check db version with typeORM

backend/src/database/connection.ts

@@ -1,18 +0,0 @@
-import { createConnection, Connection } from 'mysql2/promise'
-import CONFIG from '../config'
-
-const connection = async (): Promise<Connection> => {
-  const con = await createConnection({
-    host: CONFIG.DB_HOST,
-    port: CONFIG.DB_PORT,
-    user: CONFIG.DB_USER,
-    password: CONFIG.DB_PASSWORD,
-    database: CONFIG.DB_DATABASE,
-  })
-
-  await con.connect()
-
-  return con
-}
-
-export default connection

backend/src/index.ts

@@ -5,12 +5,12 @@ import express from 'express'
 import cors from 'cors'
 import { buildSchema } from 'type-graphql'
 import { ApolloServer } from 'apollo-server-express'
-import { RowDataPacket } from 'mysql2/promise'
 
-import connection from './database/connection'
-import typeOrmConnection from './typeorm/connection'
 import CONFIG from './config'
 
+import connection from './typeorm/connection'
+import getDBVersion from './typeorm/getDBVersion'
+
 // TODO move to extern
 import { UserResolver } from './graphql/resolvers/UserResolver'
 import { BalanceResolver } from './graphql/resolvers/BalanceResolver'
@@ -39,20 +39,20 @@ const context = (args: any) => {
 }
 
 async function main() {
-  // check for correct database version
+  // open mysql connection
   const con = await connection()
-  const [rows] = await con.query(`SELECT * FROM migrations ORDER BY version DESC LIMIT 1;`)
-  if (
-    (<RowDataPacket>rows).length === 0 ||
-    !(<RowDataPacket>rows)[0].fileName ||
-    (<RowDataPacket>rows)[0].fileName.indexOf(DB_VERSION) === -1
-  ) {
-    throw new Error(`Wrong database version - the backend requires '${DB_VERSION}'`)
+  if (!con.isConnected) {
+    throw new Error(`Couldn't open connection to database`)
   }
 
-  const toCon = await typeOrmConnection()
-  if (!toCon.isConnected) {
-    throw new Error(`Couldn't open typeorm db connection`)
+  // check for correct database version
+  const dbVersion = await getDBVersion()
+  if (!dbVersion || dbVersion.indexOf(DB_VERSION) === -1) {
+    throw new Error(
+      `Wrong database version - the backend requires '${DB_VERSION}' but found '${
+        dbVersion || 'None'
+      }'`,
+    )
   }
 
   const schema = await buildSchema({
@@ -61,10 +61,7 @@ async function main() {
   })
 
   // Graphiql interface
-  let playground = false
-  if (CONFIG.GRAPHIQL) {
-    playground = true
-  }
+  const playground = CONFIG.GRAPHIQL
 
   // Express Server
   const server = express()

backend/src/typeorm/entity/Migration.ts

@@ -0,0 +1,21 @@
+import { BaseEntity, Entity, PrimaryGeneratedColumn, Column } from 'typeorm'
+
+@Entity('migrations')
+export class Migration extends BaseEntity {
+  @PrimaryGeneratedColumn() // This is actually not a primary column
+  version: number
+
+  @Column({ length: 256, nullable: true, default: null })
+  fileName: string
+
+  @Column({ type: 'datetime', default: () => 'CURRENT_TIMESTAMP' })
+  date: Date
+
+  /*
+  static findByUser(userId: number): Promise<Balance> {
+    return this.createQueryBuilder('balance')
+      .where('balance.userId = :userId', { userId })
+      .getOneOrFail()
+  }
+  */
+}

backend/src/typeorm/getDBVersion.ts

@@ -0,0 +1,15 @@
+import { getConnection } from 'typeorm'
+import { Migration } from './entity/Migration'
+
+const getDBVersion = async (): Promise<string | null> => {
+  const connection = getConnection()
+  const migrations = connection.getRepository(Migration)
+  try {
+    const dbVersion = await migrations.findOne({ order: { version: 'DESC' } })
+    return dbVersion ? dbVersion.fileName : null
+  } catch (error) {
+    return null
+  }
+}
+
+export default getDBVersion