feat(server): add amplify appsync simulator as an alternative development server

packages/server/src/amplify-appsync-simulator.ts

@@ -0,0 +1,157 @@
+import type { AmplifyAppSyncAPIConfig, AmplifyAppSyncSimulatorConfig, AppSyncMockFile, AppSyncSimulatorDataSourceConfig, AppSyncSimulatorPipelineResolverConfig, AppSyncSimulatorUnitResolverConfig } from 'amplify-appsync-simulator'
+
+import {
+    AmplifyAppSyncSimulator,
+    AmplifyAppSyncSimulatorAuthenticationType,
+    RESOLVER_KIND,
+} from 'amplify-appsync-simulator'
+import { cli as cleye } from 'cleye'
+import { readVTL } from '../vtl/readVTL'
+
+// npx vite-node ./server.ts --watch --
+//      --handler handler.ts
+//      --schema prisma/generated/prisma-appsync/schema.gql
+//      --resolvers prisma/generated/prisma-appsync/resolvers.yaml
+//      --httpPort 4000
+//      --wsPort 4001
+//      --watchers '[{"watch":["**/*.prisma","*.prisma"],"exec":"npx prisma generate && touch ./server.ts"}]'
+//      --headers '{"x-fingerprint":"123456"}'
+export const argv_appsync_simulator = cleye({
+    name: 'prisma-appsync-server',
+    flags: {
+        handler: {
+            type: String,
+            description: 'Lambda handler',
+            default: 'handler.ts',
+        },
+        schema: {
+            type: String,
+            description: 'GraphQL schema',
+            default: 'generated/prisma-appsync/schema.gql',
+        },
+        resolvers: {
+            type: String,
+            description: 'Resolvers',
+            default: 'generated/prisma-appsync/resolvers.yaml',
+        },
+        httpPort: {
+            type: Number,
+            description: 'Server port',
+            default: 4000,
+        },
+        wsPort: {
+            type: Number,
+            description: 'Ws port',
+            default: 4001,
+        },
+    },
+})
+
+export interface PrismaAppsyncResolverConfig {
+    typeName: string
+    fieldName: string
+    dataSource: string
+    requestMappingTemplate: string
+    responseMappingTemplate: string
+}
+
+class AppSyncSimulator {
+    mappingTemplates: AppSyncMockFile[]
+
+    private defaultMappingTemplates: AppSyncMockFile[] = [
+        {
+            path: 'lambdaRequestMappingTemplate.vtl',
+            content: readVTL('lambdaRequestMappingTemplate.vtl'),
+        },
+        {
+            path: 'lambdaResponseMappingTemplate.vtl',
+            content: readVTL('lambdaResponseMappingTemplate.vtl'),
+        },
+    ]
+
+    private appsyncConfig: AmplifyAppSyncAPIConfig = {
+        defaultAuthenticationType: {
+            authenticationType: AmplifyAppSyncSimulatorAuthenticationType.API_KEY,
+        },
+        apiKey: 'da2-fakeApiId123456', // this is the default for graphiql
+        name: 'api-local',
+        additionalAuthenticationProviders: [],
+    }
+
+    constructor(
+        private httpPort: number,
+        private lambdaHandler: any,
+        private schema: string,
+        private resolvers: PrismaAppsyncResolverConfig[],
+        appsyncConfig?: AmplifyAppSyncAPIConfig,
+        additionalMappingTemplates: AppSyncMockFile[] = [],
+        removeDefaultMappingTemplates = false,
+        private additionalDatasources: AppSyncSimulatorDataSourceConfig[] = [],
+        private wsPort?: number,
+    ) {
+        if (!process?.env?.DATABASE_URL)
+            throw new Error('Missing "DATABASE_URL" env var.')
+
+        if (!this.lambdaHandler?.main)
+            throw new Error('Handler has no exported function "main".')
+
+        if (appsyncConfig)
+            this.appsyncConfig = appsyncConfig
+
+        this.mappingTemplates = removeDefaultMappingTemplates ? additionalMappingTemplates : this.defaultMappingTemplates.concat(additionalMappingTemplates)
+    }
+
+    private static createPrismaAppSyncResolvers(resolvers: PrismaAppsyncResolverConfig[]): (AppSyncSimulatorPipelineResolverConfig | AppSyncSimulatorUnitResolverConfig)[] {
+        return resolvers.map((resolver: PrismaAppsyncResolverConfig) => ({
+            ...resolver,
+            dataSourceName: resolver.dataSource,
+            kind: RESOLVER_KIND.UNIT,
+            requestMappingTemplateLocation: 'lambdaRequestMappingTemplate.vtl',
+            responseMappingTemplateLocation: 'lambdaResponseMappingTemplate.vtl',
+        }))
+    }
+
+    async start() {
+        const simulatorConfig: AmplifyAppSyncSimulatorConfig = {
+            appSync: this.appsyncConfig,
+            schema: { content: this.schema },
+            mappingTemplates: this.mappingTemplates,
+            dataSources: [
+                {
+                    type: 'AWS_LAMBDA',
+                    name: 'prisma-appsync',
+                    invoke: this.lambdaHandler.main,
+                },
+                ...this.additionalDatasources,
+
+            ],
+            resolvers: AppSyncSimulator.createPrismaAppSyncResolvers(this.resolvers),
+        }
+
+        const amplifySimulator = new AmplifyAppSyncSimulator({
+            port: this.httpPort,
+            wsPort: this.wsPort,
+        })
+        await amplifySimulator.start()
+        amplifySimulator.init(simulatorConfig)
+    }
+}
+
+export async function createAmplifyAppsyncServer(
+    httpPort: number,
+    lambdaHandler: any,
+    schema: string,
+    resolvers: PrismaAppsyncResolverConfig[],
+    appsyncConfig?: AmplifyAppSyncAPIConfig,
+    additionalMappingTemplates: AppSyncMockFile[] = [],
+    removeDefaultMappingTemplates = false,
+    additionalDatasources: AppSyncSimulatorDataSourceConfig[] = [],
+    wsPort?: number,
+) {
+    const simulator = new AppSyncSimulator(httpPort, lambdaHandler, schema, resolvers, appsyncConfig, additionalMappingTemplates, removeDefaultMappingTemplates, additionalDatasources, wsPort)
+
+    await simulator.start()
+    // eslint-disable-next-line no-console
+    console.log(`🚀 App Sync Simulator started at http://localhost:${httpPort}`)
+}
+

packages/server/src/index.d.ts

@@ -1,6 +1,10 @@
 import type { YogaServerOptions } from 'graphql-yoga'
+import type { AmplifyAppSyncAPIConfig,  AppSyncMockFile, AppSyncSimulatorDataSourceConfig } from 'amplify-appsync-simulator'
+import type { PrismaAppsyncResolverConfig} from './amplify-appsync-simulator'
+export type { PrismaAppsyncResolverConfig} from './amplify-appsync-simulator'
 
 export const argv: any
+export const argv_appsync_simulator: any
 
 export function createServer({
     schema,
@@ -19,3 +23,14 @@ export function createServer({
 }): void
 
 
+export function createAmplifyAppsyncServer(
+    httpPort: number,
+    lambdaHandler: any,
+    schema: string,
+    resolvers: PrismaAppsyncResolverConfig[],
+    appsyncConfig?: AmplifyAppSyncAPIConfig,
+    additionalMappingTemplates?: AppSyncMockFile[],
+    removeDefaultMappingTemplates?: boolean,
+    additionalDatasources?: AppSyncSimulatorDataSourceConfig[],
+    wsPort?: number
+) :Promise<void>