opentofu/terraform/transform_reference_test.go
Martin Atkins 61baceb308 core: Skip edges between resource instances in different module instances
Our reference transformer analyses and our destroy transformer analyses
are built around static (not-yet-expanded) addresses so that they can
correctly handle mixtures of expanded and not-yet-expanded objects in the
same graph.

However, this characteristic also makes them unnecessarily conservative
in their handling of references between resources within different
instances of the same module: we know they can never interact with each
other in practice because the dependencies for all instances of a module
are the same and so one instance cannot possibly depend on another.

As a compromise then, here we introduce a new helper function that can
recognize when a proposed edge is between two resource instances that
belong to different instances of the same module, and thus allow us to
skip actually creating those edges even though our imprecise analyses
believe them to be needed.

As well as significantly reducing the number of edges in situations where
multi-instance resources appear inside multi-instance modules, this also
fixes some potential cycles in situations where a single plan includes
both destroying an instance of a module and creating a new instance of the
same module: the dependencies between the objects in the instance being
destroyed and the objects in the instance being created can, if allowed
to connect, cause Terraform to believe that the create and the destroy
both depend on one another even though there is no need for that to be
true in practice.

This involves a very specialized helper function to encode the situation
where this exception applies. This function has an ugly name to reflect
how specialized it is; it's not intended to be of any use outside of these
three situations in particular.
2020-07-17 08:40:13 -07:00

339 lines
7.7 KiB
Go

package terraform
import (
"reflect"
"sort"
"strings"
"testing"
"github.com/hashicorp/terraform/addrs"
"github.com/hashicorp/terraform/dag"
)
func TestReferenceTransformer_simple(t *testing.T) {
g := Graph{Path: addrs.RootModuleInstance}
g.Add(&graphNodeRefParentTest{
NameValue: "A",
Names: []string{"A"},
})
g.Add(&graphNodeRefChildTest{
NameValue: "B",
Refs: []string{"A"},
})
tf := &ReferenceTransformer{}
if err := tf.Transform(&g); err != nil {
t.Fatalf("err: %s", err)
}
actual := strings.TrimSpace(g.String())
expected := strings.TrimSpace(testTransformRefBasicStr)
if actual != expected {
t.Fatalf("wrong result\n\ngot:\n%s\n\nwant:\n%s", actual, expected)
}
}
func TestReferenceTransformer_self(t *testing.T) {
g := Graph{Path: addrs.RootModuleInstance}
g.Add(&graphNodeRefParentTest{
NameValue: "A",
Names: []string{"A"},
})
g.Add(&graphNodeRefChildTest{
NameValue: "B",
Refs: []string{"A", "B"},
})
tf := &ReferenceTransformer{}
if err := tf.Transform(&g); err != nil {
t.Fatalf("err: %s", err)
}
actual := strings.TrimSpace(g.String())
expected := strings.TrimSpace(testTransformRefBasicStr)
if actual != expected {
t.Fatalf("wrong result\n\ngot:\n%s\n\nwant:\n%s", actual, expected)
}
}
func TestReferenceTransformer_path(t *testing.T) {
g := Graph{Path: addrs.RootModuleInstance}
g.Add(&graphNodeRefParentTest{
NameValue: "A",
Names: []string{"A"},
})
g.Add(&graphNodeRefChildTest{
NameValue: "B",
Refs: []string{"A"},
})
g.Add(&graphNodeRefParentTest{
NameValue: "child.A",
PathValue: []string{"root", "child"},
Names: []string{"A"},
})
g.Add(&graphNodeRefChildTest{
NameValue: "child.B",
PathValue: []string{"root", "child"},
Refs: []string{"A"},
})
tf := &ReferenceTransformer{}
if err := tf.Transform(&g); err != nil {
t.Fatalf("err: %s", err)
}
actual := strings.TrimSpace(g.String())
expected := strings.TrimSpace(testTransformRefPathStr)
if actual != expected {
t.Fatalf("wrong result\n\ngot:\n%s\n\nwant:\n%s", actual, expected)
}
}
func TestReferenceTransformer_resourceInstances(t *testing.T) {
// Our reference analyses are all done based on unexpanded addresses
// so that we can use this transformer both in the plan graph (where things
// are not expanded yet) and the apply graph (where resource instances are
// pre-expanded but nothing else is.)
// However, that would make the result too conservative about instances
// of the same resource in different instances of the same module, so we
// make an exception for that situation in particular, keeping references
// between resource instances segregated by their containing module
// instance.
g := Graph{Path: addrs.RootModuleInstance}
moduleInsts := []addrs.ModuleInstance{
{
{
Name: "foo", InstanceKey: addrs.IntKey(0),
},
},
{
{
Name: "foo", InstanceKey: addrs.IntKey(1),
},
},
}
resourceAs := make([]addrs.AbsResourceInstance, len(moduleInsts))
for i, moduleInst := range moduleInsts {
resourceAs[i] = addrs.Resource{
Mode: addrs.ManagedResourceMode,
Type: "thing",
Name: "a",
}.Instance(addrs.NoKey).Absolute(moduleInst)
}
resourceBs := make([]addrs.AbsResourceInstance, len(moduleInsts))
for i, moduleInst := range moduleInsts {
resourceBs[i] = addrs.Resource{
Mode: addrs.ManagedResourceMode,
Type: "thing",
Name: "b",
}.Instance(addrs.NoKey).Absolute(moduleInst)
}
g.Add(&graphNodeFakeResourceInstance{
Addr: resourceAs[0],
})
g.Add(&graphNodeFakeResourceInstance{
Addr: resourceBs[0],
Refs: []*addrs.Reference{
{
Subject: resourceAs[0].Resource,
},
},
})
g.Add(&graphNodeFakeResourceInstance{
Addr: resourceAs[1],
})
g.Add(&graphNodeFakeResourceInstance{
Addr: resourceBs[1],
Refs: []*addrs.Reference{
{
Subject: resourceAs[1].Resource,
},
},
})
tf := &ReferenceTransformer{}
if err := tf.Transform(&g); err != nil {
t.Fatalf("unexpected error: %s", err)
}
// Resource B should be connected to resource A in each module instance,
// but there should be no connections between the two module instances.
actual := strings.TrimSpace(g.String())
expected := strings.TrimSpace(`
module.foo[0].thing.a
module.foo[0].thing.b
module.foo[0].thing.a
module.foo[1].thing.a
module.foo[1].thing.b
module.foo[1].thing.a
`)
if actual != expected {
t.Fatalf("wrong result\n\ngot:\n%s\n\nwant:\n%s", actual, expected)
}
}
func TestReferenceMapReferences(t *testing.T) {
cases := map[string]struct {
Nodes []dag.Vertex
Check dag.Vertex
Result []string
}{
"simple": {
Nodes: []dag.Vertex{
&graphNodeRefParentTest{
NameValue: "A",
Names: []string{"A"},
},
},
Check: &graphNodeRefChildTest{
NameValue: "foo",
Refs: []string{"A"},
},
Result: []string{"A"},
},
}
for tn, tc := range cases {
t.Run(tn, func(t *testing.T) {
rm := NewReferenceMap(tc.Nodes)
result := rm.References(tc.Check)
var resultStr []string
for _, v := range result {
resultStr = append(resultStr, dag.VertexName(v))
}
sort.Strings(resultStr)
sort.Strings(tc.Result)
if !reflect.DeepEqual(resultStr, tc.Result) {
t.Fatalf("bad: %#v", resultStr)
}
})
}
}
type graphNodeRefParentTest struct {
NameValue string
PathValue []string
Names []string
}
var _ GraphNodeReferenceable = (*graphNodeRefParentTest)(nil)
func (n *graphNodeRefParentTest) Name() string {
return n.NameValue
}
func (n *graphNodeRefParentTest) ReferenceableAddrs() []addrs.Referenceable {
ret := make([]addrs.Referenceable, len(n.Names))
for i, name := range n.Names {
ret[i] = addrs.LocalValue{Name: name}
}
return ret
}
func (n *graphNodeRefParentTest) Path() addrs.ModuleInstance {
return normalizeModulePath(n.PathValue)
}
func (n *graphNodeRefParentTest) ModulePath() addrs.Module {
return normalizeModulePath(n.PathValue).Module()
}
type graphNodeRefChildTest struct {
NameValue string
PathValue []string
Refs []string
}
var _ GraphNodeReferencer = (*graphNodeRefChildTest)(nil)
func (n *graphNodeRefChildTest) Name() string {
return n.NameValue
}
func (n *graphNodeRefChildTest) References() []*addrs.Reference {
ret := make([]*addrs.Reference, len(n.Refs))
for i, name := range n.Refs {
ret[i] = &addrs.Reference{
Subject: addrs.LocalValue{Name: name},
}
}
return ret
}
func (n *graphNodeRefChildTest) Path() addrs.ModuleInstance {
return normalizeModulePath(n.PathValue)
}
func (n *graphNodeRefChildTest) ModulePath() addrs.Module {
return normalizeModulePath(n.PathValue).Module()
}
type graphNodeFakeResourceInstance struct {
Addr addrs.AbsResourceInstance
Refs []*addrs.Reference
}
var _ GraphNodeResourceInstance = (*graphNodeFakeResourceInstance)(nil)
var _ GraphNodeReferenceable = (*graphNodeFakeResourceInstance)(nil)
var _ GraphNodeReferencer = (*graphNodeFakeResourceInstance)(nil)
func (n *graphNodeFakeResourceInstance) ResourceInstanceAddr() addrs.AbsResourceInstance {
return n.Addr
}
func (n *graphNodeFakeResourceInstance) ModulePath() addrs.Module {
return n.Addr.Module.Module()
}
func (n *graphNodeFakeResourceInstance) ReferenceableAddrs() []addrs.Referenceable {
return []addrs.Referenceable{n.Addr.Resource}
}
func (n *graphNodeFakeResourceInstance) References() []*addrs.Reference {
return n.Refs
}
func (n *graphNodeFakeResourceInstance) StateDependencies() []addrs.ConfigResource {
return nil
}
func (n *graphNodeFakeResourceInstance) String() string {
return n.Addr.String()
}
const testTransformRefBasicStr = `
A
B
A
`
const testTransformRefBackupStr = `
A
B
A
`
const testTransformRefBackupPrimaryStr = `
A
B
C
C
`
const testTransformRefModulePathStr = `
A
B
A
`
const testTransformRefPathStr = `
A
B
A
child.A
child.B
child.A
`