google_cloud_bigquery/write/
committed.rs

1// Copyright 2026 Google LLC
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     https://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15use super::base::BaseWriter;
16use super::format::DataFormat;
17use crate::Result;
18use crate::model::FinalizeWriteStreamResponse;
19use crate::write::builder::AppendWithOffset;
20use crate::write::transport::Transport;
21use std::sync::Arc;
22
23/// A writer for a [committed stream].
24///
25/// In a committed stream, records are available for reading immediately as you
26/// write them to the stream. Use this type for streaming workloads that need
27/// minimal read latency and exactly-once semantics through the use of stream
28/// offsets.
29///
30/// [committed stream]: https://docs.cloud.google.com/bigquery/docs/write-api-grpc#committed_type
31#[derive(Debug)]
32pub struct CommittedWriter<F> {
33    pub(crate) inner: BaseWriter<F>,
34}
35
36impl<F> CommittedWriter<F>
37where
38    F: DataFormat,
39{
40    pub(crate) fn new(inner: Arc<Transport>, write_stream: String, format: F) -> Self {
41        Self {
42            inner: BaseWriter::new(inner, write_stream, format),
43        }
44    }
45
46    /// Returns the full resource name of the underlying write stream.
47    pub fn write_stream(&self) -> &str {
48        &self.inner.write_stream
49    }
50
51    /// Appends rows to the committed stream.
52    pub fn append(&self, rows: F::Rows) -> AppendWithOffset {
53        AppendWithOffset::new(
54            self.inner.runner.req_tx.clone(),
55            self.inner.append_request(rows),
56        )
57    }
58
59    /// Finalizes the stream, preventing further writes.
60    pub async fn finalize(&self) -> Result<FinalizeWriteStreamResponse> {
61        self.inner.finalize().await
62    }
63}
64
65#[cfg(test)]
66mod tests {
67    use super::*;
68    use crate::error::AppendError;
69    use crate::write::test::*;
70    use bigquery_grpc_mock::{MockBigQueryWrite, start};
71    use gaxi::grpc::tonic::Response as TonicResponse;
72    use tokio::sync::mpsc;
73
74    #[tokio::test]
75    async fn basic_success() -> anyhow::Result<()> {
76        let (response_tx, response_rx) = mpsc::channel(10);
77
78        let mut mock = MockBigQueryWrite::new();
79        mock.expect_append_rows()
80            .return_once(|_| Ok(TonicResponse::from(response_rx)));
81
82        mock.expect_finalize_write_stream().return_once(|_| {
83            Ok(TonicResponse::new(
84                bigquery_grpc_mock::google::cloud::bigquery::storage::v1::FinalizeWriteStreamResponse::default(),
85            ))
86        });
87
88        let (endpoint, _server) = start("0.0.0.0:0", mock).await?;
89        let transport = Arc::new(test_transport(endpoint).await?);
90
91        let writer = CommittedWriter::new(transport, write_stream(), format());
92        assert_eq!(writer.write_stream(), write_stream());
93
94        response_tx.send(Ok(convert(&test_response(1)))).await?;
95        let resp = writer.append(rows(1)).send().await?;
96        assert_eq!(resp.offset, Some(1));
97
98        response_tx.send(Ok(convert(&test_response(2)))).await?;
99        let resp = writer.append(rows(2)).send().await?;
100        assert_eq!(resp.offset, Some(2));
101
102        response_tx.send(Ok(convert(&test_response(3)))).await?;
103        let resp = writer.append(rows(3)).send().await?;
104        assert_eq!(resp.offset, Some(3));
105
106        drop(response_tx);
107        let err = writer.append(rows(4)).send().await.expect_err("channel");
108        assert!(matches!(err, AppendError::UnexpectedEndOfStream));
109
110        // We can still finalize the stream even if row appends hit a closed bidirectional stream
111        writer.finalize().await?;
112
113        Ok(())
114    }
115}
google_cloud_bigquery/write/committed.rs

google_cloud_bigquery/write/
committed.rs
