An emitter for numbat metrics for Rust projects.
Here's an example of using the emitter:
```rust extern crate numbat; extern crate serde_json;
use numbat::Point;
let mut opts: Point = Point::new(); opts.insert("tag", serdejson::tovalue("local"));
let mut emitter = numbat::Emitter::new(opts, "test-emitter"); emitter.connect("tcp://localhost:4677");
emitter.emitname("start"); emitter.emitfloat("floating", 232.5); emitter.emitint("integer", 2048); emitter.emitunsigned("u16", 2048);
let mut point: Point = Point::new(); point.insert("name", serdejson::tovalue("inconvenience")); point.insert("tag", serdejson::tovalue("subjective")); point.insert("value", serdejson::tovalue(500.3)); emitter.emit(point); ```
However, it might be a giant pain to pass an emitter object around. If you need only one, connected to only one numbat collector, you can use the singleton:
```rust extern crate numbat; extern crate serde_json;
use numbat::Point;
let mut defaults: Point = Point::new(); defaults.insert("usingemitter", serdejson::to_value("global"));
numbat::emitter().init(defaults, "global-emitter"); numbat::emitter().connect("tcp://localhost:4677"); numbat::emitter().emit_name("start"); ```
Numbat points are BTreeMaps:
pub type Point<'a> = BTreeMap<&'a str, serde_json::Value>
numbat::emitter()
Get the singleton emitter for use with any of the below functions (aside from new()).
numbat::Emitter::new(tmpl: Point, app: &str)
Takes a template point with defaults to use for all emitted metrics (can be empty), and the name of the app. The name of the app will be used as a prefix for all emitted metrics. E.g., if your app is named tiger and you emit a metric with name field bite, it'll be sent to the collector as tiger.bite.
connect(uri: &str)
You must call this before your metrics go anywhere. Takes a URI of the form tcp://hostname:portnum. Everything is treated as TCP at the moment, so udp numbat collectors are useless with this library.
emit(mut Point)
Emit a full numbat metric, with as many tags as you wish. The time and value fields will be filled in if you do not provide them. Behaves like the javascript numbat emitter. (If it doesn't, that's a bug!)
emit_name(&str)
Shortcut for emitting a metric with value 1.
emit_float(&str, f32)
Shortcut for emitting a metric with the given name and floating-point value.
emit_int(&str, i32)
emit_int64(&mut self, name: &'e str, value: i64)
emit_unsigned(&mut self, name: &'e str, value: u32)
emit_unsigned16(&mut self, name: &'e str, value: u16)
Shortcuts for emitting a metric with the given name and integer value, with various signedness & size.
emit_name_val_tag(name: &'e str, value: u32, tag: &'e str, tagv: &'e str)
Shortcut for another common pattern: a name/value pair with a tag/value pair (both strings). Here's an example of emitting a metric for an http response, with timing & status code:
emit_name_int_tag_uint(name: &'e str, value: u32, tag: &'e str, tagv: &'e str)
emit_name_val_tag("response", 23, "status", 200);
Emit a metric
There's no error handling to speak of yet. It won't crash on errors, but it doesn't try to reconnect if it loses a connection. (I'm slowly untangling if/when the Rust TCPStream implementation bubbles errors up.)
I have no idea how to test it other than the little program in main.rs. There's no UDP emitter implementation (just use TCP like you should anyway).
The API for creating a point with custom fields could be nicer; would be great to hide the choice of serde_json from consumers. The API above covers most of the metrics we typically emit from a service.
ISC