flume写入mysql_Flume高级之自定义MySQLSource
1 自定義Source說明
Source是負責接收數據到Flume Agent的組件。Source組件可以處理各種類型、各種格式的日志數據，包括avro、thrift、exec、jms、spooling directory、netcat、sequence generator、syslog、http、legacy。官方提供的source類型已經很多，但是有時候并不能滿足實際開發當中的需求，此時我們就需要根據實際需求自定義某些Source。
如：實時監控MySQL，從MySQL中獲取數據傳輸到HDFS或者其他存儲框架，所以此時需要我們自己實現MySQLSource。
官方也提供了自定義source的接口：
3 自定義MySQLSource組成
2 自定義MySQLSource步驟
根據官方說明自定義MySqlSource需要繼承AbstractSource類并實現Configurable和PollableSource接口。
實現相應方法：
getBackOffSleepIncrement()//暫不用
getMaxBackOffSleepInterval()//暫不用
configure(Context context)//初始化context
process()//獲取數據(從MySql獲取數據，業務處理比較復雜，所以我們定義一個專門的類——SQLSourceHelper來處理跟MySql的交互)，封裝成Event并寫入Channel，這個方法被循環調用
stop()//關閉相關的資源
4 代碼實現
4.1 導入Pom依賴
org.apache.flume
flume-ng-core
1.7.0
mysql
mysql-connector-java
5.1.27
4.2 添加配置信息
在ClassPath下添加jdbc.properties和log4j. properties
jdbc.properties:
dbDriver=com.mysql.jdbc.Driver
dbUrl=jdbc:mysql://hadoop102:3306/mysqlsource?useUnicode=true&characterEncoding=utf-8
dbUser=root
dbPassword=000000
log4j. properties:
#--------console-----------
log4j.rootLogger=info,myconsole,myfile
log4j.appender.myconsole=org.apache.log4j.ConsoleAppender
log4j.appender.myconsole.layout=org.apache.log4j.SimpleLayout
#log4j.appender.myconsole.layout.ConversionPattern =%d [%t] %-5p [%c] - %m%n
#log4j.rootLogger=error,myfile
log4j.appender.myfile=org.apache.log4j.DailyRollingFileAppender
log4j.appender.myfile.File=/tmp/flume.log
log4j.appender.myfile.layout=org.apache.log4j.PatternLayout
log4j.appender.myfile.layout.ConversionPattern =%d [%t] %-5p [%c] - %m%n
4.3 SQLSourceHelper
1)屬性說明：
屬性
說明(括號中為默認值)
runQueryDelay
查詢時間間隔(10000)
batchSize
緩存大小(100)
startFrom
查詢語句開始id(0)
currentIndex
查詢語句當前id，每次查詢之前需要查元數據表
recordSixe
查詢返回條數
table
監控的表名
columnsToSelect
查詢字段(*)
customQuery
用戶傳入的查詢語句
query
查詢語句
defaultCharsetResultSet
編碼格式(UTF-8)
2)方法說明：
方法
說明
SQLSourceHelper(Context context)
構造方法，初始化屬性及獲取JDBC連接
InitConnection(String url, String user, String pw)
獲取JDBC連接
checkMandatoryProperties()
校驗相關屬性是否設置(實際開發中可增加內容)
buildQuery()
根據實際情況構建sql語句，返回值String
executeQuery()
執行sql語句的查詢操作，返回值List>
getAllRows(List> queryResult)
將查詢結果轉換為String，方便后續操作
updateOffset2DB(int size)
根據每次查詢結果將offset寫入元數據表
execSql(String sql)
具體執行sql語句方法
getStatusDBIndex(int startFrom)
獲取元數據表中的offset
queryOne(String sql)
獲取元數據表中的offset實際sql語句執行方法
close()
關閉資源
3)代碼分析
4)代碼實現：
importorg.apache.flume.Context;importorg.apache.flume.conf.ConfigurationException;importorg.slf4j.Logger;importorg.slf4j.LoggerFactory;importjava.io.IOException;import java.sql.*;importjava.text.ParseException;importjava.util.ArrayList;importjava.util.List;importjava.util.Properties;public classSQLSourceHelper {private static final Logger LOG = LoggerFactory.getLogger(SQLSourceHelper.class);private int runQueryDelay, //兩次查詢的時間間隔
startFrom, //開始id
currentIndex, //當前id
recordSixe = 0, //每次查詢返回結果的條數
maxRow; //每次查詢的最大條數
private String table, //要操作的表
columnsToSelect, //用戶傳入的查詢的列
customQuery, //用戶傳入的查詢語句
query, //構建的查詢語句
defaultCharsetResultSet;//編碼集//上下文，用來獲取配置文件
privateContext context;//為定義的變量賦值(默認值)，可在flume任務的配置文件中修改
private static final int DEFAULT_QUERY_DELAY = 10000;private static final int DEFAULT_START_VALUE = 0;private static final int DEFAULT_MAX_ROWS = 2000;private static final String DEFAULT_COLUMNS_SELECT = "*";private static final String DEFAULT_CHARSET_RESULTSET = "UTF-8";private static Connection conn = null;private static PreparedStatement ps = null;private staticString connectionURL, connectionUserName, connectionPassword;//加載靜態資源
static{
Properties p= newProperties();try{
p.load(SQLSourceHelper.class.getClassLoader().getResourceAsStream("jdbc.properties"));
connectionURL= p.getProperty("dbUrl");
connectionUserName= p.getProperty("dbUser");
connectionPassword= p.getProperty("dbPassword");
Class.forName(p.getProperty("dbDriver"));
}catch (IOException |ClassNotFoundException e) {
LOG.error(e.toString());
}
}//獲取JDBC連接
private staticConnection InitConnection(String url, String user, String pw) {try{
Connection conn=DriverManager.getConnection(url, user, pw);if (conn == null)throw newSQLException();returnconn;
}catch(SQLException e) {
e.printStackTrace();
}return null;
}//構造方法
SQLSourceHelper(Context context) throwsParseException {//初始化上下文
this.context =context;//有默認值參數：獲取flume任務配置文件中的參數，讀不到的采用默認值
this.columnsToSelect = context.getString("columns.to.select", DEFAULT_COLUMNS_SELECT);this.runQueryDelay = context.getInteger("run.query.delay", DEFAULT_QUERY_DELAY);this.startFrom = context.getInteger("start.from", DEFAULT_START_VALUE);this.defaultCharsetResultSet = context.getString("default.charset.resultset", DEFAULT_CHARSET_RESULTSET);//無默認值參數：獲取flume任務配置文件中的參數
this.table = context.getString("table");this.customQuery = context.getString("custom.query");
connectionURL= context.getString("connection.url");
connectionUserName= context.getString("connection.user");
connectionPassword= context.getString("connection.password");
conn=InitConnection(connectionURL, connectionUserName, connectionPassword);//校驗相應的配置信息，如果沒有默認值的參數也沒賦值，拋出異常
checkMandatoryProperties();//獲取當前的id
currentIndex =getStatusDBIndex(startFrom);//構建查詢語句
query =buildQuery();
}//校驗相應的配置信息(表，查詢語句以及數據庫連接的參數)
private voidcheckMandatoryProperties() {if (table == null) {throw new ConfigurationException("property table not set");
}if (connectionURL == null) {throw new ConfigurationException("connection.url property not set");
}if (connectionUserName == null) {throw new ConfigurationException("connection.user property not set");
}if (connectionPassword == null) {throw new ConfigurationException("connection.password property not set");
}
}//構建sql語句
privateString buildQuery() {
String sql= "";//獲取當前id
currentIndex =getStatusDBIndex(startFrom);
LOG.info(currentIndex+ "");if (customQuery == null) {
sql= "SELECT " + columnsToSelect + " FROM " +table;
}else{
sql=customQuery;
}
StringBuilder execSql= newStringBuilder(sql);//以id作為offset
if (!sql.contains("where")) {
execSql.append(" where ");
execSql.append("id").append(">").append(currentIndex);returnexecSql.toString();
}else{int length =execSql.toString().length();return execSql.toString().substring(0, length - String.valueOf(currentIndex).length()) +currentIndex;
}
}//執行查詢
List>executeQuery() {try{//每次執行查詢時都要重新生成sql，因為id不同
customQuery =buildQuery();//存放結果的集合
List> results = new ArrayList<>();if (ps == null) {// ps =conn.prepareStatement(customQuery);
}
ResultSet result=ps.executeQuery(customQuery);while(result.next()) {//存放一條數據的集合(多個列)
List row = new ArrayList<>();//將返回結果放入集合
for (int i = 1; i <= result.getMetaData().getColumnCount(); i++) {
row.add(result.getObject(i));
}
results.add(row);
}
LOG.info("execSql:" + customQuery + "\nresultSize:" +results.size());returnresults;
}catch(SQLException e) {
LOG.error(e.toString());//重新連接
conn =InitConnection(connectionURL, connectionUserName, connectionPassword);
}return null;
}//將結果集轉化為字符串，每一條數據是一個list集合，將每一個小的list集合轉化為字符串
List getAllRows(List>queryResult) {
List allRows = new ArrayList<>();if (queryResult == null ||queryResult.isEmpty())returnallRows;
StringBuilder row= newStringBuilder();for (ListrawRow : queryResult) {
Object value= null;for(Object aRawRow : rawRow) {
value=aRawRow;if (value == null) {
row.append(",");
}else{
row.append(aRawRow.toString()).append(",");
}
}
allRows.add(row.toString());
row= newStringBuilder();
}returnallRows;
}//更新offset元數據狀態，每次返回結果集后調用。必須記錄每次查詢的offset值，為程序中斷續跑數據時使用，以id為offset
void updateOffset2DB(intsize) {//以source_tab做為KEY，如果不存在則插入，存在則更新(每個源表對應一條記錄)
String sql = "insert into flume_meta(source_tab,currentIndex) VALUES('"
+ this.table+ "','" + (recordSixe +=size)+ "') on DUPLICATE key update source_tab=values(source_tab),currentIndex=values(currentIndex)";
LOG.info("updateStatus Sql:" +sql);
execSql(sql);
}//執行sql語句
private voidexecSql(String sql) {try{
ps=conn.prepareStatement(sql);
LOG.info("exec::" +sql);
ps.execute();
}catch(SQLException e) {
e.printStackTrace();
}
}//獲取當前id的offset
private Integer getStatusDBIndex(intstartFrom) {//從flume_meta表中查詢出當前的id是多少
String dbIndex = queryOne("select currentIndex from flume_meta where source_tab='" + table + "'");if (dbIndex != null) {returnInteger.parseInt(dbIndex);
}//如果沒有數據，則說明是第一次查詢或者數據表中還沒有存入數據，返回最初傳入的值
returnstartFrom;
}//查詢一條數據的執行語句(當前id)
privateString queryOne(String sql) {
ResultSet result= null;try{
ps=conn.prepareStatement(sql);
result=ps.executeQuery();while(result.next()) {return result.getString(1);
}
}catch(SQLException e) {
e.printStackTrace();
}return null;
}//關閉相關資源
voidclose() {try{
ps.close();
conn.close();
}catch(SQLException e) {
e.printStackTrace();
}
}intgetCurrentIndex() {returncurrentIndex;
}void setCurrentIndex(intnewValue) {
currentIndex=newValue;
}intgetRunQueryDelay() {returnrunQueryDelay;
}
String getQuery() {returnquery;
}
String getConnectionURL() {returnconnectionURL;
}private booleanisCustomQuerySet() {return (customQuery != null);
}
Context getContext() {returncontext;
}publicString getConnectionUserName() {returnconnectionUserName;
}publicString getConnectionPassword() {returnconnectionPassword;
}
String getDefaultCharsetResultSet() {returndefaultCharsetResultSet;
}
}
4.4 MySQLSource
代碼實現：
importorg.apache.flume.Context;importorg.apache.flume.Event;importorg.apache.flume.EventDeliveryException;importorg.apache.flume.PollableSource;importorg.apache.flume.conf.Configurable;importorg.apache.flume.event.SimpleEvent;importorg.apache.flume.source.AbstractSource;importorg.slf4j.Logger;importorg.slf4j.LoggerFactory;importjava.text.ParseException;importjava.util.ArrayList;importjava.util.HashMap;importjava.util.List;public class SQLSource extends AbstractSource implementsConfigurable, PollableSource {//打印日志
private static final Logger LOG = LoggerFactory.getLogger(SQLSource.class);//定義sqlHelper
privateSQLSourceHelper sqlSourceHelper;
@Overridepublic longgetBackOffSleepIncrement() {return 0;
}
@Overridepublic longgetMaxBackOffSleepInterval() {return 0;
}
@Overridepublic voidconfigure(Context context) {try{//初始化
sqlSourceHelper = newSQLSourceHelper(context);
}catch(ParseException e) {
e.printStackTrace();
}
}
@Overridepublic Status process() throwsEventDeliveryException {try{//查詢數據表
List> result =sqlSourceHelper.executeQuery();//存放event的集合
List events = new ArrayList<>();//存放event頭集合
HashMap header = new HashMap<>();//如果有返回數據，則將數據封裝為event
if (!result.isEmpty()) {
List allRows =sqlSourceHelper.getAllRows(result);
Event event= null;for(String row : allRows) {
event= newSimpleEvent();
event.setBody(row.getBytes());
event.setHeaders(header);
events.add(event);
}//將event寫入channel
this.getChannelProcessor().processEventBatch(events);//更新數據表中的offset信息
sqlSourceHelper.updateOffset2DB(result.size());
}//等待時長
Thread.sleep(sqlSourceHelper.getRunQueryDelay());returnStatus.READY;
}catch(InterruptedException e) {
LOG.error("Error procesing row", e);returnStatus.BACKOFF;
}
}
@Overridepublic synchronized voidstop() {
LOG.info("Stopping sql source {} ...", getName());try{//關閉資源
sqlSourceHelper.close();
}finally{super.stop();
}
}
}5 測試
5.1 Jar包準備
1)將MySql驅動包放入Flume的lib目錄下
[FLY@hadoop102 flume]$ cp \
/opt/sorfware/mysql-libs/mysql-connector-java-5.1.27/mysql-connector-java-5.1.27-bin.jar \
/opt/module/flume/lib/
2)打包項目并將Jar包放入Flume的lib目錄下
5.5.2 配置文件準備
1)創建配置文件并打開
[FLY@hadoop102 job]$ touch mysql.conf
[FLY@hadoop102 job]$ vim mysql.conf
2)添加如下內容
# Name the components on this agent
a1.sources = r1
a1.sinks = k1
a1.channels = c1
# Describe/configure the source
a1.sources.r1.type = com.FLY.source.SQLSource
a1.sources.r1.connection.url = jdbc:mysql://192.168.9.102:3306/mysqlsource
a1.sources.r1.connection.user = root
a1.sources.r1.connection.password = 000000
a1.sources.r1.table = student
a1.sources.r1.columns.to.select = *
#a1.sources.r1.incremental.column.name = id
#a1.sources.r1.incremental.value = 0
a1.sources.r1.run.query.delay=5000
# Describe the sink
a1.sinks.k1.type = logger
# Describe the channel
a1.channels.c1.type = memory
a1.channels.c1.capacity = 1000
a1.channels.c1.transactionCapacity = 100
# Bind the source and sink to the channel
a1.sources.r1.channels = c1
a1.sinks.k1.channel = c1
5.5.3 MySql表準備
1)創建MySqlSource數據庫
CREATE DATABASE mysqlsource；
2)在MySqlSource數據庫下創建數據表Student和元數據表Flume_meta
CREATE TABLE `student` (
`id`int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(255) NOT NULL,
PRIMARY KEY (`id`)
);
CREATE TABLE `flume_meta` (
`source_tab` varchar(255) NOT NULL,
`currentIndex` varchar(255) NOT NULL,
PRIMARY KEY (`source_tab`)
);
3)向數據表中添加數據
1 zhangsan
2 lisi
3 wangwu
4 zhaoliu
5.5.4????? 測試并查看結果
1)任務執行
[FLY@hadoop102 flume]$ bin/flume-ng agent --conf conf/ --name a1 \--conf-file job/mysql.conf -Dflume.root.logger=INFO,console
1)結果展示，如圖6-2所示：
總結
以上是生活随笔為你收集整理的flume写入mysql_Flume高级之自定义MySQLSource的全部內容，希望文章能夠幫你解決所遇到的問題。
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