Package org.apache.druid.java.util.common

Class RetryUtils

java.lang.Object

org.apache.druid.java.util.common.RetryUtils

public class RetryUtils
extends Object

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	RetryUtils.CleanupAfterFailure
static interface	RetryUtils.Task<T>

Field Summary

Fields

Modifier and Type	Field	Description
static final long	BASE_SLEEP_MILLIS
static final int	DEFAULT_MAX_TRIES
static final Logger	log
static final long	MAX_SLEEP_MILLIS

Constructor Summary

Constructors

Constructor	Description
RetryUtils()

Method Summary

Modifier and Type	Method	Description
static void	awaitNextRetry(Throwable e, String messageOnRetry, int nTry, int maxRetries, boolean quiet)
static long	nextRetrySleepMillis(int nTry)	Calculates the duration in milliseconds to sleep before the next attempt of a retryable operation.
static <T> T	retry(RetryUtils.Task<T> f, com.google.common.base.Predicate<Throwable> shouldRetry, int maxTries)
static <T> T	retry(RetryUtils.Task<T> f, com.google.common.base.Predicate<Throwable> shouldRetry, int quietTries, int maxTries)
static <T> T	retry(RetryUtils.Task<T> f, com.google.common.base.Predicate<Throwable> shouldRetry, int quietTries, int maxTries, RetryUtils.CleanupAfterFailure cleanupAfterFailure, String messageOnRetry)	Retry an operation using fuzzy exponentially increasing backoff.
static <T> T	retry(RetryUtils.Task<T> f, com.google.common.base.Predicate<Throwable> shouldRetry, RetryUtils.CleanupAfterFailure onEachFailure, int maxTries, String messageOnRetry)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

log

public static final Logger log

MAX_SLEEP_MILLIS

public static final long MAX_SLEEP_MILLIS

See Also:

• Constant Field Values

BASE_SLEEP_MILLIS

public static final long BASE_SLEEP_MILLIS

See Also:

• Constant Field Values

DEFAULT_MAX_TRIES

public static final int DEFAULT_MAX_TRIES

See Also:

• Constant Field Values

Constructor Details

RetryUtils

public RetryUtils()

Method Details

retry

public static <T> T retry(RetryUtils.Task<T> f,
 com.google.common.base.Predicate<Throwable> shouldRetry,
 int quietTries,
 int maxTries,
 @Nullable
 RetryUtils.CleanupAfterFailure cleanupAfterFailure,
 @Nullable
 String messageOnRetry)
                   throws Exception

Retry an operation using fuzzy exponentially increasing backoff. The wait time after the nth failed attempt is min(60000ms, 1000ms * pow(2, n - 1)), fuzzed by a number drawn from a Gaussian distribution with mean 0 and standard deviation 0.2. If maxTries is exhausted, or if shouldRetry returns false, the last exception thrown by "f" will be thrown by this function.

Parameters:

f - the operation

shouldRetry - predicate determining whether we should retry after a particular exception thrown by "f"

quietTries - first quietTries attempts will log exceptions at DEBUG level rather than WARN

maxTries - maximum number of attempts

Returns:

result of the first successful operation

Throws:

Exception - if maxTries is exhausted, or shouldRetry returns false

retry

public static <T> T retry(RetryUtils.Task<T> f,
 com.google.common.base.Predicate<Throwable> shouldRetry,
 int maxTries)
                   throws Exception

Throws:

Exception

retry

public static <T> T retry(RetryUtils.Task<T> f,
 com.google.common.base.Predicate<Throwable> shouldRetry,
 int quietTries,
 int maxTries)
                   throws Exception

Throws:

Exception

retry

public static <T> T retry(RetryUtils.Task<T> f,
 com.google.common.base.Predicate<Throwable> shouldRetry,
 RetryUtils.CleanupAfterFailure onEachFailure,
 int maxTries,
 String messageOnRetry)
                   throws Exception

Throws:

Exception

awaitNextRetry

public static void awaitNextRetry(Throwable e,
 @Nullable
 String messageOnRetry,
 int nTry,
 int maxRetries,
 boolean quiet)
                           throws InterruptedException

Throws:

InterruptedException

nextRetrySleepMillis

public static long nextRetrySleepMillis(int nTry)

Calculates the duration in milliseconds to sleep before the next attempt of a retryable operation. The duration is calculated in an exponential back-off manner with a fuzzy multiplier to introduce some variance.

Sleep duration in milliseconds for subsequent retries:

• Retry 1: [0, 2000]
• Retry 2: [0, 4000]
• Retry 3: [0, 8000]
• ...
• Retry 7 and later: [0, 120,000]

Parameters:

nTry - Index of the next retry, starting with 1

Returns:

Next sleep duration in the range [0, 120,000] millis