| // Copyright 2014 The Bazel Authors. All rights reserved. |
| // |
| // 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.google.devtools.build.lib.runtime; |
| |
| import com.google.devtools.build.lib.clock.BlazeClock; |
| import com.google.devtools.build.lib.clock.Clock; |
| import com.google.devtools.build.lib.events.Event; |
| import com.google.devtools.build.lib.events.EventHandler; |
| |
| /** |
| * An event handler that rate limits events. |
| */ |
| public class RateLimitingEventHandler implements EventHandler { |
| |
| private final EventHandler outputHandler; |
| private final double intervalMillis; |
| private final Clock clock; |
| private long lastEventMillis = -1; |
| |
| /** |
| * Creates a new Event handler that rate limits the events of type PROGRESS |
| * to one per event "rateLimitation" seconds. Events that arrive too quickly are dropped; |
| * all others are are forwarded to the handler "delegateTo". |
| * |
| * @param delegateTo The event handler that ultimately handles the events |
| * @param rateLimitation The minimum number of seconds between events that will be forwarded |
| * to the delegateTo-handler. |
| * If less than zero (or NaN), all events will be forwarded. |
| */ |
| public static EventHandler create(EventHandler delegateTo, double rateLimitation) { |
| if (rateLimitation < 0.0 || Double.isNaN(rateLimitation)) { |
| return delegateTo; |
| } |
| return new RateLimitingEventHandler(delegateTo, rateLimitation); |
| } |
| |
| private RateLimitingEventHandler(EventHandler delegateTo, double rateLimitation) { |
| clock = BlazeClock.instance(); |
| outputHandler = delegateTo; |
| this.intervalMillis = rateLimitation * 1000; |
| } |
| |
| @Override |
| public void handle(Event event) { |
| switch (event.getKind()) { |
| case PROGRESS: |
| case START: |
| case FINISH: |
| long currentTime = clock.currentTimeMillis(); |
| if (lastEventMillis + intervalMillis <= currentTime) { |
| lastEventMillis = currentTime; |
| outputHandler.handle(event); |
| } |
| break; |
| default: |
| outputHandler.handle(event); |
| break; |
| } |
| } |
| } |