malstrom 0.1.0

Malstrom is a distributed, stateful stream processing framework written in Rust.
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

use crate::{
    sinks::StatelessSinkImpl,
    types::{Data, DataMessage, MaybeKey, MaybeTime},
};
use std::{ops::RangeBounds, sync::Arc, sync::Mutex};

/// A Helper to write values into a shared vector and take them out
/// again.
/// This is mainly useful to extract values from a stream in unit tests.
/// This struct uses an Arc<Mutex<Vec<T>> internally, so it can be freely
/// cloned
#[derive(Clone)]
pub struct VecSink<T> {
    inner: Arc<Mutex<Vec<T>>>,
}
impl<T> Default for VecSink<T> {
    fn default() -> Self {
        Self::new()
    }
}

impl<T> VecSink<T> {
    /// Create a new sink which collects all messages into a `Vec`
    pub fn new() -> Self {
        VecSink {
            inner: Arc::new(Mutex::new(Vec::new())),
        }
    }

    /// Put a value into this sink
    #[allow(clippy::unwrap_used)]
    pub fn give(&self, value: T) {
        self.inner.lock().unwrap().push(value)
    }

    /// Take the given range out of this sink
    #[allow(clippy::unwrap_used)]
    pub fn drain_vec<R: RangeBounds<usize>>(&self, range: R) -> Vec<T> {
        self.inner.lock().unwrap().drain(range).collect()
    }
}

impl<T> IntoIterator for VecSink<T> {
    type Item = T;

    type IntoIter = std::vec::IntoIter<T>;

    fn into_iter(self) -> Self::IntoIter {
        self.drain_vec(..).into_iter()
    }
}

impl<K, V, T> StatelessSinkImpl<K, V, T> for VecSink<DataMessage<K, V, T>>
where
    K: MaybeKey,
    V: Data,
    T: MaybeTime,
{
    fn sink(&mut self, msg: DataMessage<K, V, T>) {
        self.give(msg);
    }
}