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<pre><span class="sourceLineNo">001</span>/*<a name="line.1"></a>
<span class="sourceLineNo">002</span> * Licensed to the Apache Software Foundation (ASF) under one<a name="line.2"></a>
<span class="sourceLineNo">003</span> * or more contributor license agreements. See the NOTICE file<a name="line.3"></a>
<span class="sourceLineNo">004</span> * distributed with this work for additional information<a name="line.4"></a>
<span class="sourceLineNo">005</span> * regarding copyright ownership. The ASF licenses this file<a name="line.5"></a>
<span class="sourceLineNo">006</span> * to you under the Apache License, Version 2.0 (the<a name="line.6"></a>
<span class="sourceLineNo">007</span> * "License"); you may not use this file except in compliance<a name="line.7"></a>
<span class="sourceLineNo">008</span> * with the License. You may obtain a copy of the License at<a name="line.8"></a>
<span class="sourceLineNo">009</span> *<a name="line.9"></a>
<span class="sourceLineNo">010</span> * http://www.apache.org/licenses/LICENSE-2.0<a name="line.10"></a>
<span class="sourceLineNo">011</span> *<a name="line.11"></a>
<span class="sourceLineNo">012</span> * Unless required by applicable law or agreed to in writing, software<a name="line.12"></a>
<span class="sourceLineNo">013</span> * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.13"></a>
<span class="sourceLineNo">014</span> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.14"></a>
<span class="sourceLineNo">015</span> * See the License for the specific language governing permissions and<a name="line.15"></a>
<span class="sourceLineNo">016</span> * limitations under the License.<a name="line.16"></a>
<span class="sourceLineNo">017</span> */<a name="line.17"></a>
<span class="sourceLineNo">018</span>package org.apache.hadoop.hbase.executor;<a name="line.18"></a>
<span class="sourceLineNo">019</span><a name="line.19"></a>
<span class="sourceLineNo">020</span>import io.opentelemetry.api.trace.Span;<a name="line.20"></a>
<span class="sourceLineNo">021</span>import io.opentelemetry.context.Context;<a name="line.21"></a>
<span class="sourceLineNo">022</span>import io.opentelemetry.context.Scope;<a name="line.22"></a>
<span class="sourceLineNo">023</span>import java.io.IOException;<a name="line.23"></a>
<span class="sourceLineNo">024</span>import java.util.concurrent.atomic.AtomicLong;<a name="line.24"></a>
<span class="sourceLineNo">025</span>import org.apache.hadoop.hbase.Server;<a name="line.25"></a>
<span class="sourceLineNo">026</span>import org.apache.hadoop.hbase.trace.TraceUtil;<a name="line.26"></a>
<span class="sourceLineNo">027</span>import org.apache.yetus.audience.InterfaceAudience;<a name="line.27"></a>
<span class="sourceLineNo">028</span>import org.slf4j.Logger;<a name="line.28"></a>
<span class="sourceLineNo">029</span>import org.slf4j.LoggerFactory;<a name="line.29"></a>
<span class="sourceLineNo">030</span>import org.slf4j.MDC;<a name="line.30"></a>
<span class="sourceLineNo">031</span><a name="line.31"></a>
<span class="sourceLineNo">032</span>/**<a name="line.32"></a>
<span class="sourceLineNo">033</span> * Abstract base class for all HBase event handlers. Subclasses should implement the<a name="line.33"></a>
<span class="sourceLineNo">034</span> * {@link #process()} and {@link #prepare()} methods. Subclasses should also do all necessary checks<a name="line.34"></a>
<span class="sourceLineNo">035</span> * up in their prepare() if possible -- check table exists, is disabled, etc. -- so they fail fast<a name="line.35"></a>
<span class="sourceLineNo">036</span> * rather than later when process is running. Do it this way because process be invoked directly but<a name="line.36"></a>
<span class="sourceLineNo">037</span> * event handlers are also run in an executor context -- i.e. asynchronously -- and in this case,<a name="line.37"></a>
<span class="sourceLineNo">038</span> * exceptions thrown at process time will not be seen by the invoker, not till we implement a<a name="line.38"></a>
<span class="sourceLineNo">039</span> * call-back mechanism so the client can pick them up later.<a name="line.39"></a>
<span class="sourceLineNo">040</span> * &lt;p&gt;<a name="line.40"></a>
<span class="sourceLineNo">041</span> * Event handlers have an {@link EventType}. {@link EventType} is a list of ALL handler event types.<a name="line.41"></a>
<span class="sourceLineNo">042</span> * We need to keep a full list in one place -- and as enums is a good shorthand for an<a name="line.42"></a>
<span class="sourceLineNo">043</span> * implemenations -- because event handlers can be passed to executors when they are to be run<a name="line.43"></a>
<span class="sourceLineNo">044</span> * asynchronously. The hbase executor, see ExecutorService, has a switch for passing event type to<a name="line.44"></a>
<span class="sourceLineNo">045</span> * executor.<a name="line.45"></a>
<span class="sourceLineNo">046</span> * &lt;p&gt;<a name="line.46"></a>
<span class="sourceLineNo">047</span> * @see ExecutorService<a name="line.47"></a>
<span class="sourceLineNo">048</span> */<a name="line.48"></a>
<span class="sourceLineNo">049</span>@InterfaceAudience.Private<a name="line.49"></a>
<span class="sourceLineNo">050</span>public abstract class EventHandler implements Runnable, Comparable&lt;EventHandler&gt; {<a name="line.50"></a>
<span class="sourceLineNo">051</span> private static final Logger LOG = LoggerFactory.getLogger(EventHandler.class);<a name="line.51"></a>
<span class="sourceLineNo">052</span><a name="line.52"></a>
<span class="sourceLineNo">053</span> // type of event this object represents<a name="line.53"></a>
<span class="sourceLineNo">054</span> protected EventType eventType;<a name="line.54"></a>
<span class="sourceLineNo">055</span><a name="line.55"></a>
<span class="sourceLineNo">056</span> protected Server server;<a name="line.56"></a>
<span class="sourceLineNo">057</span><a name="line.57"></a>
<span class="sourceLineNo">058</span> // sequence id generator for default FIFO ordering of events<a name="line.58"></a>
<span class="sourceLineNo">059</span> protected static final AtomicLong seqids = new AtomicLong(0);<a name="line.59"></a>
<span class="sourceLineNo">060</span><a name="line.60"></a>
<span class="sourceLineNo">061</span> // sequence id for this event<a name="line.61"></a>
<span class="sourceLineNo">062</span> private final long seqid;<a name="line.62"></a>
<span class="sourceLineNo">063</span><a name="line.63"></a>
<span class="sourceLineNo">064</span> // Time to wait for events to happen, should be kept short<a name="line.64"></a>
<span class="sourceLineNo">065</span> protected int waitingTimeForEvents;<a name="line.65"></a>
<span class="sourceLineNo">066</span><a name="line.66"></a>
<span class="sourceLineNo">067</span> private final Span parent;<a name="line.67"></a>
<span class="sourceLineNo">068</span><a name="line.68"></a>
<span class="sourceLineNo">069</span> /**<a name="line.69"></a>
<span class="sourceLineNo">070</span> * Default base class constructor.<a name="line.70"></a>
<span class="sourceLineNo">071</span> */<a name="line.71"></a>
<span class="sourceLineNo">072</span> public EventHandler(Server server, EventType eventType) {<a name="line.72"></a>
<span class="sourceLineNo">073</span> this.parent = Span.current();<a name="line.73"></a>
<span class="sourceLineNo">074</span> this.server = server;<a name="line.74"></a>
<span class="sourceLineNo">075</span> this.eventType = eventType;<a name="line.75"></a>
<span class="sourceLineNo">076</span> seqid = seqids.incrementAndGet();<a name="line.76"></a>
<span class="sourceLineNo">077</span> if (server != null) {<a name="line.77"></a>
<span class="sourceLineNo">078</span> this.waitingTimeForEvents =<a name="line.78"></a>
<span class="sourceLineNo">079</span> server.getConfiguration().getInt("hbase.master.event.waiting.time", 1000);<a name="line.79"></a>
<span class="sourceLineNo">080</span> }<a name="line.80"></a>
<span class="sourceLineNo">081</span> }<a name="line.81"></a>
<span class="sourceLineNo">082</span><a name="line.82"></a>
<span class="sourceLineNo">083</span> /**<a name="line.83"></a>
<span class="sourceLineNo">084</span> * Event handlers should do all the necessary checks in this method (rather than in the<a name="line.84"></a>
<span class="sourceLineNo">085</span> * constructor, or in process()) so that the caller, which is mostly executed in the ipc context<a name="line.85"></a>
<span class="sourceLineNo">086</span> * can fail fast. Process is executed async from the client ipc, so this method gives a quick<a name="line.86"></a>
<span class="sourceLineNo">087</span> * chance to do some basic checks. Should be called after constructing the EventHandler, and<a name="line.87"></a>
<span class="sourceLineNo">088</span> * before process().<a name="line.88"></a>
<span class="sourceLineNo">089</span> * @return the instance of this class<a name="line.89"></a>
<span class="sourceLineNo">090</span> * @throws Exception when something goes wrong<a name="line.90"></a>
<span class="sourceLineNo">091</span> */<a name="line.91"></a>
<span class="sourceLineNo">092</span> public EventHandler prepare() throws Exception {<a name="line.92"></a>
<span class="sourceLineNo">093</span> return this;<a name="line.93"></a>
<span class="sourceLineNo">094</span> }<a name="line.94"></a>
<span class="sourceLineNo">095</span><a name="line.95"></a>
<span class="sourceLineNo">096</span> @Override<a name="line.96"></a>
<span class="sourceLineNo">097</span> public void run() {<a name="line.97"></a>
<span class="sourceLineNo">098</span> Span span = TraceUtil.getGlobalTracer().spanBuilder(getClass().getSimpleName())<a name="line.98"></a>
<span class="sourceLineNo">099</span> .setParent(Context.current().with(parent)).startSpan();<a name="line.99"></a>
<span class="sourceLineNo">100</span> // assume that this is the top of an execution on a new or reused thread, that we're safe to<a name="line.100"></a>
<span class="sourceLineNo">101</span> // blast any existing MDC state.<a name="line.101"></a>
<span class="sourceLineNo">102</span> try (Scope scope = span.makeCurrent()) {<a name="line.102"></a>
<span class="sourceLineNo">103</span> MDC.put("event_type", eventType.toString());<a name="line.103"></a>
<span class="sourceLineNo">104</span> process();<a name="line.104"></a>
<span class="sourceLineNo">105</span> } catch (Throwable t) {<a name="line.105"></a>
<span class="sourceLineNo">106</span> handleException(t);<a name="line.106"></a>
<span class="sourceLineNo">107</span> } finally {<a name="line.107"></a>
<span class="sourceLineNo">108</span> span.end();<a name="line.108"></a>
<span class="sourceLineNo">109</span> MDC.clear();<a name="line.109"></a>
<span class="sourceLineNo">110</span> }<a name="line.110"></a>
<span class="sourceLineNo">111</span> }<a name="line.111"></a>
<span class="sourceLineNo">112</span><a name="line.112"></a>
<span class="sourceLineNo">113</span> /**<a name="line.113"></a>
<span class="sourceLineNo">114</span> * This method is the main processing loop to be implemented by the various subclasses.<a name="line.114"></a>
<span class="sourceLineNo">115</span> */<a name="line.115"></a>
<span class="sourceLineNo">116</span> public abstract void process() throws IOException;<a name="line.116"></a>
<span class="sourceLineNo">117</span><a name="line.117"></a>
<span class="sourceLineNo">118</span> /**<a name="line.118"></a>
<span class="sourceLineNo">119</span> * Return the event type<a name="line.119"></a>
<span class="sourceLineNo">120</span> * @return The event type.<a name="line.120"></a>
<span class="sourceLineNo">121</span> */<a name="line.121"></a>
<span class="sourceLineNo">122</span> public EventType getEventType() {<a name="line.122"></a>
<span class="sourceLineNo">123</span> return this.eventType;<a name="line.123"></a>
<span class="sourceLineNo">124</span> }<a name="line.124"></a>
<span class="sourceLineNo">125</span><a name="line.125"></a>
<span class="sourceLineNo">126</span> /**<a name="line.126"></a>
<span class="sourceLineNo">127</span> * Get the priority level for this handler instance. This uses natural ordering so lower numbers<a name="line.127"></a>
<span class="sourceLineNo">128</span> * are higher priority.<a name="line.128"></a>
<span class="sourceLineNo">129</span> * &lt;p&gt;<a name="line.129"></a>
<span class="sourceLineNo">130</span> * Lowest priority is Integer.MAX_VALUE. Highest priority is 0.<a name="line.130"></a>
<span class="sourceLineNo">131</span> * &lt;p&gt;<a name="line.131"></a>
<span class="sourceLineNo">132</span> * Subclasses should override this method to allow prioritizing handlers.<a name="line.132"></a>
<span class="sourceLineNo">133</span> * &lt;p&gt;<a name="line.133"></a>
<span class="sourceLineNo">134</span> * Handlers with the same priority are handled in FIFO order.<a name="line.134"></a>
<span class="sourceLineNo">135</span> * &lt;p&gt;<a name="line.135"></a>
<span class="sourceLineNo">136</span> * @return Integer.MAX_VALUE by default, override to set higher priorities<a name="line.136"></a>
<span class="sourceLineNo">137</span> */<a name="line.137"></a>
<span class="sourceLineNo">138</span> public int getPriority() {<a name="line.138"></a>
<span class="sourceLineNo">139</span> return Integer.MAX_VALUE;<a name="line.139"></a>
<span class="sourceLineNo">140</span> }<a name="line.140"></a>
<span class="sourceLineNo">141</span><a name="line.141"></a>
<span class="sourceLineNo">142</span> /** Returns This events' sequence id. */<a name="line.142"></a>
<span class="sourceLineNo">143</span> public long getSeqid() {<a name="line.143"></a>
<span class="sourceLineNo">144</span> return this.seqid;<a name="line.144"></a>
<span class="sourceLineNo">145</span> }<a name="line.145"></a>
<span class="sourceLineNo">146</span><a name="line.146"></a>
<span class="sourceLineNo">147</span> /**<a name="line.147"></a>
<span class="sourceLineNo">148</span> * Default prioritized runnable comparator which implements a FIFO ordering.<a name="line.148"></a>
<span class="sourceLineNo">149</span> * &lt;p&gt;<a name="line.149"></a>
<span class="sourceLineNo">150</span> * Subclasses should not override this. Instead, if they want to implement priority beyond FIFO,<a name="line.150"></a>
<span class="sourceLineNo">151</span> * they should override {@link #getPriority()}.<a name="line.151"></a>
<span class="sourceLineNo">152</span> */<a name="line.152"></a>
<span class="sourceLineNo">153</span> @Override<a name="line.153"></a>
<span class="sourceLineNo">154</span> public int compareTo(EventHandler o) {<a name="line.154"></a>
<span class="sourceLineNo">155</span> if (o == null) {<a name="line.155"></a>
<span class="sourceLineNo">156</span> return 1;<a name="line.156"></a>
<span class="sourceLineNo">157</span> }<a name="line.157"></a>
<span class="sourceLineNo">158</span> if (getPriority() != o.getPriority()) {<a name="line.158"></a>
<span class="sourceLineNo">159</span> return (getPriority() &lt; o.getPriority()) ? -1 : 1;<a name="line.159"></a>
<span class="sourceLineNo">160</span> }<a name="line.160"></a>
<span class="sourceLineNo">161</span> return (this.seqid &lt; o.seqid) ? -1 : 1;<a name="line.161"></a>
<span class="sourceLineNo">162</span> }<a name="line.162"></a>
<span class="sourceLineNo">163</span><a name="line.163"></a>
<span class="sourceLineNo">164</span> @Override<a name="line.164"></a>
<span class="sourceLineNo">165</span> public String toString() {<a name="line.165"></a>
<span class="sourceLineNo">166</span> return "Event #" + getSeqid() + " of type " + eventType + " (" + getInformativeName() + ")";<a name="line.166"></a>
<span class="sourceLineNo">167</span> }<a name="line.167"></a>
<span class="sourceLineNo">168</span><a name="line.168"></a>
<span class="sourceLineNo">169</span> /**<a name="line.169"></a>
<span class="sourceLineNo">170</span> * Event implementations should override thie class to provide an informative name about what<a name="line.170"></a>
<span class="sourceLineNo">171</span> * event they are handling. For example, event-specific information such as which region or server<a name="line.171"></a>
<span class="sourceLineNo">172</span> * is being processed should be included if possible.<a name="line.172"></a>
<span class="sourceLineNo">173</span> */<a name="line.173"></a>
<span class="sourceLineNo">174</span> public String getInformativeName() {<a name="line.174"></a>
<span class="sourceLineNo">175</span> return this.getClass().toString();<a name="line.175"></a>
<span class="sourceLineNo">176</span> }<a name="line.176"></a>
<span class="sourceLineNo">177</span><a name="line.177"></a>
<span class="sourceLineNo">178</span> /**<a name="line.178"></a>
<span class="sourceLineNo">179</span> * Event exception handler, may be overridden<a name="line.179"></a>
<span class="sourceLineNo">180</span> * @param t Throwable object<a name="line.180"></a>
<span class="sourceLineNo">181</span> */<a name="line.181"></a>
<span class="sourceLineNo">182</span> protected void handleException(Throwable t) {<a name="line.182"></a>
<span class="sourceLineNo">183</span> String msg = "Caught throwable while processing event " + eventType;<a name="line.183"></a>
<span class="sourceLineNo">184</span> LOG.error(msg, t);<a name="line.184"></a>
<span class="sourceLineNo">185</span> if (server != null &amp;&amp; (t instanceof Error || t instanceof RuntimeException)) {<a name="line.185"></a>
<span class="sourceLineNo">186</span> server.abort(msg, t);<a name="line.186"></a>
<span class="sourceLineNo">187</span> }<a name="line.187"></a>
<span class="sourceLineNo">188</span> }<a name="line.188"></a>
<span class="sourceLineNo">189</span>}<a name="line.189"></a>
</pre>
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