terraform/internal/terraform/eval_variable.go

113 lines
4.2 KiB
Go

package terraform
import (
"fmt"
"log"
"github.com/hashicorp/hcl/v2"
"github.com/hashicorp/terraform/internal/addrs"
"github.com/hashicorp/terraform/internal/configs"
"github.com/hashicorp/terraform/internal/tfdiags"
"github.com/zclconf/go-cty/cty"
"github.com/zclconf/go-cty/cty/convert"
)
// evalVariableValidations ensures that all of the configured custom validations
// for a variable are passing.
//
// This must be used only after any side-effects that make the value of the
// variable available for use in expression evaluation, such as
// EvalModuleCallArgument for variables in descendent modules.
func evalVariableValidations(addr addrs.AbsInputVariableInstance, config *configs.Variable, expr hcl.Expression, ctx EvalContext) (diags tfdiags.Diagnostics) {
if config == nil || len(config.Validations) == 0 {
log.Printf("[TRACE] evalVariableValidations: not active for %s, so skipping", addr)
return nil
}
// Variable nodes evaluate in the parent module to where they were declared
// because the value expression (n.Expr, if set) comes from the calling
// "module" block in the parent module.
//
// Validation expressions are statically validated (during configuration
// loading) to refer only to the variable being validated, so we can
// bypass our usual evaluation machinery here and just produce a minimal
// evaluation context containing just the required value, and thus avoid
// the problem that ctx's evaluation functions refer to the wrong module.
val := ctx.GetVariableValue(addr)
hclCtx := &hcl.EvalContext{
Variables: map[string]cty.Value{
"var": cty.ObjectVal(map[string]cty.Value{
config.Name: val,
}),
},
Functions: ctx.EvaluationScope(nil, EvalDataForNoInstanceKey).Functions(),
}
for _, validation := range config.Validations {
const errInvalidCondition = "Invalid variable validation result"
const errInvalidValue = "Invalid value for variable"
result, moreDiags := validation.Condition.Value(hclCtx)
diags = diags.Append(moreDiags)
if moreDiags.HasErrors() {
log.Printf("[TRACE] evalVariableValidations: %s rule %s condition expression failed: %s", addr, validation.DeclRange, diags.Err().Error())
}
if !result.IsKnown() {
log.Printf("[TRACE] evalVariableValidations: %s rule %s condition value is unknown, so skipping validation for now", addr, validation.DeclRange)
continue // We'll wait until we've learned more, then.
}
if result.IsNull() {
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: errInvalidCondition,
Detail: "Validation condition expression must return either true or false, not null.",
Subject: validation.Condition.Range().Ptr(),
Expression: validation.Condition,
EvalContext: hclCtx,
})
continue
}
var err error
result, err = convert.Convert(result, cty.Bool)
if err != nil {
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: errInvalidCondition,
Detail: fmt.Sprintf("Invalid validation condition result value: %s.", tfdiags.FormatError(err)),
Subject: validation.Condition.Range().Ptr(),
Expression: validation.Condition,
EvalContext: hclCtx,
})
continue
}
// Validation condition may be marked if the input variable is bound to
// a sensitive value. This is irrelevant to the validation process, so
// we discard the marks now.
result, _ = result.Unmark()
if result.False() {
if expr != nil {
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: errInvalidValue,
Detail: fmt.Sprintf("%s\n\nThis was checked by the validation rule at %s.", validation.ErrorMessage, validation.DeclRange.String()),
Subject: expr.Range().Ptr(),
})
} else {
// Since we don't have a source expression for a root module
// variable, we'll just report the error from the perspective
// of the variable declaration itself.
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: errInvalidValue,
Detail: fmt.Sprintf("%s\n\nThis was checked by the validation rule at %s.", validation.ErrorMessage, validation.DeclRange.String()),
Subject: config.DeclRange.Ptr(),
})
}
}
}
return diags
}