Crius

Crius is a simple hystrix-like circuit breaker for rust.

"In the midst of chaos, there is also opportunity"

Usage

Simple command

```rust use crius::{command, Config, CriusError};

[derive(PartialEq, Debug)]

struct ExampleError; impl From for ExampleError { fn from(_: CriusError) -> Self { ExampleError } }

// Define a simple circuit breaker command: let mut cmd = command(Config::default(), |n| { if n > 10 { Err(ExampleError) } else { Ok(n * 2) }}).unwrap();

// and run it with an example input: let result = cmd.run(10); assert_eq!(Ok(20), result); ```

Command with fallback

```rust use crius::{commandwithfallback, Config, CriusError};

[derive(PartialEq, Debug)]

struct ExampleError; impl From for ExampleError { fn from(_: CriusError) -> Self { ExampleError } }

let doubleiflt_ten = |n| if n > 10 { Err(ExampleError) } else { Ok(n * 2) };

// Define a simple circuit breaker command: let mut cmd = commandwithfallback( Config::default(), doubleiflt_ten,

// Define a fallback:
|_err| 4, // It's always four.

).unwrap();

// and run it with an example input: let result = cmd.run(11); assert_eq!(Ok(4), result); ```

Command with custom configuration

```rust use crius::{command, Config, CriusError};

let config = *Config::default() .circuitopenms(5000) .errorthreshold(10) .errorthresholdpercentage(50) .bucketsinwindow(100) .bucketsizeinms(1000);

let mut cmd = command(config, |n| { if n > 10 { Err(ExampleError) } else { Ok(n * 2) }}).unwrap();

// and run it with an example input: let result = cmd.run(10); assert_eq!(Ok(20), result); ```

Configuration

circuit_open_ms - Time in ms commands are rejected after the circuit opened - Default 5000

error_threshold - Minimum amount of errors for the circuit to break - Default 10

error_threshold_percentage - Minimum error percentage for the circuit to break - Default 50

buckets_in_window - Rolling window to track success/error calls, this property defines the amount of buckets in a window (bucketsinwindow * bucketsizein_ms is the overall length in ms of the window) - Default 10

bucket_size_in_ms - This property defines the ms a bucket is long, i.e. each x ms a new bucket will be created (bucketsinwindow * bucketsizein_ms is the overall length in ms of the window) - Default 1000

circuit_breaker_enabled - Defines if the circuit breaker is enabled or not - Default true