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

use std::thread;
use std::thread::JoinHandle;

use re_log_encoding::Compression;
use re_log_types::LogMsg;
use re_protos::sdk_comms::v0::message_proxy_client::MessageProxyClient;
use tokio::runtime;
use tokio::sync::mpsc;
use tokio::sync::mpsc::Receiver;
use tokio::sync::mpsc::Sender;
use tokio::sync::mpsc::UnboundedReceiver;
use tokio::sync::mpsc::UnboundedSender;
use tokio::sync::oneshot;
use tonic::transport::Endpoint;

enum Cmd {
    LogMsg(LogMsg),
    Flush(oneshot::Sender<()>),
}

#[derive(Clone)]
pub struct Options {
    compression: Compression,
}

impl Default for Options {
    fn default() -> Self {
        Self {
            compression: Compression::LZ4,
        }
    }
}

pub struct Client {
    thread: Option<JoinHandle<()>>,
    cmd_tx: UnboundedSender<Cmd>,
    shutdown_tx: Sender<()>,
}

impl Client {
    #[expect(clippy::needless_pass_by_value)]
    pub fn new(url: impl Into<String>, options: Options) -> Self {
        let url: String = url.into();
        let (cmd_tx, cmd_rx) = mpsc::unbounded_channel();
        let (shutdown_tx, shutdown_rx) = mpsc::channel(1);

        let thread = thread::Builder::new()
            .name("message_proxy_client".to_owned())
            .spawn(move || {
                let mut runtime = runtime::Builder::new_current_thread();
                runtime.enable_all();
                runtime
                    .build()
                    .expect("Failed to build tokio runtime")
                    .block_on(message_proxy_client(
                        url,
                        cmd_rx,
                        shutdown_rx,
                        options.compression,
                    ));
            })
            .expect("Failed to spawn message proxy client thread");

        Self {
            thread: Some(thread),
            cmd_tx,
            shutdown_tx,
        }
    }

    pub fn send(&self, msg: LogMsg) {
        self.cmd_tx.send(Cmd::LogMsg(msg)).ok();
    }

    pub fn flush(&self) {
        let (tx, rx) = oneshot::channel();
        if self.cmd_tx.send(Cmd::Flush(tx)).is_err() {
            re_log::debug!("Flush failed: already shut down.");
            return;
        };

        match rx.blocking_recv() {
            Ok(_) => {
                re_log::debug!("Flush complete");
            }
            Err(_) => {
                re_log::debug!("Flush failed, not all messages were sent");
            }
        }
    }
}

impl Drop for Client {
    fn drop(&mut self) {
        re_log::debug!("Shutting down message proxy client");
        // Wait for flush
        self.flush();
        // Quit immediately after that - no messages are left in the channel
        self.shutdown_tx.try_send(()).ok();
        // Wait for the shutdown
        self.thread.take().map(|t| t.join().ok());
        re_log::debug!("Message proxy client has shut down");
    }
}

async fn message_proxy_client(
    url: String,
    mut cmd_rx: UnboundedReceiver<Cmd>,
    mut shutdown_rx: Receiver<()>,
    compression: Compression,
) {
    let endpoint = match Endpoint::from_shared(url) {
        Ok(endpoint) => endpoint,
        Err(err) => {
            re_log::error!("Failed to connect to message proxy server: {err}");
            return;
        }
    };
    let channel = match endpoint.connect().await {
        Ok(channel) => channel,
        Err(err) => {
            re_log::error!("Failed to connect to message proxy server: {err}");
            return;
        }
    };
    let mut client = MessageProxyClient::new(channel);

    let stream = async_stream::stream! {
        loop {
            tokio::select! {
                cmd = cmd_rx.recv() => {
                    match cmd {
                        Some(Cmd::LogMsg(msg)) => {
                            let msg = match re_log_encoding::protobuf_conversions::log_msg_to_proto(msg, compression) {
                                Ok(msg) => msg,
                                Err(err) => {
                                    re_log::error!("Failed to encode message: {err}");
                                    break;
                                }
                            };

                            yield msg;
                        }

                        Some(Cmd::Flush(tx)) => {
                            // Messages are received in order, so once we receive a `flush`
                            // we know we've sent all messages before that flush through already.
                            re_log::debug!("Flush requested");
                            if tx.send(()).is_err() {
                                re_log::debug!("Failed to respond to flush: channel is closed");
                                return;
                            };
                        }

                        None => {
                            re_log::debug!("Channel closed");
                            break;
                        }
                    }
                }

                _ = shutdown_rx.recv() => {
                    re_log::debug!("Shutting down without flush");
                    return;
                }
            }
        }
    };

    if let Err(err) = client.write_messages(stream).await {
        re_log::error!("Write messages call failed: {err}");
    };
}