Configure Hystrix

Overview

This page will cover several topics about Hystrix configuration:

• Configure at Different Levels
  • Apply at Class Level
  • Apply at Function Level
• Configure on Different Properties
  • Command Properties
  • Thread Pool Properties
  • Collapser Properties
• Configuration Parameter Quick Lookup
  • Thread Pool Properties
  • Command Properties
  • Collapser Properties

---

Configure at Different Levels

You can apply your configuration at different Levels:

• Class level
• Function level

Apply at Class Level

Annotate the class with the @DefaultProperties annotation. So all the functions annotated by the @HystrixCommand annotation will share the same configuration. For example

@DefaultProperties(
    commandProperties={@HystrixProperty(
        name="execution.isolation.thread.timeoutInMilliseconds", 
        value="12000")}
)
public class LicenseService {
    /* omit the details */
}

Apply at Function Level

Annotate the function with the @HystrixCommand annotation.

@HystrixCommand(
    commandProperties={@HystrixProperty(
        name="execution.isolation.thread.timeoutInMilliseconds", 
        value="12000")}
)
public List<License> getLicensesByOrg(String organizationId) {
    return licenseRepository.findByOrganizationId(organizationId);
}

---

Configure on Different Properties

There are 3 types of properties you can configure:

• Command Properties
• Thread Pool Properties
• Collapser Properties

Command Properties

@HystrixCommand (
    threadPoolProperties = {
        @HystrixProperty(name = "NameA",value="ValueA"),
	@HystrixProperty(name = "NameB",value="ValueB")
    }
)
public List<License> getLicensesByOrg(String organizationId) {
    return licenseRepository.findByOrganizationId(organizationId);
}

Thread Pool Properties

@HystrixCommand (
    commandProperties = {
        @HystrixProperty(name = "NameA",value="ValueA"),
	@HystrixProperty(name = "NameB",value="ValueB")
    }
)
public List<License> getLicensesByOrg(String organizationId) {
    return licenseRepository.findByOrganizationId(organizationId);
}

Collapser Properties

This properties can not be set in the @HystrixCommand annotation or the @DefaultProperties annotation.

---

Configuration Parameter Quick Lookup

Thread Pool Properties

Name	Description	Default Value
coreSize	Sets the core thread-pool size.	10
maximumSize	Sets the maximum thread-pool size.	10
maxQueueSize	The maximum size of the queue which is in front of the thread-pool.	-1
queueSizeRejectionThreshold	Sets the queue size rejection threshold - an artificial maximum queue size at which rejections will occur even if maxQueueSize has not been reached.	5
keepAliveTimeMinutes	Sets the keep-alive time, in minutes.	1
allowMaximumSizeToDivergeFromCoreSize	Allows the configuration for maximumSize to take effect.	false
metrics.rollingStats.timeInMilliseconds	Sets the duration of the statistical rolling window, in milliseconds. This is how long metrics are kept for the thread pool.	10000
metrics.rollingStats.numBuckets	Sets the number of buckets the rolling statistical window is divided into.	10

Command Properties

Topic	Name	Description	Default Value
Execution	execution.isolation.strategy	Indicates which isolation strategy will execute with. 2 options: THREAD, SEMAPHORE.	THREAD
Execution	execution.isolation.thread.timeoutInMilliseconds	The time in milliseconds after which the caller will observe a timeout and walk away from the command execution.	1000
Execution	execution.timeout.enabled	Indicates whether the execution should have a timeout or not.	true
Execution	execution.isolation.thread.interruptOnTimeout	Indicates whether the execution should be interrupted when a timeout occurs.	true
Execution	execution.isolation.thread.interruptOnCancel	Indicates whether the execution should be interrupted when a cancellation occurs.	false
Execution	execution.isolation.semaphore.maxConcurrentRequests	Sets the maximum number of requests allowed to a method when you are using SEMAPHORE isolation strategy.	10
Circuit Breaker	circuitBreaker.enabled	Determines whether a circuit breaker will be used to track health and to short-circuit requests if it trips.	true
Circuit Breaker	circuitBreaker.requestVolumeThreshold	Sets the minimum number of requests in a rolling window that will trip the circuit.	20
Circuit Breaker	circuitBreaker.sleepWindowInMilliseconds	Sets the amount of time, after tripping the circuit, to reject requests before allowing attempts again to determine if the circuit should again be closed.	5000
Circuit Breaker	circuitBreaker.errorThresholdPercentage	Sets the error percentage at or above which the circuit should trip open and start short-circuiting requests to fallback logic.	50
Circuit Breaker	circuitBreaker.forceOpen	Forces the circuit breaker into an open (tripped) state in which it will reject all requests.	false
Circuit Breaker	circuitBreaker.forceClosed	Forces the circuit breaker into a closed state in which it will allow requests regardless of the error percentage.	false
Metrics	metrics.rollingStats.timeInMilliseconds	Sets the duration of the statistical rolling window, in milliseconds. This is how long Hystrix keeps metrics for the circuit breaker to use and for publishing.	10000
Metrics	metrics.rollingStats.numBuckets	Sets the number of buckets the rolling statistical window is divided into.	10
Metrics	metrics.rollingPercentile.enabled	Indicates whether execution latencies should be tracked and calculated as percentiles.	true
Metrics	metrics.rollingPercentile.timeInMilliseconds	Sets the duration of the rolling window in which execution times are kept to allow for percentile calculations, in milliseconds.	60000
Metrics	metrics.rollingPercentile.numBuckets	Sets the number of buckets the rollingPercentile window will be divided into.	6
Metrics	metrics.rollingPercentile.bucketSize	Sets the maximum number of execution times that are kept per bucket.	100
Metrics	metrics.healthSnapshot.intervalInMilliseconds	Sets the time to wait, in milliseconds, between allowing health snapshots to be taken that calculate success and error percentages and affect circuit breaker status.	500
Fallback	fallback.isolation.semaphore.maxConcurrentRequests	Sets the maximum number of requests a fallback method is allowed to make from the calling thread.	10
Fallback	fallback.enabled	Determines whether a call to a fallback method will be attempted when failure or rejection occurs.	true
Request Context	requestCache.enabled	Indicates whether the getCacheKey method should be used with the request cache to provide de-duplication functionality via request-scoped caching.	true
Request Context	requestLog.enabled	Indicates whether HystrixCommand execution and events should be logged or not.	true

Collapser Properties

Name	Description	Default Value
maxRequestsInBatch	Sets the maximum number of requests allowed in a batch before this triggers a batch execution.	Integer.MAX_VALUE
timerDelayInMilliseconds	Sets the number of milliseconds after the creation of the batch that its execution is triggered.	10
requestCache.enabled	Indicates whether request caching is enabled for HystrixCollapser.execute() and HystrixCollapser.queue() invocations.	true