Expose overwrite_layer_sboms in BuildContext

libcnb/src/build.rs

@@ -140,6 +140,15 @@ impl<B: Buildpack + ?Sized> BuildContext<B> {
         )
         .map_err(crate::Error::OverwriteLayerExecdError)
     }
+
+    pub fn overwrite_layer_sboms(
+        &self,
+        layer_name: impl AsRef<LayerName>,
+        sboms: &[Sbom],
+    ) -> crate::Result<(), B::Error> {
+        crate::layer::overwrite_layer_sboms(&self.layers_dir, layer_name.as_ref(), sboms)
+            .map_err(crate::Error::OverwriteLayerSbomsError)
+    }
 }
 
 /// Describes the result of the build phase.

libcnb/src/error.rs

@@ -23,6 +23,9 @@ pub enum Error<E> {
     #[error("Couldn't write exec.d programs to layer: {0}")]
     OverwriteLayerExecdError(#[from] OverwriteLayerExecdError),
 
+    #[error("Couldn't write sboms to layer: {0}")]
+    OverwriteLayerSbomsError(#[from] std::io::Error),
+
     #[error("Process type error: {0}")]
     ProcessTypeError(#[from] ProcessTypeError),
 

libcnb/src/layer/handling.rs

@@ -280,7 +280,7 @@ pub(crate) fn delete_layer<P: AsRef<Path>>(
     Ok(())
 }
 
-fn write_layer_sboms<P: AsRef<Path>>(
+pub(crate) fn overwrite_layer_sboms<P: AsRef<Path>>(
     layers_dir: P,
     layer_name: &LayerName,
     sboms: &[Sbom],
@@ -353,7 +353,7 @@ fn write_layer<M: Serialize, P: AsRef<Path>>(
     write_toml_file(&layer_content_metadata, layer_content_metadata_path)?;
 
     match layer_sboms {
-        Sboms::Overwrite(sboms) => write_layer_sboms(layers_dir.as_ref(), layer_name, &sboms)?,
+        Sboms::Overwrite(sboms) => overwrite_layer_sboms(layers_dir.as_ref(), layer_name, &sboms)?,
         Sboms::Keep => {}
     }