com.datamountaineer.streamreactor.connect.schemas.SchemaRegistry.scala Maven / Gradle / Ivy

/*
 *  Copyright 2017 Datamountaineer.
 *
 *  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.datamountaineer.streamreactor.connect.schemas

import com.typesafe.scalalogging.slf4j.StrictLogging
import io.confluent.kafka.schemaregistry.client.rest.RestService

import scala.util.{Failure, Success, Try}
import scala.collection.JavaConverters._

/**
  * Created by [email protected] on 13/06/16. 
  * kafka-connect-common
  */
object SchemaRegistry extends StrictLogging {

  /**
    * Get a schema for a given subject
    *
    * @param url The url of the schema registry
    * @param subject The subject to het the schema for
    * @return The schema for the subject
    * */
  def getSchema(url : String, subject : String) : String = {
    val registry = new RestService(url)

    Try(registry.getLatestVersion(subject).getSchema) match {
      case Success(s) => {
        logger.info(s"Found schema for $subject")
        s
      }
      case Failure(f) => {
        logger.warn("Unable to connect to the Schema registry. An attempt will be made to create the table" +
          " on receipt of the first records.")
        ""
      }
    }
  }

  /**
    * Get a list of subjects from the registry
    *
    * @param url The url to the schema registry
    * @return A list of subjects/topics
    * */
  def getSubjects(url: String) : List[String] = {
    val registry = new RestService(url)
    val schemas: List[String] = Try(registry.getAllSubjects.asScala.toList) match {
      case Success(s) => s
      case Failure(f) => {
        logger.warn("Unable to connect to the Schema registry. An attempt will be made to create the table" +
          " on receipt of the first records.")
        List.empty[String]
      }
    }

    schemas.foreach(s=>logger.info(s"Found schemas for $s"))
    schemas
  }
}