Add caching using Redis

Author: J J Walwyn

.env.example

@@ -10,6 +10,9 @@ SERVER_PORT=3000
 # Mongo connection string. This is the default string used with the database spun up in docker-compose.yml
 MONGO_URL=mongodb://admin:password@localhost:27017/location-events-api?authSource=admin
 
+# OPTIONAL: A Redis URL for caching
+REDIS_URL=redis://localhost:6379
+
 # Google Maps API key for address lookup
 # See: https://developers.google.com/maps/documentation/javascript/get-api-key to set this up
 GOOGLE_MAPS_API_KEY=

docker-compose.yml

@@ -19,3 +19,10 @@ services:
       ME_CONFIG_MONGODB_SERVER: mongo
       ME_CONFIG_MONGODB_ADMINUSERNAME: admin
       ME_CONFIG_MONGODB_ADMINPASSWORD: password
+
+  redis:
+    image: 'redis'
+    restart: 'always'
+    ports:
+      - '6379:6379'
+

package-lock.json

@@ -51,15 +51,18 @@
     "typescript": "^4.8.2"
   },
   "dependencies": {
+    "@apollo/utils.keyvadapter": "^1.1.2",
     "@googlemaps/google-maps-services-js": "^3.3.16",
     "@graphql-tools/merge": "^8.3.6",
+    "@keyv/redis": "^2.5.1",
     "apollo-datasource-mongodb": "^0.5.4",
     "apollo-server-core": "^3.10.2",
     "apollo-server-fastify": "^3.10.2",
     "apollo-server-plugin-base": "^3.6.2",
     "dotenv": "^16.0.2",
     "fastify": "^3.29.2",
     "graphql": "^16.6.0",
+    "keyv": "^4.5.0",
     "mongoose": "^6.6.1",
     "pino": "^8.5.0"
   }

package.json

@@ -1,11 +1,15 @@
+import { KeyvAdapter } from '@apollo/utils.keyvadapter';
 import {
   ApolloServerPluginDrainHttpServer,
   ApolloServerPluginLandingPageLocalDefault,
+  Config,
 } from 'apollo-server-core';
 import { ApolloServer } from 'apollo-server-fastify';
 import { ApolloServerPlugin } from 'apollo-server-plugin-base';
 import { FastifyInstance } from 'fastify';
+import Keyv from 'keyv';
 
+import { REDIS_URL } from './consts';
 import { dataSources, resolvers, typeDefs } from './graphql';
 
 /**
@@ -16,7 +20,9 @@ import { dataSources, resolvers, typeDefs } from './graphql';
  *
  * @returns apollo server plugin
  */
-const fastifyAppClosePlugin = (fastify: FastifyInstance): ApolloServerPlugin => ({
+const fastifyAppClosePlugin = (
+  fastify: FastifyInstance,
+): ApolloServerPlugin => ({
   /* eslint-disable @typescript-eslint/require-await */
   serverWillStart: async () => ({
     async drainServer() {
@@ -39,14 +45,23 @@ export default async (fastify: FastifyInstance): Promise<ApolloServer> => {
     ApolloServerPluginLandingPageLocalDefault({ embed: true }),
   ];
 
-  const apollo = new ApolloServer({
+  const config: Config = {
     dataSources,
     typeDefs,
     resolvers,
     csrfPrevention: true,
     cache: 'bounded',
     plugins,
-  });
+  };
+
+  if (REDIS_URL) {
+    // Add Redis Cache if URL set
+    config.cache = new KeyvAdapter(new Keyv(REDIS_URL));
+  } else {
+    config.cache = 'bounded';
+  }
+
+  const apollo = new ApolloServer(config);
 
   await apollo.start();
 

src/apollo.ts

@@ -15,5 +15,8 @@ export const SERVER_HOST = process.env.SERVER_HOST || '127.0.0.1';
 // Mongo DB Connection
 export const MONGO_URL = process.env.MONGO_URL;
 
+// REDIS Connection
+export const REDIS_URL = process.env.REDIS_URL;
+
 // Google Maps API key
 export const GOOGLE_MAPS_API_KEY = process.env.GOOGLE_MAPS_API_KEY;

src/consts.ts

@@ -35,6 +35,11 @@ export type AddressInput = {
   region?: InputMaybe<Scalars['String']>;
 };
 
+export enum CacheControlScope {
+  Private = 'PRIVATE',
+  Public = 'PUBLIC'
+}
+
 export type DeleteResult = {
   __typename?: 'DeleteResult';
   _id: Scalars['ID'];
@@ -396,6 +401,7 @@ export type ResolversTypes = {
   Address: ResolverTypeWrapper<Address>;
   AddressInput: AddressInput;
   Boolean: ResolverTypeWrapper<Scalars['Boolean']>;
+  CacheControlScope: CacheControlScope;
   Date: ResolverTypeWrapper<Scalars['Date']>;
   DeleteResult: ResolverTypeWrapper<DeleteResult>;
   Event: ResolverTypeWrapper<Event>;
@@ -464,6 +470,14 @@ export type ResolversParentTypes = {
   UpdateResult: UpdateResult;
 };
 
+export type CacheControlDirectiveArgs = {
+  inheritMaxAge?: Maybe<Scalars['Boolean']>;
+  maxAge?: Maybe<Scalars['Int']>;
+  scope?: Maybe<CacheControlScope>;
+};
+
+export type CacheControlDirectiveResolver<Result, Parent, ContextType = MyContext, Args = CacheControlDirectiveArgs> = DirectiveResolverFn<Result, Parent, ContextType, Args>;
+
 export type AddressResolvers<ContextType = MyContext, ParentType extends ResolversParentTypes['Address'] = ResolversParentTypes['Address']> = {
   city?: Resolver<ResolversTypes['String'], ParentType, ContextType>;
   country?: Resolver<ResolversTypes['String'], ParentType, ContextType>;
@@ -614,3 +628,6 @@ export type Resolvers<ContextType = MyContext> = {
   UpdateResult?: UpdateResultResolvers<ContextType>;
 };
 
+export type DirectiveResolvers<ContextType = MyContext> = {
+  cacheControl?: CacheControlDirectiveResolver<any, any, ContextType>;
+};

src/generated/graphql.ts

@@ -1,5 +1,5 @@
 /* eslint-disable max-classes-per-file */
-import { MongoDataSource } from 'apollo-datasource-mongodb';
+import { MongoDataSource, Options } from 'apollo-datasource-mongodb';
 
 import type { Event, Location, Organisation } from '../generated/graphql';
 import * as Models from '../db/models';
@@ -9,8 +9,8 @@ export class MyDataSource<T> extends MongoDataSource<T> {
   /**
    * This allows us to grab ObjectIds from GraphQL types
    */
-  public findOneById(id: unknown) {
-    return super.findOneById(id as string);
+  public findOneById(id: unknown, opts?: Options) {
+    return super.findOneById(id as string, opts);
   }
 }
 

src/graphql/dataSources.ts

@@ -5,6 +5,12 @@ import orderBy from './order';
 import * as Models from '../../db/models';
 import * as Types from '../../generated/graphql';
 
+// TTL for collection and document caches.
+// Documents get removed from the cache automatically on update
+// TODO: Add smart cache clearing and warming
+const TTL_COLLECTIONS = 60; // A minute
+const TTL_DOCUMENTS = 1209600; // 2 weeks
+
 /**
  * Possible arguments for collection filtering
  */
@@ -34,21 +40,24 @@ const getCollection =
       // Find documents from data source
       const dataSource =
         ctx.dataSources[dataSourceName as keyof typeof ctx.dataSources];
-      let results = (await dataSource.findByFields(
-        args.filter || {},
-      )) as unknown[] as T[];
+      let results = (await dataSource.findByFields(args.filter || {}, {
+        ttl: TTL_COLLECTIONS,
+      })) as unknown[] as T[];
 
       // Order results by a field (or subfield)
       if (args.order?.by) {
         const dir = args.order.dir || Types.QueryOrderDir.Desc;
 
         if ((args.order.by as string) in orderBy) {
           // Check if we have a specific type of ordering function for this method
-          const sortFunc = orderBy[args.order.by as string as keyof typeof orderBy];
+          const sortFunc =
+          orderBy[args.order.by as string as keyof typeof orderBy];
           results = results.sort(sortFunc<T>(dir));
         } else {
           // Otherwise we'll use the default sort method
-          results = results.sort(orderBy.default<T>(dir, args.order.by as string));
+          results = results.sort(
+            orderBy.default<T>(dir, args.order.by as string),
+          );
         }
       }
 
@@ -74,6 +83,7 @@ const getById =
     (_: never, args: { id: string }, ctx: MyContext) =>
       ctx.dataSources[dataSourceName as keyof typeof ctx.dataSources].findOneById(
         args.id,
+        { ttl: TTL_DOCUMENTS },
       );
 
 export default {
@@ -100,7 +110,9 @@ export default {
   Organisation: {
     // Find one to one
     location: (event: Types.Event, _: never, ctx: MyContext) =>
-      ctx.dataSources.locations.findOneById(event.location),
+      ctx.dataSources.locations.findOneById(event.location, {
+        ttl: TTL_DOCUMENTS,
+      }),
     // Find one to many
     findEvents: (
       organisation: Types.Organisation,
@@ -115,9 +127,13 @@ export default {
   },
   Event: {
     organisation: (event: Types.Event, _: never, ctx: MyContext) =>
-      ctx.dataSources.organisations.findOneById(event.organisation),
+      ctx.dataSources.organisations.findOneById(event.organisation, {
+        ttl: TTL_DOCUMENTS,
+      }),
     location: (event: Types.Event, _: never, ctx: MyContext) =>
-      ctx.dataSources.locations.findOneById(event.location),
+      ctx.dataSources.locations.findOneById(event.location, {
+        ttl: TTL_DOCUMENTS,
+      }),
   },
   Location: {
     // Find one to many