rdblue commented on a change in pull request #4050: URL: https://github.com/apache/iceberg/pull/4050#discussion_r806014142
########## File path: api/src/main/java/org/apache/iceberg/metrics/MetricsContext.java ########## @@ -0,0 +1,107 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you 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 org.apache.iceberg.metrics; + +import java.io.Serializable; +import java.util.Map; +import java.util.Optional; + +/** + * Generalized interface for creating telemetry related instances for tracking + * operations. Implementations must take into account usage considerations + * like thread safety and serialization. + */ +public interface MetricsContext extends Serializable { + enum Unit { + UNDEFINED("undefined"), + BYTES("bytes"), + SCALAR("scalar"); + + private final String displayName; + + Unit(String displayName) { + this.displayName = displayName; + } + + public String displayName() { + return displayName; + } + } + + default void initialize(Map<String, String> properties) { + } + + interface Counter<T extends Number> { + /** + * Increment the counter by a single whole number value (i.e. 1). + */ + void increment(); + + /** + * Increment the counter by the provided amount. + * + * @param amount to be incremented + */ + void increment(T amount); + + /** + * Reporting count is optional if the counter is reporting externally. + * + * @return current count if available + */ + default Optional<T> count() { + return Optional.empty(); + } + + default Unit unit() { + return Unit.UNDEFINED; + } + } + + /** + * Get a named counter of a specific type. Metric implementations may impose + * restrictions on what types are supported for specific counters. + * + * @param name name of the metric + * @param type numeric type of the counter value + * @param unit the unit designation of the metric + * @return a counter implementation + */ + default <T extends Number> Counter<T> counter(String name, Class<T> type, Unit unit) { Review comment: I think it would be better to leave this empty so that it is required for implementations. Then put the default noop counter implementation in `nullMetrics`. That signals what people need to implement. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
