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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.master.procedure;<a name="line.18"></a>
<span class="sourceLineNo">019</span><a name="line.19"></a>
<span class="sourceLineNo">020</span>import java.io.IOException;<a name="line.20"></a>
<span class="sourceLineNo">021</span>import org.apache.hadoop.hbase.ServerName;<a name="line.21"></a>
<span class="sourceLineNo">022</span>import org.apache.hadoop.hbase.procedure2.FailedRemoteDispatchException;<a name="line.22"></a>
<span class="sourceLineNo">023</span>import org.apache.hadoop.hbase.procedure2.Procedure;<a name="line.23"></a>
<span class="sourceLineNo">024</span>import org.apache.hadoop.hbase.procedure2.ProcedureEvent;<a name="line.24"></a>
<span class="sourceLineNo">025</span>import org.apache.hadoop.hbase.procedure2.ProcedureSuspendedException;<a name="line.25"></a>
<span class="sourceLineNo">026</span>import org.apache.hadoop.hbase.procedure2.ProcedureYieldException;<a name="line.26"></a>
<span class="sourceLineNo">027</span>import org.apache.hadoop.hbase.procedure2.RemoteProcedureDispatcher;<a name="line.27"></a>
<span class="sourceLineNo">028</span>import org.apache.hadoop.hbase.procedure2.RemoteProcedureException;<a name="line.28"></a>
<span class="sourceLineNo">029</span>import org.apache.yetus.audience.InterfaceAudience;<a name="line.29"></a>
<span class="sourceLineNo">030</span>import org.slf4j.Logger;<a name="line.30"></a>
<span class="sourceLineNo">031</span>import org.slf4j.LoggerFactory;<a name="line.31"></a>
<span class="sourceLineNo">032</span><a name="line.32"></a>
<span class="sourceLineNo">033</span>@InterfaceAudience.Private<a name="line.33"></a>
<span class="sourceLineNo">034</span>/**<a name="line.34"></a>
<span class="sourceLineNo">035</span> * The base class for Procedures that run {@link java.util.concurrent.Callable}s on a (remote)<a name="line.35"></a>
<span class="sourceLineNo">036</span> * RegionServer; e.g. asking a RegionServer to split a WAL file as a sub-procedure of the<a name="line.36"></a>
<span class="sourceLineNo">037</span> * ServerCrashProcedure recovery process.<a name="line.37"></a>
<span class="sourceLineNo">038</span> * &lt;p&gt;<a name="line.38"></a>
<span class="sourceLineNo">039</span> * To implement a new Procedure type, extend this class and override remoteCallBuild() and<a name="line.39"></a>
<span class="sourceLineNo">040</span> * complete(). The dispatch and callback will be handled for you here, internally.<a name="line.40"></a>
<span class="sourceLineNo">041</span> * &lt;p&gt;<a name="line.41"></a>
<span class="sourceLineNo">042</span> * The Procedure works as follows. It uses {@link RSProcedureDispatcher}, the same system used<a name="line.42"></a>
<span class="sourceLineNo">043</span> * dispatching Region OPEN and CLOSE RPCs, to pass a Callable to a RegionServer. Examples include<a name="line.43"></a>
<span class="sourceLineNo">044</span> * {@link org.apache.hadoop.hbase.regionserver.SplitWALCallable} and<a name="line.44"></a>
<span class="sourceLineNo">045</span> * {@link org.apache.hadoop.hbase.replication.regionserver.RefreshPeerCallable}. Rather than<a name="line.45"></a>
<span class="sourceLineNo">046</span> * assign/unassign, the Master calls #executeProcedures against the remote RegionServer wrapping a<a name="line.46"></a>
<span class="sourceLineNo">047</span> * Callable in a {@link ExecuteProceduresRequest}. Upon successful dispatch, the Procedure then<a name="line.47"></a>
<span class="sourceLineNo">048</span> * suspends itself on the Master-side and relinqushes its executor worker. On receipt, the<a name="line.48"></a>
<span class="sourceLineNo">049</span> * RegionServer submits the Callable to its executor service. When the Callable completes, it adds<a name="line.49"></a>
<span class="sourceLineNo">050</span> * itself to a queue on the RegionServer side for processing by a background thread, the<a name="line.50"></a>
<span class="sourceLineNo">051</span> * {@link RemoteProcedureResultReporter}. It picks up the completed Callable from the queue and RPCs<a name="line.51"></a>
<span class="sourceLineNo">052</span> * the master at #reportProcedureDone with the procedure id and whether success or failure. The<a name="line.52"></a>
<span class="sourceLineNo">053</span> * master calls complete() setting success or failure state and then reschedules the suspended<a name="line.53"></a>
<span class="sourceLineNo">054</span> * Procedure so it can finish.<a name="line.54"></a>
<span class="sourceLineNo">055</span> * &lt;p&gt;<a name="line.55"></a>
<span class="sourceLineNo">056</span> * Here are some details on operation:<a name="line.56"></a>
<span class="sourceLineNo">057</span> * &lt;p&gt;<a name="line.57"></a>
<span class="sourceLineNo">058</span> * If adding the operation to the dispatcher fails, addOperationToNode will throw<a name="line.58"></a>
<span class="sourceLineNo">059</span> * FailedRemoteDispatchException, and this Procedure will return 'null'. The Procedure Executor will<a name="line.59"></a>
<span class="sourceLineNo">060</span> * then mark this procedure as 'complete' (though we failed to dispatch our task). In this case, the<a name="line.60"></a>
<span class="sourceLineNo">061</span> * upper layer of this procedure must have a way to check if this Procedure really succeeded or not<a name="line.61"></a>
<span class="sourceLineNo">062</span> * and have appropriate handling.<a name="line.62"></a>
<span class="sourceLineNo">063</span> * &lt;p&gt;<a name="line.63"></a>
<span class="sourceLineNo">064</span> * If sending the operation to remote RS failed, dispatcher will call remoteCallFailed() to handle<a name="line.64"></a>
<span class="sourceLineNo">065</span> * this which calls remoteOperationDone with the exception. If the targetServer crashed but this<a name="line.65"></a>
<span class="sourceLineNo">066</span> * procedure has no response, than dispatcher will call remoteOperationFailed() which also calls<a name="line.66"></a>
<span class="sourceLineNo">067</span> * remoteOperationDone with the exception. If the operation is successful, then<a name="line.67"></a>
<span class="sourceLineNo">068</span> * remoteOperationCompleted will be called and actually calls the remoteOperationDone without<a name="line.68"></a>
<span class="sourceLineNo">069</span> * exception. In remoteOperationDone, we'll check if the procedure is already get wake up by others.<a name="line.69"></a>
<span class="sourceLineNo">070</span> * Then developer could implement complete() based on their own purpose. But basic logic is that if<a name="line.70"></a>
<span class="sourceLineNo">071</span> * operation succeed, set succ to true and do the clean work. If operation failed and require to<a name="line.71"></a>
<span class="sourceLineNo">072</span> * resend it to the same server, leave the succ as false. If operation failed and require to resend<a name="line.72"></a>
<span class="sourceLineNo">073</span> * it to another server, set succ to true and upper layer should be able to find out this operation<a name="line.73"></a>
<span class="sourceLineNo">074</span> * not work and send a operation to another server.<a name="line.74"></a>
<span class="sourceLineNo">075</span> */<a name="line.75"></a>
<span class="sourceLineNo">076</span>public abstract class ServerRemoteProcedure extends Procedure&lt;MasterProcedureEnv&gt;<a name="line.76"></a>
<span class="sourceLineNo">077</span> implements RemoteProcedureDispatcher.RemoteProcedure&lt;MasterProcedureEnv, ServerName&gt; {<a name="line.77"></a>
<span class="sourceLineNo">078</span> protected static final Logger LOG = LoggerFactory.getLogger(ServerRemoteProcedure.class);<a name="line.78"></a>
<span class="sourceLineNo">079</span> protected ProcedureEvent&lt;?&gt; event;<a name="line.79"></a>
<span class="sourceLineNo">080</span> protected ServerName targetServer;<a name="line.80"></a>
<span class="sourceLineNo">081</span> protected boolean dispatched;<a name="line.81"></a>
<span class="sourceLineNo">082</span> protected boolean succ;<a name="line.82"></a>
<span class="sourceLineNo">083</span><a name="line.83"></a>
<span class="sourceLineNo">084</span> protected abstract void complete(MasterProcedureEnv env, Throwable error);<a name="line.84"></a>
<span class="sourceLineNo">085</span><a name="line.85"></a>
<span class="sourceLineNo">086</span> @Override<a name="line.86"></a>
<span class="sourceLineNo">087</span> protected synchronized Procedure&lt;MasterProcedureEnv&gt;[] execute(MasterProcedureEnv env)<a name="line.87"></a>
<span class="sourceLineNo">088</span> throws ProcedureYieldException, ProcedureSuspendedException, InterruptedException {<a name="line.88"></a>
<span class="sourceLineNo">089</span> if (dispatched) {<a name="line.89"></a>
<span class="sourceLineNo">090</span> if (succ) {<a name="line.90"></a>
<span class="sourceLineNo">091</span> return null;<a name="line.91"></a>
<span class="sourceLineNo">092</span> }<a name="line.92"></a>
<span class="sourceLineNo">093</span> dispatched = false;<a name="line.93"></a>
<span class="sourceLineNo">094</span> }<a name="line.94"></a>
<span class="sourceLineNo">095</span> try {<a name="line.95"></a>
<span class="sourceLineNo">096</span> env.getRemoteDispatcher().addOperationToNode(targetServer, this);<a name="line.96"></a>
<span class="sourceLineNo">097</span> } catch (FailedRemoteDispatchException frde) {<a name="line.97"></a>
<span class="sourceLineNo">098</span> LOG.warn("Can not send remote operation {} to {}, this operation will "<a name="line.98"></a>
<span class="sourceLineNo">099</span> + "be retried to send to another server", this.getProcId(), targetServer);<a name="line.99"></a>
<span class="sourceLineNo">100</span> return null;<a name="line.100"></a>
<span class="sourceLineNo">101</span> }<a name="line.101"></a>
<span class="sourceLineNo">102</span> dispatched = true;<a name="line.102"></a>
<span class="sourceLineNo">103</span> event = new ProcedureEvent&lt;&gt;(this);<a name="line.103"></a>
<span class="sourceLineNo">104</span> event.suspendIfNotReady(this);<a name="line.104"></a>
<span class="sourceLineNo">105</span> throw new ProcedureSuspendedException();<a name="line.105"></a>
<span class="sourceLineNo">106</span> }<a name="line.106"></a>
<span class="sourceLineNo">107</span><a name="line.107"></a>
<span class="sourceLineNo">108</span> @Override<a name="line.108"></a>
<span class="sourceLineNo">109</span> protected synchronized void completionCleanup(MasterProcedureEnv env) {<a name="line.109"></a>
<span class="sourceLineNo">110</span> env.getRemoteDispatcher().removeCompletedOperation(targetServer, this);<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> @Override<a name="line.113"></a>
<span class="sourceLineNo">114</span> public synchronized void remoteCallFailed(MasterProcedureEnv env, ServerName serverName,<a name="line.114"></a>
<span class="sourceLineNo">115</span> IOException exception) {<a name="line.115"></a>
<span class="sourceLineNo">116</span> remoteOperationDone(env, exception);<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> @Override<a name="line.119"></a>
<span class="sourceLineNo">120</span> public synchronized void remoteOperationCompleted(MasterProcedureEnv env) {<a name="line.120"></a>
<span class="sourceLineNo">121</span> remoteOperationDone(env, null);<a name="line.121"></a>
<span class="sourceLineNo">122</span> }<a name="line.122"></a>
<span class="sourceLineNo">123</span><a name="line.123"></a>
<span class="sourceLineNo">124</span> @Override<a name="line.124"></a>
<span class="sourceLineNo">125</span> public synchronized void remoteOperationFailed(MasterProcedureEnv env,<a name="line.125"></a>
<span class="sourceLineNo">126</span> RemoteProcedureException error) {<a name="line.126"></a>
<span class="sourceLineNo">127</span> remoteOperationDone(env, error);<a name="line.127"></a>
<span class="sourceLineNo">128</span> }<a name="line.128"></a>
<span class="sourceLineNo">129</span><a name="line.129"></a>
<span class="sourceLineNo">130</span> synchronized void remoteOperationDone(MasterProcedureEnv env, Throwable error) {<a name="line.130"></a>
<span class="sourceLineNo">131</span> if (this.isFinished()) {<a name="line.131"></a>
<span class="sourceLineNo">132</span> LOG.info("This procedure {} is already finished, skip the rest processes", this.getProcId());<a name="line.132"></a>
<span class="sourceLineNo">133</span> return;<a name="line.133"></a>
<span class="sourceLineNo">134</span> }<a name="line.134"></a>
<span class="sourceLineNo">135</span> if (event == null) {<a name="line.135"></a>
<span class="sourceLineNo">136</span> LOG.warn("procedure event for {} is null, maybe the procedure is created when recovery",<a name="line.136"></a>
<span class="sourceLineNo">137</span> getProcId());<a name="line.137"></a>
<span class="sourceLineNo">138</span> return;<a name="line.138"></a>
<span class="sourceLineNo">139</span> }<a name="line.139"></a>
<span class="sourceLineNo">140</span> complete(env, error);<a name="line.140"></a>
<span class="sourceLineNo">141</span> event.wake(env.getProcedureScheduler());<a name="line.141"></a>
<span class="sourceLineNo">142</span> event = null;<a name="line.142"></a>
<span class="sourceLineNo">143</span> }<a name="line.143"></a>
<span class="sourceLineNo">144</span>}<a name="line.144"></a>
</pre>
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