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本文主要研究一下sharding-jdbc的SQLExecutionHook
SQLExecutionHook
incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-execute/src/main/java/org/apache/shardingsphere/core/execute/hook/SQLExecutionHook.java
public interface SQLExecutionHook {
/**
* Handle when SQL execution started.
*
* @param routeUnit route unit to be executed
* @param dataSourceMetaData data source meta data
* @param isTrunkThread is execution in trunk thread
* @param shardingExecuteDataMap sharding execute data map
*/
void start(RouteUnit routeUnit, DataSourceMetaData dataSourceMetaData, boolean isTrunkThread, Map shardingExecuteDataMap);
/**
* Handle when SQL execution finished success.
*/
void finishSuccess();
/**
* Handle when SQL execution finished failure.
*
* @param cause failure cause
*/
void finishFailure(Exception cause);
} - SQLExecutionHook接口定义了start、finishSuccess、finishFailure方法
SPISQLExecutionHook
incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-execute/src/main/java/org/apache/shardingsphere/core/execute/hook/SPISQLExecutionHook.java
public final class SPISQLExecutionHook implements SQLExecutionHook {
private final Collection sqlExecutionHooks = NewInstanceServiceLoader.newServiceInstances(SQLExecutionHook.class);
static {
NewInstanceServiceLoader.register(SQLExecutionHook.class);
}
@Override
public void start(final RouteUnit routeUnit, final DataSourceMetaData dataSourceMetaData, final boolean isTrunkThread, final Map shardingExecuteDataMap) {
for (SQLExecutionHook each : sqlExecutionHooks) {
each.start(routeUnit, dataSourceMetaData, isTrunkThread, shardingExecuteDataMap);
}
}
@Override
public void finishSuccess() {
for (SQLExecutionHook each : sqlExecutionHooks) {
each.finishSuccess();
}
}
@Override
public void finishFailure(final Exception cause) {
for (SQLExecutionHook each : sqlExecutionHooks) {
each.finishFailure(cause);
}
}
} - SPISQLExecutionHook实现了SQLExecutionHook接口；它使用NewInstanceServiceLoader注册了SQLExecutionHook；sqlExecutionHooks集合由NewInstanceServiceLoader.newServiceInstances创建；start方法遍历sqlExecutionHooks，执行其start方法；finishSuccess方法则遍历sqlExecutionHooks，执行其finishSuccess方法；finishFailure方法则遍历sqlExecutionHooks，执行其finishFailure方法
OpenTracingSQLExecutionHook
incubator-shardingsphere-4.0.0-RC1/sharding-opentracing/src/main/java/org/apache/shardingsphere/opentracing/hook/OpenTracingSQLExecutionHook.java
public final class OpenTracingSQLExecutionHook implements SQLExecutionHook {
private static final String OPERATION_NAME = "/" + ShardingTags.COMPONENT_NAME + "/executeSQL/";
private ActiveSpan activeSpan;
private Span span;
@Override
public void start(final RouteUnit routeUnit, final DataSourceMetaData dataSourceMetaData, final boolean isTrunkThread, final Map shardingExecuteDataMap) {
if (!isTrunkThread) {
activeSpan = ((ActiveSpan.Continuation) shardingExecuteDataMap.get(OpenTracingRootInvokeHook.ACTIVE_SPAN_CONTINUATION)).activate();
}
span = ShardingTracer.get().buildSpan(OPERATION_NAME)
.withTag(Tags.COMPONENT.getKey(), ShardingTags.COMPONENT_NAME)
.withTag(Tags.SPAN_KIND.getKey(), Tags.SPAN_KIND_CLIENT)
.withTag(Tags.PEER_HOSTNAME.getKey(), dataSourceMetaData.getHostName())
.withTag(Tags.PEER_PORT.getKey(), dataSourceMetaData.getPort())
.withTag(Tags.DB_TYPE.getKey(), "sql")
.withTag(Tags.DB_INSTANCE.getKey(), routeUnit.getDataSourceName())
.withTag(Tags.DB_STATEMENT.getKey(), routeUnit.getSqlUnit().getSql())
.withTag(ShardingTags.DB_BIND_VARIABLES.getKey(), toString(routeUnit.getSqlUnit().getParameters())).startManual();
}
private String toString(final List - OpenTracingSQLExecutionHook实现了SQLExecutionHook接口，其start方法创建并启动span、activeSpan；finishSuccess及finishFailure方法都会执行span.finish()及activeSpan.deactivate()，只是finishFailure则会标记span的exception信息
SQLExecuteCallback
incubator-shardingsphere-4.0.0-RC1/sharding-core/sharding-core-execute/src/main/java/org/apache/shardingsphere/core/execute/sql/execute/SQLExecuteCallback.java
@RequiredArgsConstructor
public abstract class SQLExecuteCallback implements ShardingGroupExecuteCallback {
private final DatabaseType databaseType;
private final boolean isExceptionThrown;
@Override
public final Collection execute(final Collection statementExecuteUnits, final boolean isTrunkThread,
final Map shardingExecuteDataMap) throws SQLException {
Collection result = new LinkedList<>();
for (StatementExecuteUnit each : statementExecuteUnits) {
result.add(execute0(each, isTrunkThread, shardingExecuteDataMap));
}
return result;
}
private T execute0(final StatementExecuteUnit statementExecuteUnit, final boolean isTrunkThread, final Map shardingExecuteDataMap) throws SQLException {
ExecutorExceptionHandler.setExceptionThrown(isExceptionThrown);
DataSourceMetaData dataSourceMetaData = DataSourceMetaDataFactory.newInstance(databaseType, statementExecuteUnit.getStatement().getConnection().getMetaData().getURL());
SQLExecutionHook sqlExecutionHook = new SPISQLExecutionHook();
try {
sqlExecutionHook.start(statementExecuteUnit.getRouteUnit(), dataSourceMetaData, isTrunkThread, shardingExecuteDataMap);
T result = executeSQL(statementExecuteUnit.getRouteUnit(), statementExecuteUnit.getStatement(), statementExecuteUnit.getConnectionMode());
sqlExecutionHook.finishSuccess();
return result;
} catch (final SQLException ex) {
sqlExecutionHook.finishFailure(ex);
ExecutorExceptionHandler.handleException(ex);
return null;
}
}
protected abstract T executeSQL(RouteUnit routeUnit, Statement statement, ConnectionMode connectionMode) throws SQLException;
} - SQLExecuteCallback的execute0方法在执行前创建SPISQLExecutionHook，然后调用sqlExecutionHook.start方法，执行成功之后执行sqlExecutionHook.finishSuccess方法，捕获到SQLException则执行sqlExecutionHook.finishFailure方法
小结
SQLExecutionHook接口定义了start、finishSuccess、finishFailure方法；SPISQLExecutionHook实现了SQLExecutionHook接口；它使用NewInstanceServiceLoader注册了SQLExecutionHook；sqlExecutionHooks集合由NewInstanceServiceLoader.newServiceInstances创建；start方法遍历sqlExecutionHooks，执行其start方法；finishSuccess方法则遍历sqlExecutionHooks，执行其finishSuccess方法；finishFailure方法则遍历sqlExecutionHooks，执行其finishFailure方法