Resource version comparison utility

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

Author: csviri

operator-framework-core/src/main/java/io/javaoperatorsdk/operator/api/reconciler/PrimaryUpdateAndCacheUtils.java

@@ -450,4 +450,24 @@ public static <P extends HasMetadata> P addFinalizerWithSSA(
           e);
     }
   }
+
+  public static int compareResourceVersions(String v1, String v2) {
+    var v1Length = v1.length();
+    var v2Length = v2.length();
+    if (v1Length > v2Length) {
+      return 1;
+    }
+    if (v2Length > v1Length) {
+      return -1;
+    }
+    for (int i = 0; i < v1Length; i++) {
+      if (v1.charAt(i) > v2.charAt(i)) {
+        return 1;
+      }
+      if (v1.charAt(i) < v2.charAt(i)) {
+        return -1;
+      }
+    }
+    return 0;
+  }
 }

operator-framework-core/src/test/java/io/javaoperatorsdk/operator/api/reconciler/PrimaryUpdateAndCacheUtilsTest.java

@@ -20,6 +20,8 @@
 
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import io.fabric8.kubernetes.api.model.HasMetadata;
 import io.fabric8.kubernetes.client.KubernetesClient;
@@ -37,6 +39,7 @@
 import io.javaoperatorsdk.operator.sample.simple.TestCustomResource;
 
 import static io.javaoperatorsdk.operator.api.reconciler.PrimaryUpdateAndCacheUtils.DEFAULT_MAX_RETRY;
+import static io.javaoperatorsdk.operator.api.reconciler.PrimaryUpdateAndCacheUtils.compareResourceVersions;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.mockito.ArgumentMatchers.any;
@@ -47,6 +50,8 @@
 
 class PrimaryUpdateAndCacheUtilsTest {
 
+  private static final Logger log = LoggerFactory.getLogger(PrimaryUpdateAndCacheUtilsTest.class);
+
   Context<TestCustomResource> context = mock(Context.class);
   KubernetesClient client = mock(KubernetesClient.class);
   Resource resource = mock(Resource.class);
@@ -176,4 +181,34 @@ void cachePollTimeouts() {
                     10L));
     assertThat(ex.getMessage()).contains("Timeout");
   }
+
+  @Test
+  public void compareResourceVersionsTest() {
+    assertThat(compareResourceVersions("11", "22")).isNegative();
+    assertThat(compareResourceVersions("22", "11")).isPositive();
+    assertThat(compareResourceVersions("11", "11")).isZero();
+
+    assertThat(compareResourceVersions("123", "2")).isPositive();
+    assertThat(compareResourceVersions("3", "211")).isNegative();
+  }
+
+  // naive performance that compares the works case scenario for non parsing variant
+  @Test
+  public void compareResourcePerformanceTest() {
+    var execNum = 10000000;
+    var startTime = System.currentTimeMillis();
+    for (int i = 0; i < execNum; i++) {
+      var res = compareResourceVersions("123456788", "123456789");
+    }
+    var dur1 = System.currentTimeMillis() - startTime;
+    log.info("Duration without parsing: {}", dur1);
+    startTime = System.currentTimeMillis();
+    for (int i = 0; i < execNum; i++) {
+      var res = Long.parseLong("123456788") > Long.parseLong("123456789");
+    }
+    var dur2 = System.currentTimeMillis() - startTime;
+    log.info("Duration with parsing:   {}", dur2);
+
+    assertThat(dur1).isLessThan(dur2);
+  }
 }