Feature: Include module meta-data in flow export

[knolleary]

A common problem with importing/exporting flows is not knowing if additional modules are required to be installed. The user is left on their own to figure it out.

There are two possible solutions here.

Option 1

Include the module name in the exported node object, for example: m="node-red-node-random"

The downside of this approach is it greatly inflates the flow json with a lot of redundant information. If you have 100 nodes of the same type, you have 100 copies of the module name.

This isn't terrible, but it isn't great.

Option 2

Make use of the global-config config node introduced in 3.x to include a module manifest.

This is a more attractive option - as it could afford to include more meta data such as module version.

Ideally there should only be one global-config node in a deployed set of flows. To keep true to that, the editor would have to properly merge an imported global-config node with what is already there. But we'd also want to make sure both editor and runtime work okay if there are multiple nodes present (I think it does... but not sure I've explicitly tested for that).

UX

When importing a flow containing module meta-data (regardless of the approach chosen above), the editor should then prompt if there are modules that need installing. The user should then be able to pick what to do next:

• cancel the import
• one-click install of the missing modules
• let the user resolve it manually

The apis for installing modules are optimised for installing one at a time. We may want to look at enabling installing multiple modules in one api call - so we run npm once overall and not once per module.

[GogoVega]

I like option 2 because it's global and centralized. For the UX it seems complete to me.

Using this node can also allow the addition of various data. For example, when I export a flow, I add the machine name to the name of my first flow to identify which flow it is (of course the file name contains it too). Now it will be global-config which will contain this information. We can consider adding a version, a description... I don't know if it's useful but it could contain information from the FlowFuse snapshot. It's not part of this request but could it be the subject of an extension?