Typeorm + Firebase functions: "No connection options were found in any orm configuration files" after deployed

Env:nodejs12

Folder structure:

#root
/functions
  /src
    ...
    /models
    /resolvers
    index.ts
  ormconfig.json
  package.json
  tsconfig.json
  ...
.firebaserc
firebase.json

Everything worked when developing in local environment. After deployed to firebase functions, No connection options were found in any orm configuration files shows up.

What might be the cause?

I'll update with more information if needed.

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update

Below is the folder structure of deployed codes. (Cloud functions can't show more than 50 files so I downloaded the source code from GCP)

As you can see the ormconfig.json does exist in the root, but somehow it cannot be located. I have to create connection manually with typeorm.createConnection({type: "postgres",...}) to make the code work.