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, while also applying the same validation and // transformation rules that would be applied by the decoder specification // returned by method DecoderSpec. // // 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) { switch { case in.IsNull(): return cty.NullVal(b.ImpliedType()), nil case !in.IsKnown(): return cty.UnknownVal(b.ImpliedType()), nil } ty := in.Type() if !ty.IsObjectType() { return cty.UnknownVal(b.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(b.ImpliedType()), path.NewErrorf("unexpected attribute %q", name) } attrs := make(map[string]cty.Value) for name, attrS := range b.Attributes { var val cty.Value switch { case ty.HasAttribute(name): val = in.GetAttr(name) case attrS.Computed || attrS.Optional: val = cty.NullVal(attrS.Type) default: return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("attribute %q is required", name) } val, err := attrS.coerceValue(val, append(path, cty.GetAttrStep{Name: name})) if err != nil { return cty.UnknownVal(b.ImpliedType()), err } attrs[name] = val } for typeName, blockS := range b.BlockTypes { switch blockS.Nesting { case NestingSingle: 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(b.ImpliedType()), err } case blockS.MinItems != 1 && blockS.MaxItems != 1: attrs[typeName] = cty.NullVal(blockS.ImpliedType()) default: // We use the word "attribute" here because we're talking about // the cty sense of that word rather than the HCL sense. return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("attribute %q is required", typeName) } case NestingList: switch { case ty.HasAttribute(typeName): coll := in.GetAttr(typeName) switch { case coll.IsNull(): attrs[typeName] = cty.NullVal(cty.List(b.ImpliedType())) continue case !coll.IsKnown(): attrs[typeName] = cty.UnknownVal(cty.List(b.ImpliedType())) continue } if !coll.CanIterateElements() { return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("must be a list") } l := coll.LengthInt() if l < blockS.MinItems { return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("insufficient items for attribute %q; must have at least %d", typeName, blockS.MinItems) } if l > blockS.MaxItems && blockS.MaxItems > 0 { return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("too many items for attribute %q; must have at least %d", typeName, blockS.MinItems) } if l == 0 { attrs[typeName] = cty.ListValEmpty(b.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(b.ImpliedType()), err } elems = append(elems, val) } } attrs[typeName] = cty.ListVal(elems) case blockS.MinItems == 0: attrs[typeName] = cty.ListValEmpty(blockS.ImpliedType()) default: return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("attribute %q is required", typeName) } case NestingSet: switch { case ty.HasAttribute(typeName): coll := in.GetAttr(typeName) switch { case coll.IsNull(): attrs[typeName] = cty.NullVal(cty.Set(b.ImpliedType())) continue case !coll.IsKnown(): attrs[typeName] = cty.UnknownVal(cty.Set(b.ImpliedType())) continue } if !coll.CanIterateElements() { return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("must be a set") } l := coll.LengthInt() if l < blockS.MinItems { return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("insufficient items for attribute %q; must have at least %d", typeName, blockS.MinItems) } if l > blockS.MaxItems && blockS.MaxItems > 0 { return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("too many items for attribute %q; must have at least %d", typeName, blockS.MinItems) } if l == 0 { attrs[typeName] = cty.SetValEmpty(b.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(b.ImpliedType()), err } elems = append(elems, val) } } attrs[typeName] = cty.SetVal(elems) case blockS.MinItems == 0: attrs[typeName] = cty.SetValEmpty(blockS.ImpliedType()) default: return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("attribute %q is required", typeName) } case NestingMap: switch { case ty.HasAttribute(typeName): coll := in.GetAttr(typeName) switch { case coll.IsNull(): attrs[typeName] = cty.NullVal(cty.Map(b.ImpliedType())) continue case !coll.IsKnown(): attrs[typeName] = cty.UnknownVal(cty.Map(b.ImpliedType())) continue } if !coll.CanIterateElements() { return cty.UnknownVal(b.ImpliedType()), path.NewErrorf("must be a map") } l := coll.LengthInt() if l == 0 { attrs[typeName] = cty.MapValEmpty(b.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(b.ImpliedType()), path.NewErrorf("must be a map") } val, err = blockS.coerceValue(val, append(path, cty.IndexStep{Key: key})) if err != nil { return cty.UnknownVal(b.ImpliedType()), err } elems[key.AsString()] = val } } 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 } func (a *Attribute) coerceValue(in cty.Value, path cty.Path) (cty.Value, error) { val, err := convert.Convert(in, a.Type) if err != nil { return cty.UnknownVal(a.Type), path.NewError(err) } return val, nil }