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package terraform
import (
"fmt"
"log"
"github.com/zclconf/go-cty/cty"
"github.com/hashicorp/terraform/addrs"
"github.com/hashicorp/terraform/configs"
"github.com/hashicorp/terraform/plans"
"github.com/hashicorp/terraform/plans/objchange"
"github.com/hashicorp/terraform/providers"
"github.com/hashicorp/terraform/states"
"github.com/hashicorp/terraform/tfdiags"
)
// EvalReadData is an EvalNode implementation that deals with the main part
// of the data resource lifecycle: either actually reading from the data source
// or generating a plan to do so.
type EvalReadData struct {
Addr addrs.ResourceInstance
Config *configs.Resource
Dependencies []addrs.Referenceable
Provider *providers.Interface
ProviderAddr addrs.AbsProviderConfig
ProviderSchema **ProviderSchema
// Planned is set when dealing with data resources that were deferred to
// the apply walk, to let us see what was planned. If this is set, the
// evaluation of the config is required to produce a wholly-known
// configuration which is consistent with the partial object included
// in this planned change.
Planned **plans.ResourceInstanceChange
// ForcePlanRead, if true, overrides the usual behavior of immediately
// reading from the data source where possible, instead forcing us to
// _always_ generate a plan. This is used during the plan walk, since we
// mustn't actually apply anything there. (The resulting state doesn't
// get persisted)
ForcePlanRead bool
// The result from this EvalNode has a few different possibilities
// depending on the input:
// - If Planned is nil then we assume we're aiming to _produce_ the plan,
// and so the following two outcomes are possible:
// - OutputChange.Action is plans.NoOp and OutputState is the complete
// result of reading from the data source. This is the easy path.
// - OutputChange.Action is plans.Read and OutputState is a planned
// object placeholder (states.ObjectPlanned). In this case, the
// returned change must be recorded in the overral changeset and
// eventually passed to another instance of this struct during the
// apply walk.
// - If Planned is non-nil then we assume we're aiming to complete a
// planned read from an earlier plan walk. In this case the only possible
// non-error outcome is to set Output.Action (if non-nil) to a plans.NoOp
// change and put the complete resulting state in OutputState, ready to
// be saved in the overall state and used for expression evaluation.
OutputChange **plans.ResourceInstanceChange
OutputValue *cty.Value
OutputConfigValue *cty.Value
OutputState **states.ResourceInstanceObject
}
func (n *EvalReadData) Eval(ctx EvalContext) (interface{}, error) {
absAddr := n.Addr.Absolute(ctx.Path())
log.Printf("[TRACE] EvalReadData: working on %s", absAddr)
if n.ProviderSchema == nil || *n.ProviderSchema == nil {
return nil, fmt.Errorf("provider schema not available for %s", n.Addr)
}
var diags tfdiags.Diagnostics
var change *plans.ResourceInstanceChange
var configVal cty.Value
// TODO: Do we need to handle Delete changes here? EvalReadDataDiff and
// EvalReadDataApply did, but it seems like we should handle that via a
// separate mechanism since it boils down to just deleting the object from
// the state... and we do that on every plan anyway, forcing the data
// resource to re-read.
config := *n.Config
provider := *n.Provider
providerSchema := *n.ProviderSchema
schema, _ := providerSchema.SchemaForResourceAddr(n.Addr.ContainingResource())
if schema == nil {
// Should be caught during validation, so we don't bother with a pretty error here
return nil, fmt.Errorf("provider %q does not support data source %q", n.ProviderAddr.ProviderConfig.Type, n.Addr.Resource.Type)
}
// We'll always start by evaluating the configuration. What we do after
// that will depend on the evaluation result along with what other inputs
// we were given.
objTy := schema.ImpliedType()
priorVal := cty.NullVal(objTy) // for data resources, prior is always null because we start fresh every time
keyData := EvalDataForInstanceKey(n.Addr.Key)
var configDiags tfdiags.Diagnostics
configVal, _, configDiags = ctx.EvaluateBlock(config.Config, schema, nil, keyData)
diags = diags.Append(configDiags)
if configDiags.HasErrors() {
return nil, diags.Err()
}
proposedNewVal := objchange.PlannedDataResourceObject(schema, configVal)
// If our configuration contains any unknown values then we must defer the
// read to the apply phase by producing a "Read" change for this resource,
// and a placeholder value for it in the state.
if n.ForcePlanRead || !configVal.IsWhollyKnown() {
// If the configuration is still unknown when we're applying a planned
// change then that indicates a bug in Terraform, since we should have
// everything resolved by now.
if n.Planned != nil && *n.Planned != nil {
return nil, fmt.Errorf(
"configuration for %s still contains unknown values during apply (this is a bug in Terraform; please report it!)",
absAddr,
)
}
if n.ForcePlanRead {
log.Printf("[TRACE] EvalReadData: %s configuration is fully known, but we're forcing a read plan to be created", absAddr)
} else {
log.Printf("[TRACE] EvalReadData: %s configuration not fully known yet, so deferring to apply phase", absAddr)
}
err := ctx.Hook(func(h Hook) (HookAction, error) {
return h.PreDiff(absAddr, states.CurrentGen, priorVal, proposedNewVal)
})
if err != nil {
return nil, err
}
change = &plans.ResourceInstanceChange{
Addr: absAddr,
ProviderAddr: n.ProviderAddr,
Change: plans.Change{
Action: plans.Read,
Before: priorVal,
After: proposedNewVal,
},
}
err = ctx.Hook(func(h Hook) (HookAction, error) {
return h.PostDiff(absAddr, states.CurrentGen, change.Action, priorVal, proposedNewVal)
})
if err != nil {
return nil, err
}
if n.OutputChange != nil {
*n.OutputChange = change
}
if n.OutputValue != nil {
*n.OutputValue = change.After
}
if n.OutputConfigValue != nil {
*n.OutputConfigValue = configVal
}
if n.OutputState != nil {
state := &states.ResourceInstanceObject{
Value: change.After,
Status: states.ObjectPlanned, // because the partial value in the plan must be used for now
Dependencies: n.Dependencies,
}
*n.OutputState = state
}
return nil, diags.ErrWithWarnings()
}
if n.Planned != nil && *n.Planned != nil && (*n.Planned).Action != plans.Read {
// If any other action gets in here then that's always a bug; this
// EvalNode only deals with reading.
return nil, fmt.Errorf(
"invalid action %s for %s: only Read is supported (this is a bug in Terraform; please report it!)",
(*n.Planned).Action, absAddr,
)
}
log.Printf("[TRACE] Re-validating config for %s", absAddr)
validateResp := provider.ValidateDataSourceConfig(
providers.ValidateDataSourceConfigRequest{
TypeName: n.Addr.Resource.Type,
Config: configVal,
},
)
if validateResp.Diagnostics.HasErrors() {
return nil, validateResp.Diagnostics.InConfigBody(n.Config.Config).Err()
}
// If we get down here then our configuration is complete and we're read
// to actually call the provider to read the data.
log.Printf("[TRACE] EvalReadData: %s configuration is complete, so reading from provider", absAddr)
err := ctx.Hook(func(h Hook) (HookAction, error) {
// We don't have a state yet, so we'll just give the hook an
// empty one to work with.
return h.PreRefresh(absAddr, states.CurrentGen, cty.NullVal(cty.DynamicPseudoType))
})
if err != nil {
return nil, err
}
resp := provider.ReadDataSource(providers.ReadDataSourceRequest{
TypeName: n.Addr.Resource.Type,
Config: configVal,
})
diags = diags.Append(resp.Diagnostics.InConfigBody(n.Config.Config))
if diags.HasErrors() {
return nil, diags.Err()
}
newVal := resp.State
if newVal == cty.NilVal {
// This can happen with incompletely-configured mocks. We'll allow it
// and treat it as an alias for a properly-typed null value.
newVal = cty.NullVal(schema.ImpliedType())
}
for _, err := range newVal.Type().TestConformance(schema.ImpliedType()) {
diags = diags.Append(tfdiags.Sourceless(
tfdiags.Error,
"Provider produced invalid object",
fmt.Sprintf(
"Provider %q produced an invalid value for %s.\n\nThis is a bug in the provider, which should be reported in the provider's own issue tracker.",
n.ProviderAddr.ProviderConfig.Type, tfdiags.FormatErrorPrefixed(err, absAddr.String()),
),
))
}
if diags.HasErrors() {
return nil, diags.Err()
}
if newVal.IsNull() {
diags = diags.Append(tfdiags.Sourceless(
tfdiags.Error,
"Provider produced null object",
fmt.Sprintf(
"Provider %q produced a null value for %s.\n\nThis is a bug in the provider, which should be reported in the provider's own issue tracker.",
n.ProviderAddr.ProviderConfig.Type, absAddr,
),
))
}
if !newVal.IsWhollyKnown() {
diags = diags.Append(tfdiags.Sourceless(
tfdiags.Error,
"Provider produced invalid object",
fmt.Sprintf(
"Provider %q produced a value for %s that is not wholly known.\n\nThis is a bug in the provider, which should be reported in the provider's own issue tracker.",
n.ProviderAddr.ProviderConfig.Type, absAddr,
),
))
// We'll still save the object, but we need to eliminate any unknown
// values first because we can't serialize them in the state file.
// Note that this may cause set elements to be coalesced if they
// differed only by having unknown values, but we don't worry about
// that here because we're saving the value only for inspection
// purposes; the error we added above will halt the graph walk.
newVal = cty.UnknownAsNull(newVal)
}
// Since we've completed the read, we actually have no change to make, but
// we'll produce a NoOp one anyway to preserve the usual flow of the
// plan phase and allow it to produce a complete plan.
change = &plans.ResourceInstanceChange{
Addr: absAddr,
ProviderAddr: n.ProviderAddr,
Change: plans.Change{
Action: plans.NoOp,
Before: newVal,
After: newVal,
},
}
state := &states.ResourceInstanceObject{
Value: change.After,
Status: states.ObjectReady, // because we completed the read from the provider
Dependencies: n.Dependencies,
}
err = ctx.Hook(func(h Hook) (HookAction, error) {
return h.PostRefresh(absAddr, states.CurrentGen, change.Before, newVal)
})
if err != nil {
return nil, err
}
if n.OutputChange != nil {
*n.OutputChange = change
}
if n.OutputValue != nil {
*n.OutputValue = change.After
}
if n.OutputConfigValue != nil {
*n.OutputConfigValue = configVal
}
if n.OutputState != nil {
*n.OutputState = state
}
return nil, diags.ErrWithWarnings()
}
// EvalReadDataApply is an EvalNode implementation that executes a data
// resource's ReadDataApply method to read data from the data source.
type EvalReadDataApply struct {
Addr addrs.ResourceInstance
Provider *providers.Interface
ProviderAddr addrs.AbsProviderConfig
ProviderSchema **ProviderSchema
Output **states.ResourceInstanceObject
Config *configs.Resource
Change **plans.ResourceInstanceChange
StateReferences []addrs.Referenceable
}
func (n *EvalReadDataApply) Eval(ctx EvalContext) (interface{}, error) {
provider := *n.Provider
change := *n.Change
providerSchema := *n.ProviderSchema
absAddr := n.Addr.Absolute(ctx.Path())
var diags tfdiags.Diagnostics
// If the diff is for *destroying* this resource then we'll
// just drop its state and move on, since data resources don't
// support an actual "destroy" action.
if change != nil && change.Action == plans.Delete {
if n.Output != nil {
*n.Output = nil
}
return nil, nil
}
// For the purpose of external hooks we present a data apply as a
// "Refresh" rather than an "Apply" because creating a data source
// is presented to users/callers as a "read" operation.
err := ctx.Hook(func(h Hook) (HookAction, error) {
// We don't have a state yet, so we'll just give the hook an
// empty one to work with.
return h.PreRefresh(absAddr, states.CurrentGen, cty.NullVal(cty.DynamicPseudoType))
})
if err != nil {
return nil, err
}
resp := provider.ReadDataSource(providers.ReadDataSourceRequest{
TypeName: n.Addr.Resource.Type,
Config: change.After,
})
diags = diags.Append(resp.Diagnostics.InConfigBody(n.Config.Config))
if diags.HasErrors() {
return nil, diags.Err()
}
schema, _ := providerSchema.SchemaForResourceAddr(n.Addr.ContainingResource())
if schema == nil {
// Should be caught during validation, so we don't bother with a pretty error here
return nil, fmt.Errorf("provider does not support data source %q", n.Addr.Resource.Type)
}
newVal := resp.State
for _, err := range newVal.Type().TestConformance(schema.ImpliedType()) {
diags = diags.Append(tfdiags.Sourceless(
tfdiags.Error,
"Provider produced invalid object",
fmt.Sprintf(
"Provider %q planned an invalid value for %s. The result could not be saved.\n\nThis is a bug in the provider, which should be reported in the provider's own issue tracker.",
n.ProviderAddr.ProviderConfig.Type, tfdiags.FormatErrorPrefixed(err, absAddr.String()),
),
))
}
if diags.HasErrors() {
return nil, diags.Err()
}
err = ctx.Hook(func(h Hook) (HookAction, error) {
return h.PostRefresh(absAddr, states.CurrentGen, change.Before, newVal)
})
if err != nil {
return nil, err
}
if n.Output != nil {
*n.Output = &states.ResourceInstanceObject{
Value: newVal,
Status: states.ObjectReady,
Dependencies: n.StateReferences,
}
}
return nil, diags.ErrWithWarnings()
}
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