feat: implement AvroWriter Write method

src/iceberg/avro/avro_stream_internal.cc

@@ -145,4 +145,8 @@ void AvroOutputStream::flush() {
   }
 }
 
+std::shared_ptr<::arrow::io::OutputStream> AvroOutputStream::get_output_stream() const {
+  return output_stream_;
+}
+
 }  // namespace iceberg::avro

src/iceberg/avro/avro_stream_internal.h

@@ -87,6 +87,8 @@ class AvroOutputStream : public ::avro::OutputStream {
   /// store, if any.
   void flush() override;
 
+  std::shared_ptr<::arrow::io::OutputStream> get_output_stream() const;
+
  private:
   std::shared_ptr<::arrow::io::OutputStream> output_stream_;
   const int64_t buffer_size_;

src/iceberg/avro/avro_writer.cc

@@ -26,14 +26,17 @@
 #include <arrow/record_batch.h>
 #include <arrow/result.h>
 #include <avro/DataFile.hh>
+#include <avro/Generic.hh>
 #include <avro/GenericDatum.hh>
 
 #include "iceberg/arrow/arrow_error_transform_internal.h"
 #include "iceberg/arrow/arrow_fs_file_io_internal.h"
+#include "iceberg/avro/avro_data_util_internal.h"
 #include "iceberg/avro/avro_register.h"
 #include "iceberg/avro/avro_schema_util_internal.h"
 #include "iceberg/avro/avro_stream_internal.h"
 #include "iceberg/schema.h"
+#include "iceberg/schema_internal.h"
 #include "iceberg/util/checked_cast.h"
 #include "iceberg/util/macros.h"
 
@@ -67,22 +70,32 @@ class AvroWriter::Impl {
     constexpr int64_t kDefaultBufferSize = 1024 * 1024;
     ICEBERG_ASSIGN_OR_RAISE(auto output_stream,
                             CreateOutputStream(options, kDefaultBufferSize));
-
+    arrow_output_stream_ = output_stream->get_output_stream();
     writer_ = std::make_unique<::avro::DataFileWriter<::avro::GenericDatum>>(
         std::move(output_stream), *avro_schema_);
+    datum_ = std::make_unique<::avro::GenericDatum>(*avro_schema_);
+    ICEBERG_RETURN_UNEXPECTED(ToArrowSchema(*write_schema_, &arrow_schema_));
     return {};
   }
 
-  Status Write(ArrowArray /*data*/) {
-    // TODO(xiao.dong) convert data and write to avro
-    // total_bytes_+= written_bytes;
+  Status Write(ArrowArray data) {
+    ICEBERG_ARROW_ASSIGN_OR_RETURN(auto result,
+                                   ::arrow::ImportArray(&data, &arrow_schema_));
+
+    for (int64_t i = 0; i < result->length(); i++) {
+      ICEBERG_RETURN_UNEXPECTED(ExtractDatumFromArray(*result, i, datum_.get()));
+      writer_->write(*datum_);
+    }
+
     return {};
   }
 
   Status Close() {
     if (writer_ != nullptr) {
       writer_->close();
       writer_.reset();
+      ICEBERG_ARROW_ASSIGN_OR_RETURN(total_bytes_, arrow_output_stream_->Tell());
+      ICEBERG_ARROW_RETURN_NOT_OK(arrow_output_stream_->Close());
     }
     return {};
   }
@@ -99,6 +112,12 @@ class AvroWriter::Impl {
   std::shared_ptr<::avro::ValidSchema> avro_schema_;
   // The avro writer to write the data into a datum.
   std::unique_ptr<::avro::DataFileWriter<::avro::GenericDatum>> writer_;
+  // Arrow schema for data conversion (C API format)
+  ArrowSchema arrow_schema_;
+  // Reusable Avro datum for writing individual records
+  std::unique_ptr<::avro::GenericDatum> datum_;
+  // Arrow output stream for writing data to filesystem
+  std::shared_ptr<::arrow::io::OutputStream> arrow_output_stream_;
 };
 
 AvroWriter::~AvroWriter() = default;

test/avro_test.cc

@@ -19,7 +19,6 @@
 
 #include <arrow/array/array_base.h>
 #include <arrow/c/bridge.h>
-#include <arrow/c/helpers.h>
 #include <arrow/filesystem/localfs.h>
 #include <arrow/io/file.h>
 #include <arrow/json/from_string.h>
@@ -31,8 +30,10 @@
 
 #include "iceberg/arrow/arrow_fs_file_io_internal.h"
 #include "iceberg/avro/avro_register.h"
+#include "iceberg/avro/avro_writer.h"
 #include "iceberg/file_reader.h"
 #include "iceberg/schema.h"
+#include "iceberg/schema_internal.h"
 #include "iceberg/type.h"
 #include "matchers.h"
 #include "temp_file_test_base.h"
@@ -105,6 +106,44 @@ class AvroReaderTest : public TempFileTestBase {
     ASSERT_FALSE(data.value().has_value());
   }
 
+  void WriteAndVerify(std::shared_ptr<Schema> schema,
+                      const std::string& expected_string) {
+    ArrowSchema arrow_c_schema;
+    ASSERT_THAT(ToArrowSchema(*schema, &arrow_c_schema), IsOk());
+
+    auto arrow_schema_result = ::arrow::ImportType(&arrow_c_schema);
+    ASSERT_TRUE(arrow_schema_result.ok());
+    auto arrow_schema = arrow_schema_result.ValueOrDie();
+
+    auto array_result = ::arrow::json::ArrayFromJSONString(arrow_schema, expected_string);
+    ASSERT_TRUE(array_result.ok());
+    auto array = array_result.ValueOrDie();
+
+    struct ArrowArray arrow_array;
+    auto export_result = ::arrow::ExportArray(*array, &arrow_array);
+    ASSERT_TRUE(export_result.ok());
+
+    auto writer_result = WriterFactoryRegistry::Open(
+        FileFormatType::kAvro,
+        {.path = temp_avro_file_, .schema = schema, .io = file_io_});
+    ASSERT_TRUE(writer_result.has_value());
+    auto writer = std::move(writer_result.value());
+    ASSERT_THAT(writer->Write(arrow_array), IsOk());
+    ASSERT_THAT(writer->Close(), IsOk());
+
+    auto file_info_result = local_fs_->GetFileInfo(temp_avro_file_);
+    ASSERT_TRUE(file_info_result.ok());
+    ASSERT_EQ(file_info_result->size(), writer->length().value());
+
+    auto reader_result = ReaderFactoryRegistry::Open(
+        FileFormatType::kAvro,
+        {.path = temp_avro_file_, .io = file_io_, .projection = schema});
+    ASSERT_THAT(reader_result, IsOk());
+    auto reader = std::move(reader_result.value());
+    ASSERT_NO_FATAL_FAILURE(VerifyNextBatch(*reader, expected_string));
+    ASSERT_NO_FATAL_FAILURE(VerifyExhausted(*reader));
+  }
+
   std::shared_ptr<::arrow::fs::LocalFileSystem> local_fs_;
   std::shared_ptr<FileIO> file_io_;
   std::string temp_avro_file_;
@@ -161,4 +200,28 @@ TEST_F(AvroReaderTest, ReadWithBatchSize) {
   ASSERT_NO_FATAL_FAILURE(VerifyExhausted(*reader));
 }
 
+TEST_F(AvroReaderTest, AvroWriterBasicType) {
+  auto schema = std::make_shared<iceberg::Schema>(std::vector<SchemaField>{
+      SchemaField::MakeRequired(1, "name", std::make_shared<StringType>())});
+
+  std::string expected_string = R"([["Hello"], ["世界"], ["nanoarrow"]])";
+
+  WriteAndVerify(schema, expected_string);
+}
+
+TEST_F(AvroReaderTest, AvroWriterNestedType) {
+  auto schema = std::make_shared<iceberg::Schema>(std::vector<SchemaField>{
+      SchemaField::MakeRequired(1, "id", std::make_shared<IntType>()),
+      SchemaField::MakeRequired(
+          2, "info",
+          std::make_shared<iceberg::StructType>(std::vector<SchemaField>{
+              SchemaField::MakeRequired(3, "name", std::make_shared<StringType>()),
+              SchemaField::MakeRequired(4, "age", std::make_shared<IntType>())}))});
+
+  std::string expected_string =
+      R"([[1, ["Alice", 25]], [2, ["Bob", 30]], [3, ["Ivy", 35]]])";
+
+  WriteAndVerify(schema, expected_string);
+}
+
 }  // namespace iceberg::avro