io.cdap.cdap.internal.app.runtime.monitor.MonitorSchemas Maven / Gradle / Ivy
/*
* Copyright © 2018 Cask Data, Inc.
*
* 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 io.cdap.cdap.internal.app.runtime.monitor;
import org.apache.avro.Schema;
import org.apache.avro.generic.GenericData;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import javax.annotation.Nullable;
/**
* Loads Avro schemas for Monitor request and response.
*/
public final class MonitorSchemas {
private MonitorSchemas() {
// protect the constructor
}
private static final Logger LOG = LoggerFactory.getLogger(MonitorSchemas.class);
/**
* Contains Schema for V1 protocol.
*/
public static final class V1 {
/**
* Contains schema for monitor consume request.
*/
public static final class MonitorConsumeRequest {
public static final Schema SCHEMA = loadSchema(MonitorSchemas.V1.MonitorConsumeRequest.class);
}
/**
* Contains schema for monitor response.
*/
public static final class MonitorResponse {
public static final Schema SCHEMA = loadSchema(MonitorSchemas.V1.MonitorResponse.class);
}
}
/**
* Contains Schema for V2 protocol.
*/
public static final class V2 {
/**
* Contains schema for monitor request.
*/
public static final class MonitorRequest {
public static final Schema SCHEMA = loadSchema(MonitorSchemas.V2.MonitorRequest.class);
}
}
/**
* Creates a {@link Schema} instance based on the given class name.
*/
@Nullable
private static Schema loadSchema(Class cls) {
// The schema file is part of the classloader resource.
String resourceName = String.format("schema/%s/%s.avsc",
cls.getDeclaringClass().getSimpleName().toLowerCase(),
cls.getSimpleName());
URL resource = cls.getClassLoader().getResource(resourceName);
if (resource == null) {
// Shouldn't happen
LOG.warn("Failed to load schema from resource {}", resourceName);
throw new IllegalStateException("Failed to load schema from resource " + resourceName);
}
try (InputStream is = resource.openStream()) {
Schema schema = new Schema.Parser().parse(is);
// Avro converts java String to UTF8 while deserializing strings. Set String type to Java String
GenericData.setStringType(schema, GenericData.StringType.String);
return schema;
} catch (IOException e) {
// Shouldn't happen
LOG.warn("Failed to read schema from resource {}", resourceName, e);
throw new IllegalStateException("Failed to read schema from resource " + resourceName, e);
}
}
}