opentofu/instances/expansion_mode.go
Martin Atkins 1dece66b10 instances: A package for module/resource reptition
This package aims to encapsulate the module/resource repetition problem
so that Terraform Core's graph node DynamicExpand implementations can be
simpler.

This is also a building block on the path towards module repetition, by
modelling the recursive expansion of modules and their contents. This will
allow the Terraform Core plan graph to have one node per configuration
construct, each of which will DynamicExpand into as many sub-nodes as
necessary to cover all of the recursive module instantiations.

For the moment this is just dead code, because Terraform Core isn't yet
updated to use it.
2020-02-14 15:20:07 -08:00

86 lines
2.2 KiB
Go

package instances
import (
"fmt"
"sort"
"github.com/zclconf/go-cty/cty"
"github.com/hashicorp/terraform/addrs"
)
// expansion is an internal interface used to represent the different
// ways expansion can operate depending on how repetition is configured for
// an object.
type expansion interface {
instanceKeys() []addrs.InstanceKey
repetitionData(addrs.InstanceKey) RepetitionData
}
// expansionSingle is the expansion corresponding to no repetition arguments
// at all, producing a single object with no key.
//
// expansionSingleVal is the only valid value of this type.
type expansionSingle uintptr
var singleKeys = []addrs.InstanceKey{addrs.NoKey}
var expansionSingleVal expansionSingle
func (e expansionSingle) instanceKeys() []addrs.InstanceKey {
return singleKeys
}
func (e expansionSingle) repetitionData(key addrs.InstanceKey) RepetitionData {
if key != addrs.NoKey {
panic("cannot use instance key with non-repeating object")
}
return RepetitionData{}
}
// expansionCount is the expansion corresponding to the "count" argument.
type expansionCount int
func (e expansionCount) instanceKeys() []addrs.InstanceKey {
ret := make([]addrs.InstanceKey, int(e))
for i := range ret {
ret[i] = addrs.IntKey(i)
}
return ret
}
func (e expansionCount) repetitionData(key addrs.InstanceKey) RepetitionData {
i := int(key.(addrs.IntKey))
if i < 0 || i >= int(e) {
panic(fmt.Sprintf("instance key %d out of range for count %d", i, e))
}
return RepetitionData{
CountIndex: cty.NumberIntVal(int64(i)),
}
}
// expansionForEach is the expansion corresponding to the "for_each" argument.
type expansionForEach map[string]cty.Value
func (e expansionForEach) instanceKeys() []addrs.InstanceKey {
ret := make([]addrs.InstanceKey, 0, len(e))
for k := range e {
ret = append(ret, addrs.StringKey(k))
}
sort.Slice(ret, func(i, j int) bool {
return ret[i].(addrs.StringKey) < ret[j].(addrs.StringKey)
})
return ret
}
func (e expansionForEach) repetitionData(key addrs.InstanceKey) RepetitionData {
k := string(key.(addrs.StringKey))
v, ok := e[k]
if !ok {
panic(fmt.Sprintf("instance key %q does not match any instance", k))
}
return RepetitionData{
EachKey: cty.StringVal(k),
EachValue: v,
}
}