Filter out direct child objects whose key doesn't match a specific value

[sguillope]

Hi all,

I've been trying so many different combinations of del(), select() and has() but I just can't find the right expression :(

I have a yaml source that looks like this:

name: some value
# ...other keys
environment:
  prod:
    config:
      # more child keys
  staging:
    config:
      # more child keys
  dev:
    config:
      # more child keys

I'm trying to apply a filter it to remove the direct child objects of environment whose key doesn't match a specific value.
For example, if the value is prod, I want the result to be:

name: some value
# ...other keys preserved
environment:
  prod:
    config:
      # more child keys

Any ideas?

Bonus problem: if none of the child objects are matched (e.g. value == test) then I'd like environment not to be present in the result. :)

[mikefarah]

In the latest 4.8.0 release you can now do this:

yq e '.environment |= with_entries(select(.key=="prod"))' 

[sguillope]

Legend Mike! It works well, except if environment doesn't exist (it doesn't always does in my use case). Then it crashes with:

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x28 pc=0x5f20f7]

goroutine 1 [running]:
container/list.(*List).Front(...)
	/usr/local/go/src/container/list/list.go:70
github.com/mikefarah/yq/v4/pkg/yqlib.assignUpdateOperator(0x8fa788, 0xc00012f560, 0x0, 0x0, 0xc0001c0c60, 0x0, 0x0, 0x199, 0x101, 0xc0001cdb28)
	/go/src/mikefarah/yq/pkg/yqlib/operator_assign.go:25 +0x137
github.com/mikefarah/yq/v4/pkg/yqlib.(*dataTreeNavigator).GetMatchingNodes(0x8fa788, 0xc00012f560, 0x0, 0x0, 0xc0001c0c60, 0xc000000000, 0xc0000963d8, 0x0, 0x0, 0x203000)
	/go/src/mikefarah/yq/pkg/yqlib/data_tree_navigator.go:37 +0x2a5
github.com/mikefarah/yq/v4/pkg/yqlib.(*streamEvaluator).Evaluate(0xc00012f0e0, 0x7ffd7e187f7f, 0x9, 0x7514c0, 0xc0000963d8, 0xc0001c0c60, 0x7529e0, 0xc000098600, 0xc0000b6201, 0xc0001c0a60)
	/go/src/mikefarah/yq/pkg/yqlib/stream_evaluator.go:100 +0x368
github.com/mikefarah/yq/v4/pkg/yqlib.(*streamEvaluator).EvaluateFiles(0xc00012f0e0, 0x7ffd7e187f36, 0x48, 0xc0000a85d0, 0x1, 0x1, 0x7529e0, 0xc000098600, 0xc0000bdd80, 0xc0000bdd10)
	/go/src/mikefarah/yq/pkg/yqlib/stream_evaluator.go:63 +0x152
github.com/mikefarah/yq/v4/cmd.evaluateSequence(0xc0000c2c80, 0xc0000a85c0, 0x2, 0x2, 0x0, 0x0)
	/go/src/mikefarah/yq/cmd/evalute_sequence_command.go:115 +0x92a
github.com/spf13/cobra.(*Command).execute(0xc0000c2c80, 0xc0000a8560, 0x2, 0x2, 0xc0000c2c80, 0xc0000a8560)
	/go/src/mikefarah/yq/vendor/github.com/spf13/cobra/command.go:852 +0x47c
github.com/spf13/cobra.(*Command).ExecuteC(0xc0000c2a00, 0x0, 0x69d020, 0xc000080058)
	/go/src/mikefarah/yq/vendor/github.com/spf13/cobra/command.go:960 +0x375
github.com/spf13/cobra.(*Command).Execute(...)
	/go/src/mikefarah/yq/vendor/github.com/spf13/cobra/command.go:897
main.main()
	/go/src/mikefarah/yq/yq.go:11 +0x2a

I've tried with the new optional id flag but same result. Happy to report an issue if you prefer.

[mikefarah]

doh - yeah please do.

[mikefarah]

Got a workaround till I fix the bug:

yq e '(select(has("environment")) | .environment) |= with_entries(select(.key=="prod"))' 

[sguillope]

Awesome, that did the trick. Thanks!