Cannot create/link FTP channel in Scripting Engine (Jython)

UPDATE: Despite the warning about invalid channel, it works. But I am hesitant to mark it as solved… @5iver what are your thoughts on this? A human error or worth an issue on Github?

Original post:
I have migrated 99% of my DSL rules to Jython and upgraded some in the process to leverage Scripting Engine functionality (like creating Items, Metadata and Channel links).

The FTP binding gives me a bit of trouble. When defining the items in an .items file it works just fine, but when I try to create the items dynamically, it generates an error (see below). I use these items to store the base64 encoded Grafana rendered images so I can display them on HABpanel via my own openhabcloud instance. For flexibility, I want to keep stuff in Item metadata that I create on first run or if another graph is added to a Dictionary in Python.

This works (I just add the metadata programmatically and everything is fine):

// Item to store the Grafana image for Indoor temperature last 24h
Image		imgTempIndoor24h
			"Indoor Temp last 24h"

This doesn’t work:

    from core.utils import ChannelUID
    from core.items import add_item
    from core.links import add_link

        for entry in grafImgDict.values():
            imgItemName = entry.get("item_name")
            if ir.getItems(imgItemName) == []:
                add_item(imgItemName, item_type="Image", groups=[entry.get("item_group")], label=entry.get("item_description"), tags=["Grafana"])
                add_link(imgItemName, ChannelUID("ftpupload:imagereceiver:"+entry.get("ftp_channel")+":image"))
            set_metadata(imgItemName, "Grafana_Graphs", \
                {"PanelId": entry.get("grafana_panelid"), \

The error is:

[WARN ] [openhab.automation.jython.core.utils] - [ftpupload:imagereceiver:grf_temp_indoor24h:image] is not a valid Channel

What am I missing here?

I recall finding and fixing something in this area, but it wouldn’t be merged yet. I’ll do some tests, look through my commits, and get back to you. When was the last time you updated the helper libraries? Or are you using the beta Jython bundle? Also, which version of Jython, OH, and OS?

Thanks Scott!

I use the beta Jython bundle (Bundle-Version: on OH 2.5.0 release in Docker on Debian 10. The core components (in /conf/automation/jsr223/python/core/components) are dated December 8.