aws lambda function with dockerized node.js express app not working - "message: Internal Error"

Question

I'm pretty new to AWS Lambda, and can't seem to get a dockerized Node.JS express app to work correctly. Here are the steps I took:

1. Deployed my Docker image to AWS ECR. This worked correctly and I can see my images in ECR.
2. Created a Lambda Function in AWS Lambda and used my container image for the function.
3. Created a trigger for the Lambda function using API Gateway (HTTP), which gave me an endpoint URL that I assumed would be the host for my express endpoints.

When I hit that endpoint, I get a "message: Internal Error". Am I going about this totally wrong? Here's some code snippets. (very new to AWS in general)

Dockerfile

# Dockerfile
FROM node:16-alpine
WORKDIR /usr/src/app
COPY package*.json ./
RUN npm install
COPY . .
EXPOSE 5001
CMD [ "npm", "run", "docker:start" ]

Express endpoint

// Creates a school in the db
schoolApi.post("/create", async (req: Request, res: Response) => {
  try {
    const {
      id,
      gradeDistribution,
      name,
      logo,
      rateMyProfessorId,
      totalSections,
      averageGPA,
      totalStudents,
    }: {
      id: string;
      gradeDistribution: GradeDistributionObject;
      name: string;
      logo: string;
      rateMyProfessorId: number;
      totalSections: number;
      averageGPA: number;
      totalStudents: number;
    } = req.body;

    const gradeDistributionEntity = await createGradeDistribution(
      db,
      gradeDistribution,
      averageGPA,
      totalStudents
    );

    const school = await createSchool(
      db,
      id,
      gradeDistributionEntity,
      name,
      logo,
      rateMyProfessorId,
      totalSections,
      averageGPA,
      totalStudents
    );

    res.status(200).send(school);
  } catch (error) {
    res.status(500).send(SchoolErrorCodes.SCHOOL_CREATION_ERROR);
  }
});

Sample endpoint format that I'm hitting

https://xxxxxx.execute-api.us-west-2.amazonaws.com/default/myFunction/school/create

Response for above endpoint

{
    "message": "Internal Server Error"
}

CloudWatch Logs when I click Test in AWS Lambda Console

2022-04-05T12:20:45.015-07:00   > [email protected] docker:start

2022-04-05T12:20:45.015-07:00   > concurrently "tsc -w" "nodemon src/index.ts"

2022-04-05T12:20:47.706-07:00   [0] c7:20:47 PM - Starting compilation in watch mode...

2022-04-05T12:20:47.706-07:00   [0]

2022-04-05T12:20:47.751-07:00   [1] [33m[nodemon] 2.0.15[39m

2022-04-05T12:20:47.752-07:00   [1] [33m[nodemon] to restart at any time, enter `rs`[39m

2022-04-05T12:20:47.753-07:00   [1] [33m[nodemon] watching path(s): *.*[39m

2022-04-05T12:20:47.753-07:00   [1] [33m[nodemon] watching extensions: ts,json[39m

2022-04-05T12:20:47.754-07:00   [1] [32m[nodemon] starting `ts-node src/index.ts`[39m

2022-04-05T12:20:49.541-07:00   START RequestId: 8eeeffa3-86ee-4a6f-8c12-cc61bdaa0b66 Version: $LATEST

2022-04-05T12:20:52.552-07:00   END RequestId: 8eeeffa3-86ee-4a6f-8c12-cc61bdaa0b66

2022-04-05T12:20:52.552-07:00   REPORT RequestId: 8eeeffa3-86ee-4a6f-8c12-cc61bdaa0b66 Duration: 3009.12 ms Billed Duration: 3000 ms Memory Size: 128 MB Max Memory Used: 56 MB

2022-04-05T12:20:52.552-07:00   2022-04-05T19:20:52.551Z 8eeeffa3-86ee-4a6f-8c12-cc61bdaa0b66 Task timed out after 3.01 seconds

2022-04-05T12:20:53.130-07:00   > [email protected] docker:start

2022-04-05T12:20:53.130-07:00   > concurrently "tsc -w" "nodemon src/index.ts"

2022-04-05T12:20:53.872-07:00   [1] [33m[nodemon] 2.0.15[39m

2022-04-05T12:20:53.873-07:00   [1] [33m[nodemon] to restart at any time, enter `rs`[39m

2022-04-05T12:20:53.873-07:00   [1] [33m[nodemon] watching path(s): *.*[39m

2022-04-05T12:20:53.873-07:00   [1] [33m[nodemon] watching extensions: ts,json[39m

2022-04-05T12:20:53.873-07:00   [1] [32m[nodemon] starting `ts-node src/index.ts`[39m

2022-04-05T12:20:54.129-07:00   [0] c7:20:54 PM - Starting compilation in watch mode...

2022-04-05T12:20:54.129-07:00   [0]