[−][src]Struct cadence::QueuingMetricSink
Implementation of a MetricSink
that wraps another implementation
and uses it to emit metrics asynchronously, in another thread.
Metrics submitted to this sink are queued and sent to the wrapped sink
that is running in a separate thread. The wrapped implementation can
be any thread (Sync
+ Send
) and panic (RefUnwindSafe
) safe
MetricSink
. Results from the wrapped implementation will be discarded.
The thread used for network operations (actually sending the metrics
using the wrapped sink) is created and started when the QueuingMetricSink
is created. The dequeuing of metrics is stopped and the thread stopped
when QueuingMetricSink
instance is destroyed (when .drop()
is
called).
This sink may be created with either a bounded or unbounded queue connecting the sink to the thread performning network operations. When an unbounded queue is used, entries submitted to the sink will always be accepted and queued until they can be drained by the network operation thread. This means that if the network thread cannot drain entries off the queue for some reason, it will grow without bound. Alternatively, if created with a bounded queue, entries submitted to the sink will not be accepted if the queue is full. This means that the network thread must be able to keep up with the rate of entries submit to the queue or writes to this sink will begin to fail.
Entries already queued are guaranteed to be sent to the wrapped sink
before the queuing sink is stopped. Meaning, the following code ends up
calling wrapped.emit(metric)
on every metric submitted to the queuing
sink.
Example
use cadence::{MetricSink, QueuingMetricSink, NopMetricSink}; let wrapped = NopMetricSink; { let queuing = QueuingMetricSink::from(wrapped); queuing.emit("foo.counter:4|c"); queuing.emit("bar.counter:5|c"); queuing.emit("baz.gauge:6|g"); }
At the end of this code block, all metrics are guaranteed to be sent to the underlying wrapped metric sink before the thread used by the queuing sink is stopped.
Implementations
impl QueuingMetricSink
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pub fn from<T>(sink: T) -> Self where
T: MetricSink + Sync + Send + RefUnwindSafe + 'static,
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T: MetricSink + Sync + Send + RefUnwindSafe + 'static,
Construct a new QueuingMetricSink
instance wrapping another sink
implementation with an unbounded queue connecting them.
The .emit()
method of the wrapped sink will be executed in a
different thread after being passed to it via a queue. The wrapped
sink should be thread safe (Send + Sync
) and panic safe
(RefUnwindSafe
).
The thread in which the wrapped sink runs is created when the
QueuingMetricSink
is created and stopped when the queuing sink
is destroyed.
The queuing sink communicates with the wrapped sink by an unbounded queue. If entries cannot be drained from the queue for some reason, it will grow without bound.
Buffered UDP Sink Example
In this example we wrap a buffered UDP sink to execute it in a different thread.
use std::net::UdpSocket; use cadence::{BufferedUdpMetricSink, QueuingMetricSink, DEFAULT_PORT}; let socket = UdpSocket::bind("0.0.0.0:0").unwrap(); let host = ("metrics.example.com", DEFAULT_PORT); let udp_sink = BufferedUdpMetricSink::from(host, socket).unwrap(); let queuing_sink = QueuingMetricSink::from(udp_sink);
pub fn with_capacity<T>(sink: T, capacity: usize) -> Self where
T: MetricSink + Sync + Send + RefUnwindSafe + 'static,
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T: MetricSink + Sync + Send + RefUnwindSafe + 'static,
Construct a new QueuingMetricSink
instance wrapping another sink
implementation with a queue of the given size connecting them.
The .emit()
method of the wrapped sink will be executed in a
different thread after being passed to it via a queue. The wrapped
sink should be thread safe (Send + Sync
) and panic safe
(RefUnwindSafe
).
The thread in which the wrapped sink runs is created when the
QueuingMetricSink
is created and stopped when the queuing sink
is destroyed.
The queuing sink communicates with the wrapped sink by a bounded queue of the provided size. When the queue is full, writes to this sink will fail until the queue is drained.
Buffered UDP Sink Example
In this example we wrap a buffered UDP sink to execute it in a different thread.
use std::net::UdpSocket; use cadence::{BufferedUdpMetricSink, QueuingMetricSink, DEFAULT_PORT}; let socket = UdpSocket::bind("0.0.0.0:0").unwrap(); let host = ("metrics.example.com", DEFAULT_PORT); let udp_sink = BufferedUdpMetricSink::from(host, socket).unwrap(); let queuing_sink = QueuingMetricSink::with_capacity(udp_sink, 512 * 1024);
pub fn panics(&self) -> u64
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Return the number of times the wrapped sink or underlying worker thread
has panicked and needed to be restarted. In typical use this should always
be 0
but may be > 0
for buggy MetricSink
implementations.
pub fn queued(&self) -> u64
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Return the number of currently queued metrics. Note that due to the way this number is computed (submitted metrics - processed metrics), it is necessarily approximate.
pub fn submitted(&self) -> u64
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Return the number of metrics successfully submitted to this sink.
pub fn drained(&self) -> u64
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Return the number of metrics removed from the queue to be processed by the wrapped sink. Note that this does not indicate that the metric has been successfully sent to a backend, only that it has been passed to the wrapped sink.
Trait Implementations
impl Clone for QueuingMetricSink
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fn clone(&self) -> QueuingMetricSink
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fn clone_from(&mut self, source: &Self)
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impl Debug for QueuingMetricSink
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impl Drop for QueuingMetricSink
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fn drop(&mut self)
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Send the worker a signal to stop processing metrics.
Note that this destructor only sends the worker thread a signal to stop, it doesn't wait for it to stop.
impl MetricSink for QueuingMetricSink
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Auto Trait Implementations
impl RefUnwindSafe for QueuingMetricSink
impl Send for QueuingMetricSink
impl Sync for QueuingMetricSink
impl Unpin for QueuingMetricSink
impl UnwindSafe for QueuingMetricSink
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
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impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> ToOwned for T where
T: Clone,
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T: Clone,
type Owned = T
The resulting type after obtaining ownership.
fn to_owned(&self) -> T
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fn clone_into(&self, target: &mut T)
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,