szaszm commented on a change in pull request #732: MINIFICPP-1013 URL: https://github.com/apache/nifi-minifi-cpp/pull/732#discussion_r378203621
########## File path: extensions/sql/processors/QueryDatabaseTable.cpp ########## @@ -0,0 +1,475 @@ +/** + * @file QueryDatabaseTable.cpp + * PutSQL class declaration + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#include "QueryDatabaseTable.h" + +#include <vector> +#include <queue> +#include <map> +#include <set> +#include <sstream> +#include <stdio.h> +#include <string> +#include <iostream> +#include <memory> +#include <codecvt> +#include <algorithm> +#include <regex> + +#include <soci/soci.h> + +#include "io/DataStream.h" +#include "core/ProcessContext.h" +#include "core/ProcessSession.h" +#include "Exception.h" +#include "utils/OsUtils.h" +#include "data/DatabaseConnectors.h" +#include "data/JSONSQLWriter.h" +#include "data/SQLRowsetProcessor.h" +#include "data/WriteCallback.h" +#include "data/MaxCollector.h" +#include "data/Utils.h" +#include "utils/file/FileUtils.h" + +namespace org { +namespace apache { +namespace nifi { +namespace minifi { +namespace processors { + +const std::string QueryDatabaseTable::ProcessorName("QueryDatabaseTable"); + +const core::Property QueryDatabaseTable::s_tableName( + core::PropertyBuilder::createProperty("Table Name")->isRequired(true)->withDescription("The name of the database table to be queried.")->supportsExpressionLanguage(true)->build()); + +const core::Property QueryDatabaseTable::s_columnNames( + core::PropertyBuilder::createProperty("Columns to Return")->isRequired(false)->withDescription( + "A comma-separated list of column names to be used in the query. If your database requires special treatment of the names (quoting, e.g.), each name should include such treatment. " + "If no column names are supplied, all columns in the specified table will be returned. " + "NOTE: It is important to use consistent column names for a given table for incremental fetch to work properly.")->supportsExpressionLanguage(true)->build()); + +const core::Property QueryDatabaseTable::s_maxValueColumnNames( + core::PropertyBuilder::createProperty("Maximum-value Columns")->isRequired(false)->withDescription( + "A comma-separated list of column names. The processor will keep track of the maximum value for each column that has been returned since the processor started running. " + "Using multiple columns implies an order to the column list, and each column's values are expected to increase more slowly than the previous columns' values. " + "Thus, using multiple columns implies a hierarchical structure of columns, which is usually used for partitioning tables. " + "This processor can be used to retrieve only those rows that have been added/updated since the last retrieval. " + "Note that some ODBC types such as bit/boolean are not conducive to maintaining maximum value, so columns of these types should not be listed in this property, and will result in error(s) during processing. " + "If no columns are provided, all rows from the table will be considered, which could have a performance impact. " + "NOTE: It is important to use consistent max-value column names for a given table for incremental fetch to work properly. " + "NOTE: Because of a limitation of database access library 'soci', which doesn't support milliseconds in it's 'dt_date', " + "there is a possibility that flowfiles might have duplicated records, if a max-value column with 'dt_date' type has value with milliseconds.")-> + supportsExpressionLanguage(true)->build()); + +const core::Property QueryDatabaseTable::s_whereClause( + core::PropertyBuilder::createProperty("db-fetch-where-clause")->isRequired(false)->withDescription( + "A custom clause to be added in the WHERE condition when building SQL queries.")->supportsExpressionLanguage(true)->build()); + +const core::Property QueryDatabaseTable::s_sqlQuery( + core::PropertyBuilder::createProperty("db-fetch-sql-query")->isRequired(false)->withDescription( + "A custom SQL query used to retrieve data. Instead of building a SQL query from other properties, this query will be wrapped as a sub-query. " + "Query must have no ORDER BY statement.")->supportsExpressionLanguage(true)->build()); + +const core::Property QueryDatabaseTable::s_maxRowsPerFlowFile( + core::PropertyBuilder::createProperty("qdbt-max-rows")->isRequired(true)->withDefaultValue<int>(0)->withDescription( + "The maximum number of result rows that will be included in a single FlowFile. This will allow you to break up very large result sets into multiple FlowFiles. " + "If the value specified is zero, then all rows are returned in a single FlowFile.")->supportsExpressionLanguage(true)->build()); + +const core::Property QueryDatabaseTable::s_stateDirectory( + core::PropertyBuilder::createProperty("State Directory")->isRequired(false)->withDefaultValue("QDTState")->withDescription("Directory which contains processor state data.")->build()); + +const std::string QueryDatabaseTable::s_initialMaxValueDynamicPropertyPrefix("initial.maxvalue."); + +const core::Relationship QueryDatabaseTable::s_success("success", "Successfully created FlowFile from SQL query result set."); + +static const std::string ResultTableName = "tablename"; +static const std::string ResultRowCount = "querydbtable.row.count"; + +// State +class State { + public: + State(const std::string& tableName, const std::string& stateDir, const std::string& uuid, std::shared_ptr<logging::Logger> logger) + :tableName_(tableName), logger_(logger) { + if (!createUUIDDir(stateDir, uuid, filePath_)) + return; + + filePath_ += "State.txt"; + + if (!getStateFromFile()) + return; + + ok_ = true; + } + + ~State() { + if (file_.is_open()) { + file_.close(); + } + } + + operator bool() const { + return ok_; + } + + std::unordered_map<std::string, std::string> mapState() const { + return mapState_; + } + + void writeStateToFile(const std::unordered_map<std::string, std::string>& mapState) { + file_.seekp(std::ios::beg); + + file_ << tableName_ << separator(); + auto dataSize = tableName_.size() + separator().size(); + + for (const auto& el : mapState) { + file_ << el.first << '=' << el.second << separator(); + dataSize += el.first.size() + 1 + el.second.size() + separator().size(); + } + + // If dataSize_ > dataSize, then clear difference with ' '. + if (dataSize_ > dataSize) { + for (auto i = dataSize_ - dataSize; i > 0; i--) { + file_ << ' '; + } + } Review comment: Your previous reply could be a great code comment explaining why the loop is necessary, but if I understand correctly just unwrapping the `if` body and leaving the `for` loop only would have equivalent behavior with 2 less lines and 1 less indentation level. (i.e. less complexity) Correct me if I'm wrong, but I suggest this in place of lines 146-151: ``` // If a maxValueColumnName type is varchar then a new max value can be shorter than previous max value, // and due to ???, we need to pad the data in the state file for (auto i = dataSize_ - dataSize; i > 0; i--) { file_ << ' '; } ``` ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
