terraform/internal/terraform/eval_variable.go

272 lines
10 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"
)
func prepareFinalInputVariableValue(addr addrs.AbsInputVariableInstance, raw *InputValue, cfg *configs.Variable) (cty.Value, tfdiags.Diagnostics) {
var diags tfdiags.Diagnostics
convertTy := cfg.ConstraintType
log.Printf("[TRACE] prepareFinalInputVariableValue: preparing %s", addr)
var defaultVal cty.Value
if cfg.Default != cty.NilVal {
log.Printf("[TRACE] prepareFinalInputVariableValue: %s has a default value", addr)
var err error
defaultVal, err = convert.Convert(cfg.Default, convertTy)
if err != nil {
// Validation of the declaration should typically catch this,
// but we'll check it here too to be robust.
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid default value for module argument",
Detail: fmt.Sprintf(
"The default value for variable %q is incompatible with its type constraint: %s.",
cfg.Name, err,
),
Subject: &cfg.DeclRange,
})
// We'll return a placeholder unknown value to avoid producing
// redundant downstream errors.
return cty.UnknownVal(cfg.Type), diags
}
}
var sourceRange tfdiags.SourceRange
var nonFileSource string
if raw.HasSourceRange() {
sourceRange = raw.SourceRange
} else {
// If the value came from a place that isn't a file and thus doesn't
// have its own source range, we'll use the declaration range as
// our source range and generate some slightly different error
// messages.
sourceRange = tfdiags.SourceRangeFromHCL(cfg.DeclRange)
switch raw.SourceType {
case ValueFromCLIArg:
nonFileSource = fmt.Sprintf("set using -var=\"%s=...\"", addr.Variable.Name)
case ValueFromEnvVar:
nonFileSource = fmt.Sprintf("set using the TF_VAR_%s environment variable", addr.Variable.Name)
case ValueFromInput:
nonFileSource = "set using an interactive prompt"
default:
nonFileSource = "set from outside of the configuration"
}
}
given := raw.Value
if given == cty.NilVal { // The variable wasn't set at all (even to null)
log.Printf("[TRACE] prepareFinalInputVariableValue: %s has no defined value", addr)
if cfg.Required() {
// NOTE: The CLI layer typically checks for itself whether all of
// the required _root_ module variables are set, which would
// mask this error with a more specific one that refers to the
// CLI features for setting such variables. We can get here for
// child module variables, though.
log.Printf("[ERROR] prepareFinalInputVariableValue: %s is required but is not set", addr)
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: `Required variable not set`,
Detail: fmt.Sprintf(`The variable %q is required, but is not set.`, addr.Variable.Name),
Subject: cfg.DeclRange.Ptr(),
})
// We'll return a placeholder unknown value to avoid producing
// redundant downstream errors.
return cty.UnknownVal(cfg.Type), diags
}
given = defaultVal // must be set, because we checked above that the variable isn't required
}
val, err := convert.Convert(given, convertTy)
if err != nil {
log.Printf("[ERROR] prepareFinalInputVariableValue: %s has unsuitable type\n got: %s\n want: %s", addr, given.Type(), convertTy)
if nonFileSource != "" {
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid value for input variable",
Detail: fmt.Sprintf(
"Unsuitable value for %s %s: %s.",
addr, nonFileSource, err,
),
Subject: cfg.DeclRange.Ptr(),
})
} else {
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "Invalid value for input variable",
Detail: fmt.Sprintf(
"The given value is not suitable for %s declared at %s: %s.",
addr, cfg.DeclRange.String(), err,
),
Subject: sourceRange.ToHCL().Ptr(),
})
}
// We'll return a placeholder unknown value to avoid producing
// redundant downstream errors.
return cty.UnknownVal(cfg.Type), diags
}
// By the time we get here, we know:
// - val matches the variable's type constraint
// - val is definitely not cty.NilVal, but might be a null value if the given was already null.
//
// That means we just need to handle the case where the value is null,
// which might mean we need to use the default value, or produce an error.
//
// For historical reasons we do this only for a "non-nullable" variable.
// Nullable variables just appear as null if they were set to null,
// regardless of any default value.
if val.IsNull() && !cfg.Nullable {
log.Printf("[TRACE] prepareFinalInputVariableValue: %s is defined as null", addr)
if defaultVal != cty.NilVal {
val = defaultVal
} else {
log.Printf("[ERROR] prepareFinalInputVariableValue: %s is non-nullable but set to null, and is required", addr)
if nonFileSource != "" {
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: `Required variable not set`,
Detail: fmt.Sprintf(
"Unsuitable value for %s %s: required variable may not be set to null.",
addr, nonFileSource,
),
Subject: cfg.DeclRange.Ptr(),
})
} else {
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: `Required variable not set`,
Detail: fmt.Sprintf(
"The given value is not suitable for %s defined at %s: required variable may not be set to null.",
addr, cfg.DeclRange.String(),
),
Subject: sourceRange.ToHCL().Ptr(),
})
}
// Stub out our return value so that the semantic checker doesn't
// produce redundant downstream errors.
val = cty.UnknownVal(cfg.Type)
}
}
return val, diags
}
// 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: no validation rules declared for %s, so skipping", addr)
return nil
}
log.Printf("[TRACE] evalVariableValidations: validating %s", addr)
// 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)
if val == cty.NilVal {
diags = diags.Append(&hcl.Diagnostic{
Severity: hcl.DiagError,
Summary: "No final value for variable",
Detail: fmt.Sprintf("Terraform doesn't have a final value for %s during validation. This is a bug in Terraform; please report it!", addr),
})
return diags
}
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
}