/
meta_collection.go
120 lines (107 loc) · 2.94 KB
/
meta_collection.go
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package poll
import (
"log"
"github.com/mongodb/mongo-go-driver/bson/objectid"
"github.com/TerrexTech/go-mongoutils/mongo"
"github.com/pkg/errors"
)
// AggregateMeta contains current versions for Aggregates.
// This version is updated everytime an Aggregate receives an associated Event.
type AggregateMeta struct {
ID objectid.ObjectID `bson:"_id,omitempty" json:"_id,omitempty"`
AggregateID int8 `bson:"aggregateID,omitempty" json:"aggregateID,omitempty"`
Version int64 `bson:"version,omitempty" json:"version,omitempty"`
}
// createMetaCollection ensures that AggregateMeta collection exists,
// and adds meta-entry to it if required.
func createMetaCollection(
aggID int8,
conn *mongo.ConnectionConfig,
db string,
coll string,
) (*mongo.Collection, error) {
if aggID == 0 {
return nil, errors.New("aggID cannot be 0")
}
if conn == nil {
return nil, errors.New("conn cannot be nil")
}
if conn.Client == nil {
return nil, errors.New("conn: client cannot be nil")
}
if db == "" {
return nil, errors.New("db cannot be blank")
}
if coll == "" {
return nil, errors.New("coll cannot be blank")
}
// Index Configuration
indexConfigs := []mongo.IndexConfig{
mongo.IndexConfig{
ColumnConfig: []mongo.IndexColumnConfig{
mongo.IndexColumnConfig{
Name: "aggregateID",
},
},
IsUnique: true,
Name: "aggregateID_index",
},
}
c := &mongo.Collection{
Connection: conn,
Name: coll,
Database: db,
SchemaStruct: &AggregateMeta{},
Indexes: indexConfigs,
}
collection, err := mongo.EnsureCollection(c)
if err != nil {
err = errors.Wrap(err, "CreateMetaCollection: Error in EnsureCollection")
return nil, err
}
err = ensureAggMetaEntry(aggID, collection)
if err != nil {
err = errors.Wrap(err, "CreateMetaCollection: Error in ensureAggMetaEntry")
return nil, err
}
return collection, nil
}
// ensureAggMetaEntry adds meta-entry to AggregateMeta collection if required.
func ensureAggMetaEntry(aggID int8, collection *mongo.Collection) error {
_, err := collection.FindOne(&AggregateMeta{
AggregateID: aggID,
})
if err == nil {
return nil
}
err = errors.Wrap(err, "EnsureAggMetaEntry: Error while getting meta-entry")
log.Println(err)
log.Println("New entry will be created")
_, err = collection.InsertOne(&AggregateMeta{
AggregateID: aggID,
Version: 1,
})
if err != nil {
err = errors.Wrap(err, "EnsureAggMetaEntry: Error while creating meta-entry")
return err
}
return nil
}
func getVersion(aggID int8, c *mongo.Collection) (int64, error) {
result, err := c.FindOne(&AggregateMeta{
AggregateID: aggID,
})
if err != nil {
err = errors.Wrap(err, "GetVersion: Error getting AggregateMeta")
return -1, err
}
meta, assertOK := result.(*AggregateMeta)
if !assertOK {
err = errors.New(
"GetVersion: Error asserting result into AggregateMeta",
)
log.Printf("%+v", result)
return -1, err
}
return meta.Version, nil
}