package lang import ( "fmt" "github.com/hashicorp/hcl/v2" "github.com/hashicorp/hcl/v2/ext/dynblock" "github.com/hashicorp/hcl/v2/hcldec" "github.com/hashicorp/terraform/internal/addrs" "github.com/hashicorp/terraform/internal/configs/configschema" "github.com/hashicorp/terraform/internal/instances" "github.com/hashicorp/terraform/internal/lang/blocktoattr" "github.com/hashicorp/terraform/internal/tfdiags" "github.com/zclconf/go-cty/cty" "github.com/zclconf/go-cty/cty/convert" ) // ExpandBlock expands any "dynamic" blocks present in the given body. The // result is a body with those blocks expanded, ready to be evaluated with // EvalBlock. // // If the returned diagnostics contains errors then the result may be // incomplete or invalid. func (s *Scope) ExpandBlock(body hcl.Body, schema *configschema.Block) (hcl.Body, tfdiags.Diagnostics) { spec := schema.DecoderSpec() traversals := dynblock.ExpandVariablesHCLDec(body, spec) refs, diags := References(traversals) ctx, ctxDiags := s.EvalContext(refs) diags = diags.Append(ctxDiags) return dynblock.Expand(body, ctx), diags } // EvalBlock evaluates the given body using the given block schema and returns // a cty object value representing its contents. The type of the result conforms // to the implied type of the given schema. // // This function does not automatically expand "dynamic" blocks within the // body. If that is desired, first call the ExpandBlock method to obtain // an expanded body to pass to this method. // // If the returned diagnostics contains errors then the result may be // incomplete or invalid. func (s *Scope) EvalBlock(body hcl.Body, schema *configschema.Block) (cty.Value, tfdiags.Diagnostics) { spec := schema.DecoderSpec() refs, diags := ReferencesInBlock(body, schema) ctx, ctxDiags := s.EvalContext(refs) diags = diags.Append(ctxDiags) if diags.HasErrors() { // We'll stop early if we found problems in the references, because // it's likely evaluation will produce redundant copies of the same errors. return cty.UnknownVal(schema.ImpliedType()), diags } // HACK: In order to remain compatible with some assumptions made in // Terraform v0.11 and earlier about the approximate equivalence of // attribute vs. block syntax, we do a just-in-time fixup here to allow // any attribute in the schema that has a list-of-objects or set-of-objects // kind to potentially be populated instead by one or more nested blocks // whose type is the attribute name. body = blocktoattr.FixUpBlockAttrs(body, schema) val, evalDiags := hcldec.Decode(body, spec, ctx) diags = diags.Append(evalDiags) return val, diags } // EvalSelfBlock evaluates the given body only within the scope of the provided // object and instance key data. References to the object must use self, and the // key data will only contain count.index or each.key. The static values for // terraform and path will also be available in this context. func (s *Scope) EvalSelfBlock(body hcl.Body, self cty.Value, schema *configschema.Block, keyData instances.RepetitionData) (cty.Value, tfdiags.Diagnostics) { var diags tfdiags.Diagnostics spec := schema.DecoderSpec() vals := make(map[string]cty.Value) vals["self"] = self if !keyData.CountIndex.IsNull() { vals["count"] = cty.ObjectVal(map[string]cty.Value{ "index": keyData.CountIndex, }) } if !keyData.EachKey.IsNull() { vals["each"] = cty.ObjectVal(map[string]cty.Value{ "key": keyData.EachKey, }) } refs, refDiags := References(hcldec.Variables(body, spec)) diags = diags.Append(refDiags) terraformAttrs := map[string]cty.Value{} pathAttrs := map[string]cty.Value{} // We could always load the static values for Path and Terraform values, // but we want to parse the references so that we can get source ranges for // user diagnostics. for _, ref := range refs { // we already loaded the self value if ref.Subject == addrs.Self { continue } switch subj := ref.Subject.(type) { case addrs.PathAttr: val, valDiags := normalizeRefValue(s.Data.GetPathAttr(subj, ref.SourceRange)) diags = diags.Append(valDiags) pathAttrs[subj.Name] = val case addrs.TerraformAttr: val, valDiags := normalizeRefValue(s.Data.GetTerraformAttr(subj, ref.SourceRange)) diags = diags.Append(valDiags) terraformAttrs[subj.Name] = val case addrs.CountAttr, addrs.ForEachAttr: // each and count have already been handled. default: // This should have been caught in validation, but point the user // to the correct location in case something slipped through. diags = diags.Append(&hcl.Diagnostic{ Severity: hcl.DiagError, Summary: `Invalid reference`, Detail: fmt.Sprintf("The reference to %q is not valid in this context", ref.Subject), Subject: ref.SourceRange.ToHCL().Ptr(), }) } } vals["path"] = cty.ObjectVal(pathAttrs) vals["terraform"] = cty.ObjectVal(terraformAttrs) ctx := &hcl.EvalContext{ Variables: vals, Functions: s.Functions(), } val, decDiags := hcldec.Decode(body, schema.DecoderSpec(), ctx) diags = diags.Append(decDiags) return val, diags } // EvalExpr evaluates a single expression in the receiving context and returns // the resulting value. The value will be converted to the given type before // it is returned if possible, or else an error diagnostic will be produced // describing the conversion error. // // Pass an expected type of cty.DynamicPseudoType to skip automatic conversion // and just obtain the returned value directly. // // If the returned diagnostics contains errors then the result may be // incomplete, but will always be of the requested type. func (s *Scope) EvalExpr(expr hcl.Expression, wantType cty.Type) (cty.Value, tfdiags.Diagnostics) { refs, diags := ReferencesInExpr(expr) ctx, ctxDiags := s.EvalContext(refs) diags = diags.Append(ctxDiags) if diags.HasErrors() { // We'll stop early if we found problems in the references, because // it's likely evaluation will produce redundant copies of the same errors. return cty.UnknownVal(wantType), diags } val, evalDiags := expr.Value(ctx) diags = diags.Append(evalDiags) if wantType != cty.DynamicPseudoType { var convErr error val, convErr = convert.Convert(val, wantType) if convErr != nil { val = cty.UnknownVal(wantType) diags = diags.Append(&hcl.Diagnostic{ Severity: hcl.DiagError, Summary: "Incorrect value type", Detail: fmt.Sprintf("Invalid expression value: %s.", tfdiags.FormatError(convErr)), Subject: expr.Range().Ptr(), Expression: expr, EvalContext: ctx, }) } } return val, diags } // EvalReference evaluates the given reference in the receiving scope and // returns the resulting value. The value will be converted to the given type before // it is returned if possible, or else an error diagnostic will be produced // describing the conversion error. // // Pass an expected type of cty.DynamicPseudoType to skip automatic conversion // and just obtain the returned value directly. // // If the returned diagnostics contains errors then the result may be // incomplete, but will always be of the requested type. func (s *Scope) EvalReference(ref *addrs.Reference, wantType cty.Type) (cty.Value, tfdiags.Diagnostics) { var diags tfdiags.Diagnostics // We cheat a bit here and just build an EvalContext for our requested // reference with the "self" address overridden, and then pull the "self" // result out of it to return. ctx, ctxDiags := s.evalContext([]*addrs.Reference{ref}, ref.Subject) diags = diags.Append(ctxDiags) val := ctx.Variables["self"] if val == cty.NilVal { val = cty.DynamicVal } var convErr error val, convErr = convert.Convert(val, wantType) if convErr != nil { val = cty.UnknownVal(wantType) diags = diags.Append(&hcl.Diagnostic{ Severity: hcl.DiagError, Summary: "Incorrect value type", Detail: fmt.Sprintf("Invalid expression value: %s.", tfdiags.FormatError(convErr)), Subject: ref.SourceRange.ToHCL().Ptr(), }) } return val, diags } // EvalContext constructs a HCL expression evaluation context whose variable // scope contains sufficient values to satisfy the given set of references. // // Most callers should prefer to use the evaluation helper methods that // this type offers, but this is here for less common situations where the // caller will handle the evaluation calls itself. func (s *Scope) EvalContext(refs []*addrs.Reference) (*hcl.EvalContext, tfdiags.Diagnostics) { return s.evalContext(refs, s.SelfAddr) } func (s *Scope) evalContext(refs []*addrs.Reference, selfAddr addrs.Referenceable) (*hcl.EvalContext, tfdiags.Diagnostics) { if s == nil { panic("attempt to construct EvalContext for nil Scope") } var diags tfdiags.Diagnostics vals := make(map[string]cty.Value) funcs := s.Functions() ctx := &hcl.EvalContext{ Variables: vals, Functions: funcs, } if len(refs) == 0 { // Easy path for common case where there are no references at all. return ctx, diags } // First we'll do static validation of the references. This catches things // early that might otherwise not get caught due to unknown values being // present in the scope during planning. if staticDiags := s.Data.StaticValidateReferences(refs, selfAddr); staticDiags.HasErrors() { diags = diags.Append(staticDiags) return ctx, diags } // The reference set we are given has not been de-duped, and so there can // be redundant requests in it for two reasons: // - The same item is referenced multiple times // - Both an item and that item's container are separately referenced. // We will still visit every reference here and ask our data source for // it, since that allows us to gather a full set of any errors and // warnings, but once we've gathered all the data we'll then skip anything // that's redundant in the process of populating our values map. dataResources := map[string]map[string]cty.Value{} managedResources := map[string]map[string]cty.Value{} wholeModules := map[string]cty.Value{} inputVariables := map[string]cty.Value{} localValues := map[string]cty.Value{} pathAttrs := map[string]cty.Value{} terraformAttrs := map[string]cty.Value{} countAttrs := map[string]cty.Value{} forEachAttrs := map[string]cty.Value{} var self cty.Value for _, ref := range refs { rng := ref.SourceRange rawSubj := ref.Subject if rawSubj == addrs.Self { if selfAddr == nil { diags = diags.Append(&hcl.Diagnostic{ Severity: hcl.DiagError, Summary: `Invalid "self" reference`, // This detail message mentions some current practice that // this codepath doesn't really "know about". If the "self" // object starts being supported in more contexts later then // we'll need to adjust this message. Detail: `The "self" object is not available in this context. This object can be used only in resource provisioner and connection blocks.`, Subject: ref.SourceRange.ToHCL().Ptr(), }) continue } if selfAddr == addrs.Self { // Programming error: the self address cannot alias itself. panic("scope SelfAddr attempting to alias itself") } // self can only be used within a resource instance subj := selfAddr.(addrs.ResourceInstance) val, valDiags := normalizeRefValue(s.Data.GetResource(subj.ContainingResource(), rng)) diags = diags.Append(valDiags) // Self is an exception in that it must always resolve to a // particular instance. We will still insert the full resource into // the context below. var hclDiags hcl.Diagnostics // We should always have a valid self index by this point, but in // the case of an error, self may end up as a cty.DynamicValue. switch k := subj.Key.(type) { case addrs.IntKey: self, hclDiags = hcl.Index(val, cty.NumberIntVal(int64(k)), ref.SourceRange.ToHCL().Ptr()) diags = diags.Append(hclDiags) case addrs.StringKey: self, hclDiags = hcl.Index(val, cty.StringVal(string(k)), ref.SourceRange.ToHCL().Ptr()) diags = diags.Append(hclDiags) default: self = val } continue } // This type switch must cover all of the "Referenceable" implementations // in package addrs, however we are removing the possibility of // Instances beforehand. switch addr := rawSubj.(type) { case addrs.ResourceInstance: rawSubj = addr.ContainingResource() case addrs.ModuleCallInstance: rawSubj = addr.Call case addrs.AbsModuleCallOutput: rawSubj = addr.Call.Call } switch subj := rawSubj.(type) { case addrs.Resource: var into map[string]map[string]cty.Value switch subj.Mode { case addrs.ManagedResourceMode: into = managedResources case addrs.DataResourceMode: into = dataResources default: panic(fmt.Errorf("unsupported ResourceMode %s", subj.Mode)) } val, valDiags := normalizeRefValue(s.Data.GetResource(subj, rng)) diags = diags.Append(valDiags) r := subj if into[r.Type] == nil { into[r.Type] = make(map[string]cty.Value) } into[r.Type][r.Name] = val case addrs.ModuleCall: val, valDiags := normalizeRefValue(s.Data.GetModule(subj, rng)) diags = diags.Append(valDiags) wholeModules[subj.Name] = val case addrs.InputVariable: val, valDiags := normalizeRefValue(s.Data.GetInputVariable(subj, rng)) diags = diags.Append(valDiags) inputVariables[subj.Name] = val case addrs.LocalValue: val, valDiags := normalizeRefValue(s.Data.GetLocalValue(subj, rng)) diags = diags.Append(valDiags) localValues[subj.Name] = val case addrs.PathAttr: val, valDiags := normalizeRefValue(s.Data.GetPathAttr(subj, rng)) diags = diags.Append(valDiags) pathAttrs[subj.Name] = val case addrs.TerraformAttr: val, valDiags := normalizeRefValue(s.Data.GetTerraformAttr(subj, rng)) diags = diags.Append(valDiags) terraformAttrs[subj.Name] = val case addrs.CountAttr: val, valDiags := normalizeRefValue(s.Data.GetCountAttr(subj, rng)) diags = diags.Append(valDiags) countAttrs[subj.Name] = val case addrs.ForEachAttr: val, valDiags := normalizeRefValue(s.Data.GetForEachAttr(subj, rng)) diags = diags.Append(valDiags) forEachAttrs[subj.Name] = val default: // Should never happen panic(fmt.Errorf("Scope.buildEvalContext cannot handle address type %T", rawSubj)) } } // Managed resources are exposed in two different locations. The primary // is at the top level where the resource type name is the root of the // traversal, but we also expose them under "resource" as an escaping // technique if we add a reserved name in a future language edition which // conflicts with someone's existing provider. for k, v := range buildResourceObjects(managedResources) { vals[k] = v } vals["resource"] = cty.ObjectVal(buildResourceObjects(managedResources)) vals["data"] = cty.ObjectVal(buildResourceObjects(dataResources)) vals["module"] = cty.ObjectVal(wholeModules) vals["var"] = cty.ObjectVal(inputVariables) vals["local"] = cty.ObjectVal(localValues) vals["path"] = cty.ObjectVal(pathAttrs) vals["terraform"] = cty.ObjectVal(terraformAttrs) vals["count"] = cty.ObjectVal(countAttrs) vals["each"] = cty.ObjectVal(forEachAttrs) if self != cty.NilVal { vals["self"] = self } return ctx, diags } func buildResourceObjects(resources map[string]map[string]cty.Value) map[string]cty.Value { vals := make(map[string]cty.Value) for typeName, nameVals := range resources { vals[typeName] = cty.ObjectVal(nameVals) } return vals } func normalizeRefValue(val cty.Value, diags tfdiags.Diagnostics) (cty.Value, tfdiags.Diagnostics) { if diags.HasErrors() { // If there are errors then we will force an unknown result so that // we can still evaluate and catch type errors but we'll avoid // producing redundant re-statements of the same errors we've already // dealt with here. return cty.UnknownVal(val.Type()), diags } return val, diags }