aion-rs 0.13.7

Transport-agnostic Aion workflow engine with durability, replay, timers, and supervision.
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

//! Non-durable diagnostic tap for the workflow-side query pump.

use beamr::native::ProcessContext;
use beamr::term::Term;

use super::engine_nifs::{decode_string_arg, error_result_term, ok_result_term};

// Pump diagnostics are already bounded before crossing the FFI. These limits
// also bound direct calls to the NIF before data reaches the tracing subscriber.
const MAX_CATEGORY_BYTES: usize = 64;
const MAX_MESSAGE_BYTES: usize = 2048;

pub(super) fn report_query_diagnostic(
    args: &[Term],
    ctx: &mut ProcessContext,
) -> Result<Term, Term> {
    if args.len() > u8::MAX.into() {
        return Err(Term::NIL);
    }
    if args.len() != 2 {
        let message = format!(
            "report_query_diagnostic: expected 2 arguments, got {}",
            args.len()
        );
        return Ok(result_or_nil(error_result_term(ctx, &message)));
    }

    // Decode both terms before allocating a result because attached calls may
    // collect during allocation and rewrite argument terms in place.
    let category = match decode_string_arg(args[0]) {
        Ok(value) => value,
        Err(error) => {
            return Ok(result_or_nil(error_result_term(
                ctx,
                &format!("report_query_diagnostic category: {error}"),
            )));
        }
    };
    let message = match decode_string_arg(args[1]) {
        Ok(value) => value,
        Err(error) => {
            return Ok(result_or_nil(error_result_term(
                ctx,
                &format!("report_query_diagnostic message: {error}"),
            )));
        }
    };

    tracing::warn!(
        workflow_pid = ?ctx.pid(),
        category = bounded_text(&category, MAX_CATEGORY_BYTES),
        diagnostic = bounded_text(&message, MAX_MESSAGE_BYTES),
        "workflow query pump diagnostic"
    );

    Ok(result_or_nil(ok_result_term(ctx, "reported")))
}

fn result_or_nil(term: Option<Term>) -> Term {
    match term {
        Some(value) => value,
        None => Term::NIL,
    }
}

fn bounded_text(value: &str, max_bytes: usize) -> &str {
    if value.len() <= max_bytes {
        return value;
    }

    let mut end = max_bytes;
    while !value.is_char_boundary(end) {
        end -= 1;
    }
    &value[..end]
}

#[cfg(test)]
mod tests {
    use super::{MAX_MESSAGE_BYTES, bounded_text};

    type TestResult = Result<(), Box<dyn std::error::Error>>;

    #[test]
    fn diagnostic_bound_preserves_utf8_boundaries() -> TestResult {
        let value = format!("{}é", "a".repeat(MAX_MESSAGE_BYTES - 1));

        let bounded = bounded_text(&value, MAX_MESSAGE_BYTES);
        let validated = std::str::from_utf8(bounded.as_bytes())?;

        assert_eq!(validated.len(), MAX_MESSAGE_BYTES - 1);
        assert!(bounded.chars().all(|character| character == 'a'));
        Ok(())
    }
}