digitalis-server 0.0.0

Base server module for Foxflove
Documentation 
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

use std::sync::Arc;

use digitalis_core::{
    common::{ChannelId, SubscriptionId},
    server::MessageData,
    Control, DigitalisError, DigitalisResult, MessageMinimal,
};
use tokio::sync::mpsc;

use crate::client::{Client, ClientId};

#[derive(Debug)]
pub struct Channel {
    _id: ChannelId,
    subscriptions: Vec<(Client, SubscriptionId)>,
}

impl Channel {
    fn new(id: ChannelId) -> Self {
        Self {
            _id: id,
            subscriptions: Default::default(),
        }
    }

    pub fn start(id: ChannelId) -> ChannelQueue {
        let (tx, mut rx) = mpsc::channel(100);

        tokio::spawn(async move {
            let mut channel = Self::new(id);

            loop {
                if let Some(msg) = rx.recv().await {
                    match channel.handle_message(msg) {
                        Ok(Control::Continue) => {}
                        Ok(Control::Exit) => break,
                        Err(e) => {
                            log::error!("Fail to handle message: {}", e);
                        }
                    }
                }
            }
        });

        ChannelQueue::new(id, tx)
    }

    pub fn handle_message(&mut self, msg: ChannelMessage) -> DigitalisResult<Control> {
        use ChannelMessage::*;

        match msg {
            Subscribe { client, id } => {
                self.subscriptions.push((client, id));
            }
            Unsubscribe { client_id, ids } => {
                self.subscriptions
                    .retain(|(c, i)| c.id() != client_id || !ids.contains(i));
            }
            UnsubscribeAll { client_id } => {
                self.subscriptions.retain(|(c, _)| c.id() != client_id);
            }
            Broadcast {
                message,
                receive_timestamp,
            } => {
                if self.subscriptions.is_empty() {
                    return Ok(Control::Continue);
                }

                let payload = Arc::new(message.write_to_bytes()?);

                for (client, id) in self.subscriptions.iter() {
                    let msg = MessageData {
                        subscription_id: *id,
                        receive_timestamp,
                        payload: Arc::clone(&payload),
                    }
                    .into_message()?;

                    if let Err(e) = client.nonblocking_send(msg) {
                        log::error!("Fail to send message to client: {e:?}");
                    }
                }
            }
            Terminate => return Ok(Control::Exit),
        }

        Ok(Control::Continue)
    }
}

#[allow(missing_debug_implementations)]
pub enum ChannelMessage {
    Subscribe {
        client: Client,
        id: SubscriptionId,
    },
    Unsubscribe {
        client_id: ClientId,
        ids: Arc<Vec<SubscriptionId>>,
    },
    UnsubscribeAll {
        client_id: ClientId,
    },
    Broadcast {
        message: Box<dyn MessageMinimal>,
        receive_timestamp: u64,
    },
    Terminate,
}

#[derive(Debug, Clone)]
pub struct ChannelQueue {
    id: ChannelId,
    sender: mpsc::Sender<ChannelMessage>,
}

impl ChannelQueue {
    pub const fn new(id: ChannelId, sender: mpsc::Sender<ChannelMessage>) -> Self {
        Self { id, sender }
    }

    pub const fn id(&self) -> ChannelId {
        self.id
    }

    fn try_send(&self, msg: ChannelMessage) -> DigitalisResult<()> {
        self.sender
            .try_send(msg)
            .map_err(|_| DigitalisError::ChannelSendError)
    }

    pub fn broadcast<T: MessageMinimal>(
        &self,
        msg: T,
        receive_timestamp: u64,
    ) -> DigitalisResult<()> {
        self.try_send(ChannelMessage::Broadcast {
            message: Box::new(msg),
            receive_timestamp,
        })
    }

    pub fn subscribe(&self, client: Client, id: SubscriptionId) -> DigitalisResult<()> {
        self.try_send(ChannelMessage::Subscribe { client, id })
    }

    pub fn unsubscribe(
        &self,
        client_id: ClientId,
        ids: Arc<Vec<SubscriptionId>>,
    ) -> DigitalisResult<()> {
        self.try_send(ChannelMessage::Unsubscribe { client_id, ids })
    }

    pub fn unsubscribe_all(&self, client_id: ClientId) -> DigitalisResult<()> {
        self.try_send(ChannelMessage::UnsubscribeAll { client_id })
    }

    pub fn terminate(&self) -> DigitalisResult<()> {
        self.try_send(ChannelMessage::Terminate)
    }
}