StatusWith<ServerSelectionMetadata> ServerSelectionMetadata::readFromMetadata(
const BSONObj& metadata) {
auto secondaryOkField = metadata.getField(kSecondaryOkFieldName);
bool secondaryOk = !secondaryOkField.eoo();
boost::optional<ReadPreferenceSetting> readPreference;
BSONElement rpElem;
auto readPrefExtractStatus =
bsonExtractTypedField(metadata, kReadPreferenceFieldName, mongo::Object, &rpElem);
if (readPrefExtractStatus == ErrorCodes::NoSuchKey) {
// Do nothing, it's valid to have no ReadPreference
} else if (!readPrefExtractStatus.isOK()) {
return readPrefExtractStatus;
} else {
// We have a read preference in the metadata object.
auto parsedRps = ReadPreferenceSetting::fromBSON(rpElem.Obj());
if (!parsedRps.isOK()) {
return parsedRps.getStatus();
}
readPreference.emplace(std::move(parsedRps.getValue()));
}
return ServerSelectionMetadata(secondaryOk, std::move(readPreference));
}
StatusWith<ServerSelectionMetadata> ServerSelectionMetadata::readFromMetadata(
const BSONElement& metadataElem) {
if (metadataElem.eoo()) {
return ServerSelectionMetadata{};
} else if (metadataElem.type() != mongo::Object) {
return {ErrorCodes::TypeMismatch,
str::stream() << "ServerSelectionMetadata element has incorrect type: expected"
<< mongo::Object
<< " but got "
<< metadataElem.type()};
}
bool secondaryOk = false;
boost::optional<ReadPreferenceSetting> readPreference;
BSONElement rpElem;
for (const auto& ssmElem : metadataElem.Obj()) {
auto ssmElemFieldName = ssmElem.fieldNameStringData();
if (ssmElemFieldName == kSecondaryOkFieldName) {
secondaryOk = ssmElem.trueValue();
} else if (ssmElemFieldName == kReadPreferenceFieldName) {
if (ssmElem.type() != mongo::Object) {
return Status(ErrorCodes::TypeMismatch,
str::stream() << "ReadPreference has incorrect type: expected"
<< mongo::Object
<< "but got"
<< metadataElem.type());
}
auto parsedRps = ReadPreferenceSetting::fromBSON(ssmElem.Obj());
if (!parsedRps.isOK()) {
return parsedRps.getStatus();
}
readPreference.emplace(std::move(parsedRps.getValue()));
}
}
return ServerSelectionMetadata(secondaryOk, std::move(readPreference));
}
