Using handlebars.js

[jeau]

I would like activate handelbars (an extension to the Mustache templating language) for Function-nodes so I've had this line in /app/data/.env

export NODE_FUNCTION_ALLOW_EXTERNAL=handlebars

but, it doesn't work when I execute my workflow, I have this error

"Cannot find module 'handlebars'"

[nebulon]

@jeau I have to check in the package, but looks like we could add the required handlebars node module then in the package directly to get it supported if this is a common thing in n8n

[girish]

The package already has N8N_CUSTOM_EXTENSIONS="/app/data/custom" though I don't know if this means that a user can npm install handlebars in that directory and use it. Maybe @BrutalBirdie knows.

[BrutalBirdie]

@girish Got no clue either
Will have to take a look at it.

[girish]

@brutalbirdie looks like N8N_CUSTOM_EXTENSIONS is for custom nodes - https://docs.n8n.io/getting-started/installation/advanced/configuration.html#examples and not for custom node modules

[jeau]

thanks to all, I am a newbe with n8n

@girish @BrutalBirdie this doc indicate that for security reasons, importing modules is restricted by default in the Function-Nodes and that it is possible to lift that restriction by setting the following environment variables:

• NODE_FUNCTION_ALLOW_BUILTIN: For builtin modules
• NODE_FUNCTION_ALLOW_EXTERNAL: For external modules sourced from n8n/node_modules directory

So I created a node_modules directory in /app/data/ and installed in it the module handlebars with the command npm install handlebars but it doesn't work. I also tried in /app/data/.n8n directory with the same result.

[girish]

@jeau I think the module has to be installed in the docker image itself. Is there a way to not use handlebars? Just curious why it's needed. Maybe we can add it to the n8n image itself.

[jeau]

@girish you can read this discussion https://community.n8n.io/t/text-templating-node/1965

handelbars is a template system to facilitate the creation of html document pages, https://handlebarsjs.com/

in my case, I want to get information from baserow tables and use n8n to generate reports and send them by mails

[girish]

@jeau there is a env var NODE_PATH that tells node where to find additional node modules. So, you can set the variable in /app/data/env like NODE_PATH=/app/data/modules and then in Web Terminal:

mkdir /app/data/modules
cd /app/data/modules
npm install handlebars

Restart the app afterwards.

[jeau]

@girish thanks, however I have this errors after passing the command npm install handlebars

npm ERR! code EROFS
npm ERR! syscall open
npm ERR! path /root/.npm/_cacache/tmp/2122bb8f
npm ERR! errno -30
npm ERR! rofs EROFS: read-only file system, open '/root/.npm/_cacache/tmp/2122bb8f'
npm ERR! rofs Often virtualized file systems, or other file systems
npm ERR! rofs that don't support symlinks, give this error.

I tried npm install --prefix /app/data/modules handlebars but the result was the same

however, I have already successfully installed handelbars before, but I forgot how to do it

[robi]

This post is deleted!

[girish]

@jeau I can fix that . Can you try npm install handlebars --cache /tmp/foo in the meantime ?

[jeau]

@girish I went back to a fresh installation, because I had not checked the changes of the recent updates. This fix allows me to install handelbars. But it still doesn't work, I still get the message Cannot find module 'handlebars' with this example.

My session:

root@XYZ:/app/data# vi env
root@XYZ:/app/data# cat env
# Set the logging level to 'debug'
export EXECUTIONS_DATA_SAVE_MANUAL_EXECUTIONS=true
export EXECUTIONS_DATA_SAVE_ON_ERROR=all
export EXECUTIONS_DATA_SAVE_ON_SUCCESS=all
export N8N_LOG_LEVEL=info
export NODE_PATH=/app/data/modules
export NODE_FUNCTION_ALLOW_EXTERNAL=handlebars
root@XYZ:/app/data# mkdir modules
root@XYZ:/app/data# cd /app/data/modules
root@XYZ:/app/data/modules# npm install handlebars --cache /tmp/foo
npm WARN saveError ENOENT: no such file or directory, open '/app/data/modules/package.json'
npm notice created a lockfile as package-lock.json. You should commit this file.
npm WARN enoent ENOENT: no such file or directory, open '/app/data/modules/package.json'
npm WARN modules No description
npm WARN modules No repository field.
npm WARN modules No README data
npm WARN modules No license field.

+ handlebars@4.7.7
added 6 packages from 39 contributors and audited 6 packages in 0.834s
found 0 vulnerabilities

┌───────────────────────────────────────────────────┐
│              npm update check failed              │
│        Try running with sudo or get access        │
│       to the local update config store via        │
│ sudo chown -R $USER:$(id -gn $USER) /root/.config │
└───────────────────────────────────────────────────┘
root@XYZ:/app/data/modules# ls -al
total 16
drwxr-xr-x 3 root     root     4096 Oct  9 16:25 .
drwxr-xr-x 8 cloudron cloudron 4096 Oct  9 16:23 ..
drwxr-xr-x 9 root     root     4096 Oct  9 16:25 node_modules
-rw-r--r-- 1 root     root     1711 Oct  9 16:25 package-lock.json
root@XYZ:/app/data/modules# ls -al node_modules/
total 36
drwxr-xr-x 9 root root 4096 Oct  9 16:25 .
drwxr-xr-x 3 root root 4096 Oct  9 16:25 ..
drwxr-xr-x 2 root root 4096 Oct  9 16:25 .bin
drwxr-xr-x 6 root root 4096 Oct  9 16:25 handlebars
drwxr-xr-x 4 root root 4096 Oct  9 16:25 minimist
drwxr-xr-x 2 root root 4096 Oct  9 16:25 neo-async
drwxr-xr-x 4 root root 4096 Oct  9 16:25 source-map
drwxr-xr-x 5 root root 4096 Oct  9 16:25 uglify-js
drwxr-xr-x 4 root root 4096 Oct  9 16:25 wordwrap
root@XYZ:/app/data/modules#

[girish]

@jeau I have fixed the package to support this. Please try https://docs.cloudron.io/apps/n8n/#custom-node-modules with the latest package 1.16.0

[jeau]

@girish great thank's, it works

[rmdes]

@girish Two questions:

Do I understand correctly that this is the only way to install external modules ?

Is there anything that need to be done (beside app restart) after adding the line in the env file?

[girish]

@rmdes right, if you want external modules, we have to fix the package. The modules are hardcoded in the Dockerfile.