I would probably suggest to use something like this:

config = fmf.Tree('.').find("/provision").data['standard-inventory-qcow2']

Then you can easily access all configuration values directly:

config['qemu']['net_nic']['model']

Hope this helps.

@psss

cat provision.fmf 
---
# qemu options: https://qemu.weilnetz.de/doc/qemu-doc.html
standard-inventory-qcow2:
  qemu:
    # RAM size in megabytes. Optionally, a suffix of “M” or “G”.
    m: 3G
    net_nic:
      # Use qemu-system-x86_64 -net nic,model=help for a list of available devices.
      model: e1000
standard-inventory-docker:
  dumb_option: dumb_parameter
# vim:ft=yaml: ts=2 sts=2 sw=2 expandtab

Of course we can use : config['qemu']['net_nic']['model']
With above approach we must always run in try/catch + specify backup code to set default value.

If we want to use function, as I did, that we need represent ['qemu']['net_nic']['model'] as a parameter to function fmf_get(). How to do this ? I use list.

Think about fmf_get() as the same as dict.get(key[, default]).

@psss I have a question:

fmf.Tree('.') - does it scans all work dir each time?

If I want to get many parameters, how is to safe to call fmf.Tree('.') each time?

Thank you for your time.

I see. Thanks for clarification. Make sense to handle default values in the functin. Regarding the scanning: Yes, when construction a new tree the directory is scanned again. It might make sense to implement something like this:

class Config(object):
    tree = None
    def get(self):
        if self.tree is None:
            Config.tree = fmf.Tree(".")
        return self.tree

If this is more common use case we could also consider support for simple caching directly in FMF. BTW, the extended .get() functionality might be an interesting future feature as well.

@psss I was trying to use .find(), but it is not easy as it would seem:

for node in tree.climb(): print node.name
empty/3/output-document-file
empty/3/output-document-pipe
empty/provision

works:

tree.find("empty/provision")
Out[25]: <fmf.base.Tree at 0x248dcd0>

but doesn't work:

tree.find("/provision")

Nothing

Yes, Tree.find() expects a full name of the node to be found. If you need to search among multiple nodes you can use Tree.prune(names=[".*/provision"]) which supports regular expressions. The FmfMetadataTree class looks fine.

@psss Thank you for the Tree.prune() hint. I updated PR.

pretty please pagure-ci rebuild

pretty please pagure-ci rebuild

pretty please pagure-ci rebuild

pretty please pagure-ci rebuild

Commit 9e216f62 fixes this pull-request

FYI, as this seems to be quite useful feature (and possible common use case) I've implemented the deep dictionary attribute retrieval directly in fmf:

https://github.com/psss/fmf/commit/b537c59

@psss nice, when it is in stable RPM branch we can update this code.
Thank you.

It would be nice if you could provide some example how to use this.

I've added basic documentation including a simple example here:
https://fedoraproject.org/wiki/CI/Metadata#Provision