migration generator

migrate.js

'use strict'

const fs = require('fs')
const path = require('path')
const migrationsFolder = path.join(__dirname, "/migrations")
const recordFile = path.join(__dirname, "/schema_migrations")

let client = require('./connection')()
let Commands = {
  make: make,
  run: run
}

// npm run migrate:make make stuff_in_underscore_or_whatever

function make(filename) {
  // check if a file_name is passed else throw an error
  // create a file with the timestamp followed by the first text that follows

  if(!filename) throw new Error("Expected a file name, npm run migrate:make filename")

  let calculatedFilename = `${Date.now()}_${filename}`
  let filepath = `${migrationsFolder}/${calculatedFilename}.sql`

  fs.closeSync(fs.openSync(filepath, 'w'));

  console.log('Created file ', filepath);
  console.log('write your migrations and run npm run migrate:latest')
}

function run() {
  // if a schema_migrations file is not present, create it
  // get the files in directory ./db/migrations
  // get the last run migration version
  // filter the files and run the migrations

  let files = getFiles(migrationsFolder)
  let lastMigration = fs.readFileSync(recordFile, 'utf8')

  client.connect();

  Promise.all(files.slice(files.indexOf(lastMigration) + 1).map(file => runQuery(client, file, lastMigration)))
    .then(() => client.end())
    .then(() => console.log("migrations completed"))
    .catch(e => {
      client.end();
      console.log("migration failed at ", lastMigration, " error ", e.message)
    })
}

function runQuery(conn, file, lastMigration) {
  let migration = fs.readFileSync(migrationsFolder + '/' + file, 'utf8')
  return conn.query(migration).then(() => {
    lastMigration = file
    return new Promise(res => fs.writeFile(recordFile, file, 'utf8', res))
  })
}

function getFiles(dir){
  let fileList = [];

  let files = fs.readdirSync(dir);

  for (let i = 0, len = files.length; i < len; i++) {
    fileList.push(files[i])
  }

  return fileList;
}

let command = process.argv[2]
let todo = process.argv[3]

Commands[command](todo)