Added example for using custom state storage

Squashed commit of the following: commit 86e0795a46fd813aefc8afbd7da5d450211fed0c Author: Wes Todd <[email protected]> Date: Mon Sep 24 16:59:45 2018 -0700 example cleanup commit 2bb649489ffb86451f82303e5be32a4b04b1301b Merge: b62234a 9ee0385 Author: Wes Todd <[email protected]> Date: Mon Sep 24 16:45:12 2018 -0700 Merge branch 'master' of https://github.com/roemba/node-migrate into roemba-master commit 9ee0385 Author: Roemer Hendrikx <[email protected]> Date: Sun Sep 16 22:17:51 2018 +0200 Small fix so that inserting into the migrations table with a new migration object generates a proper conflict commit b6eed64 Author: Roemer Hendrikx <[email protected]> Date: Sun Sep 16 21:26:19 2018 +0200 Changed database column type from text to jsonb and made delete and insert an upsert This removes the need foor JSON.parse or JSON.stringify commit c663c9a Author: Roemer Hendrikx <[email protected]> Date: Tue Aug 21 17:54:58 2018 +0200 Moved the custom state storage example to its own example folder commit 07cb6d3 Author: Roemer Hendrikx <[email protected]> Date: Tue Aug 21 17:53:58 2018 +0200 Rewritten the example to use promises instead of async, as async is not supported in node 6. Also added a create table statement in the save function. commit 076aa67 Author: Roemer Hendrikx <[email protected]> Date: Mon Aug 20 22:17:05 2018 +0200 added example for using a custom state storage
tj · Sep 25, 2018 · 067797c · 067797c
1 parent b62234a
commit 067797c
Showing 1 changed file with 66 additions and 0 deletions.
diff --git a/examples/custom-state-storage/custom-state-storage.js b/examples/custom-state-storage/custom-state-storage.js
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+'use strict'
+const migrate = require('migrate')
+const {Client} = require('pg')
+const pg = new Client()
+
+/**
+ * Stores and loads the executed migrations in the database. The table
+ * migrations is only one row and stores a JSON of the data that the
+ * migrate package uses to know which migrations have been executed.
+ */
+const customStateStorage = {
+  load: async function (fn) {
+    await pg.connect()
+
+    // Load the single row of migration data from the database
+    const {rows} = await pg.query('SELECT data FROM schema.migrations')
+
+    if (rows.length !== 1) {
+      console.log('Cannot read migrations from database. If this is the first time you run migrations, then this is normal.')
+      return fn(null, {})
+    }
+
+    // Call callback with new migration data object
+    await pg.end()
+    fn(null, rows[0].data)
+  },
+
+  save: async function (set, fn) {
+    await pg.connect()
+
+    // Check if table 'migrations' exists and if not, create it.
+    await pg.query('CREATE TABLE IF NOT EXISTS schema.migrations (id integer PRIMARY KEY, data jsonb NOT NULL)')
+
+    await pg.query(`
+      INSERT INTO schema.migrations (id, data)
+      VALUES (1, $1)
+      ON CONFLICT (id) DO UPDATE SET data = $1
+    `, [{
+      lastRun: set.lastRun,
+      migrations: set.migrations
+    }])
+
+    await pg.end()
+    fn()
+  }
+}
+
+/**
+ * Main application code
+ */
+migrate.load({
+  // Set class as custom stateStore
+  stateStore: customStateStorage
+}, function (err, set) {
+  if (err) {
+    throw err
+  }
+
+  set.up((err2) => {
+    if (err2) {
+      throw err2
+    }
+
+    console.log('Migrations successfully ran')
+  })
+})