feat: config option to not exit when stops leading (#2500)

* feat: config option to not exit when stops leading

Signed-off-by: Attila Mészáros <a_meszaros@apple.com>

* Update operator-framework-core/src/main/java/io/javaoperatorsdk/operator/LeaderElectionManager.java

Co-authored-by: Chris Laprun <metacosm@users.noreply.github.com>

---------

Signed-off-by: Attila Mészáros <a_meszaros@apple.com>
Co-authored-by: Chris Laprun <metacosm@users.noreply.github.com>

Author: csviri

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/LeaderElectionManager.java

@@ -102,11 +102,15 @@ private void startLeading() {
   }
 
   private void stopLeading() {
-    log.info("Stopped leading for identity: {}. Exiting.", identity);
-    // When leader stops leading the process ends immediately to prevent multiple reconciliations
-    // running parallel.
-    // Note that some reconciliations might run for a very long time.
-    System.exit(1);
+    if (configurationService.getLeaderElectionConfiguration().orElseThrow().isExitOnStopLeading()) {
+      log.info("Stopped leading for identity: {}. Exiting.", identity);
+      // When leader stops leading the process ends immediately to prevent multiple reconciliations
+      // running parallel.
+      // Note that some reconciliations might run for a very long time.
+      System.exit(1);
+    } else {
+      log.info("Stopped leading, configured not to exit");
+    }
   }
 
   private String identity(LeaderElectionConfiguration config) {

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/config/LeaderElectionConfiguration.java

@@ -20,14 +20,15 @@ public class LeaderElectionConfiguration {
   private final Duration retryPeriod;
 
   private final LeaderCallbacks leaderCallbacks;
+  private final boolean exitOnStopLeading;
 
   public LeaderElectionConfiguration(String leaseName, String leaseNamespace, String identity) {
     this(
         leaseName,
         leaseNamespace,
         LEASE_DURATION_DEFAULT_VALUE,
         RENEW_DEADLINE_DEFAULT_VALUE,
-        RETRY_PERIOD_DEFAULT_VALUE, identity, null);
+        RETRY_PERIOD_DEFAULT_VALUE, identity, null, true);
   }
 
   public LeaderElectionConfiguration(String leaseName, String leaseNamespace) {
@@ -36,7 +37,7 @@ public LeaderElectionConfiguration(String leaseName, String leaseNamespace) {
         leaseNamespace,
         LEASE_DURATION_DEFAULT_VALUE,
         RENEW_DEADLINE_DEFAULT_VALUE,
-        RETRY_PERIOD_DEFAULT_VALUE, null, null);
+        RETRY_PERIOD_DEFAULT_VALUE, null, null, true);
   }
 
   public LeaderElectionConfiguration(String leaseName) {
@@ -45,7 +46,7 @@ public LeaderElectionConfiguration(String leaseName) {
         null,
         LEASE_DURATION_DEFAULT_VALUE,
         RENEW_DEADLINE_DEFAULT_VALUE,
-        RETRY_PERIOD_DEFAULT_VALUE, null, null);
+        RETRY_PERIOD_DEFAULT_VALUE, null, null, true);
   }
 
   public LeaderElectionConfiguration(
@@ -54,7 +55,7 @@ public LeaderElectionConfiguration(
       Duration leaseDuration,
       Duration renewDeadline,
       Duration retryPeriod) {
-    this(leaseName, leaseNamespace, leaseDuration, renewDeadline, retryPeriod, null, null);
+    this(leaseName, leaseNamespace, leaseDuration, renewDeadline, retryPeriod, null, null, true);
   }
 
   public LeaderElectionConfiguration(
@@ -64,14 +65,16 @@ public LeaderElectionConfiguration(
       Duration renewDeadline,
       Duration retryPeriod,
       String identity,
-      LeaderCallbacks leaderCallbacks) {
+      LeaderCallbacks leaderCallbacks,
+      boolean exitOnStopLeading) {
     this.leaseName = leaseName;
     this.leaseNamespace = leaseNamespace;
     this.leaseDuration = leaseDuration;
     this.renewDeadline = renewDeadline;
     this.retryPeriod = retryPeriod;
     this.identity = identity;
     this.leaderCallbacks = leaderCallbacks;
+    this.exitOnStopLeading = exitOnStopLeading;
   }
 
   public Optional<String> getLeaseNamespace() {
@@ -101,4 +104,8 @@ public Optional<String> getIdentity() {
   public Optional<LeaderCallbacks> getLeaderCallbacks() {
     return Optional.ofNullable(leaderCallbacks);
   }
+
+  public boolean isExitOnStopLeading() {
+    return exitOnStopLeading;
+  }
 }

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/config/LeaderElectionConfigurationBuilder.java

@@ -16,6 +16,7 @@ public final class LeaderElectionConfigurationBuilder {
   private Duration renewDeadline = RENEW_DEADLINE_DEFAULT_VALUE;
   private Duration retryPeriod = RETRY_PERIOD_DEFAULT_VALUE;
   private LeaderCallbacks leaderCallbacks;
+  private boolean exitOnStopLeading = true;
 
   private LeaderElectionConfigurationBuilder(String leaseName) {
     this.leaseName = leaseName;
@@ -55,8 +56,13 @@ public LeaderElectionConfigurationBuilder withLeaderCallbacks(LeaderCallbacks le
     return this;
   }
 
+  public LeaderElectionConfigurationBuilder withExitOnStopLeading(boolean exitOnStopLeading) {
+    this.exitOnStopLeading = exitOnStopLeading;
+    return this;
+  }
+
   public LeaderElectionConfiguration build() {
     return new LeaderElectionConfiguration(leaseName, leaseNamespace, leaseDuration, renewDeadline,
-        retryPeriod, identity, leaderCallbacks);
+        retryPeriod, identity, leaderCallbacks, exitOnStopLeading);
   }
 }