terraform/helper/schema/field_reader_map.go

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package schema
import (
"fmt"
"strings"
)
// MapFieldReader reads fields out of an untyped map[string]string to
// the best of its ability.
type MapFieldReader struct {
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Map MapReader
Schema map[string]*Schema
}
func (r *MapFieldReader) ReadField(address []string) (FieldReadResult, error) {
k := strings.Join(address, ".")
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schemaList := addrToSchema(address, r.Schema)
if len(schemaList) == 0 {
return FieldReadResult{}, nil
}
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schema := schemaList[len(schemaList)-1]
switch schema.Type {
case TypeBool:
fallthrough
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case TypeFloat:
fallthrough
case TypeInt:
fallthrough
case TypeString:
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return r.readPrimitive(address, schema)
case TypeList:
return readListField(r, address, schema)
case TypeMap:
return r.readMap(k)
case TypeSet:
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return r.readSet(address, schema)
case typeObject:
return readObjectField(r, address, schema.Elem.(map[string]*Schema))
default:
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panic(fmt.Sprintf("Unknown type: %s", schema.Type))
}
}
func (r *MapFieldReader) readMap(k string) (FieldReadResult, error) {
result := make(map[string]interface{})
resultSet := false
// If the name of the map field is directly in the map with an
// empty string, it means that the map is being deleted, so mark
// that is is set.
if v, ok := r.Map.Access(k); ok && v == "" {
resultSet = true
}
prefix := k + "."
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r.Map.Range(func(k, v string) bool {
if strings.HasPrefix(k, prefix) {
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key := k[len(prefix):]
if key != "#" {
result[key] = v
resultSet = true
}
}
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return true
})
var resultVal interface{}
if resultSet {
resultVal = result
}
return FieldReadResult{
Value: resultVal,
Exists: resultSet,
}, nil
}
func (r *MapFieldReader) readPrimitive(
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address []string, schema *Schema) (FieldReadResult, error) {
k := strings.Join(address, ".")
result, ok := r.Map.Access(k)
if !ok {
return FieldReadResult{}, nil
}
returnVal, err := stringToPrimitive(result, false, schema)
if err != nil {
return FieldReadResult{}, err
}
return FieldReadResult{
Value: returnVal,
Exists: true,
}, nil
}
func (r *MapFieldReader) readSet(
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address []string, schema *Schema) (FieldReadResult, error) {
// Get the number of elements in the list
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countRaw, err := r.readPrimitive(
append(address, "#"), &Schema{Type: TypeInt})
if err != nil {
return FieldReadResult{}, err
}
if !countRaw.Exists {
// No count, means we have no list
countRaw.Value = 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.Computed || countRaw.Value.(int) == 0 {
return FieldReadResult{
Value: set,
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Exists: countRaw.Exists,
Computed: countRaw.Computed,
}, nil
}
// Go through the map and find all the set items
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prefix := strings.Join(address, ".") + "."
countExpected := countRaw.Value.(int)
countActual := make(map[string]struct{})
completed := r.Map.Range(func(k, _ string) bool {
if !strings.HasPrefix(k, prefix) {
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return true
}
if strings.HasPrefix(k, prefix+"#") {
// Ignore the count field
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return true
}
// Split the key, since it might be a sub-object like "idx.field"
parts := strings.Split(k[len(prefix):], ".")
idx := parts[0]
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var raw FieldReadResult
raw, err = r.ReadField(append(address, idx))
if err != nil {
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return false
}
if !raw.Exists {
// This shouldn't happen because we just verified it does exist
panic("missing field in set: " + k + "." + idx)
}
set.Add(raw.Value)
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// Due to the way multimap readers work, if we've seen the number
// of fields we expect, then exit so that we don't read later values.
// For example: the "set" map might have "ports.#", "ports.0", and
// "ports.1", but the "state" map might have those plus "ports.2".
// We don't want "ports.2"
countActual[idx] = struct{}{}
if len(countActual) >= countExpected {
return false
}
return true
})
if !completed && err != nil {
return FieldReadResult{}, err
}
return FieldReadResult{
Value: set,
Exists: true,
}, nil
}
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// MapReader is an interface that is given to MapFieldReader for accessing
// a "map". This can be used to have alternate implementations. For a basic
// map[string]string, use BasicMapReader.
type MapReader interface {
Access(string) (string, bool)
Range(func(string, string) bool) bool
}
// BasicMapReader implements MapReader for a single map.
type BasicMapReader map[string]string
func (r BasicMapReader) Access(k string) (string, bool) {
v, ok := r[k]
return v, ok
}
func (r BasicMapReader) Range(f func(string, string) bool) bool {
for k, v := range r {
if cont := f(k, v); !cont {
return false
}
}
return true
}
// MultiMapReader reads over multiple maps, preferring keys that are
// founder earlier (lower number index) vs. later (higher number index)
type MultiMapReader []map[string]string
func (r MultiMapReader) Access(k string) (string, bool) {
for _, m := range r {
if v, ok := m[k]; ok {
return v, ok
}
}
return "", false
}
func (r MultiMapReader) Range(f func(string, string) bool) bool {
done := make(map[string]struct{})
for _, m := range r {
for k, v := range m {
if _, ok := done[k]; ok {
continue
}
if cont := f(k, v); !cont {
return false
}
done[k] = struct{}{}
}
}
return true
}