Keep getting "Cannot find module 'xlsx' " on production execution

[nk123]

Describe the problem/error/question

I host n8n on railway app and use a custom docker file as suggested here - The definitive guide to custom NPM modules for self-hosted instances - #2 by Jon
When I run the code node in test mode, everything works fine. However on production execution I get VMerror

What is the error message (if any)?

Please share your workflow

{
  "errorMessage": "Cannot find module 'xlsx' [line 1]",
  "errorDescription": "VMError",
  "errorDetails": {},
  "n8nDetails": {
    "nodeName": "Code",
    "nodeType": "n8n-nodes-base.code",
    "nodeVersion": 2,
    "n8nVersion": "1.72.1 (Self Hosted)",
    "binaryDataMode": "default",
    "stackTrace": [
      "VMError: Cannot find module 'xlsx'",
      "    at Resolver.resolveFull (/usr/local/lib/node_modules/n8n/node_modules/@n8n/vm2/lib/resolver.js:126:9)",
      "    at Resolver.resolve (/usr/local/lib/node_modules/n8n/node_modules/@n8n/vm2/lib/resolver.js:121:15)",
      "    at resolve (/usr/local/lib/node_modules/n8n/node_modules/@n8n/vm2/lib/nodevm.js:317:21)",
      "    at VM2 Wrapper.apply (/usr/local/lib/node_modules/n8n/node_modules/@n8n/vm2/lib/bridge.js:490:11)",
      "    at requireImpl (/usr/local/lib/node_modules/n8n/node_modules/@n8n/vm2/lib/setup-node-sandbox.js:90:19)",
      "    at require (/usr/local/lib/node_modules/n8n/node_modules/@n8n/vm2/lib/setup-node-sandbox.js:171:10)",
      "    at /usr/local/lib/node_modules/n8n/node_modules/n8n-nodes-base/dist/nodes/Code:1:111",
      "    at /usr/local/lib/node_modules/n8n/node_modules/n8n-nodes-base/dist/nodes/Code:238:2",
      "    at VM2 Wrapper.apply (/usr/local/lib/node_modules/n8n/node_modules/@n8n/vm2/lib/bridge.js:490:11)",
      "    at NodeVM.run (/usr/local/lib/node_modules/n8n/node_modules/@n8n/vm2/lib/nodevm.js:497:23)"
    ]
  }
}

Information on your n8n setup

• **n8n version:1.72.1 (Self Hosted)
• Database (default: SQLite):
• n8n EXECUTIONS_PROCESS setting (default: own, main):
• **Running n8n via (Docker, npm, n8n cloud, desktop app):Docker
• Operating system:

[n8n]

It looks like your topic is missing some important information. Could you provide the following if applicable.

• n8n version:
• Database (default: SQLite):
• n8n EXECUTIONS_PROCESS setting (default: own, main):
• Running n8n via (Docker, npm, n8n cloud, desktop app):
• Operating system:

[Jon]

Hey @nk123,

Are you running n8n in queue mode? It sounds like you could be and that your workers don’t have the npm package installed.

[nk123]

You are right, my workers didn’t have the package. Fixed it now. Thank you