terraform/lang/references.go

82 lines
3.0 KiB
Go

package lang
import (
"github.com/hashicorp/hcl/v2"
"github.com/hashicorp/terraform/internal/addrs"
"github.com/hashicorp/terraform/internal/configs/configschema"
"github.com/hashicorp/terraform/internal/tfdiags"
"github.com/hashicorp/terraform/lang/blocktoattr"
)
// References finds all of the references in the given set of traversals,
// returning diagnostics if any of the traversals cannot be interpreted as a
// reference.
//
// This function does not do any de-duplication of references, since references
// have source location information embedded in them and so any invalid
// references that are duplicated should have errors reported for each
// occurence.
//
// If the returned diagnostics contains errors then the result may be
// incomplete or invalid. Otherwise, the returned slice has one reference per
// given traversal, though it is not guaranteed that the references will
// appear in the same order as the given traversals.
func References(traversals []hcl.Traversal) ([]*addrs.Reference, tfdiags.Diagnostics) {
if len(traversals) == 0 {
return nil, nil
}
var diags tfdiags.Diagnostics
refs := make([]*addrs.Reference, 0, len(traversals))
for _, traversal := range traversals {
ref, refDiags := addrs.ParseRef(traversal)
diags = diags.Append(refDiags)
if ref == nil {
continue
}
refs = append(refs, ref)
}
return refs, diags
}
// ReferencesInBlock is a helper wrapper around References that first searches
// the given body for traversals, before converting those traversals to
// references.
//
// A block schema must be provided so that this function can determine where in
// the body variables are expected.
func ReferencesInBlock(body hcl.Body, schema *configschema.Block) ([]*addrs.Reference, tfdiags.Diagnostics) {
if body == nil {
return nil, nil
}
// We use blocktoattr.ExpandedVariables instead of hcldec.Variables or
// dynblock.VariablesHCLDec here because when we evaluate a block we'll
// first apply the dynamic block extension and _then_ the blocktoattr
// transform, and so blocktoattr.ExpandedVariables takes into account
// both of those transforms when it analyzes the body to ensure we find
// all of the references as if they'd already moved into their final
// locations, even though we can't expand dynamic blocks yet until we
// already know which variables are required.
//
// The set of cases we want to detect here is covered by the tests for
// the plan graph builder in the main 'terraform' package, since it's
// in a better position to test this due to having mock providers etc
// available.
traversals := blocktoattr.ExpandedVariables(body, schema)
return References(traversals)
}
// ReferencesInExpr is a helper wrapper around References that first searches
// the given expression for traversals, before converting those traversals
// to references.
func ReferencesInExpr(expr hcl.Expression) ([]*addrs.Reference, tfdiags.Diagnostics) {
if expr == nil {
return nil, nil
}
traversals := expr.Variables()
return References(traversals)
}