From f53371e17b96b387c06ab1d3756dce60de46965e Mon Sep 17 00:00:00 2001
From: prathamesh0 <42446521+prathamesh0@users.noreply.github.com>
Date: Thu, 17 Nov 2022 00:32:08 -0600
Subject: [PATCH] Accomodate GQL requests caching in code generator (#237)

* Accomodate GQL requests caching in code generator

* Add GQL API request queuing
---
 packages/address-watcher/src/server.ts        |  4 +-
 packages/codegen/src/schema.ts                | 25 ++++++++-
 .../src/templates/config-template.handlebars  | 13 +++++
 .../src/templates/readme-template.handlebars  | 12 ++++
 .../templates/resolvers-template.handlebars   | 23 ++++++--
 .../src/templates/server-template.handlebars  |  4 +-
 packages/eden-watcher/src/server.ts           |  4 +-
 packages/erc20-watcher/src/server.ts          |  4 +-
 packages/erc721-watcher/src/server.ts         |  4 +-
 packages/graph-test-watcher/src/server.ts     |  4 +-
 packages/mobymask-watcher/src/server.ts       |  4 +-
 packages/util/package.json                    |  1 +
 packages/util/src/misc.ts                     | 11 +++-
 packages/util/src/server.ts                   | 56 ++-----------------
 packages/util/src/types/common/main.d.ts      |  6 ++
 packages/util/src/types/common/package.json   |  6 ++
 yarn.lock                                     | 25 ++++++++-
 17 files changed, 130 insertions(+), 76 deletions(-)
 create mode 100644 packages/util/src/types/common/main.d.ts
 create mode 100644 packages/util/src/types/common/package.json

diff --git a/packages/address-watcher/src/server.ts b/packages/address-watcher/src/server.ts
index a18a4bb5..a7e8b291 100644
--- a/packages/address-watcher/src/server.ts
+++ b/packages/address-watcher/src/server.ts
@@ -39,8 +39,6 @@ export const main = async (): Promise<any> => {
 
   assert(config.server, 'Missing server config');
 
-  const { host, port } = config.server;
-
   const { upstream, database: dbConfig, jobQueue: jobQueueConfig } = config;
 
   assert(dbConfig, 'Missing database config');
@@ -82,7 +80,7 @@ export const main = async (): Promise<any> => {
 
   // Create an Express app
   const app: Application = express();
-  const server = createAndStartServer(app, typeDefs, resolvers, { host, port });
+  const server = createAndStartServer(app, typeDefs, resolvers, config.server);
 
   return { app, server };
 };
diff --git a/packages/codegen/src/schema.ts b/packages/codegen/src/schema.ts
index 103477a0..004baea5 100644
--- a/packages/codegen/src/schema.ts
+++ b/packages/codegen/src/schema.ts
@@ -3,7 +3,7 @@
 //
 
 import assert from 'assert';
-import { GraphQLSchema, parse, printSchema, print } from 'graphql';
+import { GraphQLSchema, parse, printSchema, print, GraphQLDirective, GraphQLInt, GraphQLBoolean } from 'graphql';
 import { ObjectTypeComposer, ObjectTypeComposerDefinition, ObjectTypeComposerFieldConfigMapDefinition, SchemaComposer } from 'graphql-compose';
 import { Writable } from 'stream';
 import { utils } from 'ethers';
@@ -19,6 +19,7 @@ export class Schema {
     this._composer = new SchemaComposer();
     this._events = [];
 
+    this._addGQLCacheTypes();
     this._addBasicTypes();
   }
 
@@ -271,6 +272,28 @@ export class Schema {
     this._composer.addSchemaMustHaveType(typeComposer);
   }
 
+  _addGQLCacheTypes (): void {
+    // Create a enum type composer to add enum CacheControlScope in the schema composer.
+    const enumTypeComposer = this._composer.createEnumTC(`
+      enum CacheControlScope {
+        PUBLIC
+        PRIVATE
+      }
+    `);
+    this._composer.addSchemaMustHaveType(enumTypeComposer);
+
+    // Add the directive cacheControl in the schema composer.
+    this._composer.addDirective(new GraphQLDirective({
+      name: 'cacheControl',
+      locations: ['FIELD_DEFINITION', 'OBJECT', 'INTERFACE', 'UNION'],
+      args: {
+        maxAge: { type: GraphQLInt },
+        inheritMaxAge: { type: GraphQLBoolean },
+        scope: { type: enumTypeComposer.getType() }
+      }
+    }));
+  }
+
   /**
    * Adds types 'ResultEvent' and 'WatchedEvent' to the schema.
    */
diff --git a/packages/codegen/src/templates/config-template.handlebars b/packages/codegen/src/templates/config-template.handlebars
index 8c7f2b4d..63ea8ce3 100644
--- a/packages/codegen/src/templates/config-template.handlebars
+++ b/packages/codegen/src/templates/config-template.handlebars
@@ -30,6 +30,19 @@
   # Use -1 for skipping check on block range.
   maxEventsBlockRange = 1000
 
+  # GQL cache settings
+  [server.gqlCache]
+    enabled = true
+
+    # Max in-memory cache size (in bytes) (default 8 MB)
+    # maxCacheSize
+
+    # GQL cache-control max-age settings (in seconds)
+    maxAge = 15
+    {{#if (subgraphPath)}}
+    timeTravelMaxAge = 86400 # 1 day
+    {{/if}}
+
 [metrics]
   host = "127.0.0.1"
   port = 9000
diff --git a/packages/codegen/src/templates/readme-template.handlebars b/packages/codegen/src/templates/readme-template.handlebars
index 10228260..344c8d6e 100644
--- a/packages/codegen/src/templates/readme-template.handlebars
+++ b/packages/codegen/src/templates/readme-template.handlebars
@@ -59,6 +59,18 @@
 
   * Edit the custom hook function `createStateCheckpoint` (triggered just before default and CLI checkpoint) in [hooks.ts](./src/hooks.ts) to save the state in a `checkpoint` `State` using the `Indexer` object.
 
+### GQL Caching
+
+To enable GQL requests caching:
+
+* Update the `server.gqlCache` config with required settings.
+
+* In the GQL [schema file](./src/schema.gql), use the `cacheControl` directive to apply cache hints at schema level.
+
+  * Eg. Set `inheritMaxAge` to true for non-scalar fields of a type.
+
+* In the GQL [resolvers file](./src/resolvers.ts), uncomment the `setGQLCacheHints()` calls in resolvers for required queries.
+
 ## Run
 
 * Run the watcher:
diff --git a/packages/codegen/src/templates/resolvers-template.handlebars b/packages/codegen/src/templates/resolvers-template.handlebars
index 97d932b9..b9496fbd 100644
--- a/packages/codegen/src/templates/resolvers-template.handlebars
+++ b/packages/codegen/src/templates/resolvers-template.handlebars
@@ -8,7 +8,7 @@ import debug from 'debug';
 import Decimal from 'decimal.js';
 import { GraphQLResolveInfo, GraphQLScalarType } from 'graphql';
 
-import { ValueResult, BlockHeight, gqlTotalQueryCount, gqlQueryCount, jsonBigIntStringReplacer, getResultState } from '@cerc-io/util';
+import { ValueResult, BlockHeight, gqlTotalQueryCount, gqlQueryCount, jsonBigIntStringReplacer, getResultState, setGQLCacheHints } from '@cerc-io/util';
 
 import { Indexer } from './indexer';
 import { EventWatcher } from './events';
@@ -22,6 +22,8 @@ const log = debug('vulcanize:resolver');
 export const createResolvers = async (indexer: Indexer, eventWatcher: EventWatcher): Promise<any> => {
   assert(indexer);
 
+  const gqlCacheConfig = indexer.serverConfig.gqlCache;
+
   return {
     BigInt: new BigInt('bigInt'),
 
@@ -63,14 +65,22 @@ export const createResolvers = async (indexer: Indexer, eventWatcher: EventWatch
 
     Query: {
       {{#each queries}}
-      {{this.name}}: (_: any, { blockHash, contractAddress
-      {{~#each this.params}}, {{this.name~}} {{/each}} }: { blockHash: string, contractAddress: string
-      {{~#each this.params}}, {{this.name}}: {{this.type~}} {{/each}} }): Promise<ValueResult> => {
+      {{this.name}}: (
+        _: any,
+        { blockHash, contractAddress
+        {{~#each this.params}}, {{this.name~}} {{/each}} }: { blockHash: string, contractAddress: string
+        {{~#each this.params}}, {{this.name}}: {{this.type~}} {{/each}} },
+        __: any,
+        info: GraphQLResolveInfo
+      ): Promise<ValueResult> => {
         log('{{this.name}}', blockHash, contractAddress
         {{~#each this.params}}, {{this.name~}} {{/each}});
         gqlTotalQueryCount.inc(1);
         gqlQueryCount.labels('{{this.name}}').inc(1);
 
+        // Set cache-control hints
+        // setGQLCacheHints(info, {}, gqlCacheConfig);
+
         return indexer.{{this.name}}(blockHash, contractAddress
         {{~#each this.params}}, {{this.name~}} {{/each}});
       },
@@ -79,7 +89,7 @@ export const createResolvers = async (indexer: Indexer, eventWatcher: EventWatch
 
       {{~#each subgraphQueries}}
       {{this.queryName}}: async (
-         _: any,
+        _: any,
         { id, block = {} }: { id: string, block: BlockHeight },
         __: any,
         info: GraphQLResolveInfo
@@ -89,6 +99,9 @@ export const createResolvers = async (indexer: Indexer, eventWatcher: EventWatch
         gqlQueryCount.labels('{{this.queryName}}').inc(1);
         assert(info.fieldNodes[0].selectionSet);
 
+        // Set cache-control hints
+        // setGQLCacheHints(info, block, gqlCacheConfig);
+
         return indexer.getSubgraphEntity({{this.entityName}}, id, block, info.fieldNodes[0].selectionSet.selections);
       },
 
diff --git a/packages/codegen/src/templates/server-template.handlebars b/packages/codegen/src/templates/server-template.handlebars
index a4f9cf8f..ef635466 100644
--- a/packages/codegen/src/templates/server-template.handlebars
+++ b/packages/codegen/src/templates/server-template.handlebars
@@ -39,7 +39,7 @@ export const main = async (): Promise<any> => {
   const config: Config = await getConfig(argv.f);
   const { ethClient, ethProvider } = await initClients(config);
 
-  const { host, port, kind: watcherKind } = config.server;
+  const { kind: watcherKind } = config.server;
 
   const db = new Database(config.database);
   await db.init();
@@ -85,7 +85,7 @@ export const main = async (): Promise<any> => {
 
   // Create an Express app
   const app: Application = express();
-  const server = createAndStartServer(app, typeDefs, resolvers, { host, port });
+  const server = createAndStartServer(app, typeDefs, resolvers, config.server);
 
   startGQLMetricsServer(config);
 
diff --git a/packages/eden-watcher/src/server.ts b/packages/eden-watcher/src/server.ts
index d2f32dc1..0a2fa975 100644
--- a/packages/eden-watcher/src/server.ts
+++ b/packages/eden-watcher/src/server.ts
@@ -13,7 +13,7 @@ import { hideBin } from 'yargs/helpers';
 import debug from 'debug';
 import 'graphql-import-node';
 
-import { DEFAULT_CONFIG_PATH, getConfig, Config, JobQueue, KIND_ACTIVE, initClients, startGQLMetricsServer, createAndStartServerWithCache } from '@cerc-io/util';
+import { DEFAULT_CONFIG_PATH, getConfig, Config, JobQueue, KIND_ACTIVE, initClients, startGQLMetricsServer, createAndStartServer } from '@cerc-io/util';
 import { GraphWatcher, Database as GraphDatabase } from '@cerc-io/graph-node';
 
 import { createResolvers } from './resolvers';
@@ -79,7 +79,7 @@ export const main = async (): Promise<any> => {
 
   // Create an Express app
   const app: Application = express();
-  const server = createAndStartServerWithCache(app, typeDefs, resolvers, config.server);
+  const server = createAndStartServer(app, typeDefs, resolvers, config.server);
 
   startGQLMetricsServer(config);
 
diff --git a/packages/erc20-watcher/src/server.ts b/packages/erc20-watcher/src/server.ts
index 5c38c620..bb76b9fa 100644
--- a/packages/erc20-watcher/src/server.ts
+++ b/packages/erc20-watcher/src/server.ts
@@ -37,7 +37,7 @@ export const main = async (): Promise<any> => {
   const config: Config = await getConfig(argv.f);
   const { ethClient, ethProvider } = await initClients(config);
 
-  const { host, port, kind: watcherKind } = config.server;
+  const { kind: watcherKind } = config.server;
 
   const db = new Database(config.database);
   await db.init();
@@ -70,7 +70,7 @@ export const main = async (): Promise<any> => {
 
   // Create an Express app
   const app: Application = express();
-  const server = createAndStartServer(app, typeDefs, resolvers, { host, port });
+  const server = createAndStartServer(app, typeDefs, resolvers, config.server);
 
   return { app, server };
 };
diff --git a/packages/erc721-watcher/src/server.ts b/packages/erc721-watcher/src/server.ts
index df9c84e6..bc73c1ec 100644
--- a/packages/erc721-watcher/src/server.ts
+++ b/packages/erc721-watcher/src/server.ts
@@ -36,7 +36,7 @@ export const main = async (): Promise<any> => {
   const config: Config = await getConfig(argv.f);
   const { ethClient, ethProvider } = await initClients(config);
 
-  const { host, port, kind: watcherKind } = config.server;
+  const { kind: watcherKind } = config.server;
 
   const db = new Database(config.database);
   await db.init();
@@ -70,7 +70,7 @@ export const main = async (): Promise<any> => {
 
   // Create an Express app
   const app: Application = express();
-  const server = createAndStartServer(app, typeDefs, resolvers, { host, port });
+  const server = createAndStartServer(app, typeDefs, resolvers, config.server);
 
   return { app, server };
 };
diff --git a/packages/graph-test-watcher/src/server.ts b/packages/graph-test-watcher/src/server.ts
index b288a052..a2deaea0 100644
--- a/packages/graph-test-watcher/src/server.ts
+++ b/packages/graph-test-watcher/src/server.ts
@@ -37,7 +37,7 @@ export const main = async (): Promise<any> => {
   const config: Config = await getConfig(argv.f);
   const { ethClient, ethProvider } = await initClients(config);
 
-  const { host, port, kind: watcherKind } = config.server;
+  const { kind: watcherKind } = config.server;
 
   const db = new Database(config.database);
   await db.init();
@@ -79,7 +79,7 @@ export const main = async (): Promise<any> => {
 
   // Create an Express app
   const app: Application = express();
-  const server = createAndStartServer(app, typeDefs, resolvers, { host, port });
+  const server = createAndStartServer(app, typeDefs, resolvers, config.server);
 
   return { app, server };
 };
diff --git a/packages/mobymask-watcher/src/server.ts b/packages/mobymask-watcher/src/server.ts
index 2a8c29cd..30235e4f 100644
--- a/packages/mobymask-watcher/src/server.ts
+++ b/packages/mobymask-watcher/src/server.ts
@@ -36,7 +36,7 @@ export const main = async (): Promise<any> => {
   const config: Config = await getConfig(argv.f);
   const { ethClient, ethProvider } = await initClients(config);
 
-  const { host, port, kind: watcherKind } = config.server;
+  const { kind: watcherKind } = config.server;
 
   const db = new Database(config.database);
   await db.init();
@@ -70,7 +70,7 @@ export const main = async (): Promise<any> => {
 
   // Create an Express app
   const app: Application = express();
-  const server = createAndStartServer(app, typeDefs, resolvers, { host, port });
+  const server = createAndStartServer(app, typeDefs, resolvers, config.server);
 
   startGQLMetricsServer(config);
 
diff --git a/packages/util/package.json b/packages/util/package.json
index ee01cd93..6e5fa427 100644
--- a/packages/util/package.json
+++ b/packages/util/package.json
@@ -15,6 +15,7 @@
     "decimal.js": "^10.3.1",
     "ethers": "^5.4.4",
     "express": "^4.18.2",
+    "express-queue": "^0.0.13",
     "fs-extra": "^10.0.0",
     "graphql": "^15.5.0",
     "graphql-ws": "^5.11.2",
diff --git a/packages/util/src/misc.ts b/packages/util/src/misc.ts
index 1701e1ba..c7816a59 100644
--- a/packages/util/src/misc.ts
+++ b/packages/util/src/misc.ts
@@ -296,9 +296,14 @@ export const setGQLCacheHints = (info: GraphQLResolveInfo, block: BlockHeight, g
     return;
   }
 
-  assert(gqlCache.maxAge, 'Missing server gqlCache.maxAge');
-  assert(gqlCache.timeTravelMaxAge, 'Missing server gqlCache.timeTravelMaxAge');
+  let maxAge: number;
+  if (_.isEmpty(block)) {
+    assert(gqlCache.maxAge, 'Missing server gqlCache.maxAge');
+    maxAge = gqlCache.maxAge;
+  } else {
+    assert(gqlCache.timeTravelMaxAge, 'Missing server gqlCache.timeTravelMaxAge');
+    maxAge = gqlCache.timeTravelMaxAge;
+  }
 
-  const maxAge = _.isEmpty(block) ? gqlCache.maxAge : gqlCache.timeTravelMaxAge;
   info.cacheControl.setCacheHint({ maxAge });
 };
diff --git a/packages/util/src/server.ts b/packages/util/src/server.ts
index 1af8b9f0..efda091b 100644
--- a/packages/util/src/server.ts
+++ b/packages/util/src/server.ts
@@ -7,6 +7,7 @@ import { ApolloServerPluginDrainHttpServer } from 'apollo-server-core';
 import debug from 'debug';
 import responseCachePlugin from 'apollo-server-plugin-response-cache';
 import { InMemoryLRUCache } from '@apollo/utils.keyvaluecache';
+import queue from 'express-queue';
 
 import { TypeSource } from '@graphql-tools/utils';
 import { makeExecutableSchema } from '@graphql-tools/schema';
@@ -16,15 +17,15 @@ import { ServerConfig } from './config';
 
 const log = debug('vulcanize:server');
 
-export const createAndStartServerWithCache = async (
+export const createAndStartServer = async (
   app: Application,
   typeDefs: TypeSource,
   resolvers: any,
   serverConfig: ServerConfig
 ): Promise<ApolloServer> => {
-  const host = serverConfig.host;
-  const port = serverConfig.port;
-  const gqlCacheConfig = serverConfig.gqlCache;
+  const { host, port, gqlCache: gqlCacheConfig, maxSimultaneousRequests, maxRequestQueueLimit } = serverConfig;
+
+  app.use(queue({ activeLimit: maxSimultaneousRequests || 1, queuedLimit: maxRequestQueueLimit || -1 }));
 
   // Create HTTP server
   const httpServer = createServer(app);
@@ -76,50 +77,3 @@ export const createAndStartServerWithCache = async (
 
   return server;
 };
-
-export const createAndStartServer = async (
-  app: Application,
-  typeDefs: TypeSource,
-  resolvers: any,
-  endPoint: { host: string, port: number }
-): Promise<ApolloServer> => {
-  // Create HTTP server
-  const httpServer = createServer(app);
-
-  // Create the schema
-  const schema = makeExecutableSchema({ typeDefs, resolvers });
-
-  // Create our WebSocket server using the HTTP server we just set up.
-  const wsServer = new WebSocketServer({
-    server: httpServer,
-    path: '/graphql'
-  });
-  const serverCleanup = useServer({ schema }, wsServer);
-
-  const server = new ApolloServer({
-    schema,
-    csrfPrevention: true,
-    plugins: [
-      // Proper shutdown for the HTTP server
-      ApolloServerPluginDrainHttpServer({ httpServer }),
-      // Proper shutdown for the WebSocket server
-      {
-        async serverWillStart () {
-          return {
-            async drainServer () {
-              await serverCleanup.dispose();
-            }
-          };
-        }
-      }
-    ]
-  });
-  await server.start();
-  server.applyMiddleware({ app });
-
-  httpServer.listen(endPoint.port, endPoint.host, () => {
-    log(`Server is listening on ${endPoint.host}:${endPoint.port}${server.graphqlPath}`);
-  });
-
-  return server;
-};
diff --git a/packages/util/src/types/common/main.d.ts b/packages/util/src/types/common/main.d.ts
new file mode 100644
index 00000000..950c45b5
--- /dev/null
+++ b/packages/util/src/types/common/main.d.ts
@@ -0,0 +1,6 @@
+//
+// Copyright 2022 Vulcanize, Inc.
+//
+
+// https://medium.com/@steveruiz/using-a-javascript-library-without-type-declarations-in-a-typescript-project-3643490015f3
+declare module 'express-queue';
diff --git a/packages/util/src/types/common/package.json b/packages/util/src/types/common/package.json
new file mode 100644
index 00000000..5861d0f0
--- /dev/null
+++ b/packages/util/src/types/common/package.json
@@ -0,0 +1,6 @@
+{
+  "name": "common",
+  "version": "0.1.0",
+  "license": "AGPL-3.0",
+  "typings": "main.d.ts"
+}
diff --git a/yarn.lock b/yarn.lock
index 11c960b4..cca3f393 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -5660,7 +5660,7 @@ debug@4, debug@4.3.1, debug@^4.0.1, debug@^4.1.0, debug@^4.1.1:
   dependencies:
     ms "2.1.2"
 
-debug@4.3.4, debug@^4.3.3:
+debug@4.3.4, debug@^4.3.3, debug@^4.3.4:
   version "4.3.4"
   resolved "https://registry.yarnpkg.com/debug/-/debug-4.3.4.tgz#1319f6579357f2338d3337d2cdd4914bb5dcc865"
   integrity sha512-PRWFHuSU3eDtQJPvnNY7Jcket1j0t5OuOsFzPPzsekD52Zl8qUfFIPEiswXqIvHWGVHOgX+7G/vCNNhehwxfkQ==
@@ -7073,6 +7073,22 @@ expand-brackets@^2.1.4:
     snapdragon "^0.8.1"
     to-regex "^3.0.1"
 
+express-end@0.0.8:
+  version "0.0.8"
+  resolved "https://registry.yarnpkg.com/express-end/-/express-end-0.0.8.tgz#0c8fd95428932158f2b4cf91f4045346bf2c5323"
+  integrity sha512-PPntzICAq006LBpXKBVJtmRUiCRqTMZ+OB8L2RFXgx+OmkMWU66IL4DTEPF/DOcxmsuC7Y0NdbT2R71lb+pBpg==
+  dependencies:
+    debug "^2.2.0"
+
+express-queue@^0.0.13:
+  version "0.0.13"
+  resolved "https://registry.yarnpkg.com/express-queue/-/express-queue-0.0.13.tgz#e9800d67749d4dfab7c34223f00595af933ce5df"
+  integrity sha512-C4OEDasGDqpXLrZICSUxbY47p5c0bKqf/3/3hwauSCmI+jVVxKBWU2w39BuKLP6nF65z87uDFBbJMPAn2ZrG3g==
+  dependencies:
+    debug "^4.3.4"
+    express-end "0.0.8"
+    mini-queue "0.0.14"
+
 express@^4.14.0:
   version "4.17.1"
   resolved "https://registry.yarnpkg.com/express/-/express-4.17.1.tgz#4491fc38605cf51f8629d39c2b5d026f98a4c134"
@@ -10371,6 +10387,13 @@ min-indent@^1.0.0:
   resolved "https://registry.yarnpkg.com/min-indent/-/min-indent-1.0.1.tgz#a63f681673b30571fbe8bc25686ae746eefa9869"
   integrity sha512-I9jwMn07Sy/IwOj3zVkVik2JTvgpaykDZEigL6Rx6N9LbMywwUSMtxET+7lVoDLLd3O3IXwJwvuuns8UB/HeAg==
 
+mini-queue@0.0.14:
+  version "0.0.14"
+  resolved "https://registry.yarnpkg.com/mini-queue/-/mini-queue-0.0.14.tgz#83d2f3f908e3cac5390bd986d1e6fbbfa0d95b93"
+  integrity sha512-DNh9Wn8U1jrmn1yVfpviwClyER/Y4ltgGbG+LF/KIdKJ8BEo2Q9jDDPG7tEhz6F/DTZ/ohv5D7AAXFVSFyP05Q==
+  dependencies:
+    debug "^3.1.0"
+
 minimalistic-assert@^1.0.0, minimalistic-assert@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/minimalistic-assert/-/minimalistic-assert-1.0.1.tgz#2e194de044626d4a10e7f7fbc00ce73e83e4d5c7"