             .map_err(|_| format!("unable to read {:?}", filename.to_str().unwrap()).into())
+    } else if config_path.is_some() {
+        Err(format!("`{}` does not exist", root.display()).into())
     } else {
         Ok("".to_string())
     }