GitHub #8: Seed indexes from index.yml

service/datastore/index.go

Index: service/datastore/index.go
diff --git a/service/datastore/index.go b/service/datastore/index.go
index fe0ca4fd4fd67d7007ecd705a0546bb1a8b88ead..a100b57171a5b3c669833760b330a4c83f400b90 100644
--- a/service/datastore/index.go
+++ b/service/datastore/index.go
@@ -8,6 +8,8 @@ import (
 	"bytes"
 	"fmt"
 	"strings"
+
+	"gopkg.in/yaml.v2"
 )
 
 // IndexColumn represents a sort order for a single entity field.
@@ -49,6 +51,38 @@ func (i IndexColumn) cmp(o IndexColumn) int {
 	return cmpString(i.Property, o.Property)()
 }
 
+// UnmarshalYAML deserializes a index.yml `property` into an IndexColumn.
+func (i *IndexColumn) UnmarshalYAML(unmarshal func(interface{}) error) error {

[iannucci, 2016/01/13 19:12:20]

I would consider making the Property and Descending fields be their own types
which independently implement the *marshalYAML functions. That said, if it
requires you to start changing oodles of files then never mind :).

[nishanths (utexas), 2016/01/14 21:12:56]

Good idea. Will create a separate issue for these changes. :)

+	var m map[string]string
+
+	if err := unmarshal(&m); err != nil {
+		return err
+	}
+
+	i.Property = m["name"]

[iannucci, 2016/01/13 19:12:20]

should return an error if there's somehow no name

[nishanths (utexas), 2016/01/14 21:12:56]

Done.

+	i.Descending = false // default direction is "asc"
+
+	if v, ok := m["direction"]; ok && v == "desc" {
+		i.Descending = true
+	}
+
+	return nil
+}
+
+// MarshalYAML serializes an IndexColumn into a index.yml `property`.
+func (i *IndexColumn) MarshalYAML() (interface{}, error) {
+	direction := "asc"
+
+	if i.Descending {
+		direction = "desc"
+	}
+
+	return yaml.Marshal(map[string]string{
+		"name":      i.Property,
+		"direction": direction,
+	})
+}
+
 // String returns a human-readable version of this IndexColumn which is
 // compatible with ParseIndexColumn.
 func (i IndexColumn) String() string {
@@ -73,9 +107,22 @@ func (i IndexColumn) GQL() string {
 
 // IndexDefinition holds the parsed definition of a datastore index definition.
 type IndexDefinition struct {
-	Kind     string
-	Ancestor bool
-	SortBy   []IndexColumn
+	Kind     string        `yaml:"kind"`
+	Ancestor bool          `yaml:"ancestor"`
+	SortBy   []IndexColumn `yaml:"properties"`
+}
+
+// MarshalYAML serializes an IndexDefinition into a index.yml `index`.
+func (id *IndexDefinition) MarshalYAML() (interface{}, error) {
+	if id.Builtin() || !id.Compound() {
+		return nil, fmt.Errorf("cannot generate YAML for %s", id)
+	}
+
+	return yaml.Marshal(map[string]interface{}{
+		"kind":       id.Kind,
+		"ancestor":   id.Ancestor,
+		"properties": id.SortBy,
+	})
 }
 
 // Equal returns true if the two IndexDefinitions are equivalent.