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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.util;<a name="line.18"></a>
<span class="sourceLineNo">019</span><a name="line.19"></a>
<span class="sourceLineNo">020</span>import com.google.errorprone.annotations.RestrictedApi;<a name="line.20"></a>
<span class="sourceLineNo">021</span>import java.io.EOFException;<a name="line.21"></a>
<span class="sourceLineNo">022</span>import java.io.FileNotFoundException;<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.zip.CRC32;<a name="line.24"></a>
<span class="sourceLineNo">025</span>import org.apache.hadoop.fs.FSDataInputStream;<a name="line.25"></a>
<span class="sourceLineNo">026</span>import org.apache.hadoop.fs.FSDataOutputStream;<a name="line.26"></a>
<span class="sourceLineNo">027</span>import org.apache.hadoop.fs.FileSystem;<a name="line.27"></a>
<span class="sourceLineNo">028</span>import org.apache.hadoop.fs.Path;<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>import org.apache.hbase.thirdparty.com.google.protobuf.ByteString;<a name="line.33"></a>
<span class="sourceLineNo">034</span><a name="line.34"></a>
<span class="sourceLineNo">035</span>import org.apache.hadoop.hbase.shaded.protobuf.generated.HBaseProtos;<a name="line.35"></a>
<span class="sourceLineNo">036</span><a name="line.36"></a>
<span class="sourceLineNo">037</span>/**<a name="line.37"></a>
<span class="sourceLineNo">038</span> * A file storage which supports atomic update through two files, i.e, rotating. The implementation<a name="line.38"></a>
<span class="sourceLineNo">039</span> * does not require atomic rename.<a name="line.39"></a>
<span class="sourceLineNo">040</span> */<a name="line.40"></a>
<span class="sourceLineNo">041</span>@InterfaceAudience.Private<a name="line.41"></a>
<span class="sourceLineNo">042</span>public class RotateFile {<a name="line.42"></a>
<span class="sourceLineNo">043</span><a name="line.43"></a>
<span class="sourceLineNo">044</span> private static final Logger LOG = LoggerFactory.getLogger(RotateFile.class);<a name="line.44"></a>
<span class="sourceLineNo">045</span><a name="line.45"></a>
<span class="sourceLineNo">046</span> private final FileSystem fs;<a name="line.46"></a>
<span class="sourceLineNo">047</span><a name="line.47"></a>
<span class="sourceLineNo">048</span> private final long maxFileSize;<a name="line.48"></a>
<span class="sourceLineNo">049</span><a name="line.49"></a>
<span class="sourceLineNo">050</span> private final Path[] files = new Path[2];<a name="line.50"></a>
<span class="sourceLineNo">051</span><a name="line.51"></a>
<span class="sourceLineNo">052</span> // this is used to make sure that we do not go backwards<a name="line.52"></a>
<span class="sourceLineNo">053</span> private long prevTimestamp = -1;<a name="line.53"></a>
<span class="sourceLineNo">054</span><a name="line.54"></a>
<span class="sourceLineNo">055</span> private int nextFile = -1;<a name="line.55"></a>
<span class="sourceLineNo">056</span><a name="line.56"></a>
<span class="sourceLineNo">057</span> /**<a name="line.57"></a>
<span class="sourceLineNo">058</span> * Constructs a new RotateFile object with the given parameters.<a name="line.58"></a>
<span class="sourceLineNo">059</span> * @param fs the file system to use.<a name="line.59"></a>
<span class="sourceLineNo">060</span> * @param dir the directory where the files will be created.<a name="line.60"></a>
<span class="sourceLineNo">061</span> * @param name the base name for the files.<a name="line.61"></a>
<span class="sourceLineNo">062</span> * @param maxFileSize the maximum size of each file.<a name="line.62"></a>
<span class="sourceLineNo">063</span> */<a name="line.63"></a>
<span class="sourceLineNo">064</span> public RotateFile(FileSystem fs, Path dir, String name, long maxFileSize) {<a name="line.64"></a>
<span class="sourceLineNo">065</span> this.fs = fs;<a name="line.65"></a>
<span class="sourceLineNo">066</span> this.maxFileSize = maxFileSize;<a name="line.66"></a>
<span class="sourceLineNo">067</span> this.files[0] = new Path(dir, name + "-0");<a name="line.67"></a>
<span class="sourceLineNo">068</span> this.files[1] = new Path(dir, name + "-1");<a name="line.68"></a>
<span class="sourceLineNo">069</span> }<a name="line.69"></a>
<span class="sourceLineNo">070</span><a name="line.70"></a>
<span class="sourceLineNo">071</span> private HBaseProtos.RotateFileData read(Path path) throws IOException {<a name="line.71"></a>
<span class="sourceLineNo">072</span> byte[] data;<a name="line.72"></a>
<span class="sourceLineNo">073</span> int expectedChecksum;<a name="line.73"></a>
<span class="sourceLineNo">074</span> try (FSDataInputStream in = fs.open(path)) {<a name="line.74"></a>
<span class="sourceLineNo">075</span> int length = in.readInt();<a name="line.75"></a>
<span class="sourceLineNo">076</span> if (length &lt;= 0 || length &gt; maxFileSize) {<a name="line.76"></a>
<span class="sourceLineNo">077</span> throw new IOException("Invalid file length " + length<a name="line.77"></a>
<span class="sourceLineNo">078</span> + ", either less than 0 or greater then max allowed size " + maxFileSize);<a name="line.78"></a>
<span class="sourceLineNo">079</span> }<a name="line.79"></a>
<span class="sourceLineNo">080</span> data = new byte[length];<a name="line.80"></a>
<span class="sourceLineNo">081</span> in.readFully(data);<a name="line.81"></a>
<span class="sourceLineNo">082</span> expectedChecksum = in.readInt();<a name="line.82"></a>
<span class="sourceLineNo">083</span> }<a name="line.83"></a>
<span class="sourceLineNo">084</span> CRC32 crc32 = new CRC32();<a name="line.84"></a>
<span class="sourceLineNo">085</span> crc32.update(data);<a name="line.85"></a>
<span class="sourceLineNo">086</span> int calculatedChecksum = (int) crc32.getValue();<a name="line.86"></a>
<span class="sourceLineNo">087</span> if (expectedChecksum != calculatedChecksum) {<a name="line.87"></a>
<span class="sourceLineNo">088</span> throw new IOException(<a name="line.88"></a>
<span class="sourceLineNo">089</span> "Checksum mismatch, expected " + expectedChecksum + ", actual " + calculatedChecksum);<a name="line.89"></a>
<span class="sourceLineNo">090</span> }<a name="line.90"></a>
<span class="sourceLineNo">091</span> return HBaseProtos.RotateFileData.parseFrom(data);<a name="line.91"></a>
<span class="sourceLineNo">092</span> }<a name="line.92"></a>
<span class="sourceLineNo">093</span><a name="line.93"></a>
<span class="sourceLineNo">094</span> private int select(HBaseProtos.RotateFileData[] datas) {<a name="line.94"></a>
<span class="sourceLineNo">095</span> if (datas[0] == null) {<a name="line.95"></a>
<span class="sourceLineNo">096</span> return 1;<a name="line.96"></a>
<span class="sourceLineNo">097</span> }<a name="line.97"></a>
<span class="sourceLineNo">098</span> if (datas[1] == null) {<a name="line.98"></a>
<span class="sourceLineNo">099</span> return 0;<a name="line.99"></a>
<span class="sourceLineNo">100</span> }<a name="line.100"></a>
<span class="sourceLineNo">101</span> return datas[0].getTimestamp() &gt;= datas[1].getTimestamp() ? 0 : 1;<a name="line.101"></a>
<span class="sourceLineNo">102</span> }<a name="line.102"></a>
<span class="sourceLineNo">103</span><a name="line.103"></a>
<span class="sourceLineNo">104</span> /**<a name="line.104"></a>
<span class="sourceLineNo">105</span> * Reads the content of the rotate file by selecting the winner file based on the timestamp of the<a name="line.105"></a>
<span class="sourceLineNo">106</span> * data inside the files. It reads the content of both files and selects the one with the latest<a name="line.106"></a>
<span class="sourceLineNo">107</span> * timestamp as the winner. If a file is incomplete or does not exist, it logs the error and moves<a name="line.107"></a>
<span class="sourceLineNo">108</span> * on to the next file. It returns the content of the winner file as a byte array. If none of the<a name="line.108"></a>
<span class="sourceLineNo">109</span> * files have valid data, it returns null.<a name="line.109"></a>
<span class="sourceLineNo">110</span> * @return a byte array containing the data from the winner file, or null if no valid data is<a name="line.110"></a>
<span class="sourceLineNo">111</span> * found.<a name="line.111"></a>
<span class="sourceLineNo">112</span> * @throws IOException if an error occurs while reading the files.<a name="line.112"></a>
<span class="sourceLineNo">113</span> */<a name="line.113"></a>
<span class="sourceLineNo">114</span> public byte[] read() throws IOException {<a name="line.114"></a>
<span class="sourceLineNo">115</span> HBaseProtos.RotateFileData[] datas = new HBaseProtos.RotateFileData[2];<a name="line.115"></a>
<span class="sourceLineNo">116</span> for (int i = 0; i &lt; 2; i++) {<a name="line.116"></a>
<span class="sourceLineNo">117</span> try {<a name="line.117"></a>
<span class="sourceLineNo">118</span> datas[i] = read(files[i]);<a name="line.118"></a>
<span class="sourceLineNo">119</span> } catch (FileNotFoundException e) {<a name="line.119"></a>
<span class="sourceLineNo">120</span> LOG.debug("file {} does not exist", files[i], e);<a name="line.120"></a>
<span class="sourceLineNo">121</span> } catch (EOFException e) {<a name="line.121"></a>
<span class="sourceLineNo">122</span> LOG.debug("file {} is incomplete", files[i], e);<a name="line.122"></a>
<span class="sourceLineNo">123</span> }<a name="line.123"></a>
<span class="sourceLineNo">124</span> }<a name="line.124"></a>
<span class="sourceLineNo">125</span> int winnerIndex = select(datas);<a name="line.125"></a>
<span class="sourceLineNo">126</span> nextFile = 1 - winnerIndex;<a name="line.126"></a>
<span class="sourceLineNo">127</span> if (datas[winnerIndex] != null) {<a name="line.127"></a>
<span class="sourceLineNo">128</span> prevTimestamp = datas[winnerIndex].getTimestamp();<a name="line.128"></a>
<span class="sourceLineNo">129</span> return datas[winnerIndex].getData().toByteArray();<a name="line.129"></a>
<span class="sourceLineNo">130</span> } else {<a name="line.130"></a>
<span class="sourceLineNo">131</span> return null;<a name="line.131"></a>
<span class="sourceLineNo">132</span> }<a name="line.132"></a>
<span class="sourceLineNo">133</span> }<a name="line.133"></a>
<span class="sourceLineNo">134</span><a name="line.134"></a>
<span class="sourceLineNo">135</span> @RestrictedApi(explanation = "Should only be called in tests", link = "",<a name="line.135"></a>
<span class="sourceLineNo">136</span> allowedOnPath = ".*/RotateFile.java|.*/src/test/.*")<a name="line.136"></a>
<span class="sourceLineNo">137</span> static void write(FileSystem fs, Path file, long timestamp, byte[] data) throws IOException {<a name="line.137"></a>
<span class="sourceLineNo">138</span> HBaseProtos.RotateFileData proto = HBaseProtos.RotateFileData.newBuilder()<a name="line.138"></a>
<span class="sourceLineNo">139</span> .setTimestamp(timestamp).setData(ByteString.copyFrom(data)).build();<a name="line.139"></a>
<span class="sourceLineNo">140</span> byte[] protoData = proto.toByteArray();<a name="line.140"></a>
<span class="sourceLineNo">141</span> CRC32 crc32 = new CRC32();<a name="line.141"></a>
<span class="sourceLineNo">142</span> crc32.update(protoData);<a name="line.142"></a>
<span class="sourceLineNo">143</span> int checksum = (int) crc32.getValue();<a name="line.143"></a>
<span class="sourceLineNo">144</span> // 4 bytes length, 8 bytes timestamp, 4 bytes checksum at the end<a name="line.144"></a>
<span class="sourceLineNo">145</span> try (FSDataOutputStream out = fs.create(file, true)) {<a name="line.145"></a>
<span class="sourceLineNo">146</span> out.writeInt(protoData.length);<a name="line.146"></a>
<span class="sourceLineNo">147</span> out.write(protoData);<a name="line.147"></a>
<span class="sourceLineNo">148</span> out.writeInt(checksum);<a name="line.148"></a>
<span class="sourceLineNo">149</span> }<a name="line.149"></a>
<span class="sourceLineNo">150</span> }<a name="line.150"></a>
<span class="sourceLineNo">151</span><a name="line.151"></a>
<span class="sourceLineNo">152</span> /**<a name="line.152"></a>
<span class="sourceLineNo">153</span> * Writes the given data to the next file in the rotation, with a timestamp calculated based on<a name="line.153"></a>
<span class="sourceLineNo">154</span> * the previous timestamp and the current time to make sure it is greater than the previous<a name="line.154"></a>
<span class="sourceLineNo">155</span> * timestamp. The method also deletes the previous file, which is no longer needed.<a name="line.155"></a>
<span class="sourceLineNo">156</span> * &lt;p/&gt;<a name="line.156"></a>
<span class="sourceLineNo">157</span> * Notice that, for a newly created {@link RotateFile} instance, you need to call {@link #read()}<a name="line.157"></a>
<span class="sourceLineNo">158</span> * first to initialize the nextFile index, before calling this method.<a name="line.158"></a>
<span class="sourceLineNo">159</span> * @param data the data to be written to the file<a name="line.159"></a>
<span class="sourceLineNo">160</span> * @throws IOException if an I/O error occurs while writing the data to the file<a name="line.160"></a>
<span class="sourceLineNo">161</span> */<a name="line.161"></a>
<span class="sourceLineNo">162</span> public void write(byte[] data) throws IOException {<a name="line.162"></a>
<span class="sourceLineNo">163</span> if (data.length &gt; maxFileSize) {<a name="line.163"></a>
<span class="sourceLineNo">164</span> throw new IOException(<a name="line.164"></a>
<span class="sourceLineNo">165</span> "Data size " + data.length + " is greater than max allowed size " + maxFileSize);<a name="line.165"></a>
<span class="sourceLineNo">166</span> }<a name="line.166"></a>
<span class="sourceLineNo">167</span> long timestamp = Math.max(prevTimestamp + 1, EnvironmentEdgeManager.currentTime());<a name="line.167"></a>
<span class="sourceLineNo">168</span> write(fs, files[nextFile], timestamp, data);<a name="line.168"></a>
<span class="sourceLineNo">169</span> prevTimestamp = timestamp;<a name="line.169"></a>
<span class="sourceLineNo">170</span> nextFile = 1 - nextFile;<a name="line.170"></a>
<span class="sourceLineNo">171</span> try {<a name="line.171"></a>
<span class="sourceLineNo">172</span> fs.delete(files[nextFile], false);<a name="line.172"></a>
<span class="sourceLineNo">173</span> } catch (IOException e) {<a name="line.173"></a>
<span class="sourceLineNo">174</span> // we will create new file with overwrite = true, so not a big deal here, only for speed up<a name="line.174"></a>
<span class="sourceLineNo">175</span> // loading as we do not need to read this file when loading<a name="line.175"></a>
<span class="sourceLineNo">176</span> LOG.debug("Failed to delete old file {}, ignoring the exception", files[nextFile], e);<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><a name="line.179"></a>
<span class="sourceLineNo">180</span> /**<a name="line.180"></a>
<span class="sourceLineNo">181</span> * Deletes the two files used for rotating data. If any of the files cannot be deleted, an<a name="line.181"></a>
<span class="sourceLineNo">182</span> * IOException is thrown.<a name="line.182"></a>
<span class="sourceLineNo">183</span> * @throws IOException if there is an error deleting either file<a name="line.183"></a>
<span class="sourceLineNo">184</span> */<a name="line.184"></a>
<span class="sourceLineNo">185</span> public void delete() throws IOException {<a name="line.185"></a>
<span class="sourceLineNo">186</span> Path next = files[nextFile];<a name="line.186"></a>
<span class="sourceLineNo">187</span> // delete next file first, and then the current file, so when failing to delete, we can still<a name="line.187"></a>
<span class="sourceLineNo">188</span> // read the correct data<a name="line.188"></a>
<span class="sourceLineNo">189</span> if (fs.exists(next) &amp;&amp; !fs.delete(next, false)) {<a name="line.189"></a>
<span class="sourceLineNo">190</span> throw new IOException("Can not delete " + next);<a name="line.190"></a>
<span class="sourceLineNo">191</span> }<a name="line.191"></a>
<span class="sourceLineNo">192</span> Path current = files[1 - nextFile];<a name="line.192"></a>
<span class="sourceLineNo">193</span> if (fs.exists(current) &amp;&amp; !fs.delete(current, false)) {<a name="line.193"></a>
<span class="sourceLineNo">194</span> throw new IOException("Can not delete " + current);<a name="line.194"></a>
<span class="sourceLineNo">195</span> }<a name="line.195"></a>
<span class="sourceLineNo">196</span> }<a name="line.196"></a>
<span class="sourceLineNo">197</span>}<a name="line.197"></a>
</pre>
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