CircuitBreaker implementation and testing
This commit is contained in:
anhefti
parent
6e020b8e6f
commit
c89d813dca
8 changed files with 526 additions and 74 deletions
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/*
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* Copyright (c) 2019 ETH Zürich, Educational Development and Technology (LET)
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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package ch.ethz.seb.sebserver.gbl.async;
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import java.util.concurrent.CompletableFuture;
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import java.util.function.Supplier;
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import org.springframework.scheduling.annotation.Async;
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import org.springframework.scheduling.annotation.EnableAsync;
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import org.springframework.stereotype.Component;
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@Component
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@EnableAsync
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public class AsyncRunner {
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@Async(AsyncServiceSpringConfig.EXECUTOR_BEAN_NAME)
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public <T> CompletableFuture<T> runAsync(final Supplier<T> supplier) {
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return CompletableFuture.completedFuture(supplier.get());
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}
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}
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/*
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* Copyright (c) 2019 ETH Zürich, Educational Development and Technology (LET)
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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package ch.ethz.seb.sebserver.gbl.async;
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import java.util.function.Supplier;
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import org.springframework.context.annotation.Lazy;
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import org.springframework.stereotype.Service;
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@Lazy
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@Service
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public class AsyncService {
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private final AsyncRunner asyncRunner;
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protected AsyncService(final AsyncRunner asyncRunner) {
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this.asyncRunner = asyncRunner;
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}
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public <T> MemoizingCircuitBreaker<T> createCircuitBreaker(final Supplier<T> blockingSupplier) {
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return new MemoizingCircuitBreaker<>(this.asyncRunner, blockingSupplier);
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}
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public <T> MemoizingCircuitBreaker<T> createCircuitBreaker(
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final Supplier<T> blockingSupplier,
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final long maxBlockingTime) {
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return new MemoizingCircuitBreaker<>(
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this.asyncRunner,
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blockingSupplier,
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MemoizingCircuitBreaker.DEFAULT_MAX_FAILING_ATTEMPTS,
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maxBlockingTime,
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MemoizingCircuitBreaker.DEFAULT_TIME_TO_RECOVER);
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}
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public <T> MemoizingCircuitBreaker<T> createCircuitBreaker(
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final Supplier<T> blockingSupplier,
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final int maxFailingAttempts,
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final long maxBlockingTime,
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final long timeToRecover) {
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return new MemoizingCircuitBreaker<>(
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this.asyncRunner,
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blockingSupplier,
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maxFailingAttempts,
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maxBlockingTime,
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timeToRecover);
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}
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}
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/*
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* Copyright (c) 2019 ETH Zürich, Educational Development and Technology (LET)
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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package ch.ethz.seb.sebserver.gbl.async;
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import java.util.concurrent.Executor;
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import org.springframework.context.annotation.Bean;
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import org.springframework.context.annotation.Configuration;
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import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
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@Configuration
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public class AsyncServiceSpringConfig {
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public static final String EXECUTOR_BEAN_NAME = "AsyncServiceExecutorBean";
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@Bean(name = EXECUTOR_BEAN_NAME)
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public Executor threadPoolTaskExecutor() {
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final ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
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executor.setCorePoolSize(7);
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executor.setMaxPoolSize(42);
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executor.setQueueCapacity(11);
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executor.setThreadNamePrefix("asyncService-");
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executor.initialize();
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return executor;
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}
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}
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/*
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* Copyright (c) 2019 ETH Zürich, Educational Development and Technology (LET)
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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package ch.ethz.seb.sebserver.gbl.async;
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import java.util.concurrent.TimeUnit;
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import java.util.concurrent.atomic.AtomicInteger;
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import java.util.function.Supplier;
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import org.slf4j.Logger;
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import org.slf4j.LoggerFactory;
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import ch.ethz.seb.sebserver.gbl.Constants;
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import ch.ethz.seb.sebserver.gbl.util.Result;
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/** A circuit breaker with three states (CLOSED, HALF_OPEN, OPEN) and memoizing.
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*
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* // TODO more docu:
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*
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* @param <T> */
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public class MemoizingCircuitBreaker<T> implements Supplier<Result<T>> {
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private static final Logger log = LoggerFactory.getLogger(MemoizingCircuitBreaker.class);
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public static final int DEFAULT_MAX_FAILING_ATTEMPTS = 5;
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public static final long DEFAULT_MAX_BLOCKING_TIME = Constants.MINUTE_IN_MILLIS;
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public static final long DEFAULT_TIME_TO_RECOVER = Constants.MINUTE_IN_MILLIS * 10;
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public enum State {
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CLOSED,
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HALF_OPEN,
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OPEN
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}
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private final AsyncRunner asyncRunner;
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private final Supplier<T> supplierThatCanFailOrBlock;
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private final int maxFailingAttempts;
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private final long maxBlockingTime;
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private final long timeToRecover;
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private State state = State.CLOSED;
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private final AtomicInteger failingCount = new AtomicInteger(0);
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private long lastSuccessTime;
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private final Result<T> notAvailable = Result.ofRuntimeError("No chached resource available");
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private Result<T> cached = null;
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MemoizingCircuitBreaker(
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final AsyncRunner asyncRunner,
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final Supplier<T> supplierThatCanFailOrBlock) {
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this(
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asyncRunner,
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supplierThatCanFailOrBlock,
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DEFAULT_MAX_FAILING_ATTEMPTS,
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DEFAULT_MAX_BLOCKING_TIME,
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DEFAULT_TIME_TO_RECOVER);
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}
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MemoizingCircuitBreaker(
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final AsyncRunner asyncRunner,
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final Supplier<T> supplierThatCanFailOrBlock,
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final int maxFailingAttempts,
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final long maxBlockingTime,
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final long timeToRecover) {
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this.asyncRunner = asyncRunner;
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this.supplierThatCanFailOrBlock = supplierThatCanFailOrBlock;
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this.maxFailingAttempts = maxFailingAttempts;
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this.maxBlockingTime = maxBlockingTime;
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this.timeToRecover = timeToRecover;
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}
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@Override
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public Result<T> get() {
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final long currentTime = System.currentTimeMillis();
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if (log.isDebugEnabled()) {
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log.debug("Called on: {} current state is: {} failing count: {}",
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currentTime,
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this.state,
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this.failingCount);
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}
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switch (this.state) {
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case CLOSED:
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return handleClosed(currentTime);
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case HALF_OPEN:
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return handleHalfOpen(currentTime);
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case OPEN:
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return handelOpen(currentTime);
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default:
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throw new IllegalStateException();
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}
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}
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public State getState() {
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return this.state;
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}
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T getChached() {
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if (this.cached == null) {
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return null;
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}
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return this.cached.get();
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}
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private Result<T> handleClosed(final long currentTime) {
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if (log.isDebugEnabled()) {
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log.debug("Handle Closed on: {}", currentTime);
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}
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final Result<T> result = attempt();
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if (result.hasError()) {
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if (log.isDebugEnabled()) {
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log.debug("Attempt failed. failing count: {}", this.failingCount);
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}
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final int failing = this.failingCount.incrementAndGet();
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if (failing > this.maxFailingAttempts) {
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if (log.isDebugEnabled()) {
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log.debug("Changing state from Open to Half Open and return cached value");
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}
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this.state = State.HALF_OPEN;
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this.failingCount.set(0);
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return getCached(result);
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} else {
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return get();
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}
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} else {
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this.lastSuccessTime = System.currentTimeMillis();
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this.cached = result;
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return result;
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}
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}
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private Result<T> handleHalfOpen(final long currentTime) {
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if (log.isDebugEnabled()) {
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log.debug("Handle Half Open on: {}", currentTime);
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}
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final Result<T> result = attempt();
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if (result.hasError()) {
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final int fails = this.failingCount.incrementAndGet();
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if (fails > this.maxFailingAttempts) {
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if (log.isDebugEnabled()) {
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log.debug("Changing state from Half Open to Open and return cached value");
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}
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this.state = State.OPEN;
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this.failingCount.set(0);
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}
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return getCached(result);
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} else {
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if (log.isDebugEnabled()) {
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log.debug("Changing state from Half Open to Closed and return value");
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}
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this.state = State.CLOSED;
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this.failingCount.set(0);
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return result;
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}
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}
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/** As long as time to recover is not reached, return from cache
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* If time to recover is reached go to half open state and try again */
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private Result<T> handelOpen(final long currentTime) {
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if (log.isDebugEnabled()) {
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log.debug("Handle Open on: {}", currentTime);
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}
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if (currentTime - this.lastSuccessTime < this.timeToRecover) {
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return getCached(this.notAvailable);
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} else {
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if (log.isDebugEnabled()) {
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log.debug("Time to recover reached. Changing state from Closed to Half Open and try agian");
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}
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this.state = State.HALF_OPEN;
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this.failingCount.set(0);
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return get();
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}
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}
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private Result<T> attempt() {
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try {
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return Result.of(this.asyncRunner.runAsync(this.supplierThatCanFailOrBlock)
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.get(this.maxBlockingTime, TimeUnit.MILLISECONDS));
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} catch (final Exception e) {
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return Result.ofError(e);
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}
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}
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private Result<T> getCached(final Result<T> error) {
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if (this.cached != null) {
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return this.cached;
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} else {
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return error;
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}
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}
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@Override
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public String toString() {
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return "MemoizingCircuitBreaker [maxFailingAttempts=" + this.maxFailingAttempts + ", maxBlockingTime="
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+ this.maxBlockingTime + ", timeToRecover=" + this.timeToRecover + ", state=" + this.state
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+ ", failingCount="
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+ this.failingCount + ", lastSuccessTime=" + this.lastSuccessTime + ", cached=" + this.cached + "]";
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}
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}
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/*
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* Copyright (c) 2019 ETH Zürich, Educational Development and Technology (LET)
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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package ch.ethz.seb.sebserver.gbl.util;
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import java.util.function.Supplier;
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public class SupplierWithCircuitBreaker<T> implements Supplier<Result<T>> {
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private final Supplier<T> supplierThatCanFailOrBlock;
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private final int maxFailingAttempts;
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private final long maxBlockingTime;
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private final T cached = null;
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public SupplierWithCircuitBreaker(
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final Supplier<T> supplierThatCanFailOrBlock,
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final int maxFailingAttempts,
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final long maxBlockingTime) {
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this.supplierThatCanFailOrBlock = supplierThatCanFailOrBlock;
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this.maxFailingAttempts = maxFailingAttempts;
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this.maxBlockingTime = maxBlockingTime;
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}
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@Override
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public Result<T> get() {
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// TODO start an async task that calls the supplierThatCanFailOrBlock and returns a Future
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// try to get the result periodically until maxBlockingTime
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// if the supplier returns error, try for maxFailingAttempts
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// if success cache and return the result
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// if failed return the cached values
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return Result.tryCatch(() -> this.supplierThatCanFailOrBlock.get());
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}
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}
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@ -24,6 +24,7 @@ import org.springframework.http.client.ClientHttpRequestFactory;
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import org.springframework.stereotype.Service;
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import ch.ethz.seb.sebserver.gbl.Constants;
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import ch.ethz.seb.sebserver.gbl.async.AsyncService;
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import ch.ethz.seb.sebserver.gbl.model.Page;
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import ch.ethz.seb.sebserver.gbl.model.exam.QuizData;
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import ch.ethz.seb.sebserver.gbl.model.institution.LmsSetup;
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@ -44,6 +45,7 @@ public class LmsAPIServiceImpl implements LmsAPIService {
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private static final Logger log = LoggerFactory.getLogger(LmsAPIServiceImpl.class);
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private final AsyncService asyncService;
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private final LmsSetupDAO lmsSetupDAO;
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private final ClientCredentialService clientCredentialService;
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private final ClientHttpRequestFactory clientHttpRequestFactory;
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@ -52,11 +54,13 @@ public class LmsAPIServiceImpl implements LmsAPIService {
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private final Map<CacheKey, LmsAPITemplate> cache = new ConcurrentHashMap<>();
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public LmsAPIServiceImpl(
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final AsyncService asyncService,
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final LmsSetupDAO lmsSetupDAO,
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final ClientCredentialService clientCredentialService,
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final ClientHttpRequestFactory clientHttpRequestFactory,
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@Value("${sebserver.lms.openedix.api.token.request.paths}") final String alternativeTokenRequestPaths) {
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this.asyncService = asyncService;
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this.lmsSetupDAO = lmsSetupDAO;
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this.clientCredentialService = clientCredentialService;
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this.clientHttpRequestFactory = clientHttpRequestFactory;
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@ -102,6 +106,7 @@ public class LmsAPIServiceImpl implements LmsAPIService {
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private Result<List<QuizData>> getAllQuizzesFromLMSSetups(final FilterMap filterMap) {
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return Result.tryCatch(() -> {
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// case 1. if lmsSetupId is available only get quizzes from specified LmsSetup
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final Long lmsSetupId = filterMap.getLmsSetupId();
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if (lmsSetupId != null) {
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return getLmsAPITemplate(lmsSetupId)
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@ -110,6 +115,7 @@ public class LmsAPIServiceImpl implements LmsAPIService {
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.getOrThrow();
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}
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// case 2. get quizzes from all LmsSetups of specified institution
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final Long institutionId = filterMap.getInstitutionId();
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if (institutionId == null) {
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throw new IllegalAPIArgumentException("Missing institution identifier");
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@ -182,6 +188,7 @@ public class LmsAPIServiceImpl implements LmsAPIService {
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this.clientCredentialService);
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case OPEN_EDX:
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return new OpenEdxLmsAPITemplate(
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this.asyncService,
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lmsSetup,
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credentials,
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this.clientCredentialService,
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@ -15,6 +15,7 @@ import java.util.HashSet;
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import java.util.Iterator;
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import java.util.List;
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import java.util.Set;
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import java.util.function.Supplier;
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import org.apache.commons.lang3.StringUtils;
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import org.slf4j.Logger;
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@ -38,11 +39,12 @@ import org.springframework.util.LinkedMultiValueMap;
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import org.springframework.util.MultiValueMap;
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import ch.ethz.seb.sebserver.gbl.api.APIMessage;
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import ch.ethz.seb.sebserver.gbl.async.AsyncService;
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import ch.ethz.seb.sebserver.gbl.async.MemoizingCircuitBreaker;
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import ch.ethz.seb.sebserver.gbl.model.exam.QuizData;
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import ch.ethz.seb.sebserver.gbl.model.institution.LmsSetup;
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import ch.ethz.seb.sebserver.gbl.model.institution.LmsSetupTestResult;
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import ch.ethz.seb.sebserver.gbl.util.Result;
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import ch.ethz.seb.sebserver.gbl.util.SupplierWithCircuitBreaker;
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import ch.ethz.seb.sebserver.webservice.servicelayer.client.ClientCredentialService;
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import ch.ethz.seb.sebserver.webservice.servicelayer.client.ClientCredentials;
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import ch.ethz.seb.sebserver.webservice.servicelayer.dao.FilterMap;
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@ -67,9 +69,10 @@ final class OpenEdxLmsAPITemplate implements LmsAPITemplate {
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private final Set<String> knownTokenAccessPaths;
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private OAuth2RestTemplate restTemplate = null;
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private SupplierWithCircuitBreaker<List<QuizData>> allQuizzesSupplier = null;
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private final MemoizingCircuitBreaker<List<QuizData>> allQuizzesSupplier;
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OpenEdxLmsAPITemplate(
|
||||
final AsyncService asyncService,
|
||||
final LmsSetup lmsSetup,
|
||||
final ClientCredentials credentials,
|
||||
final ClientCredentialService clientCredentialService,
|
||||
|
|
@ -85,6 +88,8 @@ final class OpenEdxLmsAPITemplate implements LmsAPITemplate {
|
|||
if (alternativeTokenRequestPaths != null) {
|
||||
this.knownTokenAccessPaths.addAll(Arrays.asList(alternativeTokenRequestPaths));
|
||||
}
|
||||
|
||||
this.allQuizzesSupplier = asyncService.createCircuitBreaker(allQuizzesSupplier(lmsSetup));
|
||||
}
|
||||
|
||||
@Override
|
||||
|
|
@ -115,20 +120,10 @@ final class OpenEdxLmsAPITemplate implements LmsAPITemplate {
|
|||
|
||||
@Override
|
||||
public Result<List<QuizData>> getQuizzes(final FilterMap filterMap) {
|
||||
return this.initRestTemplateAndRequestAccessToken()
|
||||
.flatMap(this::getAllQuizes)
|
||||
return this.allQuizzesSupplier.get()
|
||||
.map(LmsAPIService.quizzesFilterFunction(filterMap));
|
||||
}
|
||||
|
||||
public ResponseEntity<EdXPage> getEdxPage(final String pageURI) {
|
||||
final HttpHeaders httpHeaders = new HttpHeaders();
|
||||
return this.restTemplate.exchange(
|
||||
pageURI,
|
||||
HttpMethod.GET,
|
||||
new HttpEntity<>(httpHeaders),
|
||||
EdXPage.class);
|
||||
}
|
||||
|
||||
@Override
|
||||
public Collection<Result<QuizData>> getQuizzes(final Set<String> ids) {
|
||||
// TODO Auto-generated method stub
|
||||
|
|
@ -197,10 +192,38 @@ final class OpenEdxLmsAPITemplate implements LmsAPITemplate {
|
|||
return template;
|
||||
}
|
||||
|
||||
private Result<List<QuizData>> getAllQuizes(final LmsSetup lmsSetup) {
|
||||
if (this.allQuizzesSupplier == null) {
|
||||
this.allQuizzesSupplier = new SupplierWithCircuitBreaker<>(
|
||||
() -> collectAllCourses(lmsSetup.lmsApiUrl + OPEN_EDX_DEFAULT_COURSE_ENDPOINT)
|
||||
// private Result<List<QuizData>> getAllQuizes(final LmsSetup lmsSetup) {
|
||||
// if (this.allQuizzesSupplier == null) {
|
||||
// this.allQuizzesSupplier = new CircuitBreaker<>(
|
||||
// () -> collectAllCourses(lmsSetup.lmsApiUrl + OPEN_EDX_DEFAULT_COURSE_ENDPOINT)
|
||||
// .stream()
|
||||
// .reduce(
|
||||
// new ArrayList<QuizData>(),
|
||||
// (list, courseData) -> {
|
||||
// list.add(quizDataOf(lmsSetup, courseData));
|
||||
// return list;
|
||||
// },
|
||||
// (list1, list2) -> {
|
||||
// list1.addAll(list2);
|
||||
// return list1;
|
||||
// }),
|
||||
// 5, 1000L); // TODO specify better CircuitBreaker params
|
||||
// }
|
||||
//
|
||||
// return this.allQuizzesSupplier.get();
|
||||
//
|
||||
// }
|
||||
|
||||
private Supplier<List<QuizData>> allQuizzesSupplier(final LmsSetup lmsSetup) {
|
||||
return () -> {
|
||||
return initRestTemplateAndRequestAccessToken()
|
||||
.map(this::collectAllQuizzes)
|
||||
.getOrThrow();
|
||||
};
|
||||
}
|
||||
|
||||
private ArrayList<QuizData> collectAllQuizzes(final LmsSetup lmsSetup) {
|
||||
return collectAllCourses(lmsSetup.lmsApiUrl + OPEN_EDX_DEFAULT_COURSE_ENDPOINT)
|
||||
.stream()
|
||||
.reduce(
|
||||
new ArrayList<QuizData>(),
|
||||
|
|
@ -211,12 +234,7 @@ final class OpenEdxLmsAPITemplate implements LmsAPITemplate {
|
|||
(list1, list2) -> {
|
||||
list1.addAll(list2);
|
||||
return list1;
|
||||
}),
|
||||
5, 1000L); // TODO specify better CircuitBreaker params
|
||||
}
|
||||
|
||||
return this.allQuizzesSupplier.get();
|
||||
|
||||
});
|
||||
}
|
||||
|
||||
private List<CourseData> collectAllCourses(final String pageURI) {
|
||||
|
|
@ -233,7 +251,16 @@ final class OpenEdxLmsAPITemplate implements LmsAPITemplate {
|
|||
return collector;
|
||||
}
|
||||
|
||||
private QuizData quizDataOf(
|
||||
private ResponseEntity<EdXPage> getEdxPage(final String pageURI) {
|
||||
final HttpHeaders httpHeaders = new HttpHeaders();
|
||||
return this.restTemplate.exchange(
|
||||
pageURI,
|
||||
HttpMethod.GET,
|
||||
new HttpEntity<>(httpHeaders),
|
||||
EdXPage.class);
|
||||
}
|
||||
|
||||
private static QuizData quizDataOf(
|
||||
final LmsSetup lmsSetup,
|
||||
final CourseData courseData) {
|
||||
|
||||
|
|
|
|||
|
|
@ -0,0 +1,117 @@
|
|||
/*
|
||||
* Copyright (c) 2019 ETH Zürich, Educational Development and Technology (LET)
|
||||
*
|
||||
* This Source Code Form is subject to the terms of the Mozilla Public
|
||||
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
||||
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
|
||||
*/
|
||||
|
||||
package ch.ethz.seb.sebserver.gbl.async;
|
||||
|
||||
import static org.junit.Assert.*;
|
||||
|
||||
import java.util.concurrent.atomic.AtomicBoolean;
|
||||
import java.util.concurrent.atomic.AtomicInteger;
|
||||
import java.util.function.Supplier;
|
||||
|
||||
import org.junit.Test;
|
||||
import org.junit.runner.RunWith;
|
||||
import org.slf4j.Logger;
|
||||
import org.slf4j.LoggerFactory;
|
||||
import org.springframework.beans.factory.annotation.Autowired;
|
||||
import org.springframework.test.context.ContextConfiguration;
|
||||
import org.springframework.test.context.junit4.SpringRunner;
|
||||
|
||||
import ch.ethz.seb.sebserver.gbl.async.MemoizingCircuitBreaker.State;
|
||||
import ch.ethz.seb.sebserver.gbl.util.Result;
|
||||
|
||||
@RunWith(SpringRunner.class)
|
||||
@ContextConfiguration(classes = { AsyncServiceSpringConfig.class, AsyncRunner.class, AsyncService.class })
|
||||
public class MemoizingCircuitBreakerTest {
|
||||
|
||||
private static final Logger log = LoggerFactory.getLogger(MemoizingCircuitBreakerTest.class);
|
||||
|
||||
@Autowired
|
||||
AsyncService asyncService;
|
||||
|
||||
@Test
|
||||
public void testInit() {
|
||||
assertNotNull(this.asyncService);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void roundtrip1() throws InterruptedException {
|
||||
final MemoizingCircuitBreaker<String> circuitBreaker = this.asyncService.createCircuitBreaker(
|
||||
tester(100, 5, 15), 3, 500, 1000);
|
||||
|
||||
assertNull(circuitBreaker.getChached());
|
||||
|
||||
Result<String> result = circuitBreaker.get(); // 1. call...
|
||||
assertFalse(result.hasError());
|
||||
assertEquals("Hello", result.get());
|
||||
assertEquals("Hello", circuitBreaker.getChached());
|
||||
assertEquals(State.CLOSED, circuitBreaker.getState());
|
||||
|
||||
circuitBreaker.get(); // 2. call...
|
||||
circuitBreaker.get(); // 3. call...
|
||||
circuitBreaker.get(); // 4. call...
|
||||
|
||||
result = circuitBreaker.get(); // 5. call... still available
|
||||
assertFalse(result.hasError());
|
||||
assertEquals("Hello", result.get());
|
||||
assertEquals("Hello", circuitBreaker.getChached());
|
||||
assertEquals(State.CLOSED, circuitBreaker.getState());
|
||||
|
||||
result = circuitBreaker.get(); // 6. call... after the 5. call the tester is unavailable until the 15. call.. 3 try calls
|
||||
assertFalse(result.hasError());
|
||||
assertEquals("Hello", result.get());
|
||||
assertEquals("Hello", circuitBreaker.getChached());
|
||||
assertEquals(State.HALF_OPEN, circuitBreaker.getState());
|
||||
|
||||
circuitBreaker.get(); // 9. call... 1. call in HalfOpen state
|
||||
circuitBreaker.get(); // 10. call... 2. call in HalfOpen state
|
||||
result = circuitBreaker.get(); // 11. call... 3. call in HalfOpen state.. still available in Half Open state
|
||||
assertEquals(State.HALF_OPEN, circuitBreaker.getState());
|
||||
|
||||
result = circuitBreaker.get(); // 12. call... 4. is changing to Open state
|
||||
assertEquals(State.OPEN, circuitBreaker.getState());
|
||||
|
||||
// now the time to recover comes into play
|
||||
Thread.sleep(1100);
|
||||
result = circuitBreaker.get(); // 13. call... 1. call in Open state... after time to recover ended get back to Half Open
|
||||
assertEquals(State.HALF_OPEN, circuitBreaker.getState());
|
||||
assertEquals("Hello", result.get());
|
||||
|
||||
result = circuitBreaker.get(); // 14. call... 1. call in Half Open state...
|
||||
assertEquals(State.HALF_OPEN, circuitBreaker.getState());
|
||||
assertEquals("Hello", result.get());
|
||||
|
||||
result = circuitBreaker.get(); // 15. call... 2. call in Half Open state...
|
||||
assertEquals(State.CLOSED, circuitBreaker.getState());
|
||||
assertEquals("Hello back again", result.get());
|
||||
}
|
||||
|
||||
private Supplier<String> tester(final long delay, final int unavailableAfter, final int unavailableUntil) {
|
||||
final AtomicInteger count = new AtomicInteger(0);
|
||||
final AtomicBoolean wasUnavailable = new AtomicBoolean(false);
|
||||
return () -> {
|
||||
final int attempts = count.getAndIncrement();
|
||||
|
||||
log.info("tester answers {} {}", attempts, Thread.currentThread());
|
||||
|
||||
try {
|
||||
Thread.sleep(delay);
|
||||
} catch (final InterruptedException e) {
|
||||
e.printStackTrace();
|
||||
}
|
||||
|
||||
if (attempts >= unavailableAfter && attempts < unavailableUntil) {
|
||||
wasUnavailable.set(true);
|
||||
throw new RuntimeException("Error");
|
||||
}
|
||||
|
||||
return (wasUnavailable.get()) ? "Hello back again" : "Hello";
|
||||
};
|
||||
}
|
||||
|
||||
}
|
||||
Loading…
Add table
Reference in a new issue