chore: validate parquet before and after upload to object store (#1432)

after parquet file creation -
1. validate if file size > FOOTER_SIZE
2. read the file and validate if num_rows > 0

after parquet file upload to object store -
1. perform a head() to get the metadata of the file
validate if file size = file size of the parquet from staging directory

Fixes: #1430

Author: nikhilsinhaparseable

src/parseable/streams.rs

@@ -34,7 +34,10 @@ use itertools::Itertools;
 use parquet::{
     arrow::ArrowWriter,
     basic::Encoding,
-    file::{FOOTER_SIZE, properties::WriterProperties},
+    file::{
+        FOOTER_SIZE, properties::WriterProperties, reader::FileReader,
+        serialized_reader::SerializedFileReader,
+    },
     format::SortingColumn,
     schema::types::ColumnPath,
 };
@@ -409,7 +412,7 @@ impl Stream {
             .map(|file| file.path())
             .filter(|file| {
                 file.extension().is_some_and(|ext| ext.eq("parquet"))
-                    && std::fs::metadata(file).is_ok_and(|meta| meta.len() > FOOTER_SIZE as u64)
+                    && Self::is_valid_parquet_file(file, &self.stream_name)
             })
             .collect()
     }
@@ -649,7 +652,7 @@ impl Stream {
                 continue;
             }
 
-            if let Err(e) = self.finalize_parquet_file(&part_path, &parquet_path) {
+            if let Err(e) = std::fs::rename(&part_path, &parquet_path) {
                 error!("Couldn't rename part file: {part_path:?} -> {parquet_path:?}, error = {e}");
             } else {
                 self.cleanup_arrow_files_and_dir(&arrow_files);
@@ -682,12 +685,10 @@ impl Stream {
         }
         writer.close()?;
 
-        if part_file.metadata().expect("File was just created").len()
-            < parquet::file::FOOTER_SIZE as u64
-        {
+        if !Self::is_valid_parquet_file(part_path, &self.stream_name) {
             error!(
-                "Invalid parquet file {part_path:?} detected for stream {}, removing it",
-                &self.stream_name
+                "Invalid parquet file {part_path:?} detected for stream {stream_name}, removing it",
+                stream_name = &self.stream_name
             );
             remove_file(part_path).expect("File should be removable if it is invalid");
             return Ok(false);
@@ -696,8 +697,47 @@ impl Stream {
         Ok(true)
     }
 
-    fn finalize_parquet_file(&self, part_path: &Path, parquet_path: &Path) -> std::io::Result<()> {
-        std::fs::rename(part_path, parquet_path)
+    /// function to validate parquet files
+    fn is_valid_parquet_file(path: &Path, stream_name: &str) -> bool {
+        // First check file size as a quick validation
+        match path.metadata() {
+            Ok(meta) if meta.len() < FOOTER_SIZE as u64 => {
+                error!(
+                    "Invalid parquet file {path:?} detected for stream {stream_name}, size: {} bytes",
+                    meta.len()
+                );
+                return false;
+            }
+            Err(e) => {
+                error!(
+                    "Cannot read metadata for parquet file {path:?} for stream {stream_name}: {e}"
+                );
+                return false;
+            }
+            _ => {} // File size is adequate, continue validation
+        }
+
+        // Try to open and read the parquet file metadata to verify it's valid
+        match std::fs::File::open(path) {
+            Ok(file) => match SerializedFileReader::new(file) {
+                Ok(reader) => {
+                    if reader.metadata().file_metadata().num_rows() == 0 {
+                        error!("Invalid parquet file {path:?} for stream {stream_name}");
+                        false
+                    } else {
+                        true
+                    }
+                }
+                Err(e) => {
+                    error!("Failed to read parquet file {path:?} for stream {stream_name}: {e}");
+                    false
+                }
+            },
+            Err(e) => {
+                error!("Failed to open parquet file {path:?} for stream {stream_name}: {e}");
+                false
+            }
+        }
     }
 
     fn cleanup_arrow_files_and_dir(&self, arrow_files: &[PathBuf]) {
@@ -951,7 +991,10 @@ impl Stream {
         shutdown_signal: bool,
     ) -> Result<(), StagingError> {
         let start_flush = Instant::now();
-        self.flush(shutdown_signal);
+        // Force flush for init or shutdown signals to convert all .part files to .arrows
+        // For regular cycles, use false to only flush non-current writers
+        let forced = init_signal || shutdown_signal;
+        self.flush(forced);
         trace!(
             "Flushing stream ({}) took: {}s",
             self.stream_name,

src/storage/object_storage.rs

@@ -106,6 +106,12 @@ async fn upload_single_parquet_file(
         .to_str()
         .expect("filename is valid string");
 
+    // Get the local file size for validation
+    let local_file_size = path
+        .metadata()
+        .map_err(|e| ObjectStorageError::Custom(format!("Failed to get local file metadata: {e}")))?
+        .len();
+
     // Upload the file
     store
         .upload_multipart(&RelativePathBuf::from(&stream_relative_path), &path)
@@ -115,6 +121,27 @@ async fn upload_single_parquet_file(
             ObjectStorageError::Custom(format!("Failed to upload {filename}: {e}"))
         })?;
 
+    // Validate the uploaded file size matches local file
+    let upload_is_valid = validate_uploaded_parquet_file(
+        &store,
+        &stream_relative_path,
+        local_file_size,
+        &stream_name,
+    )
+    .await?;
+
+    if !upload_is_valid {
+        // Upload validation failed, clean up the uploaded file and return error
+        let _ = store
+            .delete_object(&RelativePathBuf::from(&stream_relative_path))
+            .await;
+        error!("Upload size validation failed for file {filename:?}, deleted from object storage");
+        return Ok(UploadResult {
+            file_path: path,
+            manifest_file: None, // Preserve staging file for retry; no manifest created
+        });
+    }
+
     // Update storage metrics
     update_storage_metrics(&path, &stream_name, filename)?;
 
@@ -177,6 +204,44 @@ async fn calculate_stats_if_enabled(
     }
 }
 
+/// Validates that a parquet file uploaded to object storage matches the staging file size
+async fn validate_uploaded_parquet_file(
+    store: &Arc<dyn ObjectStorage>,
+    stream_relative_path: &str,
+    expected_size: u64,
+    stream_name: &str,
+) -> Result<bool, ObjectStorageError> {
+    // Verify the file exists and has the expected size
+    match store
+        .head(&RelativePathBuf::from(stream_relative_path))
+        .await
+    {
+        Ok(metadata) => {
+            if metadata.size as u64 != expected_size {
+                warn!(
+                    "Uploaded file size mismatch for stream {}: expected {}, got {}",
+                    stream_name, expected_size, metadata.size
+                );
+                Ok(false)
+            } else {
+                tracing::trace!(
+                    "Uploaded parquet file size validated successfully for stream {}, size: {}",
+                    stream_name,
+                    expected_size
+                );
+                Ok(true)
+            }
+        }
+        Err(e) => {
+            error!(
+                "Failed to get metadata for uploaded file in stream {}: {e}",
+                stream_name
+            );
+            Ok(false)
+        }
+    }
+}
+
 pub trait ObjectStorageProvider: StorageMetrics + std::fmt::Debug + Send + Sync {
     fn get_datafusion_runtime(&self) -> RuntimeEnvBuilder;
     fn construct_client(&self) -> Arc<dyn ObjectStorage>;
@@ -880,14 +945,15 @@ async fn collect_upload_results(
                 if let Some(manifest_file) = upload_result.manifest_file {
                     uploaded_files.push((upload_result.file_path, manifest_file));
                 } else {
-                    // File failed to upload, clean up
-                    if let Err(e) = remove_file(upload_result.file_path) {
-                        warn!("Failed to remove staged file: {e}");
-                    }
+                    // File failed in upload size validation, preserve staging file for retry
+                    error!(
+                        "Parquet file upload size validation failed for {:?}, preserving in staging for retry",
+                        upload_result.file_path
+                    );
                 }
             }
             Ok(Err(e)) => {
-                error!("Error processing parquet file: {e}");
+                error!("Error uploading parquet file: {e}");
                 return Err(e);
             }
             Err(e) => {