org.apache.bookkeeper.zookeeper.ExponentialBackOffWithDeadlinePolicy Maven / Gradle / Ivy
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package org.apache.bookkeeper.zookeeper;
import java.util.Arrays;
import java.util.Random;
import lombok.extern.slf4j.Slf4j;
/**
* Backoff time determined based as a multiple of baseBackoffTime.
* The multiple value depends on retryCount.
* If the retry schedule exceeds the deadline, we schedule a final attempt exactly at the deadline.
*/
@Slf4j
public class ExponentialBackOffWithDeadlinePolicy implements RetryPolicy {
static final int [] RETRY_BACKOFF = {0, 1, 2, 3, 5, 5, 5, 10, 10, 10, 20, 40, 100};
public static final int JITTER_PERCENT = 10;
private final Random random;
private final long baseBackoffTime;
private final long deadline;
private final int maxRetries;
public ExponentialBackOffWithDeadlinePolicy(long baseBackoffTime, long deadline, int maxRetries) {
this.baseBackoffTime = baseBackoffTime;
this.deadline = deadline;
this.maxRetries = maxRetries;
this.random = new Random(System.currentTimeMillis());
}
@Override
public boolean allowRetry(int retryCount, long elapsedRetryTime) {
return retryCount <= maxRetries && elapsedRetryTime < deadline;
}
@Override
public long nextRetryWaitTime(int retryCount, long elapsedRetryTime) {
int idx = retryCount;
if (idx >= RETRY_BACKOFF.length) {
idx = RETRY_BACKOFF.length - 1;
}
long waitTime = (baseBackoffTime * RETRY_BACKOFF[idx]);
long jitter = (random.nextInt(JITTER_PERCENT) * waitTime / 100);
if (elapsedRetryTime + waitTime + jitter > deadline) {
log.warn("Final retry attempt: {}, timeleft: {}, stacktrace: {}",
retryCount, (deadline - elapsedRetryTime), Arrays.toString(Thread.currentThread().getStackTrace()));
return deadline - elapsedRetryTime;
}
return waitTime + jitter;
}
}