Get flow variable on node close callback

General
1

Hello

I would like to persist some runtime data when my node-red application shuts down. To do this I have created a node close callback.

node.on("close", function(done) { ... done() }

My question is, can i access a flow variable from the close callback. It does not seem to work, my flow var is empty.

Thanks

2

I don't know the answer to the question, but if you tell us a bit more about the data you want to persist we may be able to suggest a better solution. I presume you already know that flow and context data can be persisted automatically.

3

Hi

Thanks for you comments. The data is active alarms from an automation system. When the flow shuts down i wanted to complete all the active alarm's (calculate the duration) and persist. When the flow starts up i then get the persisted completed alarms and push them to the history database.

Yes, i guess one solution would be to 'store to file' the active alarms flow variable. I just thought that is was cleaner or nicer to not be continually writing to the file system.

4

It should be possible. But without specific details of what you've tried, it's hard to say why it isn't working for you.

5

Hello Thanks,

Problem solved, because my flow variable was declared in a subflow i think i was just getting a bit confused with what instance i was looking at.

6

I don't quite get where/how you have registered the close handler? I assumed you created a custom node, but then you mentioned subflows... :thinking:

7

I registered the close handler in a function node used inside a sub flow.

8

This topic was automatically closed 60 days after the last reply. New replies are no longer allowed.