graph2: Added post mutations. general: Did some cleaning.

internal/counter/counter.go

@@ -0,0 +1,37 @@
+package counter
+
+import (
+	"git.aiterp.net/rpdata/api/internal/store"
+	"github.com/globalsign/mgo"
+	"github.com/globalsign/mgo/bson"
+)
+
+var collection *mgo.Collection
+
+type counter struct {
+	ID    string `bson:"_id"`
+	Value int    `bson:"value"`
+}
+
+// Next gets the next value of a counter, or an error if it hasn't.
+func Next(category, name string) (int, error) {
+	id := category + "." + name
+	doc := counter{}
+
+	_, err := collection.Find(bson.M{"_id": id}).Apply(mgo.Change{
+		Update:    bson.M{"$inc": bson.M{"value": 1}},
+		Upsert:    true,
+		ReturnNew: true,
+	}, &doc)
+	if err != nil {
+		return -1, err
+	}
+
+	return doc.Value, nil
+}
+
+func init() {
+	store.HandleInit(func(db *mgo.Database) {
+		collection = db.C("core.counters")
+	})
+}