Implement Neo4J store for migrate

backend/package.json

@@ -13,8 +13,10 @@
     "db:reset": "babel-node src/seed/reset-db.js",
     "db:seed": "babel-node src/seed/seed-db.js",
     "db:setup": "babel-node src/db/setup.js",
-    "db:migrate:create": "migrate create --template-file./src/db/migrationTemplate.js",
-    "db:migrate": "migrate --compiler 'js:@babel/register'"
+    "__migrate": "migrate --compiler 'js:@babel/register' --migrations-dir ./src/db/migrations",
+    "db:migrate": "yarn run __migrate --store ./src/db/migrate/store.js",
+    "db:migrate:create": "yarn run __migrate --template-file ./src/db/migrate/template.js create",
+    "production:db:migrate": "migrate --migrations-dir ./dist/db/migrations --store ./dist/db/migrate/store.js"
   },
   "author": "Human Connection gGmbH",
   "license": "MIT",
@@ -106,7 +108,7 @@
     "@babel/node": "~7.8.3",
     "@babel/plugin-proposal-throw-expressions": "^7.8.3",
     "@babel/preset-env": "~7.8.3",
-    "@babel/register": "~7.8.3",
+    "@babel/register": "^7.8.3",
     "apollo-server-testing": "~2.9.16",
     "babel-core": "~7.0.0-0",
     "babel-eslint": "~10.0.3",

backend/src/db/migrate/store.js

@@ -0,0 +1,57 @@
+import { getDriver } from '../../bootstrap/neo4j'
+
+class Store {
+  async load(fn) {
+    const driver = getDriver()
+    const session = driver.session()
+    const readTxResultPromise = session.readTransaction(async txc => {
+      const result = await txc.run(
+        'MATCH (migration:Migration) RETURN migration {.*} ORDER BY migration.timestamp DESC',
+      )
+      return result.records.map(r => r.get('migration'))
+    })
+    try {
+      const migrations = await readTxResultPromise
+      if (migrations.length <= 0) {
+        // eslint-disable-next-line no-console
+        console.log(
+          "No migrations found in database. If it's the first time you run migrations, then this is normal.",
+        )
+        return fn(null, {})
+      }
+      const [{ title: lastRun }] = migrations
+      fn(null, { lastRun, migrations })
+    } catch (error) {
+      console.log(error) // eslint-disable-line no-console
+    } finally {
+      session.close()
+    }
+  }
+
+  async save(set, fn) {
+    const driver = getDriver()
+    const session = driver.session()
+    const { migrations } = set
+    const writeTxResultPromise = session.writeTransaction(txc => {
+      return Promise.all(
+        migrations.map(migration => {
+          const { title, description, timestamp } = migration
+          const properties = { title, description, timestamp }
+          return txc.run('CREATE (migration:Migration) SET migration += $properties', {
+            properties,
+          })
+        }),
+      )
+    })
+    try {
+      await writeTxResultPromise
+    } catch (error) {
+      console.log(error) // eslint-disable-line no-console
+    } finally {
+      session.close()
+      fn()
+    }
+  }
+}
+
+module.exports = Store

backend/src/db/migrate/template.js

@@ -0,0 +1,7 @@
+export function up(next) {
+  next()
+}
+
+export function down(next) {
+  next()
+}

backend/src/db/migrationTemplate.js

@@ -1,7 +0,0 @@
-export function up (next) {
-  next()
-}
-
-export function down (next) {
-  next()
-}

backend/src/db/migrations/1579387929122-merge_duplicate_user_accounts.js

@@ -1,10 +1,18 @@
 import { throwError, of, concat } from 'rxjs'
 import { tap, flatMap, mergeMap, map, catchError, filter } from 'rxjs/operators'
-import CONFIG from '../src/config'
-import { getNeode, getDriver } from '../src/bootstrap/neo4j'
-import normalizeEmail from '../src/schema/resolvers//helpers/normalizeEmail'
+import CONFIG from '../../src/config'
+import { getNeode, getDriver } from '../../src/bootstrap/neo4j'
+import normalizeEmail from '../../src/schema/resolvers//helpers/normalizeEmail'
 
+export const description = `
+  This migration merges duplicate :User and :EmailAddress nodes. It became
+  necessary after we implemented the email normalization but forgot to migrate
+  the existing data. Some (40) users decided to just register with a new account
+  but the same email address. On signup our backend would normalize the email,
+  which is good, but would also keep the existing unnormalized email address.
 
+  This led to about 40 duplicate user and email address nodes in our database.
+`
 export function up (next) {
   const driver = getDriver()
   const rxSession = driver.rxSession()

backend/src/models/Post.js

@@ -11,7 +11,7 @@ export default {
     direction: 'in',
   },
   title: { type: 'string', disallow: [null], min: 3 },
-  slug: { type: 'string', allow: [null], unique: 'true', },
+  slug: { type: 'string', allow: [null], unique: 'true' },
   content: { type: 'string', disallow: [null], min: 3 },
   contentExcerpt: { type: 'string', allow: [null] },
   image: { type: 'string', allow: [null] },

backend/yarn.lock

@@ -751,7 +751,7 @@
     levenary "^1.1.0"
     semver "^5.5.0"
 
-"@babel/register@^7.8.3", "@babel/register@~7.8.3":
+"@babel/register@^7.8.3":
   version "7.8.3"
   resolved "https://registry.yarnpkg.com/@babel/register/-/register-7.8.3.tgz#5d5d30cfcc918437535d724b8ac1e4a60c5db1f8"
   integrity sha512-t7UqebaWwo9nXWClIPLPloa5pN33A2leVs8Hf0e9g9YwUP8/H9NeR7DJU+4CXo23QtjChQv5a3DjEtT83ih1rg==