How can I split a nested yaml into multiple files by iterating through multiple keys?

[dmc-94]

Hi there,

I want to split a big yaml file into multiple yaml files. I looked into the QA with following example: #1562 but I can not really figure it out, as I don't understand how to double loop through this file.

I have following data

regions:
  region1:
    item1:
      settingA: null
      settingB: null
    item2:
      - value1
      - value2
  region2:
    item1:
      settingA: something
      settingB: configured
    item2:
      - value1
      - value2

I basically need to split the files by region and item.

So in the end this example should generate 4 yaml files like region1_item1.yaml , region1_item2.yaml, region2_item1.yaml and so on..

And the content should always be a key and the values of the region map:

region1_item1.yaml

item1:
  settingA: null
  settingB: null

Any help is appreciated. Thank you!

[mikefarah]

Probably way to late for you now (sorry); but for future readers:

You'll need to use the -s command to split each result into their own file.

So the first step is to work out how to split up the doc into the components that you want in each file, then the next step is to work out the right expression to give to '-s' to generate the filenames.

First Option (easier)

yq -s '(parent | key) + "_" + (key) ' '.regions[][]' examples/data1.yaml

• The main expression splits over each "item" value map
  e.g. for the path .regions.region2.item1:

settingA: something
settingB: configured

Then the -s expression is run against that match to generate the filename. We can use 'parent' to go up the node tree to provide more context.
In this case 'parent' is the region2 map; and the key of that is "region2". The key of that map is "item2", so this will create a filename "region2_item1.yml"

Second (harder) - to get the item name as a root in each child:

./yq  -s '.region + "_" + .item' '.regions[][] | {key: ., "region": parent | key, "item": key}' examples/data1.yaml

I'll need to create a new map with that item key in each result. Because it's a new map, that maeans I can't use parent to look up the tree anymore; so we'll bake in the values of region and item name in order to be able to refer to them in the '-s' expression

This will yield a file like;
"region2_item1.yml"

item1:
  settingA: something
  settingB: configured
region: region2
item: item1