machinepack-postgresql/machines/begin-transaction.js

Structured Node.js bindings for connecting and running queries against a PostgreSQL database.

module.exports = {


  friendlyName: 'Begin transaction',


  description: 'Begin a new database transaction on the provided connection.',


  inputs: {

    connection: {
      friendlyName: 'Connection',
      description: 'An active database connection.',
      extendedDescription: 'The provided database connection instance must still be active. Only database ' +
        'connection instances created by the `getConnection()` machine in this driver are supported.',
      example: '===',
      required: true
    },

    meta: {
      friendlyName: 'Meta (custom)',
      description: 'Additional stuff to pass to the driver.',
      extendedDescription: 'This is reserved for custom driver-specific extensions. Please refer to the ' +
        'documentation for the driver you are using for more specific information.',
      example: '==='
    }

  },


  exits: {

    success: {
      description: 'The transaction was successfully started.',
      extendedDescription: 'Until it is committed, rolled back, or times out, subsequent queries run on this ' +
        'connection will be transactional. They will not have any true effect on the database until the transaction ' +
        'is committed, and will not affect queries made on other connections.',
      outputVariableName: 'report',
      outputDescription: 'The `meta` property is reserved for custom driver-specific extensions.',
      outputExample: '==='
      // example: {
      //   meta: '==='
      // }
    },

    badConnection: {
      friendlyName: 'Bad connection',
      description: 'The provided connection is not valid or no longer active. Are you sure it was obtained by ' +
        'calling this driver\'s `getConnection()` method?',
      extendedDescription: 'Usually, this means the connection to the database was lost due to a logic error or ' +
        'timing issue in userland code. In production, this can mean that the database became overwhelemed or was shut ' +
        'off while some business logic was in progress.',
      outputVariableName: 'report',
      outputDescription: 'The `error` property is a JavaScript Error instance containing the raw error from the database. ' +
        'The `meta` property is reserved for custom driver-specific extensions.',
      outputExample: '==='
      // example: {
      //   meta: '==='
      // }
    }

  },


  fn: function beginTransaction(inputs, exits) {
    // Dependencies
    var Pack = require('../');

    // Since we're using `sendNativeQuery()` to access the underlying connection,
    // we have confidence it will be validated before being used.
    Pack.sendNativeQuery({
      connection: inputs.connection,
      nativeQuery: 'BEGIN'
    }).switch({
      error: function error(err) {
        return exits.error(err);
      },
      badConnection: function badConnection() {
        return exits.badConnection({
          meta: inputs.meta
        });
      },
      success: function success() {
        return exits.success({
          meta: inputs.meta
        });
      }
    });
  }


};