package configschema import ( "fmt" "github.com/zclconf/go-cty/cty" "github.com/zclconf/go-cty/cty/convert" ) // CoerceValue attempts to force the given value to conform to the type // implied by the receiever. // // This is useful in situations where a configuration must be derived from // an already-decoded value. It is always better to decode directly from // configuration where possible since then source location information is // still available to produce diagnostics, but in special situations this // function allows a compatible result to be obtained even if the // configuration objects are not available. // // If the given value cannot be converted to conform to the receiving schema // then an error is returned describing one of possibly many problems. This // error may be a cty.PathError indicating a position within the nested // data structure where the problem applies. func (b *Block) CoerceValue(in cty.Value) (cty.Value, error) { var path cty.Path return b.coerceValue(in, path) } func (b *Block) coerceValue(in cty.Value, path cty.Path) (cty.Value, error) { convType := b.specType() impliedType := convType.WithoutOptionalAttributesDeep() switch { case in.IsNull(): return cty.NullVal(impliedType), nil case !in.IsKnown(): return cty.UnknownVal(impliedType), nil } ty := in.Type() if !ty.IsObjectType() { return cty.UnknownVal(impliedType), path.NewErrorf("an object is required") } for name := range ty.AttributeTypes() { if _, defined := b.Attributes[name]; defined { continue } if _, defined := b.BlockTypes[name]; defined { continue } return cty.UnknownVal(impliedType), path.NewErrorf("unexpected attribute %q", name) } attrs := make(map[string]cty.Value) for name, attrS := range b.Attributes { attrType := impliedType.AttributeType(name) attrConvType := convType.AttributeType(name) var val cty.Value switch { case ty.HasAttribute(name): val = in.GetAttr(name) case attrS.Computed || attrS.Optional: val = cty.NullVal(attrType) default: return cty.UnknownVal(impliedType), path.NewErrorf("attribute %q is required", name) } val, err := convert.Convert(val, attrConvType) if err != nil { return cty.UnknownVal(impliedType), append(path, cty.GetAttrStep{Name: name}).NewError(err) } attrs[name] = val } for typeName, blockS := range b.BlockTypes { switch blockS.Nesting { case NestingSingle, NestingGroup: switch { case ty.HasAttribute(typeName): var err error val := in.GetAttr(typeName) attrs[typeName], err = blockS.coerceValue(val, append(path, cty.GetAttrStep{Name: typeName})) if err != nil { return cty.UnknownVal(impliedType), err } default: attrs[typeName] = blockS.EmptyValue() } case NestingList: switch { case ty.HasAttribute(typeName): coll := in.GetAttr(typeName) switch { case coll.IsNull(): attrs[typeName] = cty.NullVal(cty.List(blockS.ImpliedType())) continue case !coll.IsKnown(): attrs[typeName] = cty.UnknownVal(cty.List(blockS.ImpliedType())) continue } if !coll.CanIterateElements() { return cty.UnknownVal(impliedType), path.NewErrorf("must be a list") } l := coll.LengthInt() if l == 0 { attrs[typeName] = cty.ListValEmpty(blockS.ImpliedType()) continue } elems := make([]cty.Value, 0, l) { path = append(path, cty.GetAttrStep{Name: typeName}) for it := coll.ElementIterator(); it.Next(); { var err error idx, val := it.Element() val, err = blockS.coerceValue(val, append(path, cty.IndexStep{Key: idx})) if err != nil { return cty.UnknownVal(impliedType), err } elems = append(elems, val) } } attrs[typeName] = cty.ListVal(elems) default: attrs[typeName] = cty.ListValEmpty(blockS.ImpliedType()) } case NestingSet: switch { case ty.HasAttribute(typeName): coll := in.GetAttr(typeName) switch { case coll.IsNull(): attrs[typeName] = cty.NullVal(cty.Set(blockS.ImpliedType())) continue case !coll.IsKnown(): attrs[typeName] = cty.UnknownVal(cty.Set(blockS.ImpliedType())) continue } if !coll.CanIterateElements() { return cty.UnknownVal(impliedType), path.NewErrorf("must be a set") } l := coll.LengthInt() if l == 0 { attrs[typeName] = cty.SetValEmpty(blockS.ImpliedType()) continue } elems := make([]cty.Value, 0, l) { path = append(path, cty.GetAttrStep{Name: typeName}) for it := coll.ElementIterator(); it.Next(); { var err error idx, val := it.Element() val, err = blockS.coerceValue(val, append(path, cty.IndexStep{Key: idx})) if err != nil { return cty.UnknownVal(impliedType), err } elems = append(elems, val) } } attrs[typeName] = cty.SetVal(elems) default: attrs[typeName] = cty.SetValEmpty(blockS.ImpliedType()) } case NestingMap: switch { case ty.HasAttribute(typeName): coll := in.GetAttr(typeName) switch { case coll.IsNull(): attrs[typeName] = cty.NullVal(cty.Map(blockS.ImpliedType())) continue case !coll.IsKnown(): attrs[typeName] = cty.UnknownVal(cty.Map(blockS.ImpliedType())) continue } if !coll.CanIterateElements() { return cty.UnknownVal(impliedType), path.NewErrorf("must be a map") } l := coll.LengthInt() if l == 0 { attrs[typeName] = cty.MapValEmpty(blockS.ImpliedType()) continue } elems := make(map[string]cty.Value) { path = append(path, cty.GetAttrStep{Name: typeName}) for it := coll.ElementIterator(); it.Next(); { var err error key, val := it.Element() if key.Type() != cty.String || key.IsNull() || !key.IsKnown() { return cty.UnknownVal(impliedType), path.NewErrorf("must be a map") } val, err = blockS.coerceValue(val, append(path, cty.IndexStep{Key: key})) if err != nil { return cty.UnknownVal(impliedType), err } elems[key.AsString()] = val } } // If the attribute values here contain any DynamicPseudoTypes, // the concrete type must be an object. useObject := false switch { case coll.Type().IsObjectType(): useObject = true default: // It's possible that we were given a map, and need to coerce it to an object ety := coll.Type().ElementType() for _, v := range elems { if !v.Type().Equals(ety) { useObject = true break } } } if useObject { attrs[typeName] = cty.ObjectVal(elems) } else { attrs[typeName] = cty.MapVal(elems) } default: attrs[typeName] = cty.MapValEmpty(blockS.ImpliedType()) } default: // should never happen because above is exhaustive panic(fmt.Errorf("unsupported nesting mode %#v", blockS.Nesting)) } } return cty.ObjectVal(attrs), nil }