dremio 实现类似官方create user sql 处理的思路

主要说明思路，后边有时间了会进行开发的说明

官方特性说明

sabot/kernel/src/main/java/com/dremio/exec/planner/sql/parser/SqlCreateUser.java

public class SqlCreateUser extends SqlCall implements SimpleDirectHandler.Creator {

  private final SqlIdentifier username;

  private final SqlNode password;

  public static final SqlSpecialOperator OPERATOR = new SqlSpecialOperator("CREATE", SqlKind.OTHER) {

    @Override

    public SqlCall createCall(SqlLiteral functionQualifier, SqlParserPos pos, SqlNode... operands) {

      Preconditions.checkArgument(operands.length == 1, "SqlCreateUser.createCall() has to get at least 1 operands!");

      if (operands.length == 2){

        return new SqlCreateUser(

          pos,

          (SqlIdentifier) operands[0],

          (SqlNode) operands[1]

        );

      }

      return new SqlCreateUser(

        pos,

        (SqlIdentifier) operands[0]

      );

    }

  };

 

  public SqlCreateUser(SqlParserPos pos, SqlIdentifier username) {

    super(pos);

    this.username = username;

    this.password = null;

  }

 

  public SqlCreateUser(SqlParserPos pos, SqlIdentifier username, SqlNode password) {

    super(pos);

    this.username = username;

    this.password = password;

  }

 

  @Override

  public SimpleDirectHandler toDirectHandler(QueryContext context) {

    try {

     // 此处是创建用户的核心

      final Class<?> cl = Class.forName("com.dremio.exec.planner.sql.handlers.UserCreateHandler");

      final Constructor<?> ctor = cl.getConstructor(QueryContext.class);

      return (SimpleDirectHandler) ctor.newInstance(context);

    } catch (ClassNotFoundException e) {

      // Assume failure to find class means that we aren't running Enterprise Edition

      throw UserException.unsupportedError(e)

        .message("CREATE USER action is only supported in Enterprise Edition.")

        .buildSilently();

    } catch (InstantiationException | IllegalAccessException | NoSuchMethodException | InvocationTargetException e) {

      throw Throwables.propagate(e);

    }

 

  }

从上边可以看出官方的就是一个class 文件。。。。

handler 开发说明

• 方法签名

public abstract class SimpleDirectHandler implements SqlDirectHandler<SimpleCommandResult> {

  @Override

  public Class<SimpleCommandResult> getResultType() {

    return SimpleCommandResult.class;

  }

 

  public interface Creator {

    SimpleDirectHandler toDirectHandler(QueryContext context);

  }

}

• 参考实现
  sabot/kernel/src/main/java/com/dremio/exec/planner/sql/handlers/direct/UseSchemaHandler.java
  dremio 内部的一个

 

public class UseSchemaHandler extends SimpleDirectHandler {

  private static final org.slf4j.Logger logger = org.slf4j.LoggerFactory.getLogger(UseSchemaHandler.class);

 

  private final UserSession session;

  private final Catalog catalog;

 

  public UseSchemaHandler(UserSession session, Catalog catalog) {

    this.session = session;

    this.catalog = catalog;

  }

 

  @Override

  public List<SimpleCommandResult> toResult(String sql, SqlNode sqlNode) throws Exception {

    final SqlUseSchema useSchema = SqlNodeUtil.unwrap(sqlNode, SqlUseSchema.class);

    // first we try locally.

    NamespaceKey orig = new NamespaceKey(useSchema.getSchema());

    NamespaceKey defaultPath = catalog.resolveToDefault(orig);

    NamespaceKey compoundPath = orig.size() == 1 && orig.getRoot().contains(".") ? new NamespaceKey(SqlUtils.parseSchemaPath(orig.getRoot())) : null;

 

    if(defaultPath != null && catalog.containerExists(defaultPath)) {

      session.setDefaultSchemaPath(defaultPath.getPathComponents());

    } else if (catalog.containerExists(orig)) {

      session.setDefaultSchemaPath(orig.getPathComponents());

    } else if(compoundPath != null && catalog.containerExists(compoundPath)) {

      // kept to support old compound use statements.

      session.setDefaultSchemaPath(compoundPath.getPathComponents());

    } else {

      throw UserException.validationError().message("Schema [%s] is not valid with respect to either root schema or current default schema.", orig).build(logger);

    }

 

    return Collections.singletonList(SimpleCommandResult.successful("Default schema changed to [%s]", session.getDefaultSchemaPath()));

  }

}

自己实现

思路就是参考以上的，只是用户管理我们需要集成官方的UserService ，参考地址，具体官方默认实现是SimpleUserService
services/users/src/main/java/com/dremio/service/users/UserService.java
services/users/src/main/java/com/dremio/service/users/SimpleUserService.java

说明

以上只是一个简单的思路，实现起来也不是很难，实际上dremio好多企业特性也是基于次方法解决的
从源码上我们也可以猜测官方企业版本主要也是多了一些jar吧，所以官方还是比较务实的，好多特性也是提供给了
社区的，只是部分企业特性独立开了jar了，后续我们的升级迭代也是比较方便的

参考资料

https://github.com/dremio/dremio-oss