Zipkin原理学习 -- Druid 追踪多种数据库 SQL 执行

在上一篇博客 《Zipkin原理学习–日志追踪 MySQL 执行语句》 中我们已经了解学习到 Zipkin 官方提供的针对 MySQL 数据库 sql 语句执行的追踪拦截器，现在我们基于数据库连接池 Druid 的 Filter 机制 写一个能支持多种数据库（mysql，postgresql、oracle、sql server 等）类型 SQL 执行日志追踪拦截器。

Druid 过滤器 Filter

DruidDataSource支持通过Filter-Chain模式进行扩展，类似Serlvet的Filter，扩展十分方便，你可以拦截任何JDBC的方法。

有两种配置Filter的方式，一种是配置filters属性，一种是配置proxyFilters属性。filters和proxyFilters的配置是组合关系，而不是替换关系。

配置filters属性

配置filters属性比较简单，filters的类型是字符串，多个filter使用逗号隔开。例如：

<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"
      init-method="init" destroy-method="close">
      <property name="url" value="jdbc:derby:memory:spring-test;create=true" />
      <property name="initialSize" value="1" />
      <property name="maxActive" value="20" />
      <property name="filters" value="stat,log4j" />
  </bean>      

filters属性的配置使用别名或者全类名，stat是com.alibaba.druid.filter.stat.StatFilter的别名。​​ 内置Filter的别名 ​​ 查看内置Filter的别名。

配置proxyFilters属性

proxyFilters的类型是List，使用proxyFilters配置，可以有更多的配置选项。

<bean id="stat-filter" class="com.alibaba.druid.filter.stat.StatFilter">
  </bean>

  <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"
      init-method="init" destroy-method="close">
      <property name="url" value="jdbc:derby:memory:spring-test;create=true" />
      <property name="initialSize" value="1" />
      <property name="maxActive" value="20" />
      <property name="proxyFilters">
          <list>
              <ref bean="stat-filter" />
          </list>
      </property>
  </bean>      

Zipkin 日志追踪过滤器 TracingStatementFilter

TracingStatementFilter 继承抽象类 FilterEventAdapter 实现以下接口：

protected void statementExecuteUpdateBefore(StatementProxy statement, String sql) {
    }

    protected void statementExecuteUpdateAfter(StatementProxy statement, String sql, int updateCount) {
    }

    protected void statementExecuteQueryBefore(StatementProxy statement, String sql) {
    }

    protected void statementExecuteQueryAfter(StatementProxy statement, String sql, ResultSetProxy resultSet) {
    }

    protected void statementExecuteBefore(StatementProxy statement, String sql) {
    }

    protected void statementExecuteAfter(StatementProxy statement, String sql, boolean result) {
    }

    protected void statementExecuteBatchBefore(StatementProxy statement) {
    }

    protected void statementExecuteBatchAfter(StatementProxy statement, int[] result) {
    }

    protected void statement_executeErrorAfter(StatementProxy statement, String sql, Throwable error) {
    }      

实现以上接口，在执行SQL语句之前、之后或抛出异常时都会执行上面接口方法，这样就可以追踪 SQL 语句的执行过程了。

完整 Zipkin 日志追踪代码：

public class TracingStatementFilter extends FilterEventAdapter {


    private String zipkinServiceName;

    public TracingStatementFilter(String zipkinServiceName){
        this.zipkinServiceName = zipkinServiceName;
    }

    public TracingStatementFilter(){

    }


    @Override
    protected void statementExecuteUpdateBefore(StatementProxy statement, String sql) {

        super.statementExecuteUpdateBefore(statement,sql);

        Before(statement,sql);

    }

    @Override
    protected void statementExecuteUpdateAfter(StatementProxy statement, String sql, int updateCount) {

        super.statementExecuteUpdateAfter(statement,sql,updateCount);

        After(statement,sql);

    }

    @Override
    protected void statementExecuteQueryBefore(StatementProxy statement, String sql) {

        super.statementExecuteQueryBefore(statement,sql);

        Before(statement,sql);

    }

    @Override
    protected void statementExecuteQueryAfter(StatementProxy statement, String sql, ResultSetProxy resultSet) {

        super.statementExecuteQueryAfter(statement,sql,resultSet);

        After(statement,sql);


    }

    @Override
    protected void statementExecuteBefore(StatementProxy statement, String sql) {

        super.statementExecuteBefore(statement,sql);
        Before(statement,sql);

    }

    @Override
    protected void statementExecuteAfter(StatementProxy statement, String sql, boolean result) {

        super.statementExecuteAfter(statement,sql,result);

        After(statement,sql);




    }

    @Override
    protected void statementExecuteBatchBefore(StatementProxy statement) {

        super.statementExecuteBatchBefore(statement);

        Before(statement , null);



    }

    @Override
    protected void statementExecuteBatchAfter(StatementProxy statement, int[] result) {

        super.statementExecuteBatchAfter(statement , result);
        After(statement , null);
    }

    @Override
    protected void statement_executeErrorAfter(StatementProxy statement, String sql, Throwable error) {

        super.statement_executeErrorAfter(statement , sql , error);
        ErrorAfter(statement , sql , error);

    }


    protected void Before(StatementProxy statement, String sql) {

        try {
            Span span = ThreadLocalSpan.CURRENT_TRACER.next();
            if (span == null || span.isNoop()) {
                return;
            }

            if(sql == null){
                sql = statement.getLastExecuteSql();
            }
            // Allow span names of single-word statements like COMMIT

            int spaceIndex = sql.indexOf(' ');
            span.kind(Span.Kind.CLIENT).name(spaceIndex == -1 ? sql : sql.substring(0, spaceIndex));
            span.tag("sql.query", sql);

            parseServerIpAndPort(statement,span);
            span.start();
        }catch (Exception e){

        }

    }

    protected void After(StatementProxy statement, String sql) {

        try {
            Span span = ThreadLocalSpan.CURRENT_TRACER.remove();
            if (span == null || span.isNoop()) {
                return;
            }
            span.finish();
            return ;
        }catch (Exception e){

        }

    }

    protected void ErrorAfter(StatementProxy statement, String sql, Throwable error) {

        try {
            Span span = ThreadLocalSpan.CURRENT_TRACER.remove();
            if (span == null || span.isNoop()) {
                return;
            }

            if (error instanceof SQLException) {
                span.tag("error", Integer.toString(((SQLException) error).getErrorCode()));
            }
            span.finish();

            return ;
        }catch (Exception e){

        }

    }


    public void parseServerIpAndPort(StatementProxy statement, Span span) {
        try {
            URI url = URI.create(statement.getConnection().getMetaData().getURL().substring(5));
            if (getZipkinServiceName() == null || "".equals(getZipkinServiceName())) {
                try {
                    zipkinServiceName = "DB"+url.getPath();
                }catch (Exception e){
                    ;
                }
            }
            span.remoteServiceName(getZipkinServiceName());
            String host = url.getHost();
            if (host != null) {
                span.remoteIpAndPort(host, url.getPort());
            }
        } catch (Exception e) {
            // remote address is optional
        }
    }

    public String getZipkinServiceName() {
        return zipkinServiceName;
    }

    public void setZipkinServiceName(String zipkinServiceName) {
        this.zipkinServiceName = zipkinServiceName;
    }
}      

使用配置示例：

<bean id="tracingStatementFilter" class="brave.druid.TracingStatementFilter">
    <property name="zipkinServiceName" value="dbServer" /></bean>

    <bean id="dataSource"  class="com.alibaba.druid.pool.DruidDataSource"
       init-method="init" destroy-method="close">
      <property name="url" value="jdbc:derby:memory:spring-test;create=true" />
      <property name="initialSize" value="1" />
      <property name="maxActive" value="20" />
      <property name="proxyFilters">
          <list>
              <ref bean="tracingStatementFilter" />
          </list>
      </property>
    </bean>