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/*
* Copyright 2018-2019 ABSA Group Limited
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package za.co.absa.enceladus.migrations.framework.migration
import org.apache.log4j.{LogManager, Logger}
import za.co.absa.enceladus.migrations.framework.MigrationUtils
import za.co.absa.enceladus.migrations.framework.dao.DocumentDb
import scala.collection.mutable.{ArrayBuffer, ListBuffer}
/**
* A CollectionMigration represents an entity that provides ability to add, rename and remove collections
*
* In order to create a collection migration you need to extend from this trait and provide the requested
* collection changes:
*
* {{{
* object MigrationTo1 extends MigrationBase with CollectionMigration {
*
* createCollection("collection1_name")
* createCollection("collection2_name")
* createCollection("collection3_name")
*
* dropCollection("collection4_name")
* dropCollection("collection5_name")
* dropCollection("collection6_name")
*
* renameCollection("collection7_name", "collection8_name")
*
* createIndex("collection1_name", "foo1" :: "bar1" :: Nil)
* dropIndex("collection2_name", "foo2" :: "bar2" :: Nil)
* }
* }}}
*/
trait CollectionMigration extends Migration {
// Index is a pair of a collection name and a list of key fields
type Index = (String, Seq[String])
private val log: Logger = LogManager.getLogger(this.getClass)
private val collectionsToCreate = new ListBuffer[String]()
private val collectionsToDrop = new ListBuffer[String]()
private val collectionsToRename = new ListBuffer[(String, String)]()
private val indexesToCreate = new ListBuffer[Index]()
private val indexesToDrop = new ListBuffer[Index]()
/**
* This method is used by derived classes to add new collection as a step of migration process.
*
* @param collectionName A collection name to be added
*/
def createCollection(collectionName: String): Unit = {
if (collectionsToCreate.contains(collectionName)) {
throw new IllegalArgumentException(s"Collection '$collectionName' is already added.")
}
if (collectionsToDrop.contains(collectionName)) {
throw new IllegalArgumentException(s"Cannot both add and remove '$collectionName' as a migration step.")
}
collectionsToCreate += collectionName
}
/**
* This method is used by derived classes to remove a collection as a step of migration process.
*
* @param collectionName A collection name to be added
*/
def dropCollection(collectionName: String): Unit = {
if (collectionsToDrop.contains(collectionName)) {
throw new IllegalArgumentException(s"Collection '$collectionName' is already in the removal list.")
}
if (collectionsToCreate.contains(collectionName)) {
throw new IllegalArgumentException(s"Cannot both add and remove '$collectionName' as a migration step.")
}
collectionsToDrop += collectionName
}
/**
* This method is used by derived classes to rename a collection as a step of migration process.
*
* @param oldName A collection to be renamed
* @param newName A new name for the collection
*/
def renameCollection(oldName: String, newName: String): Unit = {
if (collectionsToDrop.contains(oldName)) {
throw new IllegalArgumentException(s"Collection '$oldName' is in the removal list. Cannot rename it.")
}
if (collectionsToCreate.contains(oldName)) {
throw new IllegalArgumentException(s"Collection '$oldName' is in the list of new collections. Cannot rename it.")
}
if (collectionsToDrop.contains(newName)) {
throw new IllegalArgumentException(s"Collection '$newName' is in the removal list. Cannot rename it.")
}
if (collectionsToCreate.contains(newName)) {
throw new IllegalArgumentException(s"Collection '$newName' is in the list of new collections. Cannot rename it.")
}
collectionsToRename += oldName -> newName
}
/**
* This method is used by derived classes to create an index on a collection.
*
* @param collectionName A collection for setting up an index
* @param fields A list of fields that the index should contain
*/
def createIndex(collectionName: String, fields: Seq[String]): Unit = {
if (collectionsToDrop.contains(collectionName)) {
throw new IllegalArgumentException(s"Collection '$collectionName' is in the removal list. " +
s"Cannot create an index on it.")
}
indexesToCreate.append((collectionName, fields))
}
/**
* This method is used by derived classes to drop an index on a collection.
*
* @param collectionName A collection for dropping up an index
* @param fields A list of fields that the index should contain
*/
def dropIndex(collectionName: String, fields: Seq[String]): Unit = {
if (collectionsToDrop.contains(collectionName)) {
throw new IllegalArgumentException(s"Collection '$collectionName' is in the removal list. " +
s"No need to explicitly drop indexes.")
}
indexesToDrop.append((collectionName, fields))
}
/** Returns a list of collections to be added during the migration */
def getCollectionsToAdd: List[String] = collectionsToCreate.toList
/** Returns a list of collections to be removed during the migration */
def getCollectionsToRemove: List[String] = collectionsToDrop.toList
/** Returns a list of collections to be removed during the migration */
def getCollectionsToRename: List[(String, String)] = collectionsToRename.toList
/** Returns a list of indexes to be added during the migration */
def getIndexesToAdd: List[Index] = indexesToCreate.toList
/** Returns a list of indexes to be removed during the migration */
def getIndexesToRemove: List[Index] = indexesToDrop.toList
/**
* If a migration adds or removes collections it should provide a new list of collections based
* on the list of collections available for he previous version of a database.
*/
override def applyCollectionChanges(collections: List[String]): List[String] = {
val newCollections = ArrayBuffer[String](collections:_*)
for (c <- getCollectionsToAdd) {
if (!newCollections.contains(c)) {
newCollections += c
}
}
val collectionsToRemove = getCollectionsToRemove
collectionsToRemove.foreach(c => {
val i = newCollections.indexOf(c)
if (i >= 0) {
newCollections.remove(i)
}
})
val renameMap = collectionsToRename.toMap
newCollections.map(collectionName => {
renameMap.getOrElse(collectionName, collectionName)
}).toList
}
/**
* Executes a migration on a given database and a list of collection names.
*/
abstract override def execute(db: DocumentDb, collectionNames: Seq[String]): Unit = {
super.execute(db, collectionNames)
applyCreateCollections(db)
applyDropCollections(db)
applyRenameCollection(db)
applyIndexDrop(db)
applyIndexCreate(db)
}
/**
* Applies additions of new collections to the provided database.
*/
private def applyCreateCollections(db: DocumentDb): Unit = {
collectionsToCreate.foreach(c => {
val newCollection = MigrationUtils.getVersionedCollectionName(c, targetVersion)
if (db.doesCollectionExists(newCollection)) {
log.info(s"Dropping existing collection $newCollection")
db.dropCollection(newCollection)
}
log.info(s"Adding new collection $newCollection")
db.createCollection(newCollection)
})
}
/**
* Applies collection removals to the provided database.
*/
private def applyDropCollections(db: DocumentDb): Unit = {
collectionsToDrop.foreach(c => {
val collection = MigrationUtils.getVersionedCollectionName(c, targetVersion)
log.info(s"Removing collection $collection")
db.dropCollection(collection)
})
}
/**
* Applies collection renames to the provided database.
*/
private def applyRenameCollection(db: DocumentDb): Unit = {
collectionsToRename.foreach {
case (oldName, newName) =>
val oldVersionedCollection = MigrationUtils.getVersionedCollectionName(oldName, targetVersion)
val newVersionedCollection = MigrationUtils.getVersionedCollectionName(newName, targetVersion)
log.info(s"Renaming collection $oldVersionedCollection -> $newVersionedCollection")
db.renameCollection(oldVersionedCollection, newVersionedCollection)
}
}
/**
* Applies indexes creation the provided database.
*/
private def applyIndexCreate(db: DocumentDb): Unit = {
indexesToCreate.foreach {
case (collectionName, keys) =>
val collection = MigrationUtils.getVersionedCollectionName(collectionName, targetVersion)
log.info(s"Creating index '${keys.mkString(", ")}' in '$collection'")
db.createIndex(collection, keys)
}
}
/**
* Applies indexes removals the provided database.
*/
private def applyIndexDrop(db: DocumentDb): Unit = {
indexesToDrop.foreach {
case (collectionName, keys) =>
val collection = MigrationUtils.getVersionedCollectionName(collectionName, targetVersion)
log.info(s"Removing index '${keys.mkString(", ")}' from '$collection'")
db.dropIndex(collection, keys)
}
}
/**
* Validate the possibility of running a migration given a list of collection names.
*/
abstract override def validate(collectionNames: Seq[String]): Unit = {
super.validate(collectionNames)
collectionsToCreate.foreach(collectionToMigrate =>
if (collectionNames.contains(collectionToMigrate)) {
throw new IllegalStateException(
s"Attempt to add a collection that already exists in db version ${targetVersion - 1}: $collectionToMigrate.")
}
)
collectionsToDrop.foreach(collectionToMigrate =>
if (!collectionNames.contains(collectionToMigrate)) {
throw new IllegalStateException(
s"Attempt to drop a collection that does not exist in db version ${targetVersion - 1}: $collectionToMigrate.")
}
)
collectionsToRename.foreach {
case (oldName, newName) =>
if (!collectionNames.contains(oldName)) {
throw new IllegalStateException(
s"Attempt to rename a collection that does not exist: $oldName.")
}
if (collectionNames.contains(newName)) {
throw new IllegalStateException(
s"Attempt to rename a collection to a one that already exists in db version ${targetVersion - 1}: " +
s"$newName.")
}
if (collectionsToCreate.contains(oldName)) {
throw new IllegalStateException(
s"Cannot add and rename a collection as a part of single migration in db version ${targetVersion - 1}: " +
s"$oldName.")
}
if (collectionsToCreate.contains(newName)) {
throw new IllegalStateException(
s"Cannot add and rename a collection as a part of single migration in db version ${targetVersion - 1}: " +
s"$newName.")
}
if (collectionsToDrop.contains(oldName)) {
throw new IllegalStateException(
s"Cannot drop and rename a collection as a part of single migration in db version ${targetVersion - 1}: " +
s"$oldName.")
}
if (collectionsToDrop.contains(newName)) {
throw new IllegalStateException(
s"Cannot drop and rename a collection as a part of single migration in db version ${targetVersion - 1}: " +
s"$newName.")
}
}
}
/**
* Validate if migration parameters are specified properly.
*/
override protected def validateMigration(): Unit = {
if (targetVersion < 0) {
throw new IllegalStateException("The target version of a CollectionMigration should be 0 or bigger.")
}
}
}
