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//! Edge rate limiter and supporting functions.
//!
pub(crate) mod handle;
use std::time::Duration;
pub use handle::ERLError;
use handle::{ERLHandle, PenaltyboxHandle, RateCounterHandle};
/// An edge rate limiter which includes a ratecounter and a penaltybox.
///
pub struct ERL {
handle: ERLHandle,
}
/// A rate counter that can be used with a edge rate limiter or stand alone for counting and rate calculations
///
pub struct RateCounter {
handle: RateCounterHandle,
}
/// To be used for picking the window in a rate counter lookup_rate or a ERL check_rate
///
#[repr(u32)]
pub enum RateWindow {
/// A one secound rate window
OneSec = 1,
/// A ten secound rate window
TenSecs = 10,
/// A sixty secound rate window
SixtySecs = 60,
}
/// To be used for picking the duration in a rate counter lookup_count call
///
#[repr(u32)]
pub enum CounterDuration {
/// A one second counter window
TenSec = 10,
/// A twenty second counter window
TwentySecs = 20,
/// A thirty second counter window
ThirtySecs = 30,
/// A forty second counter window
FortySecs = 40,
/// A fifty second counter window
FiftySecs = 50,
/// A sixty second counter window
SixtySecs = 60,
}
/// A penaltybox that can be used with the edge rate limiter or stand alone for adding and checking if some entry is in the data set.
///
pub struct Penaltybox {
handle: PenaltyboxHandle,
}
impl ERL {
/// Open a ERL with the given ratecounter and penaltybox.
///
pub fn open(ratecounter: RateCounter, penaltybox: Penaltybox) -> Self {
Self {
handle: ERLHandle::open(ratecounter, penaltybox),
}
}
/// Increment an entry in a rate counter and check if the client has exceeded some average number of requests per second (RPS) over the window.
/// If the client is over the rps limit for the window, add to the penaltybox for ttl.
/// Valid ttl span is 1m to 1h and TTL value is truncated to the nearest minute.
///
pub fn check_rate(
&self,
entry: &str,
delta: u32,
window: RateWindow,
limit: u32,
ttl: Duration,
) -> Result<bool, ERLError> {
self.handle.check_rate(entry, delta, window, limit, ttl)
}
}
impl RateCounter {
/// Open a RateCounter with the given name for a ratecounter.
///
pub fn open(ratecounter_name: &str) -> Self {
Self {
handle: RateCounterHandle::open(ratecounter_name),
}
}
/// Increment an entry in the ratecounter by delta.
///
pub fn increment(&self, entry: &str, delta: u32) -> Result<(), ERLError> {
self.handle.increment(entry, delta)
}
/// Lookup the current rate for entry in the ratecounter for a window.
///
pub fn lookup_rate(&self, entry: &str, window: RateWindow) -> Result<u32, ERLError> {
self.handle.lookup_rate(entry, window)
}
/// Lookup the current count for entry in the ratecounter for duration.
///
pub fn lookup_count(&self, entry: &str, duration: CounterDuration) -> Result<u32, ERLError> {
self.handle.lookup_count(entry, duration)
}
}
impl Penaltybox {
/// Open a Penaltybox identified by the given name.
///
pub fn open(penaltybox_name: &str) -> Self {
Self {
handle: PenaltyboxHandle::open(penaltybox_name),
}
}
/// Add entry to a the penaltybox for the duration of ttl.
/// Valid ttl span is 1m to 1h and TTL value is truncated to the nearest minute.
///
pub fn add(&self, entry: &str, ttl: Duration) -> Result<(), ERLError> {
self.handle.add(entry, ttl)
}
/// Check if entry is in the penaltybox.
///
pub fn has(&self, entry: &str) -> Result<bool, ERLError> {
self.handle.has(entry)
}
}