pool_mod/
config.rs

1//! Pool configuration.
2
3use std::time::Duration;
4
5/// Tunable limits and lifecycle policy for a [`Pool`](crate::Pool).
6///
7/// Construct one through [`Pool::builder`](crate::Pool::builder) for the fluent
8/// path, or assemble it directly — every field is public, so a configuration can
9/// equally be deserialized from a settings file. Validation happens when the pool
10/// is built, not when the struct is created; see
11/// [`Builder::build`](crate::Builder::build).
12///
13/// # Examples
14///
15/// ```
16/// use std::time::Duration;
17/// use pool_mod::PoolConfig;
18///
19/// // Start from the defaults and adjust only what matters.
20/// let cfg = PoolConfig {
21///     max_size: 16,
22///     min_idle: 2,
23///     idle_timeout: Some(Duration::from_secs(300)),
24///     ..PoolConfig::default()
25/// };
26///
27/// assert_eq!(cfg.max_size, 16);
28/// assert_eq!(cfg.create_timeout, Some(Duration::from_secs(30))); // inherited default
29/// ```
30#[derive(Debug, Clone, Copy, PartialEq, Eq)]
31pub struct PoolConfig {
32    /// Hard upper bound on the number of resources the pool owns at once — idle
33    /// plus checked out. Must be at least 1.
34    pub max_size: usize,
35
36    /// Number of resources to create up front when the pool is built, and the
37    /// floor the pool keeps ready. Must not exceed `max_size`.
38    pub min_idle: usize,
39
40    /// How long [`Pool::get`](crate::Pool::get) waits for a resource when the
41    /// pool is saturated. `None` waits indefinitely.
42    pub create_timeout: Option<Duration>,
43
44    /// Discard and replace an idle resource that has gone unused for at least
45    /// this long, checked the next time it is borrowed. `None` disables idle
46    /// expiry.
47    pub idle_timeout: Option<Duration>,
48
49    /// Discard and replace a resource older than this, regardless of use,
50    /// checked the next time it is borrowed. `None` disables lifetime expiry.
51    pub max_lifetime: Option<Duration>,
52
53    /// How often a background thread should prune idle resources that have
54    /// outlived `idle_timeout` or `max_lifetime`, rather than waiting for them to
55    /// be rejected on their next checkout. `None` (the default) runs no
56    /// background thread; expiry is then applied lazily, on borrow.
57    ///
58    /// The reaper only prunes — it never creates resources — and has no effect
59    /// unless `idle_timeout` or `max_lifetime` is also set.
60    pub reap_interval: Option<Duration>,
61}
62
63impl Default for PoolConfig {
64    /// A pool of up to ten resources, created on demand, that waits up to thirty
65    /// seconds for a free resource, never expires idle or aged resources, and
66    /// runs no background reaper.
67    fn default() -> Self {
68        PoolConfig {
69            max_size: 10,
70            min_idle: 0,
71            create_timeout: Some(Duration::from_secs(30)),
72            idle_timeout: None,
73            max_lifetime: None,
74            reap_interval: None,
75        }
76    }
77}
pool_mod/config.rs

pool_mod/
config.rs
