Adds redis cache for distributed environments (#2691)

* Makes schemaCache clearning promise-based

* Adds redis cache adapter for distributed systems

* Adds redis service to travis

* allow pg to fail

src/Adapters/Cache/RedisCacheAdapter.js

@@ -0,0 +1,69 @@
+import redis from 'redis';
+import logger from '../../logger';
+
+function debug() {
+  logger.debug.apply(logger, ['RedisCacheAdapter', ...arguments]);
+}
+
+export class RedisCacheAdapter {
+
+  constructor(ctx) {
+    this.client = redis.createClient(ctx);
+    this.p = Promise.resolve();
+  }
+
+  get(key) {
+    debug('get', key);
+    this.p = this.p.then(() => {
+      return new Promise((resolve, _) => {
+        this.client.get(key, function(err, res) {
+          debug('-> get', key, res);
+          if(!res) {
+            return resolve(null);
+          }
+          resolve(JSON.parse(res));
+        });
+      });
+    });
+    return this.p;
+  }
+
+  put(key, value, ttl) {
+    value = JSON.stringify(value);
+    debug('put', key, value, ttl);
+    this.p = this.p.then(() => {
+      return new Promise((resolve, _) => {
+        this.client.set(key, value, function(err, res) {
+          resolve();
+        });
+      });
+    });
+    return this.p;
+  }
+
+  del(key) {
+    debug('del', key);
+    this.p = this.p.then(() => {
+      return new Promise((resolve, _) => {
+        this.client.del(key, function(err, res) {
+          resolve();
+        });
+      });
+    });
+    return this.p;
+  }
+
+  clear() {
+    debug('clear');
+    this.p = this.p.then(() => {
+      return new Promise((resolve, _) => {
+        this.client.flushall(function(err, res) {
+          resolve();
+        });
+      });
+    });
+    return this.p;
+  }
+}
+
+export default RedisCacheAdapter;

src/Controllers/SchemaController.js

@@ -323,15 +323,20 @@ export default class SchemaController {
   }
 
   reloadData(options = {clearCache: false}) {
+    let promise = Promise.resolve();
     if (options.clearCache) {
-      this._cache.clear();
+      promise = promise.then(() => {
+        return this._cache.clear();
+      });
     }
     if (this.reloadDataPromise && !options.clearCache) {
       return this.reloadDataPromise;
     }
     this.data = {};
     this.perms = {};
-    this.reloadDataPromise = this.getAllClasses(options)
+    this.reloadDataPromise = promise.then(() => {
+      return this.getAllClasses(options);
+    })
     .then(allSchemas => {
       allSchemas.forEach(schema => {
         this.data[schema.className] = injectDefaultSchema(schema).fields;
@@ -355,10 +360,13 @@ export default class SchemaController {
   }
 
   getAllClasses(options = {clearCache: false}) {
+    let promise = Promise.resolve();
     if (options.clearCache) {
-      this._cache.clear();
+      promise = this._cache.clear();
     }
-    return this._cache.getAllClasses().then((allClasses) => {
+    return promise.then(() => {
+       return this._cache.getAllClasses()
+    }).then((allClasses) => {
       if (allClasses && allClasses.length && !options.clearCache) {
         return Promise.resolve(allClasses);
       }
@@ -373,22 +381,25 @@ export default class SchemaController {
   }
 
   getOneSchema(className, allowVolatileClasses = false, options = {clearCache: false}) {
+    let promise = Promise.resolve();
     if (options.clearCache) {
-      this._cache.clear();
+      promise = this._cache.clear();
     }
-    if (allowVolatileClasses && volatileClasses.indexOf(className) > -1) {
-    	return Promise.resolve(this.data[className]);
-    }
-    return this._cache.getOneSchema(className).then((cached) => {
-      if (cached && !options.clearCache) {
-        return Promise.resolve(cached);
+    return promise.then(() => {
+      if (allowVolatileClasses && volatileClasses.indexOf(className) > -1) {
+        return Promise.resolve(this.data[className]);
       }
-      return this._dbAdapter.getClass(className)
-      .then(injectDefaultSchema)
-      .then((result) => {
-        return this._cache.setOneSchema(className, result).then(() => {
-          return result;
-        })
+      return this._cache.getOneSchema(className).then((cached) => {
+        if (cached && !options.clearCache) {
+          return Promise.resolve(cached);
+        }
+        return this._dbAdapter.getClass(className)
+        .then(injectDefaultSchema)
+        .then((result) => {
+          return this._cache.setOneSchema(className, result).then(() => {
+            return result;
+          })
+        });
       });
     });
   }
@@ -409,8 +420,9 @@ export default class SchemaController {
     return this._dbAdapter.createClass(className, convertSchemaToAdapterSchema({ fields, classLevelPermissions, className }))
     .then(convertAdapterSchemaToParseSchema)
     .then((res) => {
-      this._cache.clear();
-      return res;
+      return this._cache.clear().then(() => {
+         return Promise.resolve(res);
+      });
     })
     .catch(error => {
       if (error && error.code === Parse.Error.DUPLICATE_VALUE) {
@@ -508,6 +520,7 @@ export default class SchemaController {
       }
     })
     .catch(error => {
+      console.error(error);
       // The schema still doesn't validate. Give up
       throw new Parse.Error(Parse.Error.INVALID_JSON, 'schema class name does not revalidate');
     });

src/index.js

@@ -3,6 +3,7 @@ import S3Adapter            from 'parse-server-s3-adapter'
 import FileSystemAdapter    from 'parse-server-fs-adapter'
 import InMemoryCacheAdapter from './Adapters/Cache/InMemoryCacheAdapter'
 import NullCacheAdapter     from './Adapters/Cache/NullCacheAdapter'
+import RedisCacheAdapter    from './Adapters/Cache/RedisCacheAdapter'
 import TestUtils            from './TestUtils';
 import { useExternal }      from './deprecated';
 import { getLogger }        from './logger';
@@ -22,4 +23,4 @@ Object.defineProperty(module.exports, 'logger', {
 });
 
 export default ParseServer;
-export { S3Adapter, GCSAdapter, FileSystemAdapter, InMemoryCacheAdapter, NullCacheAdapter, TestUtils, _ParseServer as ParseServer };
+export { S3Adapter, GCSAdapter, FileSystemAdapter, InMemoryCacheAdapter, NullCacheAdapter, RedisCacheAdapter, TestUtils, _ParseServer as ParseServer };