metrics_prometheus/
failure.rs

1//! Definitions for dealing with a [`prometheus::Error`].
2
3#[doc(inline)]
4pub use self::strategy::Strategy;
5
6/// Possible actions on an encountered [`prometheus::Error`] inside
7/// [`metrics::Recorder`] methods.
8#[derive(Clone, Copy, Debug)]
9pub enum Action {
10    /// Return a no-op metric implementation (see [`metrics::Counter::noop()`]
11    /// for example).
12    NoOp,
13
14    /// Panic with the encountered [`prometheus::Error`].
15    Panic,
16}
17
18/// Strategies for dealing with a [`prometheus::Error`].
19pub mod strategy {
20    use super::Action;
21
22    /// Strategy deciding which [`Action`] should be performed on an encountered
23    /// [`prometheus::Error`] inside [`metrics::Recorder`] methods.
24    pub trait Strategy {
25        /// Inspects the encountered [`prometheus::Error`] and returns the
26        /// [`Action`] to be performed.
27        fn decide(&self, res: &prometheus::Error) -> Action;
28    }
29
30    /// [`Strategy`] returning always [`Action::NoOp`].
31    #[derive(Clone, Copy, Debug, Default)]
32    pub struct NoOp;
33
34    impl Strategy for NoOp {
35        fn decide(&self, _: &prometheus::Error) -> Action {
36            Action::NoOp
37        }
38    }
39
40    /// [`Strategy`] returning always [`Action::Panic`].
41    #[derive(Clone, Copy, Debug, Default)]
42    pub struct Panic;
43
44    impl Strategy for Panic {
45        fn decide(&self, _: &prometheus::Error) -> Action {
46            Action::Panic
47        }
48    }
49
50    /// [`Strategy`] returning an [`Action::Panic`] in debug mode, and
51    /// [`Action::NoOp`] in release mode.
52    #[derive(Clone, Copy, Debug, Default)]
53    pub struct PanicInDebugNoOpInRelease;
54
55    impl Strategy for PanicInDebugNoOpInRelease {
56        fn decide(&self, _: &prometheus::Error) -> Action {
57            #[cfg(debug_assertions)]
58            {
59                Action::Panic
60            }
61            #[cfg(not(debug_assertions))]
62            {
63                Action::NoOp
64            }
65        }
66    }
67}
metrics_prometheus/failure.rs

metrics_prometheus/
failure.rs
