Docker – Backstage failed to start up: [Error: ENOENT: no such file or directory, scandir '/app/plugins/xxx]

I have a plugin named "inventory-backend". It includes Knex migrations folder, "migrations". It works fine locally.

Here, I created a Docker image, completely following Backstage Docs (https://backstage.io/docs/deployment/k8s/ and https://backstage.io/docs/deployment/docker/). Here is my Dockerfile:

FROM node:18-bookworm-slim

RUN --mount=type=cache,target=/var/cache/apt,sharing=locked 
    --mount=type=cache,target=/var/lib/apt,sharing=locked 
    apt-get update && 
    apt-get install -y --no-install-recommends python3 g++ build-essential && 
    yarn config set python /usr/bin/python3

USER node

WORKDIR /app

ENV NODE_ENV production

COPY --chown=node:node yarn.lock package.json packages/backend/dist/skeleton.tar.gz ./
RUN tar xzf skeleton.tar.gz && rm skeleton.tar.gz

RUN --mount=type=cache,target=/home/node/.cache/yarn,sharing=locked,uid=1000,gid=1000 
    yarn install --frozen-lockfile --production --network-timeout 300000

COPY --chown=node:node packages/backend/dist/bundle.tar.gz app-config*.yaml ./
RUN tar xzf bundle.tar.gz && rm bundle.tar.gz

CMD ["node", "packages/backend", "--config", "app-config.yaml"]

Next, I’m deploying Postgre and Backstage, again, in the way that docs suggest. But the pod that gets created with the deployment gets this error:

Backend failed to start up [Error: ENOENT: no such file or directory, scandir '/app/plugins/inventory-backend/migrations'] { errno: -2, code: 'ENOENT', syscall: 'scandir', path: '/app/plugins/inventory-backend/migrations' }

When I look inside the container, I don’t see my "migrations" folder. So I added this line to Dockerfile:

COPY plugins/inventory-backend/migrations /app/plugins/inventory-backend/migrations

Now when I check inside the container, I see that migrations folder is there. But it gives me the same error. How can this happen?

My package.json file:

{
  "name": "root",
  "version": "1.0.0",
  "private": true,
  "engines": {
    "node": "16 || 18"
  },
  "scripts": {
    "dev": "concurrently "yarn start" "yarn start-backend"",
    "start": "yarn workspace app start",
    "start-backend": "yarn workspace backend start",
    "build:backend": "yarn workspace backend build",
    "build:all": "backstage-cli repo build --all",
    "build-image": "yarn workspace backend build-image",
    "tsc": "tsc",
    "tsc:full": "tsc --skipLibCheck false --incremental false",
    "clean": "backstage-cli repo clean",
    "test": "backstage-cli repo test",
    "test:all": "backstage-cli repo test --coverage",
    "lint": "backstage-cli repo lint --since origin/main",
    "lint:all": "backstage-cli repo lint",
    "prettier:check": "prettier --check .",
    "new": "backstage-cli new --scope internal"
  },
  "workspaces": {
    "packages": [
      "packages/*",
      "plugins/*"
    ]
  },
  "devDependencies": {
    "@backstage/cli": "^0.22.13",
    "@spotify/prettier-config": "^12.0.0",
    "concurrently": "^6.0.0",
    "lerna": "^4.0.0",
    "prettier": "^2.3.2",
    "typescript": "~5.0.0"
  },
  "resolutions": {
    "@types/react": "^17",
    "@types/react-dom": "^17"
  },
  "prettier": "@spotify/prettier-config",
  "lint-staged": {
    "*.{js,jsx,ts,tsx,mjs,cjs}": [
      "eslint --fix",
      "prettier --write"
     ],
    "*.{json,md}": [
      "prettier --write"
    ]
  },
  "dependencies": {
    "@backstage/errors": "^1.2.2",
    "@manypkg/get-packages": "^1.1.3",
    "@types/pg": "^8.10.2",
    "@types/uuid": "^9.0.3",
    "express": "^4.18.2",
    "express-promise-router": "^4.1.1",
    "node-gyp": "^9.4.0",
    "p5": "^1.7.0",
    "pg": "^8.11.3"
  }
}

And my tsconfig file:

{
  "extends": "@backstage/cli/config/tsconfig.json",
  "include": [
    "packages/*/src",
    "plugins/*/src",
    "plugins/*/dev",
    "plugins/*/migrations"
  ],
  "exclude": ["node_modules"],
  "compilerOptions": {
    "jsx": "react",
    "outDir": "dist-types",
    "rootDir": "."
  }
}

ls output of the /app directory:

app-config.production.yaml app-config.yaml node_modules package.json packages plugins yarn.lock

Here, app-config.production.yaml does not have overriding effect on app-config.yaml, as a note.
Thank you.