opentofu/internal/terraform/graph_builder_import.go
Martin Atkins 37b1413ab3 core: Handle root and child module input variables consistently
Previously we had a significant discrepancy between these two situations:
we wrote the raw root module variables directly into the EvalContext and
then applied type conversions only at expression evaluation time, while
for child modules we converted and validated the values while visiting
the variable graph node and wrote only the _final_ value into the
EvalContext.

This confusion seems to have been the root cause for #29899, where
validation rules for root module variables were being applied at the wrong
point in the process, prior to type conversion.

To fix that bug and also make similar mistakes less likely in the future,
I've made the root module variable handling more like the child module
variable handling in the following ways:
 - The "raw value" (exactly as given by the user) lives only in the graph
   node representing the variable, which mirrors how the _expression_
   for a child module variable lives in its graph node. This means that
   the flow for the two is the same except that there's no expression
   evaluation step for root module variables, because they arrive as
   constant values from the caller.
 - The set of variable values in the EvalContext is always only "final"
   values, after type conversion is complete. That in turn means we no
   longer need to do "just in time" conversion in
   evaluationStateData.GetInputVariable, and can just return the value
   exactly as stored, which is consistent with how we handle all other
   references between objects.

This diff is noisier than I'd like because of how much it takes to wire
a new argument (the raw variable values) through to the plan graph builder,
but those changes are pretty mechanical and the interesting logic lives
inside the plan graph builder itself, in NodeRootVariable, and
the shared helper functions in eval_variable.go.

While here I also took the opportunity to fix a historical API wart in
EvalContext, where SetModuleCallArguments was built to take a set of
variable values all at once but our current caller always calls with only
one at a time. That is now just SetModuleCallArgument singular, to match
with the new SetRootModuleArgument to deal with root module variables.
2022-01-10 12:26:54 -08:00

103 lines
3.2 KiB
Go

package terraform
import (
"github.com/hashicorp/terraform/internal/addrs"
"github.com/hashicorp/terraform/internal/configs"
"github.com/hashicorp/terraform/internal/dag"
"github.com/hashicorp/terraform/internal/tfdiags"
)
// ImportGraphBuilder implements GraphBuilder and is responsible for building
// a graph for importing resources into Terraform. This is a much, much
// simpler graph than a normal configuration graph.
type ImportGraphBuilder struct {
// ImportTargets are the list of resources to import.
ImportTargets []*ImportTarget
// Module is a configuration to build the graph from. See ImportOpts.Config.
Config *configs.Config
// RootVariableValues are the raw input values for root input variables
// given by the caller, which we'll resolve into final values as part
// of the plan walk.
RootVariableValues InputValues
// Plugins is a library of plug-in components (providers and
// provisioners) available for use.
Plugins *contextPlugins
}
// Build builds the graph according to the steps returned by Steps.
func (b *ImportGraphBuilder) Build(path addrs.ModuleInstance) (*Graph, tfdiags.Diagnostics) {
return (&BasicGraphBuilder{
Steps: b.Steps(),
Validate: true,
Name: "ImportGraphBuilder",
}).Build(path)
}
// Steps returns the ordered list of GraphTransformers that must be executed
// to build a complete graph.
func (b *ImportGraphBuilder) Steps() []GraphTransformer {
// Get the module. If we don't have one, we just use an empty tree
// so that the transform still works but does nothing.
config := b.Config
if config == nil {
config = configs.NewEmptyConfig()
}
// Custom factory for creating providers.
concreteProvider := func(a *NodeAbstractProvider) dag.Vertex {
return &NodeApplyableProvider{
NodeAbstractProvider: a,
}
}
steps := []GraphTransformer{
// Create all our resources from the configuration and state
&ConfigTransformer{Config: config},
// Add dynamic values
&RootVariableTransformer{Config: b.Config, RawValues: b.RootVariableValues},
&ModuleVariableTransformer{Config: b.Config},
&LocalTransformer{Config: b.Config},
&OutputTransformer{Config: b.Config},
// Attach the configuration to any resources
&AttachResourceConfigTransformer{Config: b.Config},
// Add the import steps
&ImportStateTransformer{Targets: b.ImportTargets, Config: b.Config},
transformProviders(concreteProvider, config),
// Must attach schemas before ReferenceTransformer so that we can
// analyze the configuration to find references.
&AttachSchemaTransformer{Plugins: b.Plugins, Config: b.Config},
// Create expansion nodes for all of the module calls. This must
// come after all other transformers that create nodes representing
// objects that can belong to modules.
&ModuleExpansionTransformer{Config: b.Config},
// Connect so that the references are ready for targeting. We'll
// have to connect again later for providers and so on.
&ReferenceTransformer{},
// Make sure data sources are aware of any depends_on from the
// configuration
&attachDataResourceDependsOnTransformer{},
// Close opened plugin connections
&CloseProviderTransformer{},
// Close root module
&CloseRootModuleTransformer{},
// Optimize
&TransitiveReductionTransformer{},
}
return steps
}