opentofu/terraform/node_resource_abstract.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

482 lines
16 KiB
Go

package terraform
import (
"fmt"
"log"
"github.com/hashicorp/terraform/addrs"
"github.com/hashicorp/terraform/configs"
"github.com/hashicorp/terraform/configs/configschema"
"github.com/hashicorp/terraform/dag"
"github.com/hashicorp/terraform/lang"
"github.com/hashicorp/terraform/states"
)
// ConcreteResourceNodeFunc is a callback type used to convert an
// abstract resource to a concrete one of some type.
type ConcreteResourceNodeFunc func(*NodeAbstractResource) dag.Vertex
// GraphNodeConfigResource is implemented by any nodes that represent a resource.
// The type of operation cannot be assumed, only that this node represents
// the given resource.
type GraphNodeConfigResource interface {
ResourceAddr() addrs.ConfigResource
}
// ConcreteResourceInstanceNodeFunc is a callback type used to convert an
// abstract resource instance to a concrete one of some type.
type ConcreteResourceInstanceNodeFunc func(*NodeAbstractResourceInstance) dag.Vertex
// GraphNodeResourceInstance is implemented by any nodes that represent
// a resource instance. A single resource may have multiple instances if,
// for example, the "count" or "for_each" argument is used for it in
// configuration.
type GraphNodeResourceInstance interface {
ResourceInstanceAddr() addrs.AbsResourceInstance
// StateDependencies returns any inter-resource dependencies that are
// stored in the state.
StateDependencies() []addrs.ConfigResource
}
// NodeAbstractResource represents a resource that has no associated
// operations. It registers all the interfaces for a resource that common
// across multiple operation types.
type NodeAbstractResource struct {
Addr addrs.ConfigResource
// The fields below will be automatically set using the Attach
// interfaces if you're running those transforms, but also be explicitly
// set if you already have that information.
Schema *configschema.Block // Schema for processing the configuration body
SchemaVersion uint64 // Schema version of "Schema", as decided by the provider
Config *configs.Resource // Config is the resource in the config
// ProviderMetas is the provider_meta configs for the module this resource belongs to
ProviderMetas map[addrs.Provider]*configs.ProviderMeta
ProvisionerSchemas map[string]*configschema.Block
// Set from GraphNodeTargetable
Targets []addrs.Targetable
// Set from AttachResourceDependencies
dependsOn []addrs.ConfigResource
forceDependsOn bool
// The address of the provider this resource will use
ResolvedProvider addrs.AbsProviderConfig
}
var (
_ GraphNodeReferenceable = (*NodeAbstractResource)(nil)
_ GraphNodeReferencer = (*NodeAbstractResource)(nil)
_ GraphNodeProviderConsumer = (*NodeAbstractResource)(nil)
_ GraphNodeProvisionerConsumer = (*NodeAbstractResource)(nil)
_ GraphNodeConfigResource = (*NodeAbstractResource)(nil)
_ GraphNodeAttachResourceConfig = (*NodeAbstractResource)(nil)
_ GraphNodeAttachResourceSchema = (*NodeAbstractResource)(nil)
_ GraphNodeAttachProvisionerSchema = (*NodeAbstractResource)(nil)
_ GraphNodeAttachProviderMetaConfigs = (*NodeAbstractResource)(nil)
_ GraphNodeTargetable = (*NodeAbstractResource)(nil)
_ graphNodeAttachResourceDependencies = (*NodeAbstractResource)(nil)
_ dag.GraphNodeDotter = (*NodeAbstractResource)(nil)
)
// NewNodeAbstractResource creates an abstract resource graph node for
// the given absolute resource address.
func NewNodeAbstractResource(addr addrs.ConfigResource) *NodeAbstractResource {
return &NodeAbstractResource{
Addr: addr,
}
}
// NodeAbstractResourceInstance represents a resource instance with no
// associated operations. It embeds NodeAbstractResource but additionally
// contains an instance key, used to identify one of potentially many
// instances that were created from a resource in configuration, e.g. using
// the "count" or "for_each" arguments.
type NodeAbstractResourceInstance struct {
NodeAbstractResource
Addr addrs.AbsResourceInstance
// These are set via the AttachState method.
instanceState *states.ResourceInstance
// storedProviderConfig is the provider address retrieved from the
// state, but since it is only stored in the whole Resource rather than the
// ResourceInstance, we extract it out here.
storedProviderConfig addrs.AbsProviderConfig
Dependencies []addrs.ConfigResource
}
var (
_ GraphNodeModuleInstance = (*NodeAbstractResourceInstance)(nil)
_ GraphNodeReferenceable = (*NodeAbstractResourceInstance)(nil)
_ GraphNodeReferencer = (*NodeAbstractResourceInstance)(nil)
_ GraphNodeProviderConsumer = (*NodeAbstractResourceInstance)(nil)
_ GraphNodeProvisionerConsumer = (*NodeAbstractResourceInstance)(nil)
_ GraphNodeConfigResource = (*NodeAbstractResourceInstance)(nil)
_ GraphNodeResourceInstance = (*NodeAbstractResourceInstance)(nil)
_ GraphNodeAttachResourceState = (*NodeAbstractResourceInstance)(nil)
_ GraphNodeAttachResourceConfig = (*NodeAbstractResourceInstance)(nil)
_ GraphNodeAttachResourceSchema = (*NodeAbstractResourceInstance)(nil)
_ GraphNodeAttachProvisionerSchema = (*NodeAbstractResourceInstance)(nil)
_ GraphNodeAttachProviderMetaConfigs = (*NodeAbstractResourceInstance)(nil)
_ GraphNodeTargetable = (*NodeAbstractResourceInstance)(nil)
_ dag.GraphNodeDotter = (*NodeAbstractResourceInstance)(nil)
)
// NewNodeAbstractResourceInstance creates an abstract resource instance graph
// node for the given absolute resource instance address.
func NewNodeAbstractResourceInstance(addr addrs.AbsResourceInstance) *NodeAbstractResourceInstance {
// Due to the fact that we embed NodeAbstractResource, the given address
// actually ends up split between the resource address in the embedded
// object and the InstanceKey field in our own struct. The
// ResourceInstanceAddr method will stick these back together again on
// request.
r := NewNodeAbstractResource(addr.ContainingResource().Config())
return &NodeAbstractResourceInstance{
NodeAbstractResource: *r,
Addr: addr,
}
}
func (n *NodeAbstractResource) Name() string {
return n.ResourceAddr().String()
}
func (n *NodeAbstractResourceInstance) Name() string {
return n.ResourceInstanceAddr().String()
}
func (n *NodeAbstractResourceInstance) Path() addrs.ModuleInstance {
return n.Addr.Module
}
// GraphNodeModulePath
func (n *NodeAbstractResource) ModulePath() addrs.Module {
return n.Addr.Module
}
// GraphNodeReferenceable
func (n *NodeAbstractResource) ReferenceableAddrs() []addrs.Referenceable {
return []addrs.Referenceable{n.Addr.Resource}
}
// GraphNodeReferenceable
func (n *NodeAbstractResourceInstance) ReferenceableAddrs() []addrs.Referenceable {
addr := n.ResourceInstanceAddr()
return []addrs.Referenceable{
addr.Resource,
// A resource instance can also be referenced by the address of its
// containing resource, so that e.g. a reference to aws_instance.foo
// would match both aws_instance.foo[0] and aws_instance.foo[1].
addr.ContainingResource().Resource,
}
}
// GraphNodeReferencer
func (n *NodeAbstractResource) References() []*addrs.Reference {
// If we have a config then we prefer to use that.
if c := n.Config; c != nil {
var result []*addrs.Reference
result = append(result, n.DependsOn()...)
if n.Schema == nil {
// Should never happen, but we'll log if it does so that we can
// see this easily when debugging.
log.Printf("[WARN] no schema is attached to %s, so config references cannot be detected", n.Name())
}
refs, _ := lang.ReferencesInExpr(c.Count)
result = append(result, refs...)
refs, _ = lang.ReferencesInExpr(c.ForEach)
result = append(result, refs...)
// ReferencesInBlock() requires a schema
if n.Schema != nil {
refs, _ = lang.ReferencesInBlock(c.Config, n.Schema)
}
result = append(result, refs...)
if c.Managed != nil {
if c.Managed.Connection != nil {
refs, _ = lang.ReferencesInBlock(c.Managed.Connection.Config, connectionBlockSupersetSchema)
result = append(result, refs...)
}
for _, p := range c.Managed.Provisioners {
if p.When != configs.ProvisionerWhenCreate {
continue
}
if p.Connection != nil {
refs, _ = lang.ReferencesInBlock(p.Connection.Config, connectionBlockSupersetSchema)
result = append(result, refs...)
}
schema := n.ProvisionerSchemas[p.Type]
if schema == nil {
log.Printf("[WARN] no schema for provisioner %q is attached to %s, so provisioner block references cannot be detected", p.Type, n.Name())
}
refs, _ = lang.ReferencesInBlock(p.Config, schema)
result = append(result, refs...)
}
}
return result
}
// Otherwise, we have no references.
return nil
}
func (n *NodeAbstractResource) DependsOn() []*addrs.Reference {
var result []*addrs.Reference
if c := n.Config; c != nil {
for _, traversal := range c.DependsOn {
ref, diags := addrs.ParseRef(traversal)
if diags.HasErrors() {
// We ignore this here, because this isn't a suitable place to return
// errors. This situation should be caught and rejected during
// validation.
log.Printf("[ERROR] Can't parse %#v from depends_on as reference: %s", traversal, diags.Err())
continue
}
result = append(result, ref)
}
}
return result
}
// GraphNodeReferencer
func (n *NodeAbstractResourceInstance) References() []*addrs.Reference {
// If we have a configuration attached then we'll delegate to our
// embedded abstract resource, which knows how to extract dependencies
// from configuration. If there is no config, then the dependencies will
// be connected during destroy from those stored in the state.
if n.Config != nil {
if n.Schema == nil {
// We'll produce a log message about this out here so that
// we can include the full instance address, since the equivalent
// message in NodeAbstractResource.References cannot see it.
log.Printf("[WARN] no schema is attached to %s, so config references cannot be detected", n.Name())
return nil
}
return n.NodeAbstractResource.References()
}
// If we have neither config nor state then we have no references.
return nil
}
// converts an instance address to the legacy dotted notation
func dottedInstanceAddr(tr addrs.ResourceInstance) string {
// The legacy state format uses dot-separated instance keys,
// rather than bracketed as in our modern syntax.
var suffix string
switch tk := tr.Key.(type) {
case addrs.IntKey:
suffix = fmt.Sprintf(".%d", int(tk))
case addrs.StringKey:
suffix = fmt.Sprintf(".%s", string(tk))
}
return tr.Resource.String() + suffix
}
// StateDependencies returns the dependencies saved in the state.
func (n *NodeAbstractResourceInstance) StateDependencies() []addrs.ConfigResource {
if s := n.instanceState; s != nil {
if s.Current != nil {
return s.Current.Dependencies
}
}
return nil
}
func (n *NodeAbstractResource) SetProvider(p addrs.AbsProviderConfig) {
n.ResolvedProvider = p
}
// GraphNodeProviderConsumer
func (n *NodeAbstractResource) ProvidedBy() (addrs.ProviderConfig, bool) {
// If we have a config we prefer that above all else
if n.Config != nil {
relAddr := n.Config.ProviderConfigAddr()
return addrs.LocalProviderConfig{
LocalName: relAddr.LocalName,
Alias: relAddr.Alias,
}, false
}
// No provider configuration found; return a default address
return addrs.AbsProviderConfig{
Provider: n.Provider(),
Module: n.ModulePath(),
}, false
}
// GraphNodeProviderConsumer
func (n *NodeAbstractResource) Provider() addrs.Provider {
if n.Config != nil {
return n.Config.Provider
}
return addrs.ImpliedProviderForUnqualifiedType(n.Addr.Resource.ImpliedProvider())
}
// GraphNodeProviderConsumer
func (n *NodeAbstractResourceInstance) ProvidedBy() (addrs.ProviderConfig, bool) {
// If we have a config we prefer that above all else
if n.Config != nil {
relAddr := n.Config.ProviderConfigAddr()
return addrs.LocalProviderConfig{
LocalName: relAddr.LocalName,
Alias: relAddr.Alias,
}, false
}
// See if we have a valid provider config from the state.
if n.storedProviderConfig.Provider.Type != "" {
// An address from the state must match exactly, since we must ensure
// we refresh/destroy a resource with the same provider configuration
// that created it.
return n.storedProviderConfig, true
}
// No provider configuration found; return a default address
return addrs.AbsProviderConfig{
Provider: n.Provider(),
Module: n.ModulePath(),
}, false
}
// GraphNodeProviderConsumer
func (n *NodeAbstractResourceInstance) Provider() addrs.Provider {
if n.Config != nil {
return n.Config.Provider
}
return addrs.NewDefaultProvider(n.Addr.Resource.ContainingResource().ImpliedProvider())
}
// GraphNodeProvisionerConsumer
func (n *NodeAbstractResource) ProvisionedBy() []string {
// If we have no configuration, then we have no provisioners
if n.Config == nil || n.Config.Managed == nil {
return nil
}
// Build the list of provisioners we need based on the configuration.
// It is okay to have duplicates here.
result := make([]string, len(n.Config.Managed.Provisioners))
for i, p := range n.Config.Managed.Provisioners {
result[i] = p.Type
}
return result
}
// GraphNodeProvisionerConsumer
func (n *NodeAbstractResource) AttachProvisionerSchema(name string, schema *configschema.Block) {
if n.ProvisionerSchemas == nil {
n.ProvisionerSchemas = make(map[string]*configschema.Block)
}
n.ProvisionerSchemas[name] = schema
}
// GraphNodeResource
func (n *NodeAbstractResource) ResourceAddr() addrs.ConfigResource {
return n.Addr
}
// GraphNodeResourceInstance
func (n *NodeAbstractResourceInstance) ResourceInstanceAddr() addrs.AbsResourceInstance {
return n.Addr
}
// GraphNodeTargetable
func (n *NodeAbstractResource) SetTargets(targets []addrs.Targetable) {
n.Targets = targets
}
// graphNodeAttachResourceDependencies
func (n *NodeAbstractResource) AttachResourceDependencies(deps []addrs.ConfigResource, force bool) {
n.dependsOn = deps
n.forceDependsOn = force
}
// GraphNodeAttachResourceState
func (n *NodeAbstractResourceInstance) AttachResourceState(s *states.Resource) {
if s == nil {
log.Printf("[WARN] attaching nil state to %s", n.Addr)
return
}
n.instanceState = s.Instance(n.Addr.Resource.Key)
n.storedProviderConfig = s.ProviderConfig
}
// GraphNodeAttachResourceConfig
func (n *NodeAbstractResource) AttachResourceConfig(c *configs.Resource) {
n.Config = c
}
// GraphNodeAttachResourceSchema impl
func (n *NodeAbstractResource) AttachResourceSchema(schema *configschema.Block, version uint64) {
n.Schema = schema
n.SchemaVersion = version
}
// GraphNodeAttachProviderMetaConfigs impl
func (n *NodeAbstractResource) AttachProviderMetaConfigs(c map[addrs.Provider]*configs.ProviderMeta) {
n.ProviderMetas = c
}
// GraphNodeDotter impl.
func (n *NodeAbstractResource) DotNode(name string, opts *dag.DotOpts) *dag.DotNode {
return &dag.DotNode{
Name: name,
Attrs: map[string]string{
"label": n.Name(),
"shape": "box",
},
}
}
// graphNodesAreResourceInstancesInDifferentInstancesOfSameModule is an
// annoyingly-task-specific helper function that returns true if and only if
// the following conditions hold:
// - Both of the given vertices represent specific resource instances, as
// opposed to unexpanded resources or any other non-resource-related object.
// - The module instance addresses for both of the resource instances belong
// to the same static module.
// - The module instance addresses for both of the resource instances are
// not equal, indicating that they belong to different instances of the
// same module.
//
// This result can be used as a way to compensate for the effects of
// conservative analyses passes in our graph builders which make their
// decisions based only on unexpanded addresses, often so that they can behave
// correctly for interactions between expanded and not-yet-expanded objects.
//
// Callers of this helper function will typically skip adding an edge between
// the two given nodes if this function returns true.
func graphNodesAreResourceInstancesInDifferentInstancesOfSameModule(a, b dag.Vertex) bool {
aRI, aOK := a.(GraphNodeResourceInstance)
bRI, bOK := b.(GraphNodeResourceInstance)
if !(aOK && bOK) {
return false
}
aModInst := aRI.ResourceInstanceAddr().Module
bModInst := bRI.ResourceInstanceAddr().Module
aMod := aModInst.Module()
bMod := bModInst.Module()
if !aMod.Equal(bMod) {
return false
}
return !aModInst.Equal(bModInst)
}