Merge pull request #834 from gre/migration

Add a migration system

src/helpers/db/db.js

@@ -7,7 +7,7 @@ import get from 'lodash/get'
 
 import { decodeAccountsModel, encodeAccountsModel } from 'reducers/accounts'
 
-type DBKey = 'settings' | 'accounts' | 'countervalues' | 'user'
+type DBKey = 'settings' | 'accounts' | 'countervalues' | 'user' | 'migrations'
 
 const encryptionKey = {}
 

src/migrations/README.md

@@ -0,0 +1,15 @@
+## Migrations system
+
+this folder contains all the migration scripts.
+
+Migrations works with a nonce, number we increment.
+An app instance saves the nonce after running the migrations.
+To know what migrations need to be performed, we simply need to run all migrations that have an index higher that this nonce and then save it.
+
+The migration are run before the app starts and the idea is you need to perform everything on the db and maybe on the libcore with the commands.
+
+### Add a migration
+
+To add a migration, simply add one more item in the migrations array of index.js
+
+If a migration throw an exception, it's considered to be a critical error and app will crash forever. so make sure you only throw if necessary (user can always Hard Reset at the end)

src/migrations/index.js

@@ -0,0 +1,59 @@
+// @flow
+
+import logger from 'logger'
+import db from 'helpers/db'
+import { delay } from 'helpers/promise'
+import type { Migration } from './types'
+
+export const migrations: Migration[] = [
+  /*
+  // TODO release when libcore will fix the issue (ensure it does everyting that is needed)
+  {
+    doc: 'libcore fixed an important bug on BCH that needs a cache clear',
+    run: async () => {
+      // Clear out accounts operations because will need a full refresh
+      const accounts: mixed = db.get('accounts')
+      if (accounts && Array.isArray(accounts)) {
+        for (const acc of accounts) {
+          if (acc && typeof acc === 'object') {
+            acc.operations = []
+            acc.pendingOperations = []
+          }
+        }
+        db.set('accounts', accounts)
+      }
+
+      db.cleanCache()
+      // await delay(500)
+    },
+  },
+  */
+]
+
+// Logic to run all the migrations based on what was not yet run:
+export const runMigrations = async (): Promise<void> => {
+  const current = db.get('migrations')
+  let { nonce } = current || { nonce: migrations.length }
+  const outdated = migrations.length - nonce
+
+  if (!outdated) {
+    if (!current) {
+      db.set('migrations', { nonce })
+    }
+    return
+  }
+
+  try {
+    await delay(1000) // wait a bit the logger to be ready.
+
+    while (nonce < migrations.length) {
+      const m = migrations[nonce]
+      logger.log(`migration ${nonce}: ${m.doc}`)
+      await m.run()
+      nonce++
+    }
+    logger.log(`${outdated} migration(s) performed.`)
+  } finally {
+    db.set('migrations', { nonce })
+  }
+}

src/migrations/types.js

@@ -0,0 +1,6 @@
+// @flow
+
+export type Migration = {
+  doc: string,
+  run: () => Promise<void>,
+}

src/renderer/init.js

@@ -7,6 +7,7 @@ import { render } from 'react-dom'
 import { AppContainer } from 'react-hot-loader'
 import createHistory from 'history/createHashHistory'
 import moment from 'moment'
+import { runMigrations } from 'migrations'
 
 import createStore from 'renderer/createStore'
 import events from 'renderer/events'
@@ -42,6 +43,8 @@ async function init() {
     await hardReset()
   }
 
+  await runMigrations()
+
   // Init db with defaults if needed
   db.init('settings', {})