Adding base logic to transition step to enable policy execution

src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/ManagedIndexRunner.kt

@@ -41,6 +41,7 @@ import org.opensearch.index.engine.VersionConflictEngineException
 import org.opensearch.index.seqno.SequenceNumbers
 import org.opensearch.indexmanagement.IndexManagementIndices
 import org.opensearch.indexmanagement.IndexManagementPlugin.Companion.INDEX_MANAGEMENT_INDEX
+import org.opensearch.indexmanagement.indexstatemanagement.action.TransitionsAction
 import org.opensearch.indexmanagement.indexstatemanagement.model.ManagedIndexConfig
 import org.opensearch.indexmanagement.indexstatemanagement.model.Policy
 import org.opensearch.indexmanagement.indexstatemanagement.opensearchapi.getManagedIndexMetadata
@@ -324,7 +325,7 @@ object ManagedIndexRunner :
 
         // If this action is not allowed and the step to be executed is the first step in the action then we will fail
         // as this action has been removed from the AllowList, but if its not the first step we will let it finish as it's already inflight
-        if (action?.isAllowed(allowList) == false && action.isFirstStep(step?.name)) {
+        if (!action?.isAllowed(allowList) && action.isFirstStep(step?.name) && action.type != TransitionsAction.name) {
             val info = mapOf("message" to "Attempted to execute action=${action.type} which is not allowed.")
             val updated = updateManagedIndexMetaData(
                 managedIndexMetaData.copy(

src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/action/TransitionsAction.kt

@@ -6,6 +6,7 @@
 package org.opensearch.indexmanagement.indexstatemanagement.action
 
 import org.opensearch.indexmanagement.indexstatemanagement.model.Transition
+import org.opensearch.indexmanagement.indexstatemanagement.step.transition.AttemptTransitionStep
 import org.opensearch.indexmanagement.spi.indexstatemanagement.Action
 import org.opensearch.indexmanagement.spi.indexstatemanagement.Step
 import org.opensearch.indexmanagement.spi.indexstatemanagement.model.StepContext
@@ -14,15 +15,16 @@ class TransitionsAction(
     transitions: List<Transition>,
 ) : Action(name, -1) {
 
-    companion object {
-        const val name = "transition"
-    }
+    private val attemptTransitionStep = AttemptTransitionStep()
+    private val steps = listOf(attemptTransitionStep)
+
+    override fun getSteps(): List<Step> = steps
 
     override fun getStepToExecute(context: StepContext): Step {
-        TODO("Not yet implemented")
+        return attemptTransitionStep
     }
 
-    override fun getSteps(): List<Step> {
-        TODO("Not yet implemented")
+    companion object {
+        const val name = "transition"
     }
 }

src/main/kotlin/org/opensearch/indexmanagement/indexstatemanagement/step/transition/AttemptTransitionStep.kt

@@ -5,21 +5,36 @@
 
 package org.opensearch.indexmanagement.indexstatemanagement.step.transition
 
+import org.apache.logging.log4j.LogManager
 import org.opensearch.indexmanagement.spi.indexstatemanagement.Step
 import org.opensearch.indexmanagement.spi.indexstatemanagement.model.ManagedIndexMetaData
+import org.opensearch.indexmanagement.spi.indexstatemanagement.model.StepMetaData
 
 class AttemptTransitionStep : Step(name) {
+
+    private val logger = LogManager.getLogger(javaClass)
+    private var stateName: String? = null
+    private var stepStatus = StepStatus.STARTING
+    private var policyCompleted: Boolean = false
+    private var info: Map<String, Any>? = null
+
     override suspend fun execute(): Step {
-        TODO("Not yet implemented")
+        // TODO: Fix this to actually evaluate the conditions
+        stepStatus = StepStatus.COMPLETED
+        policyCompleted = true
+        return this
     }
 
     override fun getUpdatedManagedIndexMetadata(currentMetadata: ManagedIndexMetaData): ManagedIndexMetaData {
-        TODO("Not yet implemented")
+        return currentMetadata.copy(
+            policyCompleted = policyCompleted,
+            transitionTo = stateName,
+            stepMetaData = StepMetaData(name, getStepStartTime(currentMetadata).toEpochMilli(), stepStatus),
+            info = info
+        )
     }
 
-    override fun isIdempotent(): Boolean {
-        TODO("Not yet implemented")
-    }
+    override fun isIdempotent() = true
 
     companion object {
         const val name = "attempt_transition_step"