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package terraform
import (
"fmt"
"log"
"github.com/hashicorp/terraform/addrs"
"github.com/hashicorp/terraform/configs"
"github.com/hashicorp/terraform/providers"
"github.com/hashicorp/terraform/states"
"github.com/hashicorp/terraform/tfdiags"
)
// EvalReadState is an EvalNode implementation that reads the
// current object for a specific instance in the state.
type EvalReadState struct {
// Addr is the address of the instance to read state for.
Addr addrs.ResourceInstance
// ProviderSchema is the schema for the provider given in Provider.
ProviderSchema **ProviderSchema
// Provider is the provider that will subsequently perform actions on
// the the state object. This is used to perform any schema upgrades
// that might be required to prepare the stored data for use.
Provider *providers.Interface
// Output will be written with a pointer to the retrieved object.
Output **states.ResourceInstanceObject
}
func (n *EvalReadState) Eval(ctx EvalContext) (interface{}, error) {
if n.Provider == nil || *n.Provider == nil {
panic("EvalReadState used with no Provider object")
}
if n.ProviderSchema == nil || *n.ProviderSchema == nil {
panic("EvalReadState used with no ProviderSchema object")
}
absAddr := n.Addr.Absolute(ctx.Path())
log.Printf("[TRACE] EvalReadState: reading state for %s", absAddr)
src := ctx.State().ResourceInstanceObject(absAddr, states.CurrentGen)
if src == nil {
// Presumably we only have deposed objects, then.
log.Printf("[TRACE] EvalReadState: no state present for %s", absAddr)
return nil, nil
}
schema, currentVersion := (*n.ProviderSchema).SchemaForResourceAddr(n.Addr.ContainingResource())
if schema == nil {
// Shouldn't happen since we should've failed long ago if no schema is present
return nil, fmt.Errorf("no schema available for %s while reading state; this is a bug in Terraform and should be reported", absAddr)
}
var diags tfdiags.Diagnostics
src, diags = UpgradeResourceState(absAddr, *n.Provider, src, schema, currentVersion)
if diags.HasErrors() {
// Note that we don't have any channel to return warnings here. We'll
// accept that for now since warnings during a schema upgrade would
// be pretty weird anyway, since this operation is supposed to seem
// invisible to the user.
return nil, diags.Err()
}
obj, err := src.Decode(schema.ImpliedType())
if err != nil {
return nil, err
}
if n.Output != nil {
*n.Output = obj
}
return obj, nil
}
// EvalReadStateDeposed is an EvalNode implementation that reads the
// deposed InstanceState for a specific resource out of the state
type EvalReadStateDeposed struct {
// Addr is the address of the instance to read state for.
Addr addrs.ResourceInstance
// Key identifies which deposed object we will read.
Key states.DeposedKey
// ProviderSchema is the schema for the provider given in Provider.
ProviderSchema **ProviderSchema
// Provider is the provider that will subsequently perform actions on
// the the state object. This is used to perform any schema upgrades
// that might be required to prepare the stored data for use.
Provider *providers.Interface
// Output will be written with a pointer to the retrieved object.
Output **states.ResourceInstanceObject
}
func (n *EvalReadStateDeposed) Eval(ctx EvalContext) (interface{}, error) {
if n.Provider == nil || *n.Provider == nil {
panic("EvalReadStateDeposed used with no Provider object")
}
if n.ProviderSchema == nil || *n.ProviderSchema == nil {
panic("EvalReadStateDeposed used with no ProviderSchema object")
}
key := n.Key
if key == states.NotDeposed {
return nil, fmt.Errorf("EvalReadStateDeposed used with no instance key; this is a bug in Terraform and should be reported")
}
absAddr := n.Addr.Absolute(ctx.Path())
log.Printf("[TRACE] EvalReadStateDeposed: reading state for %s deposed object %s", absAddr, n.Key)
src := ctx.State().ResourceInstanceObject(absAddr, key)
if src == nil {
// Presumably we only have deposed objects, then.
log.Printf("[TRACE] EvalReadStateDeposed: no state present for %s deposed object %s", absAddr, n.Key)
return nil, nil
}
schema, currentVersion := (*n.ProviderSchema).SchemaForResourceAddr(n.Addr.ContainingResource())
if schema == nil {
// Shouldn't happen since we should've failed long ago if no schema is present
return nil, fmt.Errorf("no schema available for %s while reading state; this is a bug in Terraform and should be reported", absAddr)
}
var diags tfdiags.Diagnostics
src, diags = UpgradeResourceState(absAddr, *n.Provider, src, schema, currentVersion)
if diags.HasErrors() {
// Note that we don't have any channel to return warnings here. We'll
// accept that for now since warnings during a schema upgrade would
// be pretty weird anyway, since this operation is supposed to seem
// invisible to the user.
return nil, diags.Err()
}
obj, err := src.Decode(schema.ImpliedType())
if err != nil {
return nil, err
}
if n.Output != nil {
*n.Output = obj
}
return obj, nil
}
// EvalRequireState is an EvalNode implementation that exits early if the given
// object is null.
type EvalRequireState struct {
State **states.ResourceInstanceObject
}
func (n *EvalRequireState) Eval(ctx EvalContext) (interface{}, error) {
if n.State == nil {
return nil, EvalEarlyExitError{}
}
state := *n.State
if state == nil || state.Value.IsNull() {
return nil, EvalEarlyExitError{}
}
return nil, nil
}
// EvalUpdateStateHook is an EvalNode implementation that calls the
// PostStateUpdate hook with the current state.
type EvalUpdateStateHook struct{}
func (n *EvalUpdateStateHook) Eval(ctx EvalContext) (interface{}, error) {
// In principle we could grab the lock here just long enough to take a
// deep copy and then pass that to our hooks below, but we'll instead
// hold the hook for the duration to avoid the potential confusing
// situation of us racing to call PostStateUpdate concurrently with
// different state snapshots.
stateSync := ctx.State()
state := stateSync.Lock().DeepCopy()
defer stateSync.Unlock()
// Call the hook
err := ctx.Hook(func(h Hook) (HookAction, error) {
return h.PostStateUpdate(state)
})
if err != nil {
return nil, err
}
return nil, nil
}
// EvalWriteState is an EvalNode implementation that saves the given object
// as the current object for the selected resource instance.
type EvalWriteState struct {
// Addr is the address of the instance to read state for.
Addr addrs.ResourceInstance
// State is the object state to save.
State **states.ResourceInstanceObject
// ProviderSchema is the schema for the provider given in ProviderAddr.
ProviderSchema **ProviderSchema
// ProviderAddr is the address of the provider configuration that
// produced the given object.
ProviderAddr addrs.AbsProviderConfig
}
func (n *EvalWriteState) Eval(ctx EvalContext) (interface{}, error) {
if n.State == nil {
// Note that a pointer _to_ nil is valid here, indicating the total
// absense of an object as we'd see during destroy.
panic("EvalWriteState used with no ResourceInstanceObject")
}
absAddr := n.Addr.Absolute(ctx.Path())
state := ctx.State()
if n.ProviderAddr.ProviderConfig.Type == "" {
return nil, fmt.Errorf("failed to write state for %s, missing provider type", absAddr)
}
obj := *n.State
if obj == nil || obj.Value.IsNull() {
// No need to encode anything: we'll just write it directly.
state.SetResourceInstanceCurrent(absAddr, nil, n.ProviderAddr)
log.Printf("[TRACE] EvalWriteState: removing state object for %s", absAddr)
return nil, nil
}
if n.ProviderSchema == nil || *n.ProviderSchema == nil {
// Should never happen, unless our state object is nil
panic("EvalWriteState used with pointer to nil ProviderSchema object")
}
if obj != nil {
log.Printf("[TRACE] EvalWriteState: writing current state object for %s", absAddr)
} else {
log.Printf("[TRACE] EvalWriteState: removing current state object for %s", absAddr)
}
schema, currentVersion := (*n.ProviderSchema).SchemaForResourceAddr(n.Addr.ContainingResource())
if schema == nil {
// It shouldn't be possible to get this far in any real scenario
// without a schema, but we might end up here in contrived tests that
// fail to set up their world properly.
return nil, fmt.Errorf("failed to encode %s in state: no resource type schema available", absAddr)
}
src, err := obj.Encode(schema.ImpliedType(), currentVersion)
if err != nil {
return nil, fmt.Errorf("failed to encode %s in state: %s", absAddr, err)
}
state.SetResourceInstanceCurrent(absAddr, src, n.ProviderAddr)
return nil, nil
}
// EvalWriteStateDeposed is an EvalNode implementation that writes
// an InstanceState out to the Deposed list of a resource in the state.
type EvalWriteStateDeposed struct {
// Addr is the address of the instance to read state for.
Addr addrs.ResourceInstance
// Key indicates which deposed object to write to.
Key states.DeposedKey
// State is the object state to save.
State **states.ResourceInstanceObject
// ProviderSchema is the schema for the provider given in ProviderAddr.
ProviderSchema **ProviderSchema
// ProviderAddr is the address of the provider configuration that
// produced the given object.
ProviderAddr addrs.AbsProviderConfig
}
func (n *EvalWriteStateDeposed) Eval(ctx EvalContext) (interface{}, error) {
if n.State == nil {
// Note that a pointer _to_ nil is valid here, indicating the total
// absense of an object as we'd see during destroy.
panic("EvalWriteStateDeposed used with no ResourceInstanceObject")
}
absAddr := n.Addr.Absolute(ctx.Path())
key := n.Key
state := ctx.State()
if key == states.NotDeposed {
// should never happen
return nil, fmt.Errorf("can't save deposed object for %s without a deposed key; this is a bug in Terraform that should be reported", absAddr)
}
obj := *n.State
if obj == nil {
// No need to encode anything: we'll just write it directly.
state.SetResourceInstanceDeposed(absAddr, key, nil, n.ProviderAddr)
log.Printf("[TRACE] EvalWriteStateDeposed: removing state object for %s deposed %s", absAddr, key)
return nil, nil
}
if n.ProviderSchema == nil || *n.ProviderSchema == nil {
// Should never happen, unless our state object is nil
panic("EvalWriteStateDeposed used with no ProviderSchema object")
}
schema, currentVersion := (*n.ProviderSchema).SchemaForResourceAddr(n.Addr.ContainingResource())
if schema == nil {
// It shouldn't be possible to get this far in any real scenario
// without a schema, but we might end up here in contrived tests that
// fail to set up their world properly.
return nil, fmt.Errorf("failed to encode %s in state: no resource type schema available", absAddr)
}
src, err := obj.Encode(schema.ImpliedType(), currentVersion)
if err != nil {
return nil, fmt.Errorf("failed to encode %s in state: %s", absAddr, err)
}
log.Printf("[TRACE] EvalWriteStateDeposed: writing state object for %s deposed %s", absAddr, key)
state.SetResourceInstanceDeposed(absAddr, key, src, n.ProviderAddr)
return nil, nil
}
// EvalDeposeState is an EvalNode implementation that moves the current object
// for the given instance to instead be a deposed object, leaving the instance
// with no current object.
// This is used at the beginning of a create-before-destroy replace action so
// that the create can create while preserving the old state of the
// to-be-destroyed object.
type EvalDeposeState struct {
Addr addrs.ResourceInstance
// ForceKey, if a value other than states.NotDeposed, will be used as the
// key for the newly-created deposed object that results from this action.
// If set to states.NotDeposed (the zero value), a new unique key will be
// allocated.
ForceKey states.DeposedKey
// OutputKey, if non-nil, will be written with the deposed object key that
// was generated for the object. This can then be passed to
// EvalUndeposeState.Key so it knows which deposed instance to forget.
OutputKey *states.DeposedKey
}
// TODO: test
func (n *EvalDeposeState) Eval(ctx EvalContext) (interface{}, error) {
absAddr := n.Addr.Absolute(ctx.Path())
state := ctx.State()
var key states.DeposedKey
if n.ForceKey == states.NotDeposed {
key = state.DeposeResourceInstanceObject(absAddr)
} else {
key = n.ForceKey
state.DeposeResourceInstanceObjectForceKey(absAddr, key)
}
log.Printf("[TRACE] EvalDeposeState: prior object for %s now deposed with key %s", absAddr, key)
if n.OutputKey != nil {
*n.OutputKey = key
}
return nil, nil
}
// EvalMaybeRestoreDeposedObject is an EvalNode implementation that will
// restore a particular deposed object of the specified resource instance
// to be the "current" object if and only if the instance doesn't currently
// have a current object.
//
// This is intended for use when the create leg of a create before destroy
// fails with no partial new object: if we didn't take any action, the user
// would be left in the unfortunate situation of having no current object
// and the previously-workign object now deposed. This EvalNode causes a
// better outcome by restoring things to how they were before the replace
// operation began.
//
// The create operation may have produced a partial result even though it
// failed and it's important that we don't "forget" that state, so in that
// situation the prior object remains deposed and the partial new object
// remains the current object, allowing the situation to hopefully be
// improved in a subsequent run.
type EvalMaybeRestoreDeposedObject struct {
Addr addrs.ResourceInstance
// Key is a pointer to the deposed object key that should be forgotten
// from the state, which must be non-nil.
Key *states.DeposedKey
}
// TODO: test
func (n *EvalMaybeRestoreDeposedObject) Eval(ctx EvalContext) (interface{}, error) {
absAddr := n.Addr.Absolute(ctx.Path())
dk := *n.Key
state := ctx.State()
restored := state.MaybeRestoreResourceInstanceDeposed(absAddr, dk)
if restored {
log.Printf("[TRACE] EvalMaybeRestoreDeposedObject: %s deposed object %s was restored as the current object", absAddr, dk)
} else {
log.Printf("[TRACE] EvalMaybeRestoreDeposedObject: %s deposed object %s remains deposed", absAddr, dk)
}
return nil, nil
}
// EvalWriteResourceState is an EvalNode implementation that ensures that
// a suitable resource-level state record is present in the state, if that's
// required for the "each mode" of that resource.
//
// This is important primarily for the situation where count = 0, since this
// eval is the only change we get to set the resource "each mode" to list
// in that case, allowing expression evaluation to see it as a zero-element
// list rather than as not set at all.
type EvalWriteResourceState struct {
Addr addrs.Resource
Config *configs.Resource
ProviderAddr addrs.AbsProviderConfig
}
// TODO: test
func (n *EvalWriteResourceState) Eval(ctx EvalContext) (interface{}, error) {
var diags tfdiags.Diagnostics
absAddr := n.Addr.Absolute(ctx.Path())
state := ctx.State()
count, countDiags := evaluateResourceCountExpression(n.Config.Count, ctx)
diags = diags.Append(countDiags)
if countDiags.HasErrors() {
return nil, diags.Err()
}
// Currently we ony support NoEach and EachList, because for_each support
// is not fully wired up across Terraform. Once for_each support is added,
// we'll need to handle that here too, setting states.EachMap if the
// assigned expression is a map.
eachMode := states.NoEach
if count >= 0 { // -1 signals "count not set"
eachMode = states.EachList
}
// This method takes care of all of the business logic of updating this
// while ensuring that any existing instances are preserved, etc.
state.SetResourceMeta(absAddr, eachMode, n.ProviderAddr)
return nil, nil
}
// EvalForgetResourceState is an EvalNode implementation that prunes out an
// empty resource-level state for a given resource address, or produces an
// error if it isn't empty after all.
//
// This should be the last action taken for a resource that has been removed
// from the configuration altogether, to clean up the leftover husk of the
// resource in the state after other EvalNodes have destroyed and removed
// all of the instances and instance objects beneath it.
type EvalForgetResourceState struct {
Addr addrs.Resource
}
func (n *EvalForgetResourceState) Eval(ctx EvalContext) (interface{}, error) {
absAddr := n.Addr.Absolute(ctx.Path())
state := ctx.State()
pruned := state.RemoveResourceIfEmpty(absAddr)
if !pruned {
// If this produces an error, it indicates a bug elsewhere in Terraform
// -- probably missing graph nodes, graph edges, or
// incorrectly-implemented evaluation steps.
return nil, fmt.Errorf("orphan resource %s still has a non-empty state after apply; this is a bug in Terraform", absAddr)
}
log.Printf("[TRACE] EvalForgetResourceState: Pruned husk of %s from state", absAddr)
return nil, nil
}
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