io.github.resilience4j.kotlin.bulkhead.Bulkhead.kt Maven / Gradle / Ivy

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Resilience4j is a lightweight, easy-to-use fault tolerance library designed for Java8 and functional programming

There is a newer version: 2.2.0

/*
 *
 *  Copyright 2019: Brad Newman
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *
 */
package io.github.resilience4j.kotlin.bulkhead

import io.github.resilience4j.bulkhead.Bulkhead
import io.github.resilience4j.bulkhead.BulkheadConfig
import io.github.resilience4j.kotlin.isCancellation
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.withContext
import kotlin.coroutines.coroutineContext

/**
 * Decorates and executes the given suspend function [block].
 *
 * If [BulkheadConfig.maxWaitDuration] is non-zero, *blocks* until the max wait time is reached or permission is obtained.
 * For this reason, it is not recommended to use this extension function with Bulkheads with non-zero max wait times.
 */
suspend fun  Bulkhead.executeSuspendFunction(block: suspend () -> T): T {
    acquirePermissionSuspend()
    return try {
        block().also { onComplete() }
    } catch (e: Throwable) {
        if (isCancellation(coroutineContext, e)) {
            releasePermission()
        } else {
            onComplete()
        }
        throw e
    }
}

/**
 * Decorates the given function [block] and returns it.
 *
 * If [BulkheadConfig.maxWaitDuration] is non-zero, *blocks* until the max wait time is reached or permission is obtained.
 * For this reason, it is not recommended to use this extension function with Bulkheads with non-zero max wait times.
 */
fun  Bulkhead.decorateFunction(block: () -> T): () -> T = {
    executeFunction(block)
}

/**
 * Decorates and executes the given function [block].
 *
 * If [BulkheadConfig.maxWaitDuration] is non-zero, *blocks* until the max wait time is reached or permission is obtained.
 * For this reason, it is not recommended to use this extension function with Bulkheads with non-zero max wait times.
 */
fun  Bulkhead.executeFunction(block: () -> T): T {
    return this.executeCallable(block)
}

/**
 * Decorates the given suspend function [block] and returns it.
 *
 * If [BulkheadConfig.maxWaitDuration] is non-zero, *blocks* until the max wait time is reached or permission is obtained.
 * For this reason, it is not recommended to use this extension function with Bulkheads with non-zero max wait times.
 */
fun  Bulkhead.decorateSuspendFunction(block: suspend () -> T): suspend () -> T = {
    executeSuspendFunction(block)
}

/**
 * Try to immediately acquire permission from the bulkhead when it is not expected to block.
 *
 * If a wait duration is configured on the bulkhead, then attempt to acquire permission within
 * the confines of a dispatcher specialized for blocking calls.
 *
 */
internal suspend fun Bulkhead.acquirePermissionSuspend() {
    // Fast path. Avoid dispatch context switch.
    if (bulkheadConfig.maxWaitDuration.isZero) {
        acquirePermission()
    } else {
        withContext(Dispatchers.IO) { acquirePermission() }
    }
}