Conditionally including CUE files using build attributes | CUE

Jonathan Matthews

language

This guide demonstrates how to include CUE files in an evaluation conditionally, using build attributes.

The example CUE package is composed of three files:

@if(foo)
package example

"data from foo.cue": true

@if(!bar)
package example

"data from bar.cue": true

package example

"data from qux.cue": true

Two of these files contain build attributes, which control if the file’s contents are included in evaluations of the example package based on the presence or absence of tags:

foo.cue is included only when the foo tag is present.
bar.cue is included only when the bar tag is not present.
qux.cue is always included.

TERMINAL

$ cue export
{
    "data from bar.cue": true,
    "data from qux.cue": true
}
$ cue export -t foo
{
    "data from bar.cue": true,
    "data from foo.cue": true,
    "data from qux.cue": true
}
$ cue export -t bar
{
    "data from qux.cue": true
}
$ cue export -t foo -t bar
{
    "data from foo.cue": true,
    "data from qux.cue": true
}

The foo and bar tags are only aligned with their respective filenames to help you understand their relationships in this example. Tags and filenames do not need to overlap in any way: they are entirely unrelated strings.

Reference: cue help injection – injecting tags and values into cue command invocations

Related content