dactor 0.3.3

An abstract framework for distributed actors 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
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

//! DropObserver for monitoring interceptor-driven message drops.
//!
//! Run with: cargo run --example dead_letters --features test-support

use std::any::Any;
use std::sync::{Arc, Mutex};

use async_trait::async_trait;
use dactor::actor::{Actor, ActorContext, ActorRef, Handler};
use dactor::interceptor::{
    Disposition, DropNotice, DropObserver, OutboundContext, OutboundInterceptor,
};
use dactor::message::{Headers, Message, RuntimeHeaders};
use dactor::TestRuntime;

// ---------------------------------------------------------------------------
// Messages
// ---------------------------------------------------------------------------

struct ProcessItem(String);
impl Message for ProcessItem {
    type Reply = ();
}

// ---------------------------------------------------------------------------
// Actor
// ---------------------------------------------------------------------------

struct Processor {
    processed: Vec<String>,
}

impl Actor for Processor {
    type Args = ();
    type Deps = ();
    fn create(_: (), _: ()) -> Self {
        Processor {
            processed: Vec::new(),
        }
    }
}

#[async_trait]
impl Handler<ProcessItem> for Processor {
    async fn handle(&mut self, msg: ProcessItem, _ctx: &mut ActorContext) {
        println!("  [Processor] handled: {}", msg.0);
        self.processed.push(msg.0);
    }
}

// ---------------------------------------------------------------------------
// DropObserver — collects drop notices
// ---------------------------------------------------------------------------

struct CollectingObserver {
    notices: Arc<Mutex<Vec<String>>>,
}

impl DropObserver for CollectingObserver {
    fn on_drop(&self, notice: DropNotice) {
        let entry = format!(
            "DROPPED target={} msg={} by={} ctx={}",
            notice.target_name, notice.message_type, notice.interceptor_name, notice.context
        );
        println!("  [DropObserver] {}", entry);
        self.notices.lock().unwrap().push(entry);
    }
}

// ---------------------------------------------------------------------------
// Outbound interceptor — drops messages containing "spam"
// ---------------------------------------------------------------------------

struct SpamFilter;

impl OutboundInterceptor for SpamFilter {
    fn name(&self) -> &'static str {
        "spam-filter"
    }

    fn on_send(
        &self,
        _ctx: &OutboundContext<'_>,
        _rh: &RuntimeHeaders,
        _headers: &mut Headers,
        msg: &dyn Any,
    ) -> Disposition {
        if let Some(item) = msg.downcast_ref::<ProcessItem>() {
            if item.0.contains("spam") {
                println!("  [SpamFilter] dropping: {}", item.0);
                return Disposition::Drop;
            }
        }
        Disposition::Continue
    }
}

// ---------------------------------------------------------------------------
// Main
// ---------------------------------------------------------------------------

#[tokio::main]
async fn main() {
    println!("=== Dead Letters / Drop Observer Example ===\n");

    let drop_log: Arc<Mutex<Vec<String>>> = Arc::new(Mutex::new(Vec::new()));

    let mut runtime = TestRuntime::new();
    runtime.set_drop_observer(Arc::new(CollectingObserver {
        notices: drop_log.clone(),
    }));
    runtime.add_outbound_interceptor(Box::new(SpamFilter));

    let processor = runtime.spawn::<Processor>("processor", ()).await.unwrap();

    // Send a mix of valid and spam messages
    println!("--- Sending messages ---");
    let items = vec![
        "order-001",
        "spam-promo",
        "order-002",
        "spam-newsletter",
        "order-003",
    ];

    for item in &items {
        processor.tell(ProcessItem(item.to_string())).unwrap();
    }

    // Allow processing to complete
    tokio::time::sleep(std::time::Duration::from_millis(100)).await;

    // Show collected drop notices
    println!("\n--- Drop notices ---");
    let notices = drop_log.lock().unwrap();
    for notice in notices.iter() {
        println!("  {}", notice);
    }

    assert_eq!(notices.len(), 2, "expected 2 dropped messages");
    println!("\n  ✓ 2 spam messages dropped, 3 valid messages processed");
    println!("\n=== Done ===");
}