feat(trpc): restructure trpc backend code for separation of procedures

Split procedures out from the router and separate middleware into individual files. Additionally
ensure api gateway lambda event is provided to context.

re #49

Author: cogwirrel

packages/nx-plugin/src/trpc/backend/__snapshots__/generator.spec.ts.snap

@@ -1,18 +1,257 @@
 // Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html
 
-exports[`trpc backend generator > should generate backend and schema projects > backend-index.ts 1`] = `
-"export * from './lambdas/index.js';
+exports[`trpc backend generator > should generate backend and schema projects 1`] = `
+"export type { AppRouter } from './router.js';
+export type { Context } from './init.js';
 "
 `;
 
-exports[`trpc backend generator > should generate backend and schema projects > schema-index.ts 1`] = `
+exports[`trpc backend generator > should generate backend and schema projects 2`] = `
+"import { initTRPC } from '@trpc/server';
+import {
+  createErrorPlugin,
+  createLoggerPlugin,
+  createMetricsPlugin,
+  createTracerPlugin,
+  IMiddlewareContext,
+} from './middleware/index.js';
+
+export type Context = IMiddlewareContext;
+
+export const t = initTRPC.context<Context>().create();
+
+export const publicProcedure = t.procedure
+  .unstable_concat(createLoggerPlugin())
+  .unstable_concat(createTracerPlugin())
+  .unstable_concat(createMetricsPlugin())
+  .unstable_concat(createErrorPlugin());
+"
+`;
+
+exports[`trpc backend generator > should generate backend and schema projects 3`] = `
+"import { initTRPC, TRPCError } from '@trpc/server';
+
+export const createErrorPlugin = () => {
+  const t = initTRPC.context().create();
+  return t.procedure.use(async (opts) => {
+    const response = await opts.next({
+      ctx: {
+        ...opts.ctx,
+      },
+    });
+
+    if (!response.ok) {
+      if (response.error instanceof TRPCError) {
+        throw response.error;
+      }
+
+      throw new TRPCError({
+        code: 'INTERNAL_SERVER_ERROR',
+        message: 'An unexpected error occurred, please try again later.',
+        cause: response.error,
+      });
+    }
+
+    return response;
+  });
+};
+"
+`;
+
+exports[`trpc backend generator > should generate backend and schema projects 4`] = `
+"import { CreateAWSLambdaContextOptions } from '@trpc/server/adapters/aws-lambda';
+import type { APIGatewayProxyEventV2WithIAMAuthorizer } from 'aws-lambda';
+import { ILoggerContext } from './logger.js';
+import { IMetricsContext } from './metrics.js';
+import { ITracerContext } from './tracer.js';
+
+export * from './logger.js';
+export * from './metrics.js';
+export * from './tracer.js';
+export * from './error.js';
+
+export type IMiddlewareContext =
+  CreateAWSLambdaContextOptions<APIGatewayProxyEventV2WithIAMAuthorizer> &
+    ILoggerContext &
+    IMetricsContext &
+    ITracerContext;
+"
+`;
+
+exports[`trpc backend generator > should generate backend and schema projects 5`] = `
+"import { initTRPC } from '@trpc/server';
+import { Logger } from '@aws-lambda-powertools/logger';
+
+export interface ILoggerContext {
+  logger?: Logger;
+}
+
+export const createLoggerPlugin = () => {
+  const t = initTRPC.context<ILoggerContext>().create();
+  return t.procedure.use(async (opts) => {
+    const logger = new Logger();
+
+    const response = await opts.next({
+      ctx: {
+        ...opts.ctx,
+        logger,
+      },
+    });
+
+    if (!response.ok) {
+      logger.error('Unexpected error occured', response.error.cause ?? '');
+    }
+
+    return response;
+  });
+};
+"
+`;
+
+exports[`trpc backend generator > should generate backend and schema projects 6`] = `
+"import { initTRPC } from '@trpc/server';
+import { Metrics, MetricUnit } from '@aws-lambda-powertools/metrics';
+
+export interface IMetricsContext {
+  metrics?: Metrics;
+}
+
+export const createMetricsPlugin = () => {
+  const t = initTRPC.context<IMetricsContext>().create();
+
+  return t.procedure.use(async (opts) => {
+    const metrics = new Metrics();
+    metrics.captureColdStartMetric();
+
+    metrics.addMetric('requestCount', MetricUnit.Count, 1);
+
+    try {
+      const response = await opts.next({
+        ctx: {
+          ...opts.ctx,
+          metrics,
+        },
+      });
+
+      if (!response.ok) {
+        metrics.addMetric('errorCount', MetricUnit.Count, 1);
+      } else {
+        metrics.addMetric('successCount', MetricUnit.Count, 1);
+      }
+
+      return response;
+    } finally {
+      metrics.publishStoredMetrics();
+    }
+  });
+};
+"
+`;
+
+exports[`trpc backend generator > should generate backend and schema projects 7`] = `
+"import { initTRPC } from '@trpc/server';
+import { Tracer } from '@aws-lambda-powertools/tracer';
+import { Subsegment } from 'aws-xray-sdk-core';
+
+export interface ITracerContext {
+  tracer?: Tracer;
+}
+
+export const createTracerPlugin = () => {
+  const t = initTRPC.context<ITracerContext>().create();
+
+  return t.procedure.use(async (opts) => {
+    const tracer = new Tracer();
+    const segment = tracer.getSegment();
+    let handlerSegment: Subsegment | undefined;
+
+    if (segment) {
+      handlerSegment = segment.addNewSubsegment(\`## \${opts.path}\`);
+      tracer.setSegment(handlerSegment);
+    }
+
+    tracer.annotateColdStart();
+    tracer.addServiceNameAnnotation();
+
+    try {
+      const response = await opts.next({
+        ctx: {
+          ...opts.ctx,
+          tracer,
+        },
+      });
+
+      if (!response.ok && response.error.cause instanceof Error) {
+        tracer.addErrorAsMetadata(response.error.cause);
+      }
+      return response;
+    } finally {
+      if (segment && handlerSegment) {
+        handlerSegment.close();
+        tracer.setSegment(segment);
+      }
+    }
+  });
+};
+"
+`;
+
+exports[`trpc backend generator > should generate backend and schema projects 8`] = `
+"import { publicProcedure } from '../init.js';
+import { EchoInputSchema, EchoOutputSchema } from ':proj/test-api-schema';
+
+export const echo = publicProcedure
+  .input(EchoInputSchema)
+  .output(EchoOutputSchema)
+  .query((opts) => ({ result: opts.input.message }));
+"
+`;
+
+exports[`trpc backend generator > should generate backend and schema projects 9`] = `
+"import {
+  awsLambdaRequestHandler,
+  CreateAWSLambdaContextOptions,
+} from '@trpc/server/adapters/aws-lambda';
+import { echo } from './procedures/echo.js';
+import { t } from './init.js';
+import { APIGatewayProxyEventV2WithIAMAuthorizer } from 'aws-lambda';
+
+export const router = t.router;
+
+const appRouter = router({
+  echo,
+});
+
+export const handler = awsLambdaRequestHandler({
+  router: appRouter,
+  createContext: (
+    ctx: CreateAWSLambdaContextOptions<APIGatewayProxyEventV2WithIAMAuthorizer>,
+  ) => ctx,
+});
+
+export type AppRouter = typeof appRouter;
+"
+`;
+
+exports[`trpc backend generator > should generate backend and schema projects 10`] = `
+"export * from './procedures/echo.js';
+"
+`;
+
+exports[`trpc backend generator > should generate backend and schema projects 11`] = `
 "import { z } from 'zod';
 
-export const EchoSchema = z.object({
+export const EchoInputSchema = z.object({
+  message: z.string(),
+});
+
+export type IEchoInput = z.TypeOf<typeof EchoInputSchema>;
+
+export const EchoOutputSchema = z.object({
   result: z.string(),
 });
 
-export type IEcho = z.TypeOf<typeof EchoSchema>;
+export type IEchoOutput = z.TypeOf<typeof EchoOutputSchema>;
 "
 `;
 
@@ -33,7 +272,7 @@ export class TestApi extends TrpcApi {
       defaultAuthorizer: new HttpIamAuthorizer(),
       handlerFilePath: url.fileURLToPath(
         new URL(
-          '../../../../../../apps/test-api/backend/src/lambdas/router.ts',
+          '../../../../../../apps/test-api/backend/src/router.ts',
           import.meta.url,
         ),
       ),

packages/nx-plugin/src/trpc/backend/files/backend/src/index.ts.template

@@ -1 +1,2 @@
-export * from './lambdas/index.js';
+export type { AppRouter } from './router.js';
+export type { Context } from './init.js';

packages/nx-plugin/src/trpc/backend/files/backend/src/init.ts.template

@@ -0,0 +1,18 @@
+import { initTRPC } from '@trpc/server';
+import {
+  createErrorPlugin,
+  createLoggerPlugin,
+  createMetricsPlugin,
+  createTracerPlugin,
+  IMiddlewareContext,
+} from './middleware/index.js';
+
+export type Context = IMiddlewareContext;
+
+export const t = initTRPC.context<Context>().create();
+
+export const publicProcedure = t.procedure
+  .unstable_concat(createLoggerPlugin())
+  .unstable_concat(createTracerPlugin())
+  .unstable_concat(createMetricsPlugin())
+  .unstable_concat(createErrorPlugin());