spring-boot: introduce DbSchedulerStopper

This lets the user control when the scheduler should be stopped. By
default it stops the scheduler when Spring issues the
ContextClosedEvent.

Fixes #423

db-scheduler-boot-starter/src/main/java/com/github/kagkarlsson/scheduler/boot/autoconfigure/DbSchedulerAutoConfiguration.java

@@ -20,6 +20,8 @@
 import com.github.kagkarlsson.scheduler.boot.config.DbSchedulerCustomizer;
 import com.github.kagkarlsson.scheduler.boot.config.DbSchedulerProperties;
 import com.github.kagkarlsson.scheduler.boot.config.DbSchedulerStarter;
+import com.github.kagkarlsson.scheduler.boot.config.DbSchedulerStopper;
+import com.github.kagkarlsson.scheduler.boot.config.shutdown.ContextClosedStopper;
 import com.github.kagkarlsson.scheduler.boot.config.startup.ContextReadyStart;
 import com.github.kagkarlsson.scheduler.boot.config.startup.ImmediateStart;
 import com.github.kagkarlsson.scheduler.exceptions.SerializationException;
@@ -100,7 +102,7 @@ StatsRegistry noopStatsRegistry() {
   @ConditionalOnBean(DataSource.class)
   @ConditionalOnMissingBean
   @DependsOnDatabaseInitialization
-  @Bean(destroyMethod = "stop")
+  @Bean
   public Scheduler scheduler(DbSchedulerCustomizer customizer, StatsRegistry registry) {
     log.info("Creating db-scheduler using tasks from Spring context: {}", configuredTasks);
 
@@ -192,6 +194,13 @@ public DbSchedulerStarter dbSchedulerStarter(Scheduler scheduler) {
     return new ImmediateStart(scheduler);
   }
 
+  @ConditionalOnBean(Scheduler.class)
+  @ConditionalOnMissingBean
+  @Bean
+  public DbSchedulerStopper dbSchedulerStopper(Scheduler scheduler) {
+    return new ContextClosedStopper(scheduler);
+  }
+
   private static DataSource configureDataSource(DataSource existingDataSource) {
     if (existingDataSource instanceof TransactionAwareDataSourceProxy) {
       log.debug("Using an already transaction aware DataSource");

db-scheduler-boot-starter/src/main/java/com/github/kagkarlsson/scheduler/boot/config/DbSchedulerStopper.java

@@ -0,0 +1,18 @@
+/*
+ * Copyright (C) Gustav Karlsson
+ *
+ * <p>Licensed 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
+ *
+ * <p>http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * <p>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 com.github.kagkarlsson.scheduler.boot.config;
+
+public interface DbSchedulerStopper {
+  void doStop();
+}

db-scheduler-boot-starter/src/main/java/com/github/kagkarlsson/scheduler/boot/config/shutdown/AbstractSchedulerStopper.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) Gustav Karlsson
+ *
+ * <p>Licensed 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
+ *
+ * <p>http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * <p>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 com.github.kagkarlsson.scheduler.boot.config.shutdown;
+
+import com.github.kagkarlsson.scheduler.Scheduler;
+import com.github.kagkarlsson.scheduler.SchedulerState;
+import com.github.kagkarlsson.scheduler.boot.config.DbSchedulerStopper;
+import java.util.Objects;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public abstract class AbstractSchedulerStopper implements DbSchedulerStopper {
+  private final Logger log = LoggerFactory.getLogger(this.getClass());
+  private final Scheduler scheduler;
+
+  protected AbstractSchedulerStopper(Scheduler scheduler) {
+    this.scheduler = Objects.requireNonNull(scheduler, "A scheduler must be provided");
+  }
+
+  @Override
+  public void doStop() {
+    SchedulerState state = scheduler.getSchedulerState();
+
+    if (state.isShuttingDown()) {
+      log.warn("Scheduler is already shutting down - will not attempting to stop");
+      return;
+    }
+
+    if (!state.isStarted()) {
+      log.info("Scheduler not started - will not attempt to start");
+      return;
+    }
+
+    log.info("Triggering scheduler stop");
+    scheduler.stop();
+  }
+}

db-scheduler-boot-starter/src/main/java/com/github/kagkarlsson/scheduler/boot/config/shutdown/ContextClosedStopper.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) Gustav Karlsson
+ *
+ * <p>Licensed 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
+ *
+ * <p>http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * <p>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 com.github.kagkarlsson.scheduler.boot.config.shutdown;
+
+import com.github.kagkarlsson.scheduler.Scheduler;
+import org.springframework.context.event.ContextClosedEvent;
+import org.springframework.context.event.EventListener;
+
+public class ContextClosedStopper extends AbstractSchedulerStopper {
+  public ContextClosedStopper(Scheduler scheduler) {
+    super(scheduler);
+  }
+
+  @EventListener(ContextClosedEvent.class)
+  public void whenContextIsStopped() {
+    doStop();
+  }
+}

db-scheduler-boot-starter/src/test/java/com/github/kagkarlsson/scheduler/boot/autoconfigure/DbSchedulerAutoConfigurationTest.java

@@ -11,6 +11,9 @@
 import com.github.kagkarlsson.scheduler.boot.config.DbSchedulerCustomizer;
 import com.github.kagkarlsson.scheduler.boot.config.DbSchedulerProperties;
 import com.github.kagkarlsson.scheduler.boot.config.DbSchedulerStarter;
+import com.github.kagkarlsson.scheduler.boot.config.DbSchedulerStopper;
+import com.github.kagkarlsson.scheduler.boot.config.shutdown.AbstractSchedulerStopper;
+import com.github.kagkarlsson.scheduler.boot.config.shutdown.ContextClosedStopper;
 import com.github.kagkarlsson.scheduler.boot.config.startup.AbstractSchedulerStarter;
 import com.github.kagkarlsson.scheduler.boot.config.startup.ContextReadyStart;
 import com.github.kagkarlsson.scheduler.boot.config.startup.ImmediateStart;
@@ -40,6 +43,9 @@
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.context.event.ContextClosedEvent;
+import org.springframework.context.event.ContextStoppedEvent;
+import org.springframework.context.event.EventListener;
 
 public class DbSchedulerAutoConfigurationTest {
   private static final Logger log = LoggerFactory.getLogger(DbSchedulerAutoConfigurationTest.class);
@@ -195,6 +201,30 @@ public void it_should_support_custom_starting_strategies() {
             });
   }
 
+  @Test
+  public void it_should_shut_down_with_spring_context_by_default() {
+    ctxRunner
+      .run(
+        (AssertableApplicationContext ctx) -> {
+          assertThat(ctx).hasSingleBean(Scheduler.class);
+
+          assertThat(ctx).hasSingleBean(ContextClosedStopper.class);
+        });
+  }
+
+  @Test
+  public void it_should_support_custom_stopping_strategies() {
+    ctxRunner
+      .withUserConfiguration(CustomStopperConfiguration.class)
+      .run(
+        (AssertableApplicationContext ctx) -> {
+          assertThat(ctx).hasSingleBean(Scheduler.class);
+
+          assertThat(ctx).hasSingleBean(DbSchedulerStopper.class);
+          assertThat(ctx).doesNotHaveBean(ContextClosedStopper.class);
+        });
+  }
+
   @Test
   public void it_should_provide_micrometer_registry_if_micrometer_is_present() {
     ctxRunner
@@ -289,6 +319,28 @@ static class SomeCustomStarter extends AbstractSchedulerStarter {
     }
   }
 
+  @Configuration
+  static class CustomStopperConfiguration extends SingleTaskConfiguration {
+    @Bean
+    DbSchedulerStopper someCustomStarter(Scheduler scheduler) {
+      return new SomeCustomStopper(scheduler);
+    }
+
+    static class SomeCustomStopper extends AbstractSchedulerStopper {
+      SomeCustomStopper(Scheduler scheduler) {
+        super(scheduler);
+        log.info("Creating a custom stopper");
+      }
+
+      @EventListener(ContextClosedEvent.class)
+      public void letMeThinkAboutIt() throws Exception {
+        log.info("Thinking 5 seconds before stopping the scheduler");
+        Thread.sleep(5_000);
+        doStop();
+      }
+    }
+  }
+
   @Configuration
   static class CustomStatsRegistry extends SingleTaskConfiguration {
     @Bean

examples/spring-boot-example/src/test/java/com/github/kagkarlsson/examples/boot/SmokeTest.java

@@ -7,6 +7,8 @@
 
 import com.github.kagkarlsson.scheduler.Scheduler;
 import com.github.kagkarlsson.scheduler.boot.actuator.DbSchedulerHealthIndicator;
+import com.github.kagkarlsson.scheduler.boot.config.DbSchedulerStopper;
+import com.github.kagkarlsson.scheduler.boot.config.shutdown.ContextClosedStopper;
 import com.github.kagkarlsson.scheduler.task.Task;
 import com.github.kagkarlsson.scheduler.task.TaskInstance;
 import java.time.Instant;
@@ -50,6 +52,11 @@ public void it_should_have_a_scheduler_bean() {
     assertThat(ctx).hasSingleBean(Scheduler.class);
   }
 
+  @Test
+  public void it_should_have_a_stopper_bean() {
+    assertThat(ctx).hasSingleBean(ContextClosedStopper.class);
+  }
+
   @Test
   public void it_should_have_two_tasks_exposed_as_beans() {
     assertThat(ctx.getBeansOfType(Task.class).values()).hasSizeGreaterThan(10);