@softrams/nodejs-mysql-connector/index.js

Database connector wrapper to work with MySQL database from nodejs applications

/* istanbul ignore file */
/* eslint-disable no-restricted-syntax */
/* eslint-disable no-await-in-loop */
/* eslint-disable no-else-return */
const mysql = require("mysql");
const fs = require('fs');

let pools = {};
let config = {};
const genericError = 'An error occurred communicating with the database.';

exports.init = async (cfg) => {
  config = cfg;
};

exports.createPool = async (poolName) => {
  try {
    const srcCfg = config.DATASOURCES[poolName];
    if (srcCfg) {
      const options = {
        connectionLimit: srcCfg.DB_CONNECTION_LIMIT || 5,
        host: srcCfg.DB_HOST,
        user: srcCfg.DB_USER,
        password: srcCfg.DB_PASSWORD,
        database: srcCfg.DB_DATABASE,
        port: srcCfg.PORT,
        multipleStatements: srcCfg.ALLOW_MULTI_STATEMENTS || false,
        timezone: srcCfg.TIMEZONE || 'local',
        typeCast: srcCfg.TYPE_CAST || true,
        dateStrings: srcCfg.DATE_STRINGS || false
      };

      if (srcCfg.SSL) {
        const sslConfig = {};

        if (srcCfg.SSL.CUSTOM_CERT) {
          sslConfig.ca = srcCfg.SSL.CUSTOM_CERT;
        } else {
          sslConfig.rejectUnauthorized = srcCfg.SSL.hasOwnProperty('REJECT_UNAUTHORIZED') ? srcCfg.SSL.REJECT_UNAUTHORIZED : true;
        }

        options.ssl = sslConfig;
      }

      pools[poolName] = mysql.createPool(options);
      console.debug(`MySQL Adapter: Pool ${poolName} created`);
      return true;
    } else {
      console.error(`MySQL Adapter: Missing configuration for ${poolName}`);
      return false;
    }
  } catch (err) {
    console.error("MySQL Adapter: Error while closing connection", err);
    return false;
  }
};

exports.connect = async (poolName) => {
  try {
    if (!pools[poolName]) {
      await this.createPool(poolName);
    }
    return pools[poolName];
  } catch (err) {
    console.error("MySQL Adapter: Error while retrieving a connection", err);
    throw new Error(err.message);
  }
};

this.query = async (conn, query, params) => {
  return new Promise((resolve, reject) => {
    try {
      conn.query(query, params, (error, results) => {
        if (error) {
          console.error("MySQL Adapter:  Failure in query: ", error);    
          this.handleError(reject, error);
        } else {
          resolve(results);
        }
      });
    } catch (err) {
      console.error("MySQL Adapter:  Failure in query: ", err);
      this.handleError(reject, err);
    }
  });
};

this.handleError = (reject, error) => {
  const errorReturn = (config && config.HIDE_DB_ERRORS) ? new Error(genericError) : error;
  reject(errorReturn);
};

exports.execute = async (srcName, query, params = {}) => {
  try {
    console.debug(query);
    if (params) {
      console.debug(JSON.stringify(params));
    }

    const start = process.hrtime();
    const conn = await this.connect(srcName);

    console.debug(
      `MySQL Adapter: Connection secured: ${process.hrtime(start)[0]}s ${
        process.hrtime(start)[1] / 1000000
      }ms`
    );
    const results = await this.query(conn, query, params);

    console.debug(
      `MySQL Adapter: Query executed: ${process.hrtime(start)[0]}s ${
        process.hrtime(start)[1] / 1000000
      }ms`
    );

    return results;
  } catch (err) {
    console.error("MySQL Adapter: Error while executing query", err);
    throw new Error(err.message);
  }
};

exports.closeAllPools = async () => {
  try {
    for (const poolAlias of Object.keys(pools)) {
      await this.closePool(poolAlias);
      delete pools[poolAlias];
      console.debug(`MySQL Adapter: Pool ${poolAlias} closed`);
    }
    return true;
  } catch (err) {
    console.error("MySQL Adapter: Error while closing connection", err);
    return false;
  }
};

exports.closePool = async (poolAlias) => {
  try {
    if (pools[poolAlias]) {
      const poolConn = pools[poolAlias];
      delete pools[poolAlias];
      await poolConn.end((err) => {
        if (err) {
          console.error(
            `Error while closing connection pool ${poolAlias}`,
            err
          );
        }
      });
      return true;
    } else {
      return true;
    }
  } catch (err) {
    console.error("MySQL Adapter: Error while closing connection", err);
    return false;
  }
};

exports.transactionConnection = (pool) => {
  return new Promise((resolve, reject) => {
      pool.getConnection((err, connection) => {
          let query;
          if (err) reject(err);
          if (connection) {
              console.log("MySQL Pool connected with threadId " + connection.threadId);
               query = (sql, params) => {
                  return new Promise((resolve, reject) => {
                      connection.query(sql, params, (err, result) => {
                          console.debug("Executing query " + sql);
                          if (params) {
                              console.debug(JSON.stringify(params));
                            }
                          if (err) reject(err);
                          resolve(result);
                      });
                  });
              };
          }
          
          const TRANSACTIONS = Object.freeze({
            START: 'START TRANSACTION',
            COMMIT: 'COMMIT',
            ROLLBACK: 'ROLLBACK'
          });

          const release = () => {
              return new Promise((resolve, reject) => {
                  if (err) reject(err);
                  if (connection) {
                      console.log("MySQL pool released the thread " + connection.threadId);
                      resolve(connection.release());
                  }
              });
          };

          const beginTransaction = () => {
              return new Promise((resolve, reject) => {
                  if (err) reject(err);
                  if (connection) {
                      console.log("MySQL beginning transaction with connection thread: " + connection.threadId);
                      resolve(connection.query(TRANSACTIONS.START));
                  }
              });
          };

          const commitTransaction = () => {
              return new Promise((resolve, reject) => {
                  if (err) reject(err);
                  if (connection) {
                      console.log("MySQL commiting transaction for connection thread: " + connection.threadId);
                      resolve(connection.query(TRANSACTIONS.COMMIT));
                  }
              });
          };

          const rollbackTransaction = () => {
              return new Promise((resolve, reject) => {
                  if (err) reject(err);
                  if (connection) {
                      console.log("MySQL rolling back the transaction of connection thread: " + connection.threadId);
                      resolve(connection.query(TRANSACTIONS.ROLLBACK));
                  }
              });
          };

          const execute = (sql, params) => {
              return new Promise((resolve, reject) => {
                  connection.query(sql, params, (err, result) => {
                      console.debug("Executing query " + sql);
                      if (params) {
                          console.debug(JSON.stringify(params));
                        }
                      if (err) reject(err);
                      resolve(result);
                  });
              });
          }

          resolve({ query, execute, release, beginTransaction, commitTransaction, rollbackTransaction});
      });
  });
};