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// Cadence - An extensible Statsd client for Rust! // // Copyright 2015-2017 TSH Labs // // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your // option. This file may not be copied, modified, or distributed // except according to those terms. use std::fmt; use std::net::{ToSocketAddrs, UdpSocket}; use std::sync::Arc; use std::time::Duration; use ::sinks::{MetricSink, UdpMetricSink}; use ::types::{MetricResult, MetricError, ErrorKind, Counter, Timer, Gauge, Meter, Histogram, Metric}; /// Trait for incrementing and decrementing counters. /// /// Counters are simple values incremented or decremented by a client. The /// rates at which these events occur or average values will be determined /// by the server receiving them. Examples of counter uses include number /// of logins to a system or requests received. /// /// See the [Statsd spec](https://github.com/b/statsd_spec) for more /// information. pub trait Counted { /// Increment the counter by `1` fn incr(&self, key: &str) -> MetricResult<Counter>; /// Decrement the counter by `1` fn decr(&self, key: &str) -> MetricResult<Counter>; /// Increment or decrement the counter by the given amount fn count(&self, key: &str, count: i64) -> MetricResult<Counter>; } /// Trait for recording timings in milliseconds. /// /// Timings are a positive number of milliseconds between a start and end /// time. Examples include time taken to render a web page or time taken /// for a database call to return. /// /// See the [Statsd spec](https://github.com/b/statsd_spec) for more /// information. pub trait Timed { /// Record a timing in milliseconds with the given key fn time(&self, key: &str, time: u64) -> MetricResult<Timer>; /// Record a timing in milliseocnds with the given key /// /// The duration will be truncated to millisecond precision. If the /// duration cannot be represented as a `u64` an error will be returned. fn time_duration(&self, key: &str, duration: Duration) -> MetricResult<Timer>; } /// Trait for recording gauge values. /// /// Gauge values are an instantaneous measurement of a value determined /// by the client. They do not change unless changed by the client. Examples /// include things like load average or how many connections are active. /// /// See the [Statsd spec](https://github.com/b/statsd_spec) for more /// information. pub trait Gauged { /// Record a gauge value with the given key fn gauge(&self, key: &str, value: u64) -> MetricResult<Gauge>; } /// Trait for recording meter values. /// /// Meter values measure the rate at which events occur. These rates are /// determined by the server, the client simply indicates when they happen. /// Meters can be thought of as increment-only counters. Examples include /// things like number of requests handled or number of times something is /// flushed to disk. /// /// See the [Statsd spec](https://github.com/b/statsd_spec) for more /// information. pub trait Metered { /// Record a single metered event with the given key fn mark(&self, key: &str) -> MetricResult<Meter>; /// Record a meter value with the given key fn meter(&self, key: &str, value: u64) -> MetricResult<Meter>; } /// Trait for recording histogram values. /// /// Histogram values are positive values that can represent anything, whose /// statistical distribution is calculated by the server. The values can be /// timings, amount of some resource consumed, size of HTTP responses in /// some application, etc. Histograms can be thought of as a more general /// form of timers. They are an extension to the Statsd protocol so you /// should check if your server supports them before using them. /// /// See the [Statsd spec](https://github.com/b/statsd_spec) for more /// information. pub trait Histogrammed { /// Record a single histogram value with the given key fn histogram(&self, key: &str, value: u64) -> MetricResult<Histogram>; } /// Trait that encompasses all other traits for sending metrics. /// /// If you wish to use `StatsdClient` with a generic type or place a /// `StatsdClient` instance behind a pointer (such as a `Box`) this will allow /// you to reference all the implemented methods for recording metrics, while /// using a single trait. An example of this is shown below. /// /// ``` /// use cadence::{MetricClient, StatsdClient, NopMetricSink}; /// /// let client: Box<MetricClient> = Box::new(StatsdClient::from_sink( /// "prefix", NopMetricSink)); /// /// client.count("some.counter", 1).unwrap(); /// client.time("some.timer", 42).unwrap(); /// client.gauge("some.gauge", 8).unwrap(); /// client.meter("some.meter", 13).unwrap(); /// client.histogram("some.histogram", 4).unwrap(); /// ``` pub trait MetricClient: Counted + Timed + Gauged + Metered + Histogrammed {} /// 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. /// /// * `Counted` for emitting counters. /// * `Timed` for emitting timings. /// * `Gauged` for emitting gauge values. /// * `Metered` for emitting meter values. /// * `Histogrammed` for emitting histogram values. /// * `MetricClient` for 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`). Some common ways to use the client in a multithreaded environment /// are given below. /// /// In each of these examples, 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` /// /// One option is to put all accesses to the client behind an atomic reference /// counting pointer (`std::sync::Arc`). If you are doing this, it makes sense /// to just 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. /// /// ``` no_run /// use std::net::UdpSocket; /// use std::sync::Arc; /// use std::thread; /// use cadence::prelude::*; /// use cadence::{StatsdClient, BufferedUdpMetricSink, DEFAULT_PORT}; /// /// struct MyRequestHandler { /// metrics: Arc<MetricClient + Send + Sync>, /// } /// /// 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.incr("request.handler"); /// }); /// /// Ok(()) /// } /// } /// ``` /// /// ## Clone Per Thread /// /// Another option for sharing the client between threads is just to clone /// client itself. Clones of the client are relatively cheap, typically only /// requiring a single heap allocation (of a `String`). While this cost isn't /// nothing, it's not too bad. An example of this is given below. /// /// ``` no_run /// use std::net::UdpSocket; /// use std::thread; /// use cadence::prelude::*; /// use cadence::{StatsdClient, BufferedUdpMetricSink, DEFAULT_PORT}; /// /// struct MyRequestHandler { /// metrics: StatsdClient, /// } /// /// 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: StatsdClient::from_sink("some.prefix", sink) /// } /// } /// /// fn handle_some_request(&self) -> Result<(), String> { /// let metric_clone = self.metrics.clone(); /// let _t = thread::spawn(move || { /// println!("Hello from the thread!"); /// metric_clone.incr("request.handler"); /// }); /// /// Ok(()) /// } /// } /// ``` /// /// As you can see, cloning the client itself looks a lot like using it with /// an `Arc`. #[derive(Clone)] pub struct StatsdClient { prefix: String, sink: Arc<MetricSink + Sync + Send>, } impl StatsdClient { /// Create a new client instance that will use the given prefix for /// all metrics emitted to the given `MetricSink` implementation. /// /// # 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); /// ``` pub fn from_sink<T>(prefix: &str, sink: T) -> StatsdClient where T: MetricSink + Sync + Send + 'static { StatsdClient { prefix: trim_key(prefix).to_string(), sink: Arc::new(sink), } } /// 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. /// /// # Example /// /// ```no_run /// 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 from_udp_host<A>(prefix: &str, host: A) -> MetricResult<StatsdClient> where A: ToSocketAddrs { let socket = UdpSocket::bind("0.0.0.0:0")?; socket.set_nonblocking(true)?; let sink = UdpMetricSink::from(host, socket)?; Ok(StatsdClient::from_sink(prefix, sink)) } // Convert a metric to its Statsd string representation and then send // it as UTF-8 bytes to the metric sink. Convert any I/O errors from the // sink to MetricResults with the metric itself as a payload for success // responses. fn send_metric<M: Metric>(&self, metric: &M) -> MetricResult<()> { let metric_string = metric.as_metric_str(); self.sink.emit(metric_string)?; Ok(()) } } impl fmt::Debug for StatsdClient { fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { write!(f, "StatsdClient {{ prefix: {:?}, sink: ... }}", self.prefix) } } impl Counted for StatsdClient { fn incr(&self, key: &str) -> MetricResult<Counter> { self.count(key, 1) } fn decr(&self, key: &str) -> MetricResult<Counter> { self.count(key, -1) } fn count(&self, key: &str, count: i64) -> MetricResult<Counter> { let counter = Counter::new(&self.prefix, key, count); self.send_metric(&counter)?; Ok(counter) } } impl Timed for StatsdClient { fn time(&self, key: &str, time: u64) -> MetricResult<Timer> { let timer = Timer::new(&self.prefix, key, time); self.send_metric(&timer)?; Ok(timer) } fn time_duration(&self, key: &str, duration: Duration) -> MetricResult<Timer> { let secs_as_ms = duration.as_secs().checked_mul(1_000); let nanos_as_ms = (duration.subsec_nanos() as u64).checked_div(1_000_000); let millis = secs_as_ms .and_then(|v1| nanos_as_ms.and_then(|v2| v1.checked_add(v2))) .ok_or_else(|| MetricError::from((ErrorKind::InvalidInput, "u64 overflow")))?; self.time(key, millis) } } impl Gauged for StatsdClient { fn gauge(&self, key: &str, value: u64) -> MetricResult<Gauge> { let gauge = Gauge::new(&self.prefix, key, value); self.send_metric(&gauge)?; Ok(gauge) } } impl Metered for StatsdClient { fn mark(&self, key: &str) -> MetricResult<Meter> { self.meter(key, 1) } fn meter(&self, key: &str, value: u64) -> MetricResult<Meter> { let meter = Meter::new(&self.prefix, key, value); self.send_metric(&meter)?; Ok(meter) } } impl Histogrammed for StatsdClient { fn histogram(&self, key: &str, value: u64) -> MetricResult<Histogram> { let histo = Histogram::new(&self.prefix, key, value); self.send_metric(&histo)?; Ok(histo) } } impl MetricClient for StatsdClient {} fn trim_key(val: &str) -> &str { if val.ends_with('.') { val.trim_right_matches('.') } else { val } } #[cfg(test)] mod tests { use std::time::Duration; use std::u64; use super::{trim_key, Counted, Timed, Gauged, Metered, Histogrammed, MetricClient, StatsdClient}; use ::sinks::NopMetricSink; use ::types::{ErrorKind, Timer}; #[test] fn test_trim_key_with_trailing_dot() { assert_eq!("some.prefix", trim_key("some.prefix.")); } #[test] fn test_trim_key_no_trailing_dot() { assert_eq!("some.prefix", trim_key("some.prefix")); } // The following tests really just ensure that we've actually // implemented all the traits we're supposed to correctly. If // we hadn't, this wouldn't compile. #[test] fn test_statsd_client_as_counted() { let client: Box<Counted> = Box::new(StatsdClient::from_sink( "prefix", NopMetricSink)); client.count("some.counter", 5).unwrap(); } #[test] fn test_statsd_client_as_timed() { let client: Box<Timed> = Box::new(StatsdClient::from_sink( "prefix", NopMetricSink)); client.time("some.timer", 20).unwrap(); } #[test] fn test_statsd_client_as_gauged() { let client: Box<Gauged> = Box::new(StatsdClient::from_sink( "prefix", NopMetricSink)); client.gauge("some.gauge", 32).unwrap(); } #[test] fn test_statsd_client_as_metered() { let client: Box<Metered> = Box::new(StatsdClient::from_sink( "prefix", NopMetricSink)); client.meter("some.meter", 9).unwrap(); } #[test] fn test_statsd_client_as_histogrammed() { let client: Box<Histogrammed> = Box::new(StatsdClient::from_sink( "prefix", NopMetricSink)); client.histogram("some.histogram", 4).unwrap(); } #[test] fn test_statsd_client_as_metric_client() { let client: Box<MetricClient> = Box::new(StatsdClient::from_sink( "prefix", NopMetricSink)); client.count("some.counter", 3).unwrap(); client.time("some.timer", 198).unwrap(); client.gauge("some.gauge", 4).unwrap(); client.meter("some.meter", 29).unwrap(); client.histogram("some.histogram", 32).unwrap(); } #[test] fn test_statsd_client_time_duration_no_overflow() { let client = StatsdClient::from_sink("prefix", NopMetricSink); let res = client.time_duration("key", Duration::from_millis(157)); let expected = Timer::new("prefix", "key", 157); assert_eq!(expected, res.unwrap()); } #[test] fn test_statsd_client_time_duration_with_overflow() { let client = StatsdClient::from_sink("prefix", NopMetricSink); let res = client.time_duration("key", Duration::from_secs(u64::MAX)); let err = res.unwrap_err(); assert_eq!(ErrorKind::InvalidInput, err.kind()) } }