Programmatically changing Hystrix properties

Question

I have a circuit breaker set up that I would like to change parameters for runtime. Things like threads and timeout needs to be tuned at customer site.

I create a HystrixCommandProperties.Setter like this:

HystrixCommandProperties.Setter hystrixProps = 
    HystrixCommandProperties.defaultSetter()
        .withCircuitBreakerSleepWindowInMilliseconds(myconf.sleepWindow);
HystrixThreadPoolProperties.Setter threadPoolSettings = 
    HystrixThreadPoolProperties.Setter()
        .withCoreSize(myconf.threadPoolSize);

new MyCommand(HystrixCommand.Setter.withGroupKey("mygroup")
    .andCommandPropertiesDefaults(hystrixProps)
    .andThreadPoolPropertiesDefaults(threadPoolSettings));

MyCommand implements standard HystrixCommand and calls super(hystrixProps).

This works the first time, but when I try to change the properties at runtime (same group name) nothing happens. Is there another way to programmatically change this?

I don't want to go through the property files or specifying an URL to Archaius.

There are also answers that tells me to go through Archaius with ConfigurationManager.getConfigInstance().setProperty("...") . But surely there has to be a way that is similar to the original setters I create? Doing it completely different because it's the second time around just feels awkward.

Answer 1

Late answer, but today i struggled with the same thing and found a way.

The way the default property manager is implemented is that it uses a cache of HystrixCommandProperties based on the name of the command you run. On the first use of the command, it caches what it gets out of the HystrixCommandProperties.Setter passed to the Command's constructor and that's it.

However, using the custom HystrixPropertiesStrategy as a Plugin you can override the cache key (and hence force Hystrix to re-evaluate the Setter passed to the new Command instance, because the cache key is new, so it thinks it's a new Command).

The code would then look similar to this:

public HystrixCommandFactory(....) {
    HystrixPlugins.getInstance().registerPropertiesStrategy(new HystrixPropertiesStrategyWithReloadableCache());
    updateHystrixSettings();        
}

//configurable attributes
private volatile int commandTimeoutMillis;
private volatile long lastSettingsUpdatedTimestamp;
private volatile HystrixCommand.Setter setterForNewCommands;

private void updateHystrixSettings() {
    lastSettingsUpdatedTimestamp = LocalDateTime.now().toDateTime().getMillis();
    HystrixCommandProperties.Setter propertiesSetter = HystrixCommandProperties.Setter()
        .withExecutionTimeoutInMilliseconds(commandTimeoutMillis)
        .withExecutionTimeoutEnabled(true);

    this.setterForNewCommands = HystrixCommand.Setter
        .withGroupKey(HystrixCommandGroupKey.Factory.asKey(GROUP_NAME))
        .andCommandPropertiesDefaults(propertiesSetter);

}

public void setCommandTimeoutMillis(int commandTimeoutMillis) {     
    this.commandTimeoutMillis = commandTimeoutMillis;
    updateHystrixSettings();        
}

private class HystrixPropertiesStrategyWithReloadableCache extends HystrixPropertiesStrategy {

    @Override
    public String getCommandPropertiesCacheKey(HystrixCommandKey commandKey, HystrixCommandProperties.Setter builder) {
        return String.format("%s-%d", commandKey.name(), lastSettingsUpdatedTimestamp);
    }
}

Alternatively, you could always return null from the getCommandPropertiesCacheKey method (that completely turns off caching), but then you have the overhead of Hystrix having to reconstruct the HystrixCommandProperties each time a Command is called

PS: Be sure to use proper thread synchronization for reading and updating these properties, because those will be called from different threads. I omitted that in this sample for simplicity, but I actually use a ReentrantReadWriteLock in my code to guard accesses to these variables

Answer 2

For future reference: I ended up using the settings through ConfigurationManager and a string property.

ConfigurationManager.getConfigInstance().setProperty("...")

It let's me change things, but in a less type-safe way than the original code. I did struggle for some time with a typo in the string which is why I'd like to avoid that.

I now use this for all the properties I need to change runtime. Creating a new Hystrix circuit breaker every time something changes (new command key) could be an option as well, but would break using properties files later on.

Answer 3

There is a very simple way of doing this. It just needs 2 steps: a. registering the right plugin b. Adding the correct strategy with the required override.

Use-case: Override ExecutionTimeoutInMilliseconds to 30000 ms from 1000 ms

HystrixPlugins.getInstance().registerPropertiesStrategy(new HystrixPropertiesStrategy() {
            @Override
            public HystrixCommandProperties getCommandProperties(HystrixCommandKey commandKey, HystrixCommandProperties.Setter builder) {
                HystrixCommandProperties.Setter timeout
                        = HystrixCommandProperties.Setter().withExecutionTimeoutInMilliseconds(30000);
                return super.getCommandProperties(commandKey, timeout);
            }
        });

Here I am just overriding the required property. When you run your application you can see this in the DEBUG mode:

2018-06-08 23:18:32 [main] DEBUG c.n.h.s.p.HystrixPropertiesChainedProperty - Flipping property: hystrix.command.Client#getAllData().execution.isolation.thread.timeoutInMilliseconds to use its current value: 30000

Answer 4

Hystrix properties can also be set in our service class inside @HystrixCommand annotation, for this we use the Hystrix-Javanica project which is used for implementing the annotations in our project. For that we need to add the dependency of hystrix-javanica into our classpath.

Dependency for Maven:

<dependency>
    <groupId>com.netflix.hystrix</groupId>
    <artifactId>hystrix-javanica</artifactId>
    <version>x.y.z</version>
</dependency>

Inside the @HystrixCommand annotation we can use @HystrixProperty to set the properties for hystrix.

sample @HystrixCommand properties setting:

@HystrixCommand(groupKey = "StoreSubmission", commandKey = "StoreSubmission", threadPoolKey = "StoreSubmission", commandProperties = {
        @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds", value = "30000"),
        @HystrixProperty(name = "circuitBreaker.requestVolumeThreshold", value = "4"),
        @HystrixProperty(name = "circuitBreaker.sleepWindowInMilliseconds", value = "60000"),
        @HystrixProperty(name = "metrics.rollingStats.timeInMilliseconds", value = "180000") }, threadPoolProperties = {
        @HystrixProperty(name = "coreSize", value = "30"),
        @HystrixProperty(name = "metrics.rollingStats.timeInMilliseconds", value = "180000") })
public String storeSubmission(ReturnType returnType, InputStream is, String id) {
}

The best way to define these properties is in externalized application.yaml, that way you can control it better & change them for different environments.

Here is the sample hystrix config in my application.yaml

hystrix:
   command.StoreSubmission.execution.isolation.thread.timeoutInMilliseconds: 30000
   command.StoreSubmission.circuitBreaker.requestVolumeThreshold: 4
   command.StoreSubmission.circuitBreaker.sleepWindowInMilliseconds: 60000
   command.StoreSubmission.metrics.rollingStats.timeInMilliseconds: 180000
   collapser.StoreSubmission.maxRequestsInBatch: 1
   collapser.StoreSubmission.requestCache.enabled: FALSE
   threadpool.StoreSubmission.coreSize: 30
   threadpool.StoreSubmission.metrics.rollingStats.timeInMilliseconds: 180000

The Exact format for the application.yml file is

hystrix:
    command:
        findAllProducts:
            execution:
                isolation:
                    thread:
                        timeoutInMilliseconds: 1000
            circuitBreaker:
                requestVolumeThreshold: 20
                errorThresholdPercentage: 50
            metrics:
                rollingStats:
                    timeInMilliseconds: 10000
                    numBuckets: 10
    threadpool:
        ProductService:
            coreSize: 10

For further information on Hystrix-Javanica visit here

Answer 5

For me HystrixPropertiesStrategy and ConfigurationManager.getConfigInstance().setProperty(..) did not help , I ended up creating my own HystrixDynamicProperty implementation as follows,

public CustomHystrixDynamicProperty extends HystrixDynamicPropertiesArchaius {

    @Override
    public HystrixDynamicProperty<Integer> getInteger(final String name, final Integer fallback) {
         if(name.equals("Your hystrix Property")){
            return new HystrixDynamicProperty<Integer>() {
            public Integer get() {
               // Place your logic here...
              return yourValue;
             }
           public String getName(){ return name;};
           public void addCallback(Runnable callback) {};

              }
           } else {
                return super.getInteger(name,fallback);
                 }


    }
}

and add below Property before you start the spring boot application.

System.setProperty("hystrix.plugin.HystrixDynamicProperties.implementation","YourPackage.CustomHystrixDynamicProperty");

For Curious developers: : getDynamicProperty method from the HystrixPropertiesChainedProperty is overriding the overridden value via HystrixPropertiesStrategy, which is being called by "AbstractCommand" everytime before setting up the HystrixCommand for execution, So HystrixPropertiesStrategy idea did not work for me.