Zipkin原理学习--日志追踪 MySQL 执行语句

Posted 2021-03-14 董俊杰

目前Zipkin官方提供了插件用于支持对mysql语句执行过程的日志追踪，提供了对MySQL5、MySQL6和MySQL8的支持，官方地址：https://github.com/openzipkin/brave/tree/master/instrumentation

一、介绍及示例
配置示例：

1、引入相关jar包：

<dependency>
<groupId>io.zipkin.brave</groupId>
<artifactId>brave-instrumentation-mysql</artifactId>
<version>5.4.3</version>
</dependency>
2、在url中添加拦截器和服务名：statementInterceptors=brave.mysql.TracingStatementInterceptor&zipkinServiceName=myDatabaseService

public void mysql() throws Exception{
Class.forName("com.mysql.jdbc.Driver");
System.out.println("成功加载驱动");

Connection connection = null;
Statement statement = null;
ResultSet resultSet = null;

try {
String url = "jdbc:mysql://localhost:3306/db?user=root&password=root&useUnicode=true&characterEncoding=UTF8&statementInterceptors=brave.mysql.TracingStatementInterceptor&zipkinServiceName=myDatabaseService";
connection = DriverManager.getConnection(url);
System.out.println("成功获取连接");

statement = connection.createStatement();
String sql = "select * from tbl_user";
resultSet = statement.executeQuery(sql);

resultSet.beforeFirst();
while (resultSet.next()) {
System.out.println(resultSet.getString(1));
}
System.out.println("成功操作数据库");
} catch(Throwable t) {
// TODO 处理异常
t.printStackTrace();
} finally {
if (resultSet != null) {
resultSet.close();
}
if (statement != null) {
statement.close();
}
if (connection != null) {
connection.close();
}
System.out.println("成功关闭资源");
}

}
3、zipserver中结果示例：

 

二、实现原理
        其实现原理也还是挺容易理解的，利用MySQL JDBC提供的拦截器机制，在sql语句执行前新建一个span调用，在sql语句执行后结束span调用，记录整个调用过程的耗时及sql语句信息。

public class TracingStatementInterceptor implements StatementInterceptorV2 {

/**
* Uses {@link ThreadLocalSpan} as there‘s no attribute namespace shared between callbacks, but
* all callbacks happen on the same thread.
*
* <p>Uses {@link ThreadLocalSpan#CURRENT_TRACER} and this interceptor initializes before
* tracing.
*/
@Override
public ResultSetInternalMethods preProcess(String sql, Statement interceptedStatement,
Connection connection) {
// Gets the next span (and places it in scope) so code between here and postProcess can read it
//新生成一个Span
Span span = ThreadLocalSpan.CURRENT_TRACER.next();
if (span == null || span.isNoop()) return null;

// When running a prepared statement, sql will be null and we must fetch the sql from the statement itself
if (interceptedStatement instanceof PreparedStatement) {
sql = ((PreparedStatement) interceptedStatement).getPreparedSql();
}
int spaceIndex = sql.indexOf(‘ ‘); // Allow span names of single-word statements like COMMIT
span.kind(Span.Kind.CLIENT).name(spaceIndex == -1 ? sql : sql.substring(0, spaceIndex));
span.tag("sql.query", sql);
parseServerIpAndPort(connection, span);
//记录启动时间
span.start();
return null;
}

@Override
public ResultSetInternalMethods postProcess(String sql, Statement interceptedStatement,
ResultSetInternalMethods originalResultSet, Connection connection, int warningCount,
boolean noIndexUsed, boolean noGoodIndexUsed, SQLException statementException) {
Span span = ThreadLocalSpan.CURRENT_TRACER.remove();
if (span == null || span.isNoop()) return null;

if (statementException != null) {
span.tag("error", Integer.toString(statementException.getErrorCode()));
}
//记录服务停止时间
span.finish();

return null;
}

/**
* MySQL exposes the host connecting to, but not the port. This attempts to get the port from the
* JDBC URL. Ex. 5555 from {@code jdbc:mysql://localhost:5555/database}, or 3306 if absent.
*/
static void parseServerIpAndPort(Connection connection, Span span) {
try {
URI url = URI.create(connection.getMetaData().getURL().substring(5)); // strip "jdbc:"
String remoteServiceName = connection.getProperties().getProperty("zipkinServiceName");
if (remoteServiceName == null || "".equals(remoteServiceName)) {
String databaseName = connection.getCatalog();
if (databaseName != null && !databaseName.isEmpty()) {
remoteServiceName = "mysql-" + databaseName;
} else {
remoteServiceName = "mysql";
}
}
//添加服务名
span.remoteServiceName(remoteServiceName);
String host = connection.getHost();
if (host != null) {
span.remoteIpAndPort(host, url.getPort() == -1 ? 3306 : url.getPort());
}
} catch (Exception e) {
// remote address is optional
}
}

@Override public boolean executeTopLevelOnly() {
return true; // True means that we don‘t get notified about queries that other interceptors issue
}

@Override public void init(Connection conn, Properties props) {
// Don‘t care
}

@Override public void destroy() {
// Don‘t care
}
}
思考：其实Zipkin官方给出的这种方案还是能给我们一些启发的，目前对于数据库官方只支持了mysql，对于Postgresql、Oracle 和 SQL Server 等可以基于技术方案有以下两种局限解决方案：

（1）利用mybatis的拦截器机制来实现，和上面的实现类似

（2）利用数据库池 Druid的过滤器同样可以实现。

以上两种方案的好处：对于数据库通用支持。
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原文链接：https://blog.csdn.net/qq924862077/article/details/88559499