com.algolia.search.RetryStrategy Maven / Gradle / Ivy
package com.algolia.search;
import com.algolia.search.models.HttpResponse;
import com.algolia.search.models.common.CallType;
import com.algolia.search.models.common.RetryOutcome;
import com.algolia.search.util.HttpStatusCodeUtils;
import java.time.Duration;
import java.time.OffsetDateTime;
import java.time.ZoneOffset;
import java.util.List;
import java.util.stream.Collectors;
/** Algolia's retry strategy in case of server error, timeouts... */
class RetryStrategy {
/** Hosts that will be used by the strategy. Could be default hosts or custom hosts */
private final List hosts;
/**
* Creates a new instance of the retry strategy. If custom hosts are provided in the configuration
* it will override the default hosts.
*/
RetryStrategy(ConfigBase config) {
hosts = config.getHosts();
}
/**
* Gives the available hosts.
*
* @param callType Algolia calltype.
*/
List getTryableHosts(CallType callType) {
synchronized (this) {
resetExpiredHosts();
if (hosts.stream().anyMatch(h -> h.isUp() && h.getAccept().contains(callType))) {
return hosts.stream()
.filter(h -> h.isUp() && h.getAccept().contains(callType))
.collect(Collectors.toList());
} else {
for (StatefulHost host :
hosts.stream()
.filter(h -> h.getAccept().contains(callType))
.collect(Collectors.toList())) {
reset(host);
}
return hosts;
}
}
}
/** Retry logic. Decide if an host is retryable or not regarding the following parameters. */
RetryOutcome decide(StatefulHost tryableHost, HttpResponse response) {
synchronized (this) {
if (!response.isTimedOut() && HttpStatusCodeUtils.isSuccess(response)) {
tryableHost.setUp(true);
tryableHost.setLastUse(OffsetDateTime.now(ZoneOffset.UTC));
return RetryOutcome.SUCCESS;
} else if (!response.isTimedOut() && isRetryable(response)) {
tryableHost.setUp(false);
tryableHost.setLastUse(OffsetDateTime.now(ZoneOffset.UTC));
return RetryOutcome.RETRY;
} else if (response.isTimedOut()) {
tryableHost.setUp(true);
tryableHost.setLastUse(OffsetDateTime.now(ZoneOffset.UTC));
tryableHost.incrementRetryCount();
return RetryOutcome.RETRY;
}
return RetryOutcome.FAILURE;
}
}
/**
* Tells if the response is retryable or not depending on the http status code
*
* @param response Algolia's API response
*/
private boolean isRetryable(HttpResponse response) {
boolean isRetryableHttpCode =
response.getHttpStatusCode() / 100 != 2 && response.getHttpStatusCode() / 100 != 4;
return isRetryableHttpCode || response.isNetworkError();
}
/**
* Reset the given hosts. Sets the retry count to 0 and set the last use to now.
*
* @param host The host to reset
*/
private void reset(StatefulHost host) {
host.setUp(true).setRetryCount(0).setLastUse(OffsetDateTime.now(ZoneOffset.UTC));
}
/** Reset all hosts down for more than 5 minutes. */
private void resetExpiredHosts() {
for (StatefulHost host : hosts) {
if (!host.isUp()
&& Math.abs(
Duration.between(OffsetDateTime.now(ZoneOffset.UTC), host.getLastUse())
.getSeconds())
> 5 * 60) {
reset(host);
}
}
}
}