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terraform/lang/data.go

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lang: new package for the runtime parts of the config language Whereas package "configs" deals with the static structure of the configuration language, this new package "lang" deals with the dynamic aspects such as expression evaluation. So far this mainly consists of populating a hcl.EvalContext that contains the values necessary to evaluate a block or an expression. There is also special handling here for dynamic block generation using the HCL "dynblock" extension, which is exposed in the public interface (rather than hiding it as an implementation detail of EvalBlock) so that the caller can then extract proper source locations for any result values using the expanded body. This also includes the beginnings of a replacement for the function table handling that currently lives in the old "config" package, but most of the functions are not yet ported and so this will expand in subsequent commits.
2018-04-04 03:11:28 +02:00
package lang
import (
"github.com/hashicorp/terraform/addrs"
"github.com/hashicorp/terraform/tfdiags"
"github.com/zclconf/go-cty/cty"
)
// Data is an interface whose implementations can provide cty.Value
// representations of objects identified by referenceable addresses from
// the addrs package.
//
// This interface will grow each time a new type of reference is added, and so
// implementations outside of the Terraform codebases are not advised.
//
// Each method returns a suitable value and optionally some diagnostics. If the
// returned diagnostics contains errors then the type of the returned value is
// used to construct an unknown value of the same type which is then used in
// place of the requested object so that type checking can still proceed. In
// cases where it's not possible to even determine a suitable result type,
// cty.DynamicVal is returned along with errors describing the problem.
type Data interface {
core: Static-validate resource references against schemas In the initial move to HCL2 we started relying only on full expression evaluation to catch attribute errors, but that's not sufficient for resource attributes in practice because during validation we can't know yet whether a resource reference evaluates to a single object or to a list of objects (if count is set). To address this, here we reinstate some static validation of resource references by analyzing directly the reference objects, disregarding any instance index if present, and produce errors if the remaining subsequent traversal steps do not correspond to items within the resource type schema. This also allows us to produce some more specialized error messages for certain situations. In particular, we can recognize a reference like aws_instance.foo.count, which in 0.11 and prior was a weird special case for determining the count value of a resource block, and offer a helpful error showing the new length(aws_instance.foo) usage pattern. This eventually delegates to the static traversal validation logic that was added to the configschema package in a previous commit, which also includes some specialized error messages that distinguish between attributes and block types in the schema so that the errors relate more directly to constructs the user can see in the configuration. In future we could potentially move more of the checks from the dynamic schema construction step to the static validation step, but resources are the reference type that most needs this immediately due to the ambiguity caused by the instance indexing syntax. We can safely refactor other reference types to be statically validated in later releases. This is verified by two pre-existing context validate tests which we temporarily disabled during earlier work (now re-enabled) and also by a new validate test aimed specifically at the special case for the "count" attribute.
2018-11-21 02:25:05 +01:00
StaticValidateReferences(refs []*addrs.Reference, self addrs.Referenceable) tfdiags.Diagnostics
lang: new package for the runtime parts of the config language Whereas package "configs" deals with the static structure of the configuration language, this new package "lang" deals with the dynamic aspects such as expression evaluation. So far this mainly consists of populating a hcl.EvalContext that contains the values necessary to evaluate a block or an expression. There is also special handling here for dynamic block generation using the HCL "dynblock" extension, which is exposed in the public interface (rather than hiding it as an implementation detail of EvalBlock) so that the caller can then extract proper source locations for any result values using the expanded body. This also includes the beginnings of a replacement for the function table handling that currently lives in the old "config" package, but most of the functions are not yet ported and so this will expand in subsequent commits.
2018-04-04 03:11:28 +02:00
GetCountAttr(addrs.CountAttr, tfdiags.SourceRange) (cty.Value, tfdiags.Diagnostics)
GetResourceInstance(addrs.ResourceInstance, tfdiags.SourceRange) (cty.Value, tfdiags.Diagnostics)
GetLocalValue(addrs.LocalValue, tfdiags.SourceRange) (cty.Value, tfdiags.Diagnostics)
GetModuleInstance(addrs.ModuleCallInstance, tfdiags.SourceRange) (cty.Value, tfdiags.Diagnostics)
GetModuleInstanceOutput(addrs.ModuleCallOutput, tfdiags.SourceRange) (cty.Value, tfdiags.Diagnostics)
GetPathAttr(addrs.PathAttr, tfdiags.SourceRange) (cty.Value, tfdiags.Diagnostics)
GetTerraformAttr(addrs.TerraformAttr, tfdiags.SourceRange) (cty.Value, tfdiags.Diagnostics)
GetInputVariable(addrs.InputVariable, tfdiags.SourceRange) (cty.Value, tfdiags.Diagnostics)
}