Struct cadence::StatsdClient
source · [−]pub struct StatsdClient { /* private fields */ }Expand description
Client for Statsd that implements various traits to record metrics.
Traits
The client is the main entry point for users of this library. It supports several traits for recording metrics of different types.
Countedfor emitting counters.Timedfor emitting timings.Gaugedfor emitting gauge values.Meteredfor emitting meter values.Histogrammedfor emitting histogram values.Distributedfor emitting distribution values.Settedfor emitting set values.MetricClientfor a combination of all of the above.
For more information about the uses for each type of metric, see the documentation for each mentioned trait.
Sinks
The client uses some implementation of a MetricSink to emit the metrics.
In simple use cases when performance isn’t critical, the UdpMetricSink
is an acceptable choice since it is the simplest to use and understand.
When performance is more important, users will want to use the
BufferedUdpMetricSink in combination with the QueuingMetricSink for
maximum isolation between the sending of metrics and your application as well
as minimum overhead when sending metrics.
Threading
The StatsdClient is designed to work in a multithreaded application. All
parts of the client can be shared between threads (i.e. it is Send and
Sync). An example of how to use the client in a multithreaded environment
is given below.
In the following example, we create a struct MyRequestHandler that has a
single method that spawns a thread to do some work and emit a metric.
Wrapping With An Arc
In order to share a client between multiple threads, you’ll need to wrap it
with an atomic reference counting pointer (std::sync::Arc). You should refer
to the client by the trait of all its methods for recording metrics
(MetricClient) as well as the Send and Sync traits since the idea is to
share this between threads.
use std::panic::RefUnwindSafe;
use std::net::UdpSocket;
use std::sync::Arc;
use std::thread;
use cadence::prelude::*;
use cadence::{StatsdClient, BufferedUdpMetricSink, DEFAULT_PORT};
struct MyRequestHandler {
metrics: Arc<dyn MetricClient + Send + Sync + RefUnwindSafe>,
}
impl MyRequestHandler {
fn new() -> MyRequestHandler {
let socket = UdpSocket::bind("0.0.0.0:0").unwrap();
let host = ("localhost", DEFAULT_PORT);
let sink = BufferedUdpMetricSink::from(host, socket).unwrap();
MyRequestHandler {
metrics: Arc::new(StatsdClient::from_sink("some.prefix", sink))
}
}
fn handle_some_request(&self) -> Result<(), String> {
let metric_ref = self.metrics.clone();
let _t = thread::spawn(move || {
println!("Hello from the thread!");
metric_ref.count("request.handler", 1);
});
Ok(())
}
}Implementations
pub fn from_sink<T>(prefix: &str, sink: T) -> Self where
T: MetricSink + Sync + Send + RefUnwindSafe + 'static,
pub fn from_sink<T>(prefix: &str, sink: T) -> Self where
T: MetricSink + Sync + Send + RefUnwindSafe + 'static,
Create a new client instance that will use the given prefix for
all metrics emitted to the given MetricSink implementation.
Note that this client will discard errors encountered when
sending metrics via the MetricBuilder::send() method.
No-op Example
use cadence::{StatsdClient, NopMetricSink};
let prefix = "my.stats";
let client = StatsdClient::from_sink(prefix, NopMetricSink);UDP Socket Example
use std::net::UdpSocket;
use cadence::{StatsdClient, UdpMetricSink, DEFAULT_PORT};
let prefix = "my.stats";
let host = ("127.0.0.1", DEFAULT_PORT);
let socket = UdpSocket::bind("0.0.0.0:0").unwrap();
socket.set_nonblocking(true).unwrap();
let sink = UdpMetricSink::from(host, socket).unwrap();
let client = StatsdClient::from_sink(prefix, sink);Buffered UDP Socket Example
use std::net::UdpSocket;
use cadence::{StatsdClient, BufferedUdpMetricSink, DEFAULT_PORT};
let prefix = "my.stats";
let host = ("127.0.0.1", DEFAULT_PORT);
let socket = UdpSocket::bind("0.0.0.0:0").unwrap();
let sink = BufferedUdpMetricSink::from(host, socket).unwrap();
let client = StatsdClient::from_sink(prefix, sink);👎 Deprecated since 0.19.0: Superseded by ::from_sink() and ::builder()
Superseded by ::from_sink() and ::builder()
Create a new client instance that will use the given prefix to send metrics to the given host over UDP using an appropriate sink.
The created UDP socket will be put into non-blocking mode.
Note that this client will discard errors encountered when
sending metrics via the MetricBuilder::send() method.
Example
use cadence::{StatsdClient, UdpMetricSink};
let prefix = "my.stats";
let host = ("metrics.example.com", 8125);
let client = StatsdClient::from_udp_host(prefix, host);Failures
This method may fail if:
- It is unable to create a local UDP socket.
- It is unable to put the UDP socket into non-blocking mode.
- It is unable to resolve the hostname of the metric server.
- The host address is otherwise unable to be parsed.
pub fn builder<T>(prefix: &str, sink: T) -> StatsdClientBuilder where
T: MetricSink + Sync + Send + RefUnwindSafe + 'static,
pub fn builder<T>(prefix: &str, sink: T) -> StatsdClientBuilder where
T: MetricSink + Sync + Send + RefUnwindSafe + 'static,
Create a new builder with the provided prefix and metric sink.
A prefix and a metric sink are required to create a new client instance. All other optional customizations can be set by calling methods on the returned builder. Any customizations that aren’t set by the caller will use defaults.
Note, though a metric prefix is required, you may pass an empty string as a prefix. In this case, the metrics emitted will use only the bare keys supplied when you call the various methods to emit metrics.
General defaults:
- A no-op error handler will be used by default. Note that this
only affects errors encountered when using the
MetricBuilder::send()method (as opposed to.try_send()or any other method for sending metrics).
Example
use cadence::prelude::*;
use cadence::{StatsdClient, MetricError, NopMetricSink};
fn my_handler(err: MetricError) {
println!("Metric error: {}", err);
}
let client = StatsdClient::builder("some.prefix", NopMetricSink)
.with_error_handler(my_handler)
.build();
client.gauge_with_tags("some.key", 7)
.with_tag("region", "us-west-1")
.send();Trait Implementations
Use client.time_with_tags(key, val)
Use client.gauge_with_tags(key, val)
Use client.meter_with_tags(key, 1)
Use client.histogram_with_tags(key, val)
Use client.time(key, val)
Use client.gauge(key, val)
Use client.meter(key, 1)
Use client.histogram(key, val)
Record a single distribution value with the given key and return a
MetricBuilder that can be used to add tags to the metric. Read more
Record a single distribution value with the given key