noxu-db 3.0.2

Noxu DB - An embedded transactional database engine
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

//! Compile-time observability stubs.
//!
//! When the `observability` feature is enabled, these macros emit real
//! metrics and tracing spans. When disabled, they compile to nothing.

/// Increment a counter metric. No-op when `observability` is disabled.
macro_rules! observe_counter {
    ($name:expr, $($label_key:expr => $label_val:expr),* $(,)?) => {
        #[cfg(feature = "observability")]
        {
            ::metrics::counter!($name, $($label_key => $label_val),*).increment(1);
        }
        #[cfg(not(feature = "observability"))]
        {
            $(let _ = ($label_key, $label_val);)*
            let _ = $name;
        }
    };
}

/// Increment a counter by a given value. No-op when `observability` is disabled.
macro_rules! observe_counter_add {
    ($name:expr, $val:expr, $($label_key:expr => $label_val:expr),* $(,)?) => {
        #[cfg(feature = "observability")]
        {
            ::metrics::counter!($name, $($label_key => $label_val),*).increment($val);
        }
        #[cfg(not(feature = "observability"))]
        {
            $(let _ = ($label_key, $label_val);)*
            let _ = ($name, $val);
        }
    };
}

/// Record a histogram value. No-op when `observability` is disabled.
macro_rules! observe_histogram {
    ($name:expr, $val:expr, $($label_key:expr => $label_val:expr),* $(,)?) => {
        #[cfg(feature = "observability")]
        {
            ::metrics::histogram!($name, $($label_key => $label_val),*).record($val);
        }
        #[cfg(not(feature = "observability"))]
        {
            $(let _ = ($label_key, $label_val);)*
            let _ = ($name, $val);
        }
    };
}

/// Increment a gauge by 1. No-op when `observability` is disabled.
macro_rules! observe_gauge_inc {
    ($name:expr) => {
        #[cfg(feature = "observability")]
        {
            ::metrics::gauge!($name).increment(1.0);
        }
        #[cfg(not(feature = "observability"))]
        {
            let _ = $name;
        }
    };
}

/// Decrement a gauge by 1. No-op when `observability` is disabled.
macro_rules! observe_gauge_dec {
    ($name:expr) => {
        #[cfg(feature = "observability")]
        {
            ::metrics::gauge!($name).decrement(1.0);
        }
        #[cfg(not(feature = "observability"))]
        {
            let _ = $name;
        }
    };
}

/// Create a tracing span. No-op when `observability` is disabled.
/// Returns an `Option<tracing::span::EnteredSpan>` when enabled, `()` when disabled.
macro_rules! observe_span {
    ($name:expr, $($field_key:ident = $field_val:expr),* $(,)?) => {
        #[cfg(feature = "observability")]
        let _obs_span = {
            let _span = ::tracing::info_span!($name, $($field_key = $field_val),*);
            Some(_span.entered())
        };
        #[cfg(not(feature = "observability"))]
        let _obs_span: () = {
            $(let _ = $field_val;)*
            let _ = $name;
        };
    };
}

/// Start a timer. Returns `Option<std::time::Instant>` when enabled, `()` when disabled.
macro_rules! observe_timer_start {
    () => {{
        #[cfg(feature = "observability")]
        {
            Some(std::time::Instant::now())
        }
        #[cfg(not(feature = "observability"))]
        {
            None::<std::time::Instant>
        }
    }};
}

/// Record elapsed time from a timer into a histogram. No-op when disabled.
macro_rules! observe_timer_record {
    ($timer:expr, $name:expr, $($label_key:expr => $label_val:expr),* $(,)?) => {
        #[cfg(feature = "observability")]
        {
            if let Some(start) = $timer {
                let elapsed = start.elapsed().as_secs_f64();
                ::metrics::histogram!($name, $($label_key => $label_val),*).record(elapsed);
            }
        }
        #[cfg(not(feature = "observability"))]
        {
            let _ = ($timer, $name);
            $(let _ = ($label_key, $label_val);)*
        }
    };
}

pub(crate) use observe_counter;
pub(crate) use observe_counter_add;
pub(crate) use observe_gauge_dec;
pub(crate) use observe_gauge_inc;
pub(crate) use observe_histogram;
pub(crate) use observe_span;
pub(crate) use observe_timer_record;
pub(crate) use observe_timer_start;