jfix-stdlib

Provides common functionality that enhance usability of standard jvm.

• jfix-stdlib-concurrency
• jfix-stdlib-ratelimiter
• jfix-stdlib-socket

jfix-stdlib-concurrency

NamedExecutors DynamicPool

Named executors helps to monitor threads state, tasks latency and throughput.
All pools can be dynamically reconfigured

@PropertyId("dao.thread.pool.size")
lateinit var daoPoolSize: DynamicProperty<Integer>
lateinit var profiler: Profiler
...

val executor = NamedExecutors.newDynamicPool(
                "dao-pool",
                daoPoolSize,
                profiler)

NamedExecutors Scheduler

Scheduler is based on ScheduledThreadPoolExecutor but it can change it's rate dynamically.

@PropertyId("work.rate")
lateinit var rate: DynamicProperty<Long>
@PropertyId("pool.size")
lateinit var poolSize: DynamicProperty<Int>

lateinit var profiler: Profiler
...

val scheduler = NamedExecutors.newScheduler(
        "regular-work-pool",
        poolSize,
        profiler)         
        
scheduler.schedule(
        Schedule.withRate(rate),
        0,//delay
        Runnable {
            //do work here
        })        
               

NamedExecutors metrics

Common metrics that will work out of the box:

• pool.<poolName>.queue - size of pending tasks submitted to pool
• pool.<poolName>.activeThreads - count of currently running threads
• pool.<poolName>.await - how many ms spent task in pending state before pool took task for execution
• pool.<poolName>.run - how many ms task executed
• pool.<poolName>.poolSize - current size of the pool

Special case is Common Fork Join Pool that uses different set of metrics:

lateinit var profiler: Profiler
...
//Enable Common Fork Join Pool profiling
NamedExecutors.profileCommonPool(profiler)

• pool.commonPool.poolSize - current size of the pool
• pool.commonPool.activeThread - count of threads in the pool
• pool.commonPool.runningThread - count of currently active not blocking threads
• pool.commonPool.queue - size of pending tasks submitted to pool
• pool.commonPool.steal - count of stolen tasks

ThreadPoolGuard

CommonThreadPoolGuard, ThreadPoolGuard allows you to watch for queue size of the thread pool. If it outgrows threshold guard will invoke user handler and print stack trace of all threads.

val guard = CommonThreadPoolGuard(
                profiler,
                checkRate,
                threshold) { queueSize, dump ->
            log.error("Queue size $queueSize is too big. Current threads state: $dump")
        }

jfix-stdlib-ratelimiter

Provides RateLimiter and RateLimitedDispatcher.

RateLimiter

RateLimiter interface is defined here as abstraction for RateLimitedDispatcher. You can wrap whatever rate limiter implementation you want into it.

Out of the box there is one implementation - ConfigurableRateLimiter. Under the hood it uses AtomicRateLimiter of resilience4j-ratelimiter preconfigured it to acquire limits smoothly. AtomicRateLimiter does not distribute events inside refresh period, it releases all available permits immediately on interval start if there is a demand for them. To distribute event in our interval of 1 second ConfigurableRateLimiter divides it into chunks so that 1 chunk of time is limited to 1 permit.The drawback is that actual rate will be lower than configured - depending on requests' distribution.

RateLimitedDispatcher

Enables async usage of rate limiter. Submitted tasks are executed in the order of submission.

Provides following metrics:

• RateLimiterDispatcher.<dispatcherName>.queue_size – incoming tasks queue size
• RateLimiterDispatcher.<dispatcherName>.queue_wait – task's wait time in the queue before execution
• RateLimiterDispatcher.<dispatcherName>.acquire_limit - time to acquire limit
• RateLimiterDispatcher.<dispatcherName>.supplied_operation - supplied task execution duration

jfix-stdlib-socket

Provides SocketChecker.

SocketChecker

Allows to check port availability by its port number. Allows to get random free port number in range from 30000 to 60000.

JMH

Hot to run jmh tests for id generator:

cd jfix-stdlib-id-generator-jmh
gradle --stop
gradle --no-daemon clean build jmh

jfix-stdlib-batching

Encapsulates batching execution of several client's operations as one task.

Follow example of batch sending of http requests to different hosts:

import ru.fix.aggregating.profiler.AggregatingProfiler
import ru.fix.stdlib.batching.BatchTask
import ru.fix.stdlib.batching.BatchingManager
import ru.fix.stdlib.batching.BatchingParameters
import java.net.URI
import java.net.http.HttpClient
import java.net.http.HttpRequest
import java.net.http.HttpResponse
import java.util.concurrent.CompletableFuture
import java.util.concurrent.Executors
import kotlin.streams.asSequence

data class SimpleHttpBatchingConfig(
    val httpClient: HttpClient
)

data class SimpleBatchedHttpPayload(
    val batchItemContent: Int
) {
    val resultFuture: CompletableFuture<String> = CompletableFuture()
}

data class SimpleHttpBatchKeyType(val httpUri: URI)

object SimpleHttpBatchTask : BatchTask<SimpleHttpBatchingConfig, SimpleBatchedHttpPayload, SimpleHttpBatchKeyType> {

    override fun process(
        config: SimpleHttpBatchingConfig,
        batch: MutableList<SimpleBatchedHttpPayload>,
        key: SimpleHttpBatchKeyType
    ) {
        // merge content from several requests into one batched
        val joinedContent =
            batch.joinToString(separator = ", ", prefix = "[", postfix = "]") { it.batchItemContent.toString() }

        // send batched http request
        config.httpClient.sendAsync(
            HttpRequest.newBuilder()
                .uri(key.httpUri)
                .POST(HttpRequest.BodyPublishers.ofString(joinedContent))
                .build(),
            HttpResponse.BodyHandlers.ofLines()
        ).thenApplyAsync {
            // let client code know that some response arrived
            for ((index, response) in it.body().asSequence().withIndex()) {
                batch[index].resultFuture.complete(response)
            }
        }
        // do not block and process to the next batch
        // HOWEVER it is up to client to decide whether to block or not
    }

}

val batchingManagerProfiler = AggregatingProfiler()

val batchingManager = BatchingManager<SimpleHttpBatchingConfig, SimpleBatchedHttpPayload, SimpleHttpBatchKeyType>(
    SimpleHttpBatchingConfig(
        httpClient = HttpClient.newBuilder()
            .executor(Executors.newSingleThreadExecutor())
            .build()
    ),
    SimpleHttpBatchTask,
    BatchingParameters().apply {
        batchSize = 256
        batchThreads = 2
    },
    "simple-batch-manager",
    batchingManagerProfiler
)


// Usage in clients
val testHost1 = SimpleHttpBatchKeyType(httpUri = URI.create("http://test-host-1"))
val testHost2 = SimpleHttpBatchKeyType(httpUri = URI.create("http://test-host-2"))

val testHost1Requests = (1..3).map {
    SimpleBatchedHttpPayload(batchItemContent = it)
}

val testHost2Requests = (2..7).map {
    SimpleBatchedHttpPayload(batchItemContent = it)
}

for (testHost1Request in testHost1Requests) {
    batchingManager.enqueue(testHost1, testHost1Request)
}
for (testHost2Request in testHost2Requests) {
    batchingManager.enqueue(testHost2, testHost2Request)
}

(testHost1Requests + testHost2Requests).forEach { request ->
    request.resultFuture.thenApplyAsync { response ->
        println("""Request with content='${request.batchItemContent} - response is '$response''""")
    }
}