adds audit state in Alert (#461) (#462)

Signed-off-by: Surya Sashank Nistala <[email protected]>
(cherry picked from commit f1c0f1d)

Co-authored-by: Surya Sashank Nistala <[email protected]>

src/main/kotlin/org/opensearch/commons/alerting/model/Alert.kt

@@ -171,7 +171,12 @@ data class Alert(
     )
 
     enum class State {
-        ACTIVE, ACKNOWLEDGED, COMPLETED, ERROR, DELETED
+        ACTIVE, ACKNOWLEDGED, COMPLETED, ERROR, DELETED,
+        // Alerts are created in audit state when they are generated by delegate monitors of a workflow.
+        // since chained alerts can be configured and acknowledged, the underlying monitors' alerts are simply
+        // for evaluating chained alert triggers and auditing purpose.
+        // Audit state alerts will be created in the history index and do not need to be acknowledged by users.
+        AUDIT
     }
 
     @Throws(IOException::class)

src/test/kotlin/org/opensearch/commons/alerting/AlertTests.kt

@@ -4,7 +4,8 @@ import org.junit.jupiter.api.Assertions
 import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.Test
 import org.opensearch.commons.alerting.model.Alert
-import kotlin.test.assertTrue
+import java.time.Instant
+import java.time.temporal.ChronoUnit
 
 class AlertTests {
     @Test
@@ -60,6 +61,15 @@ class AlertTests {
         Assertions.assertFalse(activeAlert.isAcknowledged(), "Alert is acknowledged")
     }
 
+    @Test
+    fun `test alert in audit state`() {
+        val auditAlert = Alert(
+            randomQueryLevelMonitor(), randomQueryLevelTrigger(), Instant.now().truncatedTo(ChronoUnit.MILLIS),
+            null, actionExecutionResults = listOf(randomActionExecutionResult())
+        )
+        Assertions.assertFalse(auditAlert.isAcknowledged(), "Alert should not be in acknowledged state")
+    }
+
     @Test
     fun `test chained alert`() {
         val workflow = randomWorkflow()