Request for an example usage of the cue.mod/usr dir

[PierreR]

I would love to see an example of a CUE config that uses cue.mod/usr (https://cuelang.org/docs/concepts/packages/#the-cuemod-directory).

Particularly I would like to add constraints on the generated kubernetes api (stored in cue.mod/gen). A file that looks likes:

import (
	core_v1 "k8s.io/api/core/v1"
)

#ConfigMap: core_v1.#ConfigMap & {
	apiVersion: "v1"
	kind:       "ConfigMap"
}

#Deployment: apps_v1.#Deployment & {
	apiVersion: "apps/v1"
	kind:       "Deployment"
}
...

I did try to access the refined definitions in the cue-managed directories by importing the cue module (from the cue.mod/module.cue file) but without success.

[PierreR]

I have actually just found out I need to duplicate the same hierarchy and re-use the same package.
That makes sense.

[myitcv]

For those looking for a complete example:

exec go mod tidy
exec cue get go k8s.io/api/core/v1
! exec cue eval
cmp stderr stderr.golden

-- cue.mod/usr/k8s.io/api/core/v1/v1.cue --
package v1

#Protocol: #enumProtocol
-- cuedeps.go --
//go:build cuedeps
// +build cuedeps

package cuedeps

import _ "k8s.io/api/core/v1"
-- go.mod --
module mod.com

go 1.16

require (
	k8s.io/api v0.21.1
)
-- x.cue --
package x

import "k8s.io/api/core/v1"

p1: v1.#Protocol
p1: "TCP"

p2: v1.#Protocol
p2: "TTCP"
-- stderr.golden --
p2: 3 errors in empty disjunction:
p2: conflicting values "SCTP" and "TTCP":
    ./cue.mod/gen/k8s.io/api/core/v1/types_go_gen.cue:1065:2
    ./cue.mod/gen/k8s.io/api/core/v1/types_go_gen.cue:1074:28
    ./cue.mod/usr/k8s.io/api/core/v1/v1.cue:3:12
    ./x.cue:8:5
    ./x.cue:9:5
p2: conflicting values "TCP" and "TTCP":
    ./cue.mod/gen/k8s.io/api/core/v1/types_go_gen.cue:1063:2
    ./cue.mod/gen/k8s.io/api/core/v1/types_go_gen.cue:1068:27
    ./cue.mod/usr/k8s.io/api/core/v1/v1.cue:3:12
    ./x.cue:8:5
    ./x.cue:9:5
p2: conflicting values "UDP" and "TTCP":
    ./cue.mod/gen/k8s.io/api/core/v1/types_go_gen.cue:1064:2
    ./cue.mod/gen/k8s.io/api/core/v1/types_go_gen.cue:1071:27
    ./cue.mod/usr/k8s.io/api/core/v1/v1.cue:3:12
    ./x.cue:8:5
    ./x.cue:9:5

[cueckoo]

This discussion has been migrated to cue-lang/cue#908.

For more details about CUE's migration to a new home, please see cue-lang/cue#1078.