Added adapter caching based on features

refs https://github.com/TryGhost/Toolbox/issues/384

- Adapter cache was not able to store multiple object instances derived from same Base class. This created a need to create boilerplate "shell" classes inheriting from the Base class, e.g.: ImageSizeCacheSyncInMemory etc.
- Having feature-based adapter instance caching in the adapter manager allows to simplify configuration and reuse the "base class" instead of creating artificial "shell" classes.
- For example with this change both image sizes and settings caches will create separate cache instances deriving from default "Memory" class. Less code, less configuration!

ghost/adapter-manager/lib/AdapterManager.js

@@ -84,8 +84,10 @@ module.exports = class AdapterManager {
             });
         }
 
-        if (adapterCache[adapterName]) {
-            return adapterCache[adapterName];
+        // @NOTE: example cache key value 'email:newsletters:custom-newsletter-adapter'
+        const adapterCacheKey = `${adapterName}:${adapterClassName}`;
+        if (adapterCache[adapterCacheKey]) {
+            return adapterCache[adapterCacheKey];
         }
 
         /** @type AdapterConstructor */
@@ -143,7 +145,7 @@ module.exports = class AdapterManager {
             }
         }
 
-        adapterCache[adapterName] = adapter;
+        adapterCache[adapterCacheKey] = adapter;
 
         return adapter;
     }

ghost/adapter-manager/test/AdapterManager.test.js

@@ -129,4 +129,48 @@ describe('AdapterManager', function () {
             should.fail(err, null, 'Should not have errored');
         }
     });
+
+    it('Creates separate class instances for adapters requested for different features', function () {
+        const pathsToAdapters = [
+            '/path'
+        ];
+
+        const loadAdapterFromPath = sinon.stub();
+
+        loadAdapterFromPath.withArgs('/path/mail/custom')
+            .returns(CustomMailAdapter);
+        loadAdapterFromPath.withArgs('/path/mail/default')
+            .returns(DefaultMailAdapter);
+
+        const adapterManager = new AdapterManager({
+            loadAdapterFromPath,
+            pathsToAdapters
+        });
+        adapterManager.registerAdapter('mail', BaseMailAdapter);
+
+        let mailNewslettersAdapter;
+        try {
+            mailNewslettersAdapter = adapterManager.getAdapter('mail:newsletters', 'custom');
+
+            should.ok(mailNewslettersAdapter instanceof BaseMailAdapter);
+            should.ok(mailNewslettersAdapter instanceof CustomMailAdapter);
+        } catch (err) {
+            should.fail(err, null, 'Should not have errored');
+        }
+
+        let mailNotificationsAdapter;
+        try {
+            mailNotificationsAdapter = adapterManager.getAdapter('mail:notifications', 'custom');
+
+            should.ok(mailNotificationsAdapter instanceof BaseMailAdapter);
+            should.ok(mailNotificationsAdapter instanceof CustomMailAdapter);
+        } catch (err) {
+            should.fail(err, null, 'Should not have errored');
+        }
+
+        should.notEqual(mailNewslettersAdapter, mailNotificationsAdapter);
+
+        const secondMailNewslettersAdapter = adapterManager.getAdapter('mail:newsletters', 'custom');
+        should.equal(mailNewslettersAdapter, secondMailNewslettersAdapter);
+    });
 });

ghost/core/core/server/adapters/cache/ImageSizesCacheSyncInMemory.js

@@ -1,7 +0,0 @@
-const Memory = require('./Memory');
-
-class ImageSizesCacheSyncInMemory extends Memory {
-
-}
-
-module.exports = ImageSizesCacheSyncInMemory;

ghost/core/core/server/adapters/cache/SettingsCacheSyncInMemory.js

@@ -1,7 +0,0 @@
-const Memory = require('./Memory');
-
-class SettingsCacheSyncInMemory extends Memory {
-
-}
-
-module.exports = SettingsCacheSyncInMemory;

ghost/core/core/server/services/adapter-manager/index.js

@@ -26,8 +26,8 @@ module.exports = {
     getAdapter(name) {
         const adapterServiceConfig = getAdapterServiceConfig(config);
 
-        const {adapterType, adapterName, adapterConfig} = resolveAdapterOptions(name, adapterServiceConfig);
+        const {adapterName, adapterConfig} = resolveAdapterOptions(name, adapterServiceConfig);
 
-        return adapterManager.getAdapter(adapterType, adapterName, adapterConfig);
+        return adapterManager.getAdapter(name, adapterName, adapterConfig);
     }
 };

ghost/core/core/shared/config/defaults.json

@@ -26,10 +26,8 @@
         },
         "cache": {
             "active": "Memory",
-            "settings": "SettingsCacheSyncInMemory",
-            "SettingsCacheSyncInMemory": {},
-            "imageSizes": "ImageSizesCacheSyncInMemory",
-            "ImageSizesCacheSyncInMemory": {}
+            "settings": {},
+            "imageSizes": {}
         }
     },
     "storage": {