org.apache.hadoop.fs.s3a.FailureInjectionPolicy Maven / Gradle / Ivy
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* http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.hadoop.fs.s3a;
import org.apache.hadoop.thirdparty.com.google.common.base.Preconditions;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.hadoop.conf.Configuration;
import static org.apache.hadoop.fs.s3a.Constants.*;
/**
* Simple object which stores current failure injection settings.
* "Delaying a key" can mean:
* - Removing it from the S3 client's listings while delay is in effect.
* - Causing input stream reads to fail.
* - Causing the S3 side of getFileStatus(), i.e.
* AmazonS3#getObjectMetadata(), to throw FileNotFound.
*/
public class FailureInjectionPolicy {
/**
* Keys containing this substring will be subject to delayed visibility.
*/
public static final String DEFAULT_DELAY_KEY_SUBSTRING = "DELAY_LISTING_ME";
/**
* How many seconds affected keys will have delayed visibility.
* This should probably be a config value.
*/
public static final long DEFAULT_DELAY_KEY_MSEC = 5 * 1000;
public static final float DEFAULT_DELAY_KEY_PROBABILITY = 1.0f;
/** Special config value since we can't store empty strings in XML. */
public static final String MATCH_ALL_KEYS = "*";
private static final Logger LOG =
LoggerFactory.getLogger(InconsistentAmazonS3Client.class);
/** Empty string matches all keys. */
private String delayKeySubstring;
/** Probability to delay visibility of a matching key. */
private float delayKeyProbability;
/** Time in milliseconds to delay visibility of newly modified object. */
private long delayKeyMsec;
/**
* Probability of throttling a request.
*/
private float throttleProbability;
/**
* limit for failures before operations succeed; if 0 then "no limit".
*/
private int failureLimit = 0;
public FailureInjectionPolicy(Configuration conf) {
this.delayKeySubstring = conf.get(FAIL_INJECT_INCONSISTENCY_KEY,
DEFAULT_DELAY_KEY_SUBSTRING);
// "" is a substring of all strings, use it to match all keys.
if (this.delayKeySubstring.equals(MATCH_ALL_KEYS)) {
this.delayKeySubstring = "";
}
this.delayKeyProbability = validProbability(
conf.getFloat(FAIL_INJECT_INCONSISTENCY_PROBABILITY,
DEFAULT_DELAY_KEY_PROBABILITY));
this.delayKeyMsec = conf.getLong(FAIL_INJECT_INCONSISTENCY_MSEC,
DEFAULT_DELAY_KEY_MSEC);
this.setThrottleProbability(conf.getFloat(FAIL_INJECT_THROTTLE_PROBABILITY,
0.0f));
}
public String getDelayKeySubstring() {
return delayKeySubstring;
}
public float getDelayKeyProbability() {
return delayKeyProbability;
}
public long getDelayKeyMsec() {
return delayKeyMsec;
}
public float getThrottleProbability() {
return throttleProbability;
}
public int getFailureLimit() {
return failureLimit;
}
public void setFailureLimit(int failureLimit) {
this.failureLimit = failureLimit;
}
/**
* Set the probability of throttling a request.
* @param throttleProbability the probability of a request being throttled.
*/
public void setThrottleProbability(float throttleProbability) {
this.throttleProbability = validProbability(throttleProbability);
}
public static boolean trueWithProbability(float p) {
return Math.random() < p;
}
/**
* Should we delay listing visibility for this key?
* @param key key which is being put
* @return true if we should delay
*/
public boolean shouldDelay(String key) {
float p = getDelayKeyProbability();
boolean delay = key.contains(getDelayKeySubstring());
delay = delay && trueWithProbability(p);
LOG.debug("{}, p={} -> {}", key, p, delay);
return delay;
}
@Override
public String toString() {
return String.format("FailureInjectionPolicy:" +
" %s msec delay, substring %s, delay probability %s;" +
" throttle probability %s" + "; failure limit %d",
delayKeyMsec, delayKeySubstring, delayKeyProbability,
throttleProbability, failureLimit);
}
/**
* Validate a probability option.
* @param p probability
* @return the probability, if valid
* @throws IllegalArgumentException if the probability is out of range.
*/
private static float validProbability(float p) {
Preconditions.checkArgument(p >= 0.0f && p <= 1.0f,
"Probability out of range 0 to 1 %s", p);
return p;
}
}