refactor(error): improve error messages and file handling

- Update error messages for file operations in the `LocalBackendErrorKind` enum. - Refactor the `ReadBackend` and `WriteBackend` implementations in the `LocalBackend` module to handle file opening errors more accurately. - Add error variants `OpeningFileForPartialReadingFailed` and `OpeningFileForWritingFailed` to provide specific information about file opening failures. - Create parent directory if it does not exist before opening the file for writing. Fixes #rustic-rs/rustic#1315 Signed-off-by: simonsan <[email protected]>
rustic-rs · Oct 14, 2024 · ac73cc1 · ac73cc1
1 parent 2b32031
commit ac73cc1
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diff --git a/crates/backend/src/error.rs b/crates/backend/src/error.rs
@@ -117,8 +117,20 @@ pub enum LocalBackendErrorKind {
     FromWalkdirError(#[from] walkdir::Error),
     /// removing file failed: `{0:?}`
     FileRemovalFailed(std::io::Error),
-    /// opening file failed: `{0:?}`
-    OpeningFileFailed(std::io::Error),
+    /// Writing to file failed: `{path}` : `{source}`
+    OpeningFileForPartialReadingFailed {
+        /// Path to file
+        path: std::path::PathBuf,
+        /// Source of the error
+        source: std::io::Error,
+    },
+    /// Writing to file failed: `{path}` : `{source}`
+    OpeningFileForWritingFailed {
+        /// Path to file
+        path: std::path::PathBuf,
+        /// Source of the error
+        source: std::io::Error,
+    },
     /// setting file length failed: `{0:?}`
     SettingFileLengthFailed(std::io::Error),
     /// can't jump to position in file: `{0:?}`

diff --git a/crates/backend/src/local.rs b/crates/backend/src/local.rs
@@ -259,12 +259,12 @@ impl ReadBackend for LocalBackend {
     ///
     /// # Errors
     ///
-    /// * [`LocalBackendErrorKind::OpeningFileFailed`] - If the file could not be opened.
+    /// * [`LocalBackendErrorKind::OpeningFileForPartialReadingFailed`] - If the file could not be opened for partial reading.
     /// * [`LocalBackendErrorKind::CouldNotSeekToPositionInFile`] - If the file could not be seeked to the given position.
     /// * [`LocalBackendErrorKind::FromTryIntError`] - If the length of the file could not be converted to u32.
     /// * [`LocalBackendErrorKind::ReadingExactLengthOfFileFailed`] - If the length of the file could not be read.
     ///
-    /// [`LocalBackendErrorKind::OpeningFileFailed`]: LocalBackendErrorKind::OpeningFileFailed
+    /// [`LocalBackendErrorKind::OpeningFileForPartialReadingFailed`]: LocalBackendErrorKind::OpeningFileForPartialReadingFailed
     /// [`LocalBackendErrorKind::CouldNotSeekToPositionInFile`]: LocalBackendErrorKind::CouldNotSeekToPositionInFile
     /// [`LocalBackendErrorKind::FromTryIntError`]: LocalBackendErrorKind::FromTryIntError
     /// [`LocalBackendErrorKind::ReadingExactLengthOfFileFailed`]: LocalBackendErrorKind::ReadingExactLengthOfFileFailed
@@ -277,8 +277,13 @@ impl ReadBackend for LocalBackend {
         length: u32,
     ) -> Result<Bytes> {
         trace!("reading tpe: {tpe:?}, id: {id}, offset: {offset}, length: {length}");
-        let mut file =
-            File::open(self.path(tpe, id)).map_err(LocalBackendErrorKind::OpeningFileFailed)?;
+        let filename = self.path(tpe, id);
+        let mut file = File::open(&filename).map_err(|err| {
+            LocalBackendErrorKind::OpeningFileForPartialReadingFailed {
+                path: filename,
+                source: err,
+            }
+        })?;
         _ = file
             .seek(SeekFrom::Start(offset.into()))
             .map_err(LocalBackendErrorKind::CouldNotSeekToPositionInFile)?;
@@ -328,26 +333,36 @@ impl WriteBackend for LocalBackend {
     ///
     /// # Errors
     ///
-    /// * [`LocalBackendErrorKind::OpeningFileFailed`] - If the file could not be opened.
+    /// * [`LocalBackendErrorKind::OpeningFileForWritingFailed`] - If the file could not be opened for writing.
     /// * [`LocalBackendErrorKind::FromTryIntError`] - If the length of the bytes could not be converted to u64.
     /// * [`LocalBackendErrorKind::SettingFileLengthFailed`] - If the length of the file could not be set.
     /// * [`LocalBackendErrorKind::CouldNotWriteToBuffer`] - If the bytes could not be written to the file.
     /// * [`LocalBackendErrorKind::SyncingOfOsMetadataFailed`] - If the metadata of the file could not be synced.
     ///
-    /// [`LocalBackendErrorKind::OpeningFileFailed`]: LocalBackendErrorKind::OpeningFileFailed
+    /// [`LocalBackendErrorKind::OpeningFileForWritingFailed`]: LocalBackendErrorKind::OpeningFileForWritingFailed
     /// [`LocalBackendErrorKind::FromTryIntError`]: LocalBackendErrorKind::FromTryIntError
     /// [`LocalBackendErrorKind::SettingFileLengthFailed`]: LocalBackendErrorKind::SettingFileLengthFailed
     /// [`LocalBackendErrorKind::CouldNotWriteToBuffer`]: LocalBackendErrorKind::CouldNotWriteToBuffer
     /// [`LocalBackendErrorKind::SyncingOfOsMetadataFailed`]: LocalBackendErrorKind::SyncingOfOsMetadataFailed
     fn write_bytes(&self, tpe: FileType, id: &Id, _cacheable: bool, buf: Bytes) -> Result<()> {
         trace!("writing tpe: {:?}, id: {}", &tpe, &id);
         let filename = self.path(tpe, id);
+
+        // create parent directory if it does not exist
+        if let Some(parent) = filename.parent() {
+            fs::create_dir_all(parent).map_err(LocalBackendErrorKind::DirectoryCreationFailed)?;
+        }
+
         let mut file = fs::OpenOptions::new()
             .create(true)
             .truncate(true)
             .write(true)
             .open(&filename)
-            .map_err(LocalBackendErrorKind::OpeningFileFailed)?;
+            .map_err(|err| LocalBackendErrorKind::OpeningFileForWritingFailed {
+                path: filename.clone(),
+                source: err,
+            })?;
+
         file.set_len(
             buf.len()
                 .try_into()