com.builtamont.cassandra.migration.internal.resolver.cql.CqlMigrationResolver.kt Maven / Gradle / Ivy
/**
* File : CqlMigrationResolver.kt
* License :
* Original - Copyright (c) 2015 - 2016 Contrast Security
* Derivative - Copyright (c) 2016 Citadel Technology Solutions Pte Ltd
*
* 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 com.builtamont.cassandra.migration.internal.resolver.cql
import com.builtamont.cassandra.migration.api.CassandraMigrationException
import com.builtamont.cassandra.migration.api.MigrationType
import com.builtamont.cassandra.migration.api.resolver.MigrationResolver
import com.builtamont.cassandra.migration.api.resolver.ResolvedMigration
import com.builtamont.cassandra.migration.internal.resolver.MigrationInfoHelper
import com.builtamont.cassandra.migration.internal.resolver.ResolvedMigrationComparator
import com.builtamont.cassandra.migration.internal.resolver.ResolvedMigrationImpl
import com.builtamont.cassandra.migration.internal.util.Location
import com.builtamont.cassandra.migration.internal.util.scanner.Resource
import com.builtamont.cassandra.migration.internal.util.scanner.Scanner
import java.io.BufferedReader
import java.io.IOException
import java.io.StringReader
import java.util.zip.CRC32
/**
* Migration resolver for CQL files on the classpath.
* The CQL files must have names like V1__Description.cql or V1_1__Description.cql.
*
* @param classLoader The ClassLoader for loading migrations on the classpath.
* @param location The location on the classpath where the migrations are located.
* @param encoding The encoding of the .cql file.
*/
class CqlMigrationResolver(
classLoader: ClassLoader,
private val location: Location,
private val encoding: String
) : MigrationResolver {
/** The scanner to use. */
private val scanner: Scanner
/**
* CqlMigrationResolver initialization.
*/
init {
this.scanner = Scanner(classLoader)
}
/**
* Resolves the available migrations.
*
* @return The available migrations.
*/
override fun resolveMigrations(): List {
val resources = scanner.scanForResources(location, CQL_MIGRATION_PREFIX, CQL_MIGRATION_SUFFIX)
return resources.map { resource ->
val resolvedMigration = extractMigrationInfo(resource)
resolvedMigration.physicalLocation = resource.locationOnDisk
resolvedMigration.executor = CqlMigrationExecutor(resource, encoding)
resolvedMigration
}.sortedWith(ResolvedMigrationComparator())
}
/**
* Extracts the migration info for this resource.
*
* @param resource The resource to analyse.
* @return The migration info.
*/
private fun extractMigrationInfo(resource: Resource): ResolvedMigration {
val info = MigrationInfoHelper.extractVersionAndDescription(
resource.filename,
CQL_MIGRATION_PREFIX,
CQL_MIGRATION_SEPARATOR,
CQL_MIGRATION_SUFFIX
)
val migration = ResolvedMigrationImpl()
migration.version = info.left
migration.description = info.right
migration.script = extractScriptName(resource)
migration.checksum = calculateChecksum(resource, resource.loadAsString("UTF-8"))
migration.type = MigrationType.CQL
return migration
}
/**
* Extracts the script name from this resource.
*
* @param resource The resource to process.
* @return The script name.
*/
fun extractScriptName(resource: Resource): String {
return if (location.path!!.isEmpty()) {
resource.location
} else {
resource.location.substring(location.path!!.length + 1)
}
}
/**
* CqlMigrationResolver companion object.
*/
companion object {
/** The prefix for CQL migrations. */
private val CQL_MIGRATION_PREFIX = "V"
/** The separator for CQL migrations. */
private val CQL_MIGRATION_SEPARATOR = "__"
/** The suffix for cql migrations. */
private val CQL_MIGRATION_SUFFIX = ".cql"
/**
* Calculates the checksum of these bytes.
*
* @param bytes The bytes to calculate the checksum for.
* @return The crc-32 checksum of the bytes.
*/
@Deprecated("Replaced with `calculateChecksum(resource: Resource, str: String)` as per Flyway 4.x")
private fun calculateChecksum(bytes: ByteArray): Int {
val crc32 = CRC32()
crc32.update(bytes)
return crc32.value.toInt()
}
/**
* Calculates the checksum of this string.
*
* @param resource The resource to process.
* @param str The string to calculate the checksum for.
* @return The crc-32 checksum of the bytes.
*/
private fun calculateChecksum(resource: Resource, str: String): Int {
val crc32 = CRC32()
try {
BufferedReader(StringReader(str)).forEachLine { line ->
crc32.update(line.toByteArray(charset("UTF-8")))
}
} catch (e: IOException) {
val message = "Unable to calculate checksum for ${resource.location} (${resource.locationOnDisk})"
throw CassandraMigrationException(message, e)
}
return crc32.value.toInt()
}
}
}