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Subject [GitHub] [nifi-minifi-cpp] arpadboda commented on a change in pull request #656: MINIFI-1013 Used soci library.
Date Mon, 16 Dec 2019 22:58:15 GMT
arpadboda commented on a change in pull request #656: MINIFI-1013 Used soci library.
URL: https://github.com/apache/nifi-minifi-cpp/pull/656#discussion_r358510127
 
 

 ##########
 File path: extensions/sql/processors/QueryDatabaseTable.cpp
 ##########
 @@ -0,0 +1,453 @@
+/**
+ * @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.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/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");
+
+static const core::Property s_dbControllerService(
+    core::PropertyBuilder::createProperty("DB Controller Service")->isRequired(true)->withDescription("Database
Controller Service.")->supportsExpressionLanguage(true)->build());
+
+static const core::Property s_tableName(
+  core::PropertyBuilder::createProperty("Table Name")->isRequired(true)->withDescription("The
name of the database table to be queried.")->supportsExpressionLanguage(true)->build());
+
+static const core::Property 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());
+
+static const core::Property 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.")->supportsExpressionLanguage(true)->build());
+
+static const core::Property 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());
+
+static const core::Property 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());
+
+static const core::Property 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());
+
+static core::Property s_stateDirectory(
+  core::PropertyBuilder::createProperty("State Directory")->isRequired(false)->withDefaultValue("QDTState")->withDescription("Directory
which contains processor state data.")->build());
+
+static const core::Relationship s_success("success", "Successfully created FlowFile from
SQL query result set.");
+
+// Probably need to have `FragmentAttributes` like nifi has https://github.com/apache/nifi/blob/master/nifi-commons/nifi-utils/src/main/java/org/apache/nifi/flowfile/attributes/FragmentAttributes.java.
+static const std::string FragmentId = "fragment.identifier";
+static const std::string FragmentIndex = "fragment.index";
+static const std::string FragmentCount = "fragment.count";
+
+// State
+class State {
+ public:
+  State(const std::string& stateDir, const std::string& uuid, std::shared_ptr<logging::Logger>
logger)
+    :logger_(logger) {
+    if (!createUUIDDir(stateDir, uuid, filePath_)) {
+      return;
+    }
+
+    filePath_ += "State.txt";
+
+    if (!getStateFromFile()) {
+      return;
+    }
+
+    ok_ = true;
+  }
+
+  State::~State() {
+    if (file_.is_open()) {
+      file_.close();
+    }
+  }
+
+  operator bool() const {
+    return ok_;
+  }
+
+  std::unordered_map<std::string, std::string> mapState() const {
+    return mapState_;
+  }
+
+  bool writeStateToFile(const std::unordered_map<std::string, std::string>& mapState)
{
+    file_.seekp(std::ios::beg);
+
+    auto dataSize = 0;
+    for (const auto& el : mapState) {
+      file_ << el.first << '=' << el.second << separator();
+      dataSize += el.first.size() + 1 + el.second.size() + separator().size();
+    }
+
+    // Clear old data with ' '. 
+    for (auto i = dataSize_ - dataSize; i > 0; i--) {
+      file_ << ' ';
+    }
+    dataSize_ = dataSize;
+
+    file_.flush();
+
+    mapState_ = mapState;
+  }
+
+ private:
+   static const std::string& separator() {
+     static const std::string s_separator = "@!qdt!@";
+     return s_separator;
+   }
+
+   bool createUUIDDir(const std::string& stateDir, const std::string& uuid, std::string&
dir)
+   {
+     if (stateDir.empty()) {
+       dir.clear();
+       return false;
+     }
+
+     auto dirWithBackslash = stateDir;
+     if (stateDir.back() != '\\') {
+       dirWithBackslash += '\\';
+     }
+
+     dir = dirWithBackslash + "uuid\\" + uuid + "\\";
 
 Review comment:
   It's not going to work on Linux. 
   Fileutils has a function to get separator. 

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