package database import ( "bytes" "fmt" "reflect" "strconv" "strings" "text/template" "go.mongodb.org/mongo-driver/bson/primitive" "go.mongodb.org/mongo-driver/mongo" "go.mongodb.org/mongo-driver/mongo/options" ) // IndexEnsure function ensures index in mongo collection of document // `index:""` -- https://docs.mongodb.com/manual/indexes/#create-an-index // `index:"-"` -- (descending) // `index:"-,+foo,+-bar"` -- https://docs.mongodb.com/manual/core/index-compound // `index:"-,+foo,+-bar,unique"` -- https://docs.mongodb.com/manual/core/index-unique // `index:"-,+foo,+-bar,unique,allowNull"` -- https://docs.mongodb.com/manual/core/index-partial // `index:"-,unique,allowNull,expireAfter=86400"` -- https://docs.mongodb.com/manual/core/index-ttl // `index:"-,unique,allowNull,expireAfter={{.Expire}}"` -- evaluate index as a golang template with `cfg` arguments func (d *Database) IndexEnsure(cfg interface{}, document interface{}) (err error) { el := reflect.ValueOf(document).Elem().Type() numField := el.NumField() documents := d.GetCollectionOf(document) for i := 0; i < numField; i++ { field := el.Field(i) tag := field.Tag indexTag, ok := tag.Lookup("index") if !ok { continue } bsonTag, ok := tag.Lookup("bson") if !ok { return fmt.Errorf("bson tag is not defined for field:%v document:%v", field, document) } var tmpBuffer = &bytes.Buffer{} var tpl *template.Template tpl, err = template.New("").Parse(indexTag) if err != nil { panic(fmt.Errorf("invalid prop template %v, err:%w", indexTag, err)) } err = tpl.Execute(tmpBuffer, cfg) if err != nil { panic(fmt.Errorf("failed to evaluate prop template %v, err:%w", indexTag, err)) } indexString := tmpBuffer.String() indexValues := strings.Split(indexString, ",") bsonValues := strings.Split(bsonTag, ",") var f = false var t = true var key = bsonValues[0] var name = fmt.Sprintf("%s_%s_", indexString, key) if len(key) == 0 { panic(fmt.Errorf("cannot evaluate index key")) } opts := &options.IndexOptions{ Background: &f, Unique: &f, Name: &name, } index := primitive.D{{Key: key, Value: 1}} if indexValues[0] == "-" { index = primitive.D{{Key: key, Value: -1}} } for _, prop := range indexValues[1:] { var left string var right string pair := strings.SplitN(prop, "=", 2) left = pair[0] if len(pair) > 1 { right = pair[1] } switch { case left == "unique": opts.Unique = &t case left == "allowNull": expression, isMap := opts.PartialFilterExpression.(primitive.M) if !isMap || expression == nil { expression = primitive.M{} } expression[key] = primitive.M{"$exists": true} opts.PartialFilterExpression = expression case left == "expireAfter": expireAfter, err := strconv.Atoi(right) if err != nil || expireAfter < 1 { panic(fmt.Errorf("invalid expireAfter value, err: %w", err)) } expireAfterInt32 := int32(expireAfter) opts.ExpireAfterSeconds = &expireAfterInt32 case len(left) > 0 && left[0] == '+': compoundValue := left[1:] if len(compoundValue) == 0 { panic(fmt.Errorf("invalid compound value")) } if compoundValue[0] == '-' { index = append(index, primitive.E{compoundValue[1:], -1}) } else { index = append(index, primitive.E{compoundValue, 1}) } default: panic(fmt.Errorf("unsupported flag:%q in tag:%q of type:%s", prop, tag, el)) } } _, err = documents.Indexes().CreateOne(d.Context(), mongo.IndexModel{Keys: index, Options: opts}) if err != nil { return } } return }