Deploy NestJS to AWS Lambda - aws-lambda

Question

I have a REST API built using NestJS and I'm trying to deploy this to AWS Lambda.
I've created a file called serverless.ts in the src directory of my app -
import { NestFactory } from '#nestjs/core';
import { AppModule } from './app.module';
import serverlessExpress from '#vendia/serverless-express';
import { Handler, Callback, Context } from 'aws-lambda';
let server: Handler;
async function bootstrap() {
const app = await NestFactory.create(AppModule);
await app.init();
const expressApp = app.getHttpAdapter().getInstance();
return serverlessExpress({ app: expressApp });
}
bootstrap();
export const handler: Handler = async (
event: any,
context: Context,
callback: Callback,
) => {
server = server ?? (await bootstrap());
return server(event, context, callback);
};
Now, when I tried deploying this app/handler to AWS Lambda using Serverless framework, it failed a couple of times due to big package size (Lambda limits it to 250Mb).
The next option I had was to use docker and Elastic Container Registry (AWS ECR) to upload an image to Lambda.
Dockerfile -
FROM public.ecr.aws/lambda/nodejs:14
COPY package*.json ${LAMBDA_TASK_ROOT}
RUN npm install
COPY . ${LAMBDA_TASK_ROOT}
RUN npm run build
CMD [ "dist/serverless.handler" ]
I build this image and push to ECR Repository using the following commands -
aws ecr get-login-password --region region | docker login --username AWS --password-stdin aws_account_id.dkr.ecr.region.amazonaws.com
docker tag e9ae3c220b23 aws_account_id.dkr.ecr.region.amazonaws.com/my-repository:tag
docker push aws_account_id.dkr.ecr.region.amazonaws.com/my-repository:tag
The push is successful now. Then I import this image to AWS Lambda and add a API Gateway Trigger to generate an HTTP endpoint.
When I try to access this endpoint, it says -
{ message: Internal server error }
When I view logs in Cloudwatch, this is what I see -
{
"errorType": "Runtime.ImportModuleError",
"errorMessage": "Error: Cannot find module 'serverless'\nRequire stack:\n- /var/runtime/UserFunction.js\n- /var/runtime/Runtime.js\n- /var/runtime/index.js",
"stack": [
"Runtime.ImportModuleError: Error: Cannot find module 'serverless'",
"Require stack:",
"- /var/runtime/UserFunction.js",
"- /var/runtime/Runtime.js",
"- /var/runtime/index.js",
" at _loadUserApp (/var/runtime/UserFunction.js:221:13)",
" at Object.module.exports.load (/var/runtime/UserFunction.js:279:17)",
" at Object. (/var/runtime/index.js:43:34)",
" at Module._compile (internal/modules/cjs/loader.js:1085:14)",
" at Object.Module._extensions..js (internal/modules/cjs/loader.js:1114:10)",
" at Module.load (internal/modules/cjs/loader.js:950:32)",
" at Function.Module._load (internal/modules/cjs/loader.js:790:12)",
" at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:75:12)",
" at internal/main/run_main_module.js:17:47"
]
}
I am unable to figure out the root cause and a fix for this issue. How do I resolve this?