org.swisspush.gateleen.queue.queuing.circuitbreaker.QueueCircuitBreaker Maven / Gradle / Ivy
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package org.swisspush.gateleen.queue.queuing.circuitbreaker;
import io.vertx.core.Future;
import org.swisspush.gateleen.core.http.HttpRequest;
import org.swisspush.gateleen.queue.queuing.circuitbreaker.util.QueueCircuitState;
import org.swisspush.gateleen.queue.queuing.circuitbreaker.util.QueueResponseType;
/**
* The QueueCircuitBreaker monitors the queue activity and protects the system from too much load when circuits/endpoints
* are not reachable.
*
* @author https://github.com/mcweba [Marc-Andre Weber]
*/
public interface QueueCircuitBreaker {
/**
* Handles a queued request by checking the current {@link QueueCircuitState} of the corresponding circuit.
* When the {@link QueueCircuitState} of the corresponding circuit equals {@link QueueCircuitState#OPEN},
* the provided queueName will be locked.
*
* @param queueName the name of the queue
* @param queuedRequest the queued request
* @return returns a {@link QueueCircuitState} representing the current status of the circuit
*/
Future handleQueuedRequest(String queueName, HttpRequest queuedRequest);
/**
* Updates the statistics of the corresponding circuit based on the provided request to execute.
* Updating the statistics includes the following steps:
*
* - Record queuedRequest as failed when queueResponseType equals {@link QueueResponseType#FAILURE}
* - Record queuedRequest as success when queueResponseType equals {@link QueueResponseType#SUCCESS}
* - Calculate failRatio based on fail/success records
* - Change status of corresponding circuit to 'OPEN' when failRatio threshold is reached
*
*
* @param queueName the name of the queue
* @param queuedRequest the queued request
* @param queueResponseType the {@link QueueResponseType} representing the execution result of the queuedRequest
* @return returns a void future when statistics could be updated successfully.
*/
Future updateStatistics(String queueName, HttpRequest queuedRequest, QueueResponseType queueResponseType);
/**
* Check whether the circuit check is enabled. The circuit check can be enabled/disabled with the 'circuitCheckEnabled'
* configuration property.
*
* @return returns true when circuit check is enabled, false otherwise
*/
boolean isCircuitCheckEnabled();
/**
* Check whether the statistics update is enabled. The statistics update can be enabled/disabled with the 'statisticsUpdateEnabled'
* configuration property.
*
* @return returns true when statistics update is enabled, false otherwise
*/
boolean isStatisticsUpdateEnabled();
/**
* Locks the queue having the provided queueName by calling the vertx-redisques API. Additionally, marks the queueName
* as a locked queue of the circuit representing the provided queuedRequest.
*
* @param queueName the name of the queue
* @param queuedRequest the queued request
* @return returns a void future when the queue could be locked successfully through vertx-redisques and also
* successfully marked as a locked queue of the circuit.
*/
Future lockQueue(String queueName, HttpRequest queuedRequest);
/**
* Unlocks the queue having the provided queueName by calling the vertx-redisques API.
*
* @param queueName the name of the queue
* @return returns a string future holding the name of the queue when successfully unlocked. Also returns the name
* of the queue (as failureMessage) when the unlocking failed.
*/
Future unlockQueue(String queueName);
/**
* Unlocks the next queue in-line. Does nothing when there's no next queue to unlock. Returns a null
* string in this case.
*
* @return returns a string future holding the name of the queue which was successfully unlocked. Also returns the name
* of the queue (as failureMessage) when the next queue could not be unlocked. Returns a null string
* when no queue was available to unlock.
*/
Future unlockNextQueue();
/**
* Closes the circuit representing the queued request.
* Closing the circuit includes the following steps:
*
* - Clear statistics of this circuit
* - Reset failRatio of this circuit to zero
* - Set status of this circuit to 'CLOSED'
* - Unlock all queues related to this circuit
*
*
*
* @param queuedRequest the queued request
* @return returns a void future when circuit could be closed successfully.
*/
Future closeCircuit(HttpRequest queuedRequest);
/**
* Closes all non-closed circuits.
* Closing all non-closed circuits includes the following steps:
*
* - Clear statistics of all non-closed circuits
* - Reset failRatio of all non-closed circuits to zero
* - Set status of all non-closed circuits to 'CLOSED'
* - Unlock all queues related to all non-closed circuits
*
*
*
* @return returns a void future when all non-closed circuits could be closed successfully.
*/
Future closeAllCircuits();
/**
* Re-Opens the (half-open) circuit representing the provided queued request again. Circuits should be re-opened
* after a sample queue request was not successful.
*
* @param queuedRequest the queued request
* @return returns a void future when the circuit representing the provided queued request could be re-opened successfully
*/
Future reOpenCircuit(HttpRequest queuedRequest);
/**
* Changes the status of all circuits having a status equals {@link QueueCircuitState#OPEN}
* to {@link QueueCircuitState#HALF_OPEN}.
*
* @return returns a future holding the amount of circuits updated
*/
Future setOpenCircuitsToHalfOpen();
/**
* Unlocks a sample queue of all circuits having a status equals {@link QueueCircuitState#HALF_OPEN}. The sample
* queues are always the queues which have not been unlocked the longest.
*
* @return returns a future holding the amount of unlocked sample queues
*/
Future unlockSampleQueues();
}