Refactor IndexManagement to support custom actions

build.gradle

@@ -104,7 +104,7 @@ task ktlint(type: JavaExec, group: "verification") {
     description = "Check Kotlin code style."
     main = "com.pinterest.ktlint.Main"
     classpath = configurations.ktlint
-    args "src/**/*.kt"
+    args "src/**/*.kt", "spi/src/main/**/*.kt"
 }
 
 check.dependsOn ktlint
@@ -113,7 +113,7 @@ task ktlintFormat(type: JavaExec, group: "formatting") {
     description = "Fix Kotlin code style deviations."
     main = "com.pinterest.ktlint.Main"
     classpath = configurations.ktlint
-    args "-F", "src/**/*.kt"
+    args "-F", "src/**/*.kt", "spi/src/main/**/*.kt"
 }
 
 detekt {
@@ -148,6 +148,7 @@ dependencies {
     compile "org.jetbrains.kotlin:kotlin-stdlib-jdk8:${kotlin_version}"
     compile 'org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.9'
     compile "org.jetbrains:annotations:13.0"
+    compile project(path: ":${rootProject.name}-spi", configuration: 'shadow')
     compile "org.opensearch:notification:${notification_version}"
     compile "org.opensearch:common-utils:${common_utils_version}"
     compile "com.github.seancfoley:ipaddress:5.3.3"

settings.gradle

@@ -4,3 +4,6 @@
  */
 
 rootProject.name = 'opensearch-index-management'
+
+include "spi"
+project(":spi").name = rootProject.name + "-spi"

spi/build.gradle

@@ -0,0 +1,85 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+import org.opensearch.gradle.test.RestIntegTestTask
+
+plugins {
+    id 'com.github.johnrengelman.shadow'
+    id 'jacoco'
+}
+
+apply plugin: 'opensearch.java'
+apply plugin: 'opensearch.testclusters'
+apply plugin: 'opensearch.java-rest-test'
+apply plugin: 'kotlin'
+apply plugin: 'org.jetbrains.kotlin.jvm'
+apply plugin: 'org.jetbrains.kotlin.plugin.allopen'
+
+ext {
+    projectSubstitutions = [:]
+    licenseFile = rootProject.file('LICENSE.txt')
+    noticeFile = rootProject.file('NOTICE')
+}
+
+jacoco {
+    toolVersion = '0.8.5'
+    reportsDir = file("$buildDir/JacocoReport")
+}
+
+jacocoTestReport {
+    reports {
+        xml.enabled false
+        csv.enabled false
+        html.destination file("${buildDir}/jacoco/")
+    }
+}
+check.dependsOn jacocoTestReport
+
+repositories {
+    mavenLocal()
+    mavenCentral()
+    maven { url "https://plugins.gradle.org/m2/" }
+    maven { url "https://aws.oss.sonatype.org/content/repositories/snapshots" }
+}
+
+configurations.all {
+    if (it.state != Configuration.State.UNRESOLVED) return
+    resolutionStrategy {
+        force "org.jetbrains.kotlin:kotlin-stdlib:${kotlin_version}"
+        force "org.jetbrains.kotlin:kotlin-stdlib-common:${kotlin_version}"
+    }
+}
+
+dependencies {
+    compileOnly "org.opensearch:opensearch:${opensearch_version}"
+    compileOnly "org.jetbrains.kotlin:kotlin-stdlib:${kotlin_version}"
+    compileOnly "org.jetbrains.kotlin:kotlin-stdlib-common:${kotlin_version}"
+    compileOnly "org.jetbrains.kotlin:kotlin-stdlib-jdk8:${kotlin_version}"
+    compileOnly "org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.9"
+    compileOnly "org.opensearch:common-utils:${common_utils_version}"
+
+    testImplementation "org.opensearch.test:framework:${opensearch_version}"
+    testImplementation "org.apache.logging.log4j:log4j-core:${versions.log4j}"
+}
+
+test {
+    doFirst {
+        test.classpath -= project.files(project.tasks.named('shadowJar'))
+        test.classpath -= project.configurations.getByName(ShadowBasePlugin.CONFIGURATION_NAME)
+        test.classpath += project.extensions.getByType(SourceSetContainer).getByName(SourceSet.MAIN_SOURCE_SET_NAME).runtimeClasspath
+    }
+    systemProperty 'tests.security.manager', 'false'
+}
+
+task integTest(type: RestIntegTestTask) {
+    description 'Run integ test with opensearch test framework'
+    group 'verification'
+    systemProperty 'tests.security.manager', 'false'
+    dependsOn test
+}
+check.dependsOn integTest
+
+testClusters.javaRestTest {
+    testDistribution = 'INTEG_TEST'
+}

spi/src/main/kotlin/org.opensearch.indexmanagement.spi/IndexManagementExtension.kt

@@ -0,0 +1,57 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.indexmanagement.spi
+
+import org.opensearch.indexmanagement.spi.indexstatemanagement.ActionParser
+import org.opensearch.indexmanagement.spi.indexstatemanagement.DefaultStatusChecker
+import org.opensearch.indexmanagement.spi.indexstatemanagement.IndexMetadataService
+import org.opensearch.indexmanagement.spi.indexstatemanagement.StatusChecker
+
+/**
+ * SPI for IndexManagement
+ */
+interface IndexManagementExtension {
+
+    /**
+     * List of action parsers that are supported by the extension, each of the action parser will parse the policy action into the defined action.
+     * The ActionParser provides the ability to parse the action
+     */
+    fun getISMActionParsers(): List<ActionParser>
+
+    /**
+     * Status checker is used by IndexManagement to check the status of the extension before executing the actions registered by the extension.
+     * Actions registered by the plugin can only be executed if in enabled, otherwise the action fails without retries. The status returned
+     * should represent if the extension is enabled or disabled, and should not represent extension health or the availability of some extension
+     * dependency.
+     */
+    fun statusChecker(): StatusChecker {
+        return DefaultStatusChecker()
+    }
+
+    /**
+     * Name of the extension
+     */
+    fun getExtensionName(): String
+
+    /**
+     * Not Required to override but if extension moves the index metadata outside of cluster state and requires IndexManagement to manage these
+     * indices provide the metadata service that can provide the index metadata for these indices. An extension need to label the metadata service
+     * with a type string which is used to distinguish indices in IndexManagement plugin
+     */
+    fun getIndexMetadataService(): Map<String, IndexMetadataService> {
+        return mapOf()
+    }
+
+    /**
+     * Caution: Experimental and can be removed in future
+     *
+     * If extension wants IndexManagement to determine cluster state indices UUID based on custom index setting if
+     * present of cluster state override this method.
+     */
+    fun overrideClusterStateIndexUuidSetting(): String? {
+        return null
+    }
+}

spi/src/main/kotlin/org.opensearch.indexmanagement.spi/indexstatemanagement/Action.kt

@@ -0,0 +1,121 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.indexmanagement.spi.indexstatemanagement
+
+import org.opensearch.common.io.stream.StreamOutput
+import org.opensearch.common.io.stream.Writeable
+import org.opensearch.common.xcontent.ToXContent
+import org.opensearch.common.xcontent.ToXContentObject
+import org.opensearch.common.xcontent.XContentBuilder
+import org.opensearch.indexmanagement.spi.indexstatemanagement.model.ActionMetaData
+import org.opensearch.indexmanagement.spi.indexstatemanagement.model.ActionRetry
+import org.opensearch.indexmanagement.spi.indexstatemanagement.model.ActionTimeout
+import org.opensearch.indexmanagement.spi.indexstatemanagement.model.ManagedIndexMetaData
+import org.opensearch.indexmanagement.spi.indexstatemanagement.model.StepContext
+import java.time.Instant
+
+abstract class Action(
+    val type: String,
+    val actionIndex: Int
+) : ToXContentObject, Writeable {
+
+    var configTimeout: ActionTimeout? = null
+    var configRetry: ActionRetry? = ActionRetry(DEFAULT_RETRIES)
+    var customAction: Boolean = false
+
+    final override fun toXContent(builder: XContentBuilder, params: ToXContent.Params): XContentBuilder {
+        builder.startObject()
+        configTimeout?.toXContent(builder, params)
+        configRetry?.toXContent(builder, params)
+        // Include a "custom" object wrapper for custom actions to allow extensions to put arbitrary action configs in the config
+        // index. The EXCLUDE_CUSTOM_FIELD_PARAM is used to not include this wrapper in api responses
+        if (customAction && !params.paramAsBoolean(EXCLUDE_CUSTOM_FIELD_PARAM, false)) builder.startObject(CUSTOM_ACTION_FIELD)
+        populateAction(builder, params)
+        if (customAction && !params.paramAsBoolean(EXCLUDE_CUSTOM_FIELD_PARAM, false)) builder.endObject()
+        return builder.endObject()
+    }
+
+    /**
+     * The implementer of Action can change this method to correctly serialize the internals of the action
+     * when stored internally or returned as response
+     */
+    open fun populateAction(builder: XContentBuilder, params: ToXContent.Params) {
+        builder.startObject(type).endObject()
+    }
+
+    final override fun writeTo(out: StreamOutput) {
+        out.writeString(type)
+        out.writeOptionalWriteable(configTimeout)
+        out.writeOptionalWriteable(configRetry)
+        populateAction(out)
+    }
+
+    fun getUpdatedActionMetadata(managedIndexMetaData: ManagedIndexMetaData, stateName: String): ActionMetaData {
+        val stateMetaData = managedIndexMetaData.stateMetaData
+        val actionMetaData = managedIndexMetaData.actionMetaData
+
+        return when {
+            // start a new action
+            stateMetaData?.name != stateName ->
+                ActionMetaData(this.type, Instant.now().toEpochMilli(), this.actionIndex, false, 0, 0, null)
+            actionMetaData?.index != this.actionIndex ->
+                ActionMetaData(this.type, Instant.now().toEpochMilli(), this.actionIndex, false, 0, 0, null)
+            // RetryAPI will reset startTime to null for actionMetaData and we'll reset it to "now" here
+            else -> actionMetaData.copy(startTime = actionMetaData.startTime ?: Instant.now().toEpochMilli())
+        }
+    }
+
+    /**
+     * The implementer of Action can change this method to correctly serialize the internals of the action
+     * when data is shared between nodes
+     */
+    open fun populateAction(out: StreamOutput) {
+        out.writeInt(actionIndex)
+    }
+
+    /**
+     * Get all the steps associated with the action
+     */
+    abstract fun getSteps(): List<Step>
+
+    /**
+     * Get the current step to execute in the action
+     */
+    abstract fun getStepToExecute(context: StepContext): Step
+
+    final fun isLastStep(stepName: String): Boolean = getSteps().last().name == stepName
+
+    final fun isFirstStep(stepName: String): Boolean = getSteps().first().name == stepName
+
+    /*
+     * Gets if the managedIndexMetaData reflects a state in which this action has completed successfully. Used in the
+     * runner when determining if the index metadata should be deleted. If the action isFinishedSuccessfully and
+     * deleteIndexMetadataAfterFinish is set to true, then we issue a request to delete the managedIndexConfig and its
+     * managedIndexMetadata.
+     */
+    final fun isFinishedSuccessfully(managedIndexMetaData: ManagedIndexMetaData): Boolean {
+        val policyRetryInfo = managedIndexMetaData.policyRetryInfo
+        if (policyRetryInfo?.failed == true) return false
+        val actionMetaData = managedIndexMetaData.actionMetaData
+        if (actionMetaData == null || actionMetaData.failed || actionMetaData.name != this.type) return false
+        val stepMetaData = managedIndexMetaData.stepMetaData
+        if (stepMetaData == null || !isLastStep(stepMetaData.name) || stepMetaData.stepStatus != Step.StepStatus.COMPLETED) return false
+        return true
+    }
+
+    /*
+     * Denotes if the index metadata in the config index should be deleted for the index this action has just
+     * successfully finished running on. This may be used by custom actions which delete some off-cluster index,
+     * and following the action's success, the managed index config and metadata need to be deleted.
+     */
+    open fun deleteIndexMetadataAfterFinish(): Boolean = false
+
+    companion object {
+        const val DEFAULT_RETRIES = 3L
+        const val CUSTOM_ACTION_FIELD = "custom"
+        const val EXCLUDE_CUSTOM_FIELD_PARAM = "exclude_custom"
+    }
+}

spi/src/main/kotlin/org.opensearch.indexmanagement.spi/indexstatemanagement/ActionParser.kt

@@ -0,0 +1,27 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.indexmanagement.spi.indexstatemanagement
+
+import org.opensearch.common.io.stream.StreamInput
+import org.opensearch.common.xcontent.XContentParser
+
+abstract class ActionParser(var customAction: Boolean = false) {
+
+    /**
+     * The action type parser will parse
+     */
+    abstract fun getActionType(): String
+
+    /**
+     * Deserialize Action from stream input
+     */
+    abstract fun fromStreamInput(sin: StreamInput): Action
+
+    /**
+     * Deserialize Action from xContent
+     */
+    abstract fun fromXContent(xcp: XContentParser, index: Int): Action
+}

spi/src/main/kotlin/org.opensearch.indexmanagement.spi/indexstatemanagement/IndexMetadataService.kt

@@ -0,0 +1,39 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.indexmanagement.spi.indexstatemanagement
+
+import org.opensearch.client.Client
+import org.opensearch.cluster.service.ClusterService
+import org.opensearch.indexmanagement.spi.indexstatemanagement.model.ISMIndexMetadata
+
+/**
+ * ISM by default considers all the index metadata to be part of the cluster state,
+ * if that doesn't hold true and indices metadata is present in some other place and
+ * ISM still need to manage these indices the following interface provides a mechanism
+ * for ISM extensions to register the metadata service for the type so ISM can get the
+ * index metadata for these special type of indices.
+ *
+ * ISM Rest APIs allows support for type param which determines the type of index, if there
+ * is a registered metadata service for the type - ISM will use the service to get the metadata
+ * else uses the default i.e cluster state
+ */
+interface IndexMetadataService {
+
+    /**
+     * Returns the index metadata needed for ISM
+     */
+    suspend fun getMetadata(indices: List<String>, client: Client, clusterService: ClusterService): Map<String, ISMIndexMetadata>
+
+    /**
+     * Returns all the indices metadata
+     */
+    suspend fun getMetadataForAllIndices(client: Client, clusterService: ClusterService): Map<String, ISMIndexMetadata>
+
+    /**
+     * Returns an optional setting path which, when set to true in the index settings, overrides a cluster level metadata write block.
+     */
+    fun getIndexMetadataWriteOverrideSetting(): String? = null
+}

spi/src/main/kotlin/org.opensearch.indexmanagement.spi/indexstatemanagement/StatusChecker.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.indexmanagement.spi.indexstatemanagement
+
+import org.opensearch.cluster.ClusterState
+
+interface StatusChecker {
+
+    /**
+     * checks and returns the status of the extension
+     */
+    fun check(clusterState: ClusterState): Status {
+        return Status.ENABLED
+    }
+}
+
+enum class Status(private val value: String) {
+    ENABLED("enabled"),
+    DISABLED("disabled");
+
+    override fun toString(): String {
+        return value
+    }
+}
+
+class DefaultStatusChecker : StatusChecker