chuggin 0.6.4

A terminal harness for persistent projects and continuous local model refinement
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

//! Provider availability is separate from model reasoning recovery.
use std::time::{Duration, SystemTime};

#[derive(Debug)]
pub struct Unavailable {
    pub reason: &'static str,
    pub retry_after: Option<Duration>,
}
impl std::fmt::Display for Unavailable {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.write_str(self.reason)
    }
}
impl std::error::Error for Unavailable {}
#[derive(Debug)]
pub struct Stopped(pub String);
impl std::fmt::Display for Stopped {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        f.write_str(&self.0)
    }
}
impl std::error::Error for Stopped {}

pub fn retry_after(value: Option<&str>, now: SystemTime) -> Option<Duration> {
    let value = value?;
    value
        .trim()
        .parse::<u64>()
        .ok()
        .map(Duration::from_secs)
        .or_else(|| {
            httpdate::parse_http_date(value)
                .ok()
                .map(|t| t.duration_since(now).unwrap_or_default())
        })
        .map(|d| d.max(Duration::from_secs(1)))
}
pub fn classify(status: u16, message: &str, retry_after: Option<Duration>) -> Option<Unavailable> {
    let text = message.to_ascii_lowercase();
    let legacy_window = ["session limit", "weekly limit", "5-hour", "five-hour"]
        .iter()
        .any(|s| text.contains(s));
    let exhausted = (status == 402 && !legacy_window)
        || [
            "insufficient credits",
            "insufficient balance",
            "credits exhausted",
            "credit balance",
            "out of credits",
            "payment required",
            "monthly usage limit",
            "monthly limit",
        ]
        .iter()
        .any(|s| text.contains(s));
    let limited = status == 429
        || legacy_window
        || [
            "usage limit",
            "rate limit",
            "quota exceeded",
            "too many requests",
            "weekly limit",
            "session limit",
        ]
        .iter()
        .any(|s| text.contains(s));
    let auth = matches!(status, 401 | 403) && !limited && !exhausted;
    if !(exhausted || limited || auth || (500..600).contains(&status)) {
        return None;
    }
    Some(Unavailable {
        reason: if exhausted {
            "Provider credits exhausted or payment required"
        } else if auth {
            "Provider authentication or access needs attention"
        } else if limited {
            "Provider usage or rate limit reached"
        } else {
            "Provider temporarily unavailable"
        },
        retry_after,
    })
}
pub fn backoff(attempt: u32) -> Duration {
    Duration::from_secs(60 * (1u64 << attempt.saturating_sub(1).min(4)))
        .min(Duration::from_secs(900))
}
#[cfg(test)]
mod tests {
    use super::*;
    #[test]
    fn legacy_limits_credits_and_authentication_share_wait_policy() {
        for text in [
            "usage limit reached",
            "weekly limit reached",
            "session limit exceeded",
        ] {
            assert!(classify(200, text, None).is_some());
        }
        assert!(classify(402, "", None).is_some());
        assert!(classify(200, "insufficient credits", None).is_some());
        assert_eq!(
            classify(402, "", Some(Duration::from_secs(3600)))
                .unwrap()
                .retry_after,
            Some(Duration::from_secs(3600))
        );
        assert!(classify(401, "", None).is_some());
        assert!(classify(400, "invalid tool schema", None).is_none());
        assert!(classify(503, "", None).is_some());
    }
    #[test]
    fn retry_headers_and_fallback_delays() {
        let now = SystemTime::UNIX_EPOCH + Duration::from_secs(1_000_000);
        assert_eq!(
            retry_after(Some("3600"), now),
            Some(Duration::from_secs(3600))
        );
        let date = httpdate::fmt_http_date(now + Duration::from_secs(7200));
        assert_eq!(
            retry_after(Some(&date), now),
            Some(Duration::from_secs(7200))
        );
        assert_eq!(retry_after(Some("bad"), now), None);
        assert_eq!(retry_after(Some("0"), now), Some(Duration::from_secs(1)));
        assert_eq!(
            (1..=6).map(|n| backoff(n).as_secs()).collect::<Vec<_>>(),
            [60, 120, 240, 480, 900, 900]
        );
        for attempt in [100, 10_000, u32::MAX] {
            assert_eq!(backoff(attempt), Duration::from_secs(900));
        }
    }
}