github.com/hashicorp/terraform-plugin-sdk@v1.17.2/terraform/graph_builder_eval.go (about)

     1  package terraform
     2  
     3  import (
     4  	"github.com/hashicorp/terraform-plugin-sdk/internal/addrs"
     5  	"github.com/hashicorp/terraform-plugin-sdk/internal/configs"
     6  	"github.com/hashicorp/terraform-plugin-sdk/internal/dag"
     7  	"github.com/hashicorp/terraform-plugin-sdk/internal/states"
     8  	"github.com/hashicorp/terraform-plugin-sdk/internal/tfdiags"
     9  )
    10  
    11  // EvalGraphBuilder implements GraphBuilder and constructs a graph suitable
    12  // for evaluating in-memory values (input variables, local values, output
    13  // values) in the state without any other side-effects.
    14  //
    15  // This graph is used only in weird cases, such as the "terraform console"
    16  // CLI command, where we need to evaluate expressions against the state
    17  // without taking any other actions.
    18  //
    19  // The generated graph will include nodes for providers, resources, etc
    20  // just to allow indirect dependencies to be resolved, but these nodes will
    21  // not take any actions themselves since we assume that their parts of the
    22  // state, if any, are already complete.
    23  //
    24  // Although the providers are never configured, they must still be available
    25  // in order to obtain schema information used for type checking, etc.
    26  type EvalGraphBuilder struct {
    27  	// Config is the configuration tree.
    28  	Config *configs.Config
    29  
    30  	// State is the current state
    31  	State *states.State
    32  
    33  	// Components is a factory for the plug-in components (providers and
    34  	// provisioners) available for use.
    35  	Components contextComponentFactory
    36  
    37  	// Schemas is the repository of schemas we will draw from to analyse
    38  	// the configuration.
    39  	Schemas *Schemas
    40  }
    41  
    42  // See GraphBuilder
    43  func (b *EvalGraphBuilder) Build(path addrs.ModuleInstance) (*Graph, tfdiags.Diagnostics) {
    44  	return (&BasicGraphBuilder{
    45  		Steps:    b.Steps(),
    46  		Validate: true,
    47  		Name:     "EvalGraphBuilder",
    48  	}).Build(path)
    49  }
    50  
    51  // See GraphBuilder
    52  func (b *EvalGraphBuilder) Steps() []GraphTransformer {
    53  	concreteProvider := func(a *NodeAbstractProvider) dag.Vertex {
    54  		return &NodeEvalableProvider{
    55  			NodeAbstractProvider: a,
    56  		}
    57  	}
    58  
    59  	steps := []GraphTransformer{
    60  		// Creates all the data resources that aren't in the state. This will also
    61  		// add any orphans from scaling in as destroy nodes.
    62  		&ConfigTransformer{
    63  			Concrete: nil, // just use the abstract type
    64  			Config:   b.Config,
    65  			Unique:   true,
    66  		},
    67  
    68  		// Attach the state
    69  		&AttachStateTransformer{State: b.State},
    70  
    71  		// Attach the configuration to any resources
    72  		&AttachResourceConfigTransformer{Config: b.Config},
    73  
    74  		// Add root variables
    75  		&RootVariableTransformer{Config: b.Config},
    76  
    77  		// Add the local values
    78  		&LocalTransformer{Config: b.Config},
    79  
    80  		// Add the outputs
    81  		&OutputTransformer{Config: b.Config},
    82  
    83  		// Add module variables
    84  		&ModuleVariableTransformer{Config: b.Config},
    85  
    86  		TransformProviders(b.Components.ResourceProviders(), concreteProvider, b.Config),
    87  
    88  		// Must attach schemas before ReferenceTransformer so that we can
    89  		// analyze the configuration to find references.
    90  		&AttachSchemaTransformer{Schemas: b.Schemas},
    91  
    92  		// Connect so that the references are ready for targeting. We'll
    93  		// have to connect again later for providers and so on.
    94  		&ReferenceTransformer{},
    95  
    96  		// Although we don't configure providers, we do still start them up
    97  		// to get their schemas, and so we must shut them down again here.
    98  		&CloseProviderTransformer{},
    99  
   100  		// Single root
   101  		&RootTransformer{},
   102  
   103  		// Remove redundant edges to simplify the graph.
   104  		&TransitiveReductionTransformer{},
   105  	}
   106  
   107  	return steps
   108  }