about summary refs log tree commit diff
path: root/tvix/castore/src/blobservice/grpc.rs
blob: 834c0c7bf57a80c3e1637fd390fac6a9b214203f (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
use super::{BlobReader, BlobService, BlobWriter, ChunkedReader};
use crate::{
    proto::{self, stat_blob_response::ChunkMeta},
    B3Digest,
};
use futures::sink::SinkExt;
use std::{
    io::{self, Cursor},
    pin::pin,
    sync::Arc,
    task::Poll,
};
use tokio::io::AsyncWriteExt;
use tokio::task::JoinHandle;
use tokio_stream::{wrappers::ReceiverStream, StreamExt};
use tokio_util::{
    io::{CopyToBytes, SinkWriter},
    sync::PollSender,
};
use tonic::{async_trait, Code, Status};
use tracing::{instrument, Instrument as _};

/// Connects to a (remote) tvix-store BlobService over gRPC.
#[derive(Clone)]
pub struct GRPCBlobService<T> {
    /// The internal reference to a gRPC client.
    /// Cloning it is cheap, and it internally handles concurrent requests.
    grpc_client: proto::blob_service_client::BlobServiceClient<T>,
}

impl<T> GRPCBlobService<T> {
    /// construct a [GRPCBlobService] from a [proto::blob_service_client::BlobServiceClient].
    /// panics if called outside the context of a tokio runtime.
    pub fn from_client(grpc_client: proto::blob_service_client::BlobServiceClient<T>) -> Self {
        Self { grpc_client }
    }
}

#[async_trait]
impl<T> BlobService for GRPCBlobService<T>
where
    T: tonic::client::GrpcService<tonic::body::BoxBody> + Send + Sync + Clone + 'static,
    T::ResponseBody: tonic::codegen::Body<Data = tonic::codegen::Bytes> + Send + 'static,
    <T::ResponseBody as tonic::codegen::Body>::Error: Into<tonic::codegen::StdError> + Send,
    T::Future: Send,
{
    #[instrument(skip(self, digest), fields(blob.digest=%digest))]
    async fn has(&self, digest: &B3Digest) -> io::Result<bool> {
        let mut grpc_client = self.grpc_client.clone();
        let resp = grpc_client
            .stat(proto::StatBlobRequest {
                digest: digest.clone().into(),
                ..Default::default()
            })
            .await;

        match resp {
            Ok(_blob_meta) => Ok(true),
            Err(e) if e.code() == Code::NotFound => Ok(false),
            Err(e) => Err(io::Error::new(io::ErrorKind::Other, e)),
        }
    }

    #[instrument(skip(self, digest), fields(blob.digest=%digest), err)]
    async fn open_read(&self, digest: &B3Digest) -> io::Result<Option<Box<dyn BlobReader>>> {
        // First try to get a list of chunks. In case there's only one chunk returned,
        // buffer its data into a Vec, otherwise use a ChunkedReader.
        // We previously used NaiveSeeker here, but userland likes to seek backwards too often,
        // and without store composition this will get very noisy.
        // FUTUREWORK: use CombinedBlobService and store composition.
        match self.chunks(digest).await {
            Ok(None) => Ok(None),
            Ok(Some(chunks)) => {
                if chunks.is_empty() || chunks.len() == 1 {
                    // No more granular chunking info, treat this as an individual chunk.
                    // Get a stream of [proto::BlobChunk], or return an error if the blob
                    // doesn't exist.
                    return match self
                        .grpc_client
                        .clone()
                        .read(proto::ReadBlobRequest {
                            digest: digest.clone().into(),
                        })
                        .await
                    {
                        Ok(stream) => {
                            let data_stream = stream.into_inner().map(|e| {
                                e.map(|c| c.data)
                                    .map_err(|s| std::io::Error::new(io::ErrorKind::InvalidData, s))
                            });

                            // Use StreamReader::new to convert to an AsyncRead.
                            let mut data_reader = tokio_util::io::StreamReader::new(data_stream);

                            let mut buf = Vec::new();
                            // TODO: only do this up to a certain limit.
                            tokio::io::copy(&mut data_reader, &mut buf).await?;

                            Ok(Some(Box::new(Cursor::new(buf))))
                        }
                        Err(e) if e.code() == Code::NotFound => Ok(None),
                        Err(e) => Err(io::Error::new(io::ErrorKind::Other, e)),
                    };
                }

                // The chunked case. Let ChunkedReader do individual reads.
                // TODO: we should store the chunking data in some local cache,
                // so `ChunkedReader` doesn't call `self.chunks` *again* for every chunk.
                // Think about how store composition will fix this.
                let chunked_reader = ChunkedReader::from_chunks(
                    chunks.into_iter().map(|chunk| {
                        (
                            chunk.digest.try_into().expect("invalid b3 digest"),
                            chunk.size,
                        )
                    }),
                    Arc::new(self.clone()) as Arc<dyn BlobService>,
                );
                Ok(Some(Box::new(chunked_reader)))
            }
            Err(e) => Err(e)?,
        }
    }

    /// Returns a BlobWriter, that'll internally wrap each write in a
    /// [proto::BlobChunk], which is send to the gRPC server.
    #[instrument(skip_all)]
    async fn open_write(&self) -> Box<dyn BlobWriter> {
        // set up an mpsc channel passing around Bytes.
        let (tx, rx) = tokio::sync::mpsc::channel::<bytes::Bytes>(10);

        // bytes arriving on the RX side are wrapped inside a
        // [proto::BlobChunk], and a [ReceiverStream] is constructed.
        let blobchunk_stream = ReceiverStream::new(rx).map(|x| proto::BlobChunk { data: x });

        // spawn the gRPC put request, which will read from blobchunk_stream.
        let task = tokio::spawn({
            let mut grpc_client = self.grpc_client.clone();
            async move { Ok::<_, Status>(grpc_client.put(blobchunk_stream).await?.into_inner()) }
                // instrument the task with the current span, this is not done by default
                .in_current_span()
        });

        // The tx part of the channel is converted to a sink of byte chunks.
        let sink = PollSender::new(tx)
            .sink_map_err(|e| std::io::Error::new(std::io::ErrorKind::BrokenPipe, e));

        // … which is turned into an [tokio::io::AsyncWrite].
        let writer = SinkWriter::new(CopyToBytes::new(sink));

        Box::new(GRPCBlobWriter {
            task_and_writer: Some((task, writer)),
            digest: None,
        })
    }

    #[instrument(skip(self, digest), fields(blob.digest=%digest), err)]
    async fn chunks(&self, digest: &B3Digest) -> io::Result<Option<Vec<ChunkMeta>>> {
        let resp = self
            .grpc_client
            .clone()
            .stat(proto::StatBlobRequest {
                digest: digest.clone().into(),
                send_chunks: true,
                ..Default::default()
            })
            .await;

        match resp {
            Err(e) if e.code() == Code::NotFound => Ok(None),
            Err(e) => Err(io::Error::new(io::ErrorKind::Other, e)),
            Ok(resp) => {
                let resp = resp.into_inner();

                resp.validate()
                    .map_err(|e| std::io::Error::new(io::ErrorKind::InvalidData, e))?;

                Ok(Some(resp.chunks))
            }
        }
    }
}

pub struct GRPCBlobWriter<W: tokio::io::AsyncWrite> {
    /// The task containing the put request, and the inner writer, if we're still writing.
    task_and_writer: Option<(JoinHandle<Result<proto::PutBlobResponse, Status>>, W)>,

    /// The digest that has been returned, if we successfully closed.
    digest: Option<B3Digest>,
}

#[async_trait]
impl<W: tokio::io::AsyncWrite + Send + Sync + Unpin + 'static> BlobWriter for GRPCBlobWriter<W> {
    async fn close(&mut self) -> io::Result<B3Digest> {
        if self.task_and_writer.is_none() {
            // if we're already closed, return the b3 digest, which must exist.
            // If it doesn't, we already closed and failed once, and didn't handle the error.
            match &self.digest {
                Some(digest) => Ok(digest.clone()),
                None => Err(io::Error::new(io::ErrorKind::BrokenPipe, "already closed")),
            }
        } else {
            let (task, mut writer) = self.task_and_writer.take().unwrap();

            // invoke shutdown, so the inner writer closes its internal tx side of
            // the channel.
            writer.shutdown().await?;

            // block on the RPC call to return.
            // This ensures all chunks are sent out, and have been received by the
            // backend.

            match task.await? {
                Ok(resp) => {
                    // return the digest from the response, and store it in self.digest for subsequent closes.
                    let digest_len = resp.digest.len();
                    let digest: B3Digest = resp.digest.try_into().map_err(|_| {
                        io::Error::new(
                            io::ErrorKind::Other,
                            format!("invalid root digest length {} in response", digest_len),
                        )
                    })?;
                    self.digest = Some(digest.clone());
                    Ok(digest)
                }
                Err(e) => Err(io::Error::new(io::ErrorKind::Other, e.to_string())),
            }
        }
    }
}

impl<W: tokio::io::AsyncWrite + Unpin> tokio::io::AsyncWrite for GRPCBlobWriter<W> {
    fn poll_write(
        mut self: std::pin::Pin<&mut Self>,
        cx: &mut std::task::Context<'_>,
        buf: &[u8],
    ) -> std::task::Poll<Result<usize, io::Error>> {
        match &mut self.task_and_writer {
            None => Poll::Ready(Err(io::Error::new(
                io::ErrorKind::NotConnected,
                "already closed",
            ))),
            Some((_, ref mut writer)) => {
                let pinned_writer = pin!(writer);
                pinned_writer.poll_write(cx, buf)
            }
        }
    }

    fn poll_flush(
        mut self: std::pin::Pin<&mut Self>,
        cx: &mut std::task::Context<'_>,
    ) -> std::task::Poll<Result<(), io::Error>> {
        match &mut self.task_and_writer {
            None => Poll::Ready(Err(io::Error::new(
                io::ErrorKind::NotConnected,
                "already closed",
            ))),
            Some((_, ref mut writer)) => {
                let pinned_writer = pin!(writer);
                pinned_writer.poll_flush(cx)
            }
        }
    }

    fn poll_shutdown(
        self: std::pin::Pin<&mut Self>,
        _cx: &mut std::task::Context<'_>,
    ) -> std::task::Poll<Result<(), io::Error>> {
        // TODO(raitobezarius): this might not be a graceful shutdown of the
        // channel inside the gRPC connection.
        Poll::Ready(Ok(()))
    }
}

#[cfg(test)]
mod tests {
    use std::time::Duration;

    use tempfile::TempDir;
    use tokio::net::UnixListener;
    use tokio_retry::strategy::ExponentialBackoff;
    use tokio_retry::Retry;
    use tokio_stream::wrappers::UnixListenerStream;

    use crate::blobservice::MemoryBlobService;
    use crate::fixtures;
    use crate::proto::blob_service_client::BlobServiceClient;
    use crate::proto::GRPCBlobServiceWrapper;

    use super::BlobService;
    use super::GRPCBlobService;

    /// This ensures connecting via gRPC works as expected.
    #[tokio::test]
    async fn test_valid_unix_path_ping_pong() {
        let tmpdir = TempDir::new().unwrap();
        let socket_path = tmpdir.path().join("daemon");

        let path_clone = socket_path.clone();

        // Spin up a server
        tokio::spawn(async {
            let uds = UnixListener::bind(path_clone).unwrap();
            let uds_stream = UnixListenerStream::new(uds);

            // spin up a new server
            let mut server = tonic::transport::Server::builder();
            let router =
                server.add_service(crate::proto::blob_service_server::BlobServiceServer::new(
                    GRPCBlobServiceWrapper::new(
                        Box::<MemoryBlobService>::default() as Box<dyn BlobService>
                    ),
                ));
            router.serve_with_incoming(uds_stream).await
        });

        // wait for the socket to be created
        Retry::spawn(
            ExponentialBackoff::from_millis(20).max_delay(Duration::from_secs(10)),
            || async {
                if socket_path.exists() {
                    Ok(())
                } else {
                    Err(())
                }
            },
        )
        .await
        .expect("failed to wait for socket");

        // prepare a client
        let grpc_client = {
            let url = url::Url::parse(&format!(
                "grpc+unix://{}?wait-connect=1",
                socket_path.display()
            ))
            .expect("must parse");
            let client = BlobServiceClient::new(
                crate::tonic::channel_from_url(&url)
                    .await
                    .expect("must succeed"),
            );
            GRPCBlobService::from_client(client)
        };

        let has = grpc_client
            .has(&fixtures::BLOB_A_DIGEST)
            .await
            .expect("must not be err");

        assert!(!has);
    }
}