phet commented on code in PR #3700: URL: https://github.com/apache/gobblin/pull/3700#discussion_r1211107701
########## gobblin-runtime/src/main/java/org/apache/gobblin/runtime/api/SchedulerLeaseDeterminationStore.java: ########## @@ -0,0 +1,73 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.gobblin.runtime.api; + +import java.io.IOException; +import java.sql.Timestamp; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + + +/** + * Interface defines the two basic actions required for lease determination for each FlowActionType event for a flow. + * It is used by the {@link SchedulerLeaseAlgoHandler} to allow multiple scheduler's on different hosts to determine + * which scheduler is tasked with ensuring the FlowAction is taken for the trigger. + */ +public interface SchedulerLeaseDeterminationStore { + static final Logger LOG = LoggerFactory.getLogger(SchedulerLeaseDeterminationStore.class); + + // Enum is used to reason about the three possible scenarios that can result from an attempt to obtain a lease for a + // particular trigger event of a flow + enum LeaseAttemptStatus { + LEASE_OBTAINED, + PREVIOUS_LEASE_EXPIRED, + PREVIOUS_LEASE_VALID Review Comment: we're thinking similarly, but I see a few diffs: a. the most consequential discernment is whether the current host succeeded in acquiring the lease (hence must be separated out as THE ONLY state for case 1) b. the "linger" timeout should not be so short that the current host would fail to acquire, but at that same moment discover that whoever else "has" the lease has actually exceeded its expiration. why? because each host must defer for the "linger" period, and *should only attempt to acquire after* that expires. hence, if acquisition should fail because another won the race, that newly granted lease should be nowhere near expiration. c. with `NO_LONGER_LEASING`, I sought to capture the termination case, where a host realizes the trigger event has been fully handled, so there's neither a need to try to acquire nor even set a reminder. in fact, under normal operating conditions, such a self-timer should regularly conclude by the host determining "there's nothing to lease", because the trigger event has been fully handled. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
