opentofu/internal/terraform/graph_builder_eval.go
Martin Atkins 38ec730b0e core: Opportunistic schema loading during graph construction
Previously the graph builders all expected to be given a full manifest
of all of the plugin component schemas that they could need during their
analysis work. That made sense when terraform.NewContext would always
proactively load all of the schemas before doing any other work, but we
now have a load-as-needed strategy for schemas.

We'll now have the graph builders use the contextPlugins object they each
already hold to retrieve individual schemas when needed. This avoids the
need to prepare a redundant data structure to pass alongside the
contextPlugins object, and leans on the memoization behavior inside
contextPlugins to preserve the old behavior of loading each provider's
schema only once.
2021-09-10 14:56:49 -07:00

102 lines
3.3 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/states"
"github.com/hashicorp/terraform/internal/tfdiags"
)
// EvalGraphBuilder implements GraphBuilder and constructs a graph suitable
// for evaluating in-memory values (input variables, local values, output
// values) in the state without any other side-effects.
//
// This graph is used only in weird cases, such as the "terraform console"
// CLI command, where we need to evaluate expressions against the state
// without taking any other actions.
//
// The generated graph will include nodes for providers, resources, etc
// just to allow indirect dependencies to be resolved, but these nodes will
// not take any actions themselves since we assume that their parts of the
// state, if any, are already complete.
//
// Although the providers are never configured, they must still be available
// in order to obtain schema information used for type checking, etc.
type EvalGraphBuilder struct {
// Config is the configuration tree.
Config *configs.Config
// State is the current state
State *states.State
// Plugins is a library of plug-in components (providers and
// provisioners) available for use.
Plugins *contextPlugins
}
// See GraphBuilder
func (b *EvalGraphBuilder) Build(path addrs.ModuleInstance) (*Graph, tfdiags.Diagnostics) {
return (&BasicGraphBuilder{
Steps: b.Steps(),
Validate: true,
Name: "EvalGraphBuilder",
}).Build(path)
}
// See GraphBuilder
func (b *EvalGraphBuilder) Steps() []GraphTransformer {
concreteProvider := func(a *NodeAbstractProvider) dag.Vertex {
return &NodeEvalableProvider{
NodeAbstractProvider: a,
}
}
steps := []GraphTransformer{
// Creates all the data resources that aren't in the state. This will also
// add any orphans from scaling in as destroy nodes.
&ConfigTransformer{
Config: b.Config,
},
// Add dynamic values
&RootVariableTransformer{Config: b.Config},
&ModuleVariableTransformer{Config: b.Config},
&LocalTransformer{Config: b.Config},
&OutputTransformer{Config: b.Config},
// Attach the configuration to any resources
&AttachResourceConfigTransformer{Config: b.Config},
// Attach the state
&AttachStateTransformer{State: b.State},
transformProviders(concreteProvider, b.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{},
// Although we don't configure providers, we do still start them up
// to get their schemas, and so we must shut them down again here.
&CloseProviderTransformer{},
// Close root module
&CloseRootModuleTransformer{},
// Remove redundant edges to simplify the graph.
&TransitiveReductionTransformer{},
}
return steps
}