helper/schema: FieldReader and MapFieldReader

helper/schema/field_reader.go

@@ -0,0 +1,240 @@
+package schema
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+// FieldReaders are responsible for decoding fields out of data into
+// the proper typed representation. ResourceData uses this to query data
+// out of multiple sources: config, state, diffs, etc.
+type FieldReader interface {
+	ReadField([]string, *Schema) (interface{}, bool, error)
+}
+
+// MapFieldReader reads fields out of an untyped map[string]string to
+// the best of its ability.
+type MapFieldReader struct {
+	Map map[string]string
+}
+
+func (r *MapFieldReader) ReadField(
+	address []string, schema *Schema) (interface{}, bool, error) {
+	k := strings.Join(address, ".")
+
+	switch schema.Type {
+	case TypeBool:
+		fallthrough
+	case TypeInt:
+		fallthrough
+	case TypeString:
+		return r.readPrimitive(k, schema)
+	case TypeList:
+		return r.readList(k, schema)
+	case TypeMap:
+		return r.readMap(k)
+	case TypeSet:
+		return r.readSet(k, schema)
+	case typeObject:
+		return r.readObject(k, schema.Elem.(map[string]*Schema))
+	default:
+		panic(fmt.Sprintf("Unknown type: %#v", schema.Type))
+	}
+}
+
+func (r *MapFieldReader) readObject(
+	k string, schema map[string]*Schema) (interface{}, bool, error) {
+	result := make(map[string]interface{})
+	for field, schema := range schema {
+		v, ok, err := r.ReadField([]string{k, field}, schema)
+		if err != nil {
+			return nil, false, err
+		}
+		if !ok {
+			continue
+		}
+
+		result[field] = v
+	}
+
+	return result, true, nil
+}
+
+func (r *MapFieldReader) readList(
+	k string, schema *Schema) (interface{}, bool, error) {
+	// Get the number of elements in the list
+	countRaw, countOk, err := r.readPrimitive(
+		k+".#", &Schema{Type: TypeInt})
+	if err != nil {
+		return nil, false, err
+	}
+	if !countOk {
+		// No count, means we have no list
+		countRaw = 0
+	}
+
+	// If we have an empty list, then return an empty list
+	if countRaw.(int) == 0 {
+		return []interface{}{}, true, nil
+	}
+
+	// Get the schema for the elements
+	var elemSchema *Schema
+	switch t := schema.Elem.(type) {
+	case *Resource:
+		elemSchema = &Schema{
+			Type: typeObject,
+			Elem: t.Schema,
+		}
+	case *Schema:
+		elemSchema = t
+	}
+
+	// Go through each count, and get the item value out of it
+	result := make([]interface{}, countRaw.(int))
+	for i, _ := range result {
+		is := strconv.FormatInt(int64(i), 10)
+		raw, ok, err := r.ReadField([]string{k, is}, elemSchema)
+		if err != nil {
+			return nil, false, err
+		}
+		if !ok {
+			// This should never happen, because by the time the data
+			// gets to the FieldReaders, all the defaults should be set by
+			// Schema.
+			raw = nil
+		}
+
+		result[i] = raw
+	}
+
+	return result, true, nil
+}
+
+func (r *MapFieldReader) readMap(k string) (interface{}, bool, error) {
+	result := make(map[string]interface{})
+	resultSet := false
+
+	prefix := k + "."
+	for k, v := range r.Map {
+		if !strings.HasPrefix(k, prefix) {
+			continue
+		}
+
+		result[k[len(prefix):]] = v
+		resultSet = true
+	}
+
+	var resultVal interface{}
+	if resultSet {
+		resultVal = result
+	}
+
+	return resultVal, resultSet, nil
+}
+
+func (r *MapFieldReader) readPrimitive(
+	k string, schema *Schema) (interface{}, bool, error) {
+	result, ok := r.Map[k]
+	if !ok {
+		return nil, false, nil
+	}
+
+	var returnVal interface{}
+	switch schema.Type {
+	case TypeBool:
+		if result == "" {
+			returnVal = false
+			break
+		}
+
+		v, err := strconv.ParseBool(result)
+		if err != nil {
+			return nil, false, err
+		}
+
+		returnVal = v
+	case TypeInt:
+		if result == "" {
+			returnVal = 0
+			break
+		}
+
+		v, err := strconv.ParseInt(result, 0, 0)
+		if err != nil {
+			return nil, false, err
+		}
+
+		returnVal = int(v)
+	case TypeString:
+		returnVal = result
+	default:
+		panic(fmt.Sprintf("Unknown type: %#v", schema.Type))
+	}
+
+	return returnVal, true, nil
+}
+
+func (r *MapFieldReader) readSet(
+	k string, schema *Schema) (interface{}, bool, error) {
+	// Get the number of elements in the list
+	countRaw, countOk, err := r.readPrimitive(
+		k+".#", &Schema{Type: TypeInt})
+	if err != nil {
+		return nil, false, err
+	}
+	if !countOk {
+		// No count, means we have no list
+		countRaw = 0
+	}
+
+	// Create the set that will be our result
+	set := &Set{F: schema.Set}
+
+	// If we have an empty list, then return an empty list
+	if countRaw.(int) == 0 {
+		return set, true, nil
+	}
+
+	// Get the schema for the elements
+	var elemSchema *Schema
+	switch t := schema.Elem.(type) {
+	case *Resource:
+		elemSchema = &Schema{
+			Type: typeObject,
+			Elem: t.Schema,
+		}
+	case *Schema:
+		elemSchema = t
+	}
+
+	// Go through the map and find all the set items
+	prefix := k + "."
+	for k, _ := range r.Map {
+		if !strings.HasPrefix(k, prefix) {
+			continue
+		}
+		if strings.HasPrefix(k, prefix+"#") {
+			// Ignore the count field
+			continue
+		}
+
+		// Split the key, since it might be a sub-object like "idx.field"
+		parts := strings.Split(k[len(prefix):], ".")
+		idx := parts[0]
+
+		v, ok, err := r.ReadField([]string{prefix + idx}, elemSchema)
+		if err != nil {
+			return nil, false, err
+		}
+		if !ok {
+			// This shouldn't happen because we just verified it does exist
+			panic("missing field in set: " + k + "." + idx)
+		}
+
+		set.Add(v)
+	}
+
+	return set, true, nil
+}

helper/schema/field_reader_test.go

@@ -0,0 +1,189 @@
+package schema
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestMapFieldReader_impl(t *testing.T) {
+	var _ FieldReader = new(MapFieldReader)
+}
+
+func TestMapFieldReader(t *testing.T) {
+	r := &MapFieldReader{
+		Map: map[string]string{
+			"bool":   "true",
+			"int":    "42",
+			"string": "string",
+
+			"list.#": "2",
+			"list.0": "foo",
+			"list.1": "bar",
+
+			"listInt.#": "2",
+			"listInt.0": "21",
+			"listInt.1": "42",
+
+			"map.foo": "bar",
+			"map.bar": "baz",
+
+			"set.#":  "2",
+			"set.10": "10",
+			"set.50": "50",
+
+			"setDeep.#":        "2",
+			"setDeep.10.index": "10",
+			"setDeep.10.value": "foo",
+			"setDeep.50.index": "50",
+			"setDeep.50.value": "bar",
+		},
+	}
+
+	cases := map[string]struct {
+		Addr   []string
+		Schema *Schema
+		Out    interface{}
+		OutOk  bool
+		OutErr bool
+	}{
+		"noexist": {
+			[]string{"boolNOPE"},
+			&Schema{Type: TypeBool},
+			nil,
+			false,
+			false,
+		},
+
+		"bool": {
+			[]string{"bool"},
+			&Schema{Type: TypeBool},
+			true,
+			true,
+			false,
+		},
+
+		"int": {
+			[]string{"int"},
+			&Schema{Type: TypeInt},
+			42,
+			true,
+			false,
+		},
+
+		"string": {
+			[]string{"string"},
+			&Schema{Type: TypeString},
+			"string",
+			true,
+			false,
+		},
+
+		"list": {
+			[]string{"list"},
+			&Schema{
+				Type: TypeList,
+				Elem: &Schema{Type: TypeString},
+			},
+			[]interface{}{
+				"foo",
+				"bar",
+			},
+			true,
+			false,
+		},
+
+		"listInt": {
+			[]string{"listInt"},
+			&Schema{
+				Type: TypeList,
+				Elem: &Schema{Type: TypeInt},
+			},
+			[]interface{}{
+				21,
+				42,
+			},
+			true,
+			false,
+		},
+
+		"map": {
+			[]string{"map"},
+			&Schema{Type: TypeMap},
+			map[string]interface{}{
+				"foo": "bar",
+				"bar": "baz",
+			},
+			true,
+			false,
+		},
+
+		"mapelem": {
+			[]string{"map", "foo"},
+			&Schema{Type: TypeString},
+			"bar",
+			true,
+			false,
+		},
+
+		"set": {
+			[]string{"set"},
+			&Schema{
+				Type: TypeSet,
+				Elem: &Schema{Type: TypeInt},
+				Set: func(a interface{}) int {
+					return a.(int)
+				},
+			},
+			[]interface{}{10, 50},
+			true,
+			false,
+		},
+
+		"setDeep": {
+			[]string{"setDeep"},
+			&Schema{
+				Type: TypeSet,
+				Elem: &Resource{
+					Schema: map[string]*Schema{
+						"index": &Schema{Type: TypeInt},
+						"value": &Schema{Type: TypeString},
+					},
+				},
+				Set: func(a interface{}) int {
+					return a.(map[string]interface{})["index"].(int)
+				},
+			},
+			[]interface{}{
+				map[string]interface{}{
+					"index": 10,
+					"value": "foo",
+				},
+				map[string]interface{}{
+					"index": 50,
+					"value": "bar",
+				},
+			},
+			true,
+			false,
+		},
+	}
+
+	for name, tc := range cases {
+		out, outOk, outErr := r.ReadField(tc.Addr, tc.Schema)
+		if (outErr != nil) != tc.OutErr {
+			t.Fatalf("%s: err: %s", name, outErr)
+		}
+
+		if s, ok := out.(*Set); ok {
+			// If it is a set, convert to a list so its more easily checked.
+			out = s.List()
+		}
+
+		if !reflect.DeepEqual(out, tc.Out) {
+			t.Fatalf("%s: out: %#v", name, out)
+		}
+		if outOk != tc.OutOk {
+			t.Fatalf("%s: outOk: %#v", name, outOk)
+		}
+	}
+}

helper/schema/schema.go

@@ -33,6 +33,7 @@ const (
 	TypeList
 	TypeMap
 	TypeSet
+	typeObject
 )
 
 // Schema is used to describe the structure of a value.