✨ Handle own core config migration logic

packages/core/src/config.js

@@ -67,3 +67,28 @@ export const schema = {
     }
   }
 };
+
+// Migration function
+export function migration(input, set) {
+  /* eslint-disable curly */
+  if (input.version < 2) {
+    // previous snapshot options map 1:1
+    if (input.snapshot != null)
+      set('snapshot', input.snapshot);
+    // request-headers option moved
+    if (input.agent?.assetDiscovery?.requestHeaders != null)
+      set('snapshot.requestHeaders', input.agent.assetDiscovery.requestHeaders);
+    // allowed-hostnames moved
+    if (input.agent?.assetDiscovery?.allowedHostnames != null)
+      set('discovery.allowedHostnames', input.agent.assetDiscovery.allowedHostnames);
+    // network-idle-timeout moved
+    if (input.agent?.assetDiscovery?.networkIdleTimeout != null)
+      set('discovery.networkIdleTimeout', input.agent.assetDiscovery.networkIdleTimeout);
+    // page pooling was rewritten to be a concurrent task queue
+    if (input.agent?.assetDiscovery?.pagePoolSizeMax != null)
+      set('discovery.concurrency', input.agent.assetDiscovery.pagePoolSizeMax);
+    // cache-responses was renamed to match the CLI flag
+    if (input.agent?.assetDiscovery?.cacheResponses != null)
+      set('discovery.disableCache', !input.agent.assetDiscovery.cacheResponses);
+  }
+}

packages/core/src/index.js

@@ -1 +1,9 @@
+// Register core config options
+const { default: PercyConfig } = require('@percy/config');
+const CoreConfig = require('./config');
+
+PercyConfig.addSchema(CoreConfig.schema);
+PercyConfig.addMigration(CoreConfig.migration);
+
+// Export the Percy class with commonjs compatibility
 module.exports = require('./percy').default;

packages/core/src/percy.js

@@ -2,7 +2,6 @@ import { promises as fs } from 'fs';
 import PercyClient from '@percy/client';
 import PercyConfig from '@percy/config';
 import logger from '@percy/logger';
-import { schema } from './config';
 import Queue from './queue';
 import Discoverer from './discovery/discoverer';
 import createPercyServer from './server';
@@ -12,9 +11,6 @@ import injectPercyCSS from './utils/percy-css';
 import { createRootResource, createLogResource } from './utils/resources';
 import { normalizeURL } from './utils/url';
 
-// Register core config options
-PercyConfig.addSchema(schema);
-
 // A Percy instance will create a new build when started, handle snapshot
 // creation, asset discovery, and resource uploads, and will finalize the build
 // when stopped. Snapshots are processed concurrently and the build is not

packages/core/test/unit/config.test.js

@@ -0,0 +1,63 @@
+import expect from 'expect';
+import { migration } from '../../src/config';
+
+describe('Unit / Config', () => {
+  let migrate;
+  let set = (key, value) => (migrate[key] = value);
+
+  beforeEach(() => {
+    migrate = {};
+  });
+
+  it('migrates v1 config', () => {
+    migration({
+      version: 1,
+      snapshot: {
+        widths: [1000]
+      },
+      agent: {
+        assetDiscovery: {
+          requestHeaders: { foo: 'bar' },
+          allowedHostnames: ['allowed'],
+          networkIdleTimeout: 150,
+          pagePoolSizeMin: 1,
+          pagePoolSizeMax: 5,
+          cacheResponses: false
+        }
+      }
+    }, set);
+
+    expect(migrate).toEqual({
+      snapshot: { widths: [1000] },
+      'snapshot.requestHeaders': { foo: 'bar' },
+      'discovery.allowedHostnames': ['allowed'],
+      'discovery.networkIdleTimeout': 150,
+      'discovery.concurrency': 5,
+      'discovery.disableCache': true
+    });
+  });
+
+  it('only migrates own config options', () => {
+    migration({
+      version: 1,
+      otherOptions: {
+        baseUrl: 'base-url',
+        snapshotFiles: '*.html',
+        ignoreFiles: '*.htm'
+      }
+    }, set);
+
+    expect(migrate).toEqual({});
+  });
+
+  it('does not migrate when not needed', () => {
+    migration({
+      version: 2,
+      discovery: {
+        allowedHostnames: ['allowed']
+      }
+    }, set);
+
+    expect(migrate).toEqual({});
+  });
+});