Return error when layer is missing

heroku · Feb 26, 2024 · 2a6bc55 · 2a6bc55
1 parent c72e304
commit 2a6bc55
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Showing 2 changed files with 33 additions and 7 deletions.
diff --git a/libcnb/src/error.rs b/libcnb/src/error.rs
@@ -1,7 +1,7 @@
 use crate::data::launch::ProcessTypeError;
 use crate::layer::{
     DeleteLayerError, HandleLayerError, ReadLayerError, ReplaceLayerExecdProgramsError,
-    WriteLayerMetadataError,
+    ReplaceLayerSbomsError, WriteLayerMetadataError,
 };
 use libcnb_common::toml_file::TomlFileError;
 use std::fmt::Debug;
@@ -30,7 +30,7 @@ pub enum Error<E> {
     ReplaceLayerExecdProgramsError(#[from] ReplaceLayerExecdProgramsError),
 
     #[error("Couldn't replace SBOMs of layer: {0}")]
-    ReplaceLayerSbomsError(#[from] std::io::Error),
+    ReplaceLayerSbomsError(#[from] ReplaceLayerSbomsError),
 
     #[error("Process type error: {0}")]
     ProcessTypeError(#[from] ProcessTypeError),

diff --git a/libcnb/src/layer/handling.rs b/libcnb/src/layer/handling.rs
@@ -247,6 +247,9 @@ pub enum WriteLayerError {
     #[error("{0}")]
     WriteLayerEnvError(#[from] std::io::Error),
 
+    #[error("{0}")]
+    ReplaceLayerSbomsError(#[from] ReplaceLayerSbomsError),
+
     #[error("{0}")]
     WriteLayerMetadataError(#[from] WriteLayerMetadataError),
 
@@ -261,6 +264,18 @@ pub enum ReplaceLayerExecdProgramsError {
 
     #[error("Couldn't find exec.d file for copying: {0}")]
     MissingExecDFile(PathBuf),
+
+    #[error("Layer doesn't exist: {0}")]
+    MissingLayer(LayerName),
+}
+
+#[derive(thiserror::Error, Debug)]
+pub enum ReplaceLayerSbomsError {
+    #[error("Layer doesn't exist: {0}")]
+    MissingLayer(LayerName),
+
+    #[error("Unexpected I/O error while replacing layer SBOMs: {0}")]
+    IoError(#[from] std::io::Error),
 }
 
 #[derive(Debug)]
@@ -293,18 +308,22 @@ pub(crate) fn replace_layer_sboms<P: AsRef<Path>>(
     layers_dir: P,
     layer_name: &LayerName,
     sboms: &[Sbom],
-) -> Result<(), std::io::Error> {
+) -> Result<(), ReplaceLayerSbomsError> {
+    let layers_dir = layers_dir.as_ref();
+
+    if !layers_dir.join(layer_name.as_str()).is_dir() {
+        return Err(ReplaceLayerSbomsError::MissingLayer(layer_name.clone()));
+    }
+
     for format in SBOM_FORMATS {
         default_on_not_found(fs::remove_file(cnb_sbom_path(
-            format,
-            &layers_dir,
-            layer_name,
+            format, layers_dir, layer_name,
         )))?;
     }
 
     for sbom in sboms {
         fs::write(
-            cnb_sbom_path(&sbom.format, &layers_dir, layer_name),
+            cnb_sbom_path(&sbom.format, layers_dir, layer_name),
             &sbom.data,
         )?;
     }
@@ -318,6 +337,13 @@ pub(crate) fn replace_layer_exec_d_programs<P: AsRef<Path>>(
     exec_d_programs: &HashMap<String, PathBuf>,
 ) -> Result<(), ReplaceLayerExecdProgramsError> {
     let layer_dir = layers_dir.as_ref().join(layer_name.as_str());
+
+    if !layer_dir.is_dir() {
+        return Err(ReplaceLayerExecdProgramsError::MissingLayer(
+            layer_name.clone(),
+        ));
+    }
+
     let exec_d_dir = layer_dir.join("exec.d");
 
     if exec_d_dir.is_dir() {