// getCursor returns a cursor that can be iterated over to get all the documents
// to export, based on the options given to mongoexport. Also returns the
// associated session, so that it can be closed once the cursor is used up.
func (exp *MongoExport) getCursor() (*mgo.Iter, *mgo.Session, error) {
sortFields := []string{}
if exp.InputOpts != nil && exp.InputOpts.Sort != "" {
sortD, err := getSortFromArg(exp.InputOpts.Sort)
if err != nil {
return nil, nil, err
}
sortFields, err = bsonutil.MakeSortString(sortD)
if err != nil {
return nil, nil, err
}
}
query := map[string]interface{}{}
if exp.InputOpts != nil && exp.InputOpts.HasQuery() {
var err error
content, err := exp.InputOpts.GetQuery()
if err != nil {
return nil, nil, err
}
query, err = getObjectFromByteArg(content)
if err != nil {
return nil, nil, err
}
}
flags := 0
if len(query) == 0 && exp.InputOpts != nil &&
exp.InputOpts.ForceTableScan != true && exp.InputOpts.Sort == "" {
flags = flags | db.Snapshot
}
session, err := exp.SessionProvider.GetSession()
if err != nil {
return nil, nil, err
}
skip := 0
if exp.InputOpts != nil {
skip = exp.InputOpts.Skip
}
limit := 0
if exp.InputOpts != nil {
limit = exp.InputOpts.Limit
}
// build the query
q := session.DB(exp.ToolOptions.Namespace.DB).
C(exp.ToolOptions.Namespace.Collection).Find(query).Sort(sortFields...).
Skip(skip).Limit(limit)
if len(exp.OutputOpts.Fields) > 0 {
q.Select(makeFieldSelector(exp.OutputOpts.Fields))
}
q = db.ApplyFlags(q, session, flags)
return q.Iter(), session, nil
}
func getDocSource(exp MongoExport) (db.DocSource, error) {
if exp.ToolOptions.Namespace.DBPath != "" {
shimPath, err := db.LocateShim()
if err != nil {
return nil, err
}
bsonTool := db.StorageShim{
DBPath: exp.ToolOptions.Namespace.DBPath,
Database: exp.ToolOptions.Namespace.DB,
Collection: exp.ToolOptions.Namespace.Collection,
Query: exp.InputOpts.Query,
Skip: exp.InputOpts.Skip,
Limit: exp.InputOpts.Limit,
ShimPath: shimPath,
}
iter, _, err := bsonTool.Open()
if err != nil {
return nil, err
}
return db.NewDecodedBSONSource(iter), nil
}
sessionProvider, err := db.InitSessionProvider(exp.ToolOptions)
if err != nil {
return nil, err
}
session, err := sessionProvider.GetSession()
if err != nil {
return nil, err
}
collection := session.DB(exp.ToolOptions.Namespace.DB).C(exp.ToolOptions.Namespace.Collection)
query := map[string]interface{}{}
if exp.InputOpts != nil && exp.InputOpts.Query != "" {
var err error
query, err = getObjectFromArg(exp.InputOpts.Query)
if err != nil {
return nil, err
}
}
q := collection.Find(query)
if exp.InputOpts != nil && exp.InputOpts.Skip > 0 {
q = q.Skip(exp.InputOpts.Skip)
}
if exp.InputOpts != nil && exp.InputOpts.Limit > 0 {
q = q.Limit(exp.InputOpts.Limit)
}
if exp.InputOpts != nil && exp.InputOpts.Sort != "" {
sortD, err := getSortFromArg(exp.InputOpts.Sort)
if err != nil {
return nil, err
}
sortFields, err := bsonutil.MakeSortString(sortD)
if err != nil {
return nil, err
}
q = q.Sort(sortFields...)
}
if len(query) == 0 && exp.InputOpts != nil && exp.InputOpts.ForceTableScan != true && exp.InputOpts.Sort == "" {
q = q.Snapshot()
}
cursor := q.Iter()
return &db.CursorDocSource{cursor, session}, nil
}