From d76144e4201e28a32d5c9f242fc31b165f10323d Mon Sep 17 00:00:00 2001
From: temz <artem.rusanov.02@gmail.com>
Date: Thu, 29 Jun 2023 23:31:18 +0700
Subject: [PATCH] feat: refactor gateway to nestjs

---
 apps/gateway/src/app/app.module.ts | 38 +++++++++++++++
 apps/gateway/src/main.ts           | 77 ++++++++++++++----------------
 2 files changed, 74 insertions(+), 41 deletions(-)
 create mode 100644 apps/gateway/src/app/app.module.ts

diff --git a/apps/gateway/src/app/app.module.ts b/apps/gateway/src/app/app.module.ts
new file mode 100644
index 0000000..58ef115
--- /dev/null
+++ b/apps/gateway/src/app/app.module.ts
@@ -0,0 +1,38 @@
+import { Module } from '@nestjs/common'
+import { EventloopFrozenDetectorModule } from 'core/eventloop-frozen-detector'
+import { GraphQLModule } from '@nestjs/graphql'
+import * as env from 'env-var'
+import { ApolloServerPluginLandingPageLocalDefault } from '@apollo/server/plugin/landingPage/default'
+import { ApolloGatewayDriver, ApolloGatewayDriverConfig } from '@nestjs/apollo'
+import { IntrospectAndCompose } from '@apollo/gateway'
+
+@Module({
+    imports: [
+        EventloopFrozenDetectorModule.forRoot({
+            delay: 3000,
+        }),
+        GraphQLModule.forRoot<ApolloGatewayDriverConfig>({
+            driver: ApolloGatewayDriver,
+            server: {
+                playground: false,
+                plugins: [ApolloServerPluginLandingPageLocalDefault()],
+            },
+            gateway: {
+                supergraphSdl: new IntrospectAndCompose({
+                    subgraphs: env
+                        .get('GATEWAY_SUBGRAPHS')
+                        .required()
+                        .asJsonArray() as {
+                        name: string
+                        url: string
+                    }[],
+                    subgraphHealthCheck: true,
+                    pollIntervalInMs: 10000,
+                }),
+            },
+        }),
+    ],
+    controllers: [],
+    providers: [],
+})
+export class AppModule {}
diff --git a/apps/gateway/src/main.ts b/apps/gateway/src/main.ts
index 7ff5695..fad1cff 100644
--- a/apps/gateway/src/main.ts
+++ b/apps/gateway/src/main.ts
@@ -1,23 +1,23 @@
-import { Logger } from '@nestjs/common'
-import { ApolloServer } from '@apollo/server'
-import { startStandaloneServer } from '@apollo/server/standalone'
-import { ApolloGateway, IntrospectAndCompose } from '@apollo/gateway'
+import env from 'env-var'
+import { INestApplication, Logger } from '@nestjs/common'
+import { NestFactory } from '@nestjs/core'
+import { AppModule } from './app/app.module'
+import { SpelunkerModule } from 'nestjs-spelunker'
+
 const logger = new Logger('Application')
 
-//do something when app is closing
-process.on('exit', exitHandler.bind(null, { cleanup: true }))
+async function bootstrap() {
+    const app = await NestFactory.create(AppModule)
 
-//catches ctrl+c event
-process.on('SIGINT', exitHandler.bind(null, { exit: true }))
+    // const diGraph = buildDIGraph(app)
 
-// catches "kill pid" (for example: nodemon restart)
-process.on('SIGUSR1', exitHandler.bind(null, { exit: true }))
-process.on('SIGUSR2', exitHandler.bind(null, { exit: true }))
-
-//catches uncaught exceptions
-process.on('uncaughtException', exitHandler.bind(null, { exit: true }))
+    const port = env.get('GATEWAY_PORT').default(3052).asPortNumber()
 
-import env from 'env-var'
+    await app.listen(port, () => {
+        logger.log(`🚀 Gateway is running on: http://localhost:${port}/graphql`)
+        // logger.debug(`DI Graph tree\n${diGraph}`)
+    })
+}
 
 //do something when app is closing
 process.on('exit', exitHandler.bind(null, { cleanup: true }))
@@ -32,32 +32,6 @@ process.on('SIGUSR2', exitHandler.bind(null, { exit: true }))
 //catches uncaught exceptions
 process.on('uncaughtException', exitHandler.bind(null, { exit: true }))
 
-async function bootstrap() {
-    const port = env.get('GATEWAY_PORT').default(3052).asPortNumber()
-    const subgraphs = env.get('GATEWAY_SUBGRAPHS').required().asJsonArray() as {
-        name: string
-        url: string
-    }[]
-
-    const server = new ApolloServer({
-        gateway: new ApolloGateway({
-            supergraphSdl: new IntrospectAndCompose({
-                subgraphs,
-                subgraphHealthCheck: true,
-                pollIntervalInMs: 10000,
-            }),
-        }),
-    })
-
-    const { url } = await startStandaloneServer(server, {
-        listen: {
-            port,
-        },
-    })
-
-    logger.log(`Gateway ready at ${url}`)
-}
-
 try {
     bootstrap().catch((err) => {
         logger.error(err, err.stack)
@@ -81,3 +55,24 @@ function exitHandler(options, exitCode) {
         process.exit()
     }
 }
+
+// Copy output to mermaid.live
+function buildDIGraph(app: INestApplication) {
+    const tree = SpelunkerModule.explore(app)
+    const root = SpelunkerModule.graph(tree)
+    const edges = SpelunkerModule.findGraphEdges(root)
+
+    const mermaidEdges = edges
+        .filter(
+            ({ from, to }) =>
+                !(
+                    from.module.name === 'ConfigHostModule' ||
+                    from.module.name === 'LoggerModule' ||
+                    to.module.name === 'ConfigHostModule' ||
+                    to.module.name === 'LoggerModule'
+                ),
+        )
+        .map(({ from, to }) => `${from.module.name}-->${to.module.name}`)
+
+    return `graph TD\n\t${mermaidEdges.join('\n\t')}`
+}