StatusWith<ReadPreferenceSetting> ReadPreferenceSetting::fromBSON(const BSONObj& readPrefObj) {
std::string modeStr;
auto modeExtractStatus = bsonExtractStringField(readPrefObj, kModeFieldName, &modeStr);
if (!modeExtractStatus.isOK()) {
return modeExtractStatus;
}
ReadPreference mode;
auto swReadPrefMode = parseReadPreferenceMode(modeStr);
if (!swReadPrefMode.isOK()) {
return swReadPrefMode.getStatus();
}
mode = std::move(swReadPrefMode.getValue());
TagSet tags;
BSONElement tagsElem;
auto tagExtractStatus =
bsonExtractTypedField(readPrefObj, kTagsFieldName, mongo::Array, &tagsElem);
if (tagExtractStatus.isOK()) {
tags = TagSet{BSONArray(tagsElem.Obj().getOwned())};
// In accordance with the read preference spec, passing the default wildcard tagset
// '[{}]' is the same as not passing a TagSet at all. Furthermore, passing an empty
// TagSet with a non-primary ReadPreference is equivalent to passing the wildcard
// ReadPreference.
if (tags == TagSet() || tags == TagSet::primaryOnly()) {
tags = defaultTagSetForMode(mode);
}
// If we are using a user supplied TagSet, check that it is compatible with
// the readPreference mode.
else if (ReadPreference::PrimaryOnly == mode && (tags != TagSet::primaryOnly())) {
return Status(ErrorCodes::BadValue,
"Only empty tags are allowed with primary read preference");
}
}
else if (ErrorCodes::NoSuchKey == tagExtractStatus) {
tags = defaultTagSetForMode(mode);
} else {
return tagExtractStatus;
}
return ReadPreferenceSetting(mode, tags);
}
StatusWith<ReadPreferenceSetting> ReadPreferenceSetting::fromInnerBSON(const BSONObj& readPrefObj) {
std::string modeStr;
auto modeExtractStatus = bsonExtractStringField(readPrefObj, kModeFieldName, &modeStr);
if (!modeExtractStatus.isOK()) {
return modeExtractStatus;
}
ReadPreference mode;
auto swReadPrefMode = parseReadPreferenceMode(modeStr);
if (!swReadPrefMode.isOK()) {
return swReadPrefMode.getStatus();
}
mode = std::move(swReadPrefMode.getValue());
TagSet tags;
BSONElement tagsElem;
auto tagExtractStatus =
bsonExtractTypedField(readPrefObj, kTagsFieldName, mongo::Array, &tagsElem);
if (tagExtractStatus.isOK()) {
tags = TagSet{BSONArray(tagsElem.Obj().getOwned())};
// In accordance with the read preference spec, passing the default wildcard tagset
// '[{}]' is the same as not passing a TagSet at all. Furthermore, passing an empty
// TagSet with a non-primary ReadPreference is equivalent to passing the wildcard
// ReadPreference.
if (tags == TagSet() || tags == TagSet::primaryOnly()) {
tags = defaultTagSetForMode(mode);
}
// If we are using a user supplied TagSet, check that it is compatible with
// the readPreference mode.
else if (ReadPreference::PrimaryOnly == mode && (tags != TagSet::primaryOnly())) {
return Status(ErrorCodes::BadValue,
"Only empty tags are allowed with primary read preference");
}
}
else if (ErrorCodes::NoSuchKey == tagExtractStatus) {
tags = defaultTagSetForMode(mode);
} else {
return tagExtractStatus;
}
long long maxStalenessSecondsValue;
auto maxStalenessSecondsExtractStatus = bsonExtractIntegerFieldWithDefault(
readPrefObj, kMaxStalenessSecondsFieldName, 0, &maxStalenessSecondsValue);
if (!maxStalenessSecondsExtractStatus.isOK()) {
return maxStalenessSecondsExtractStatus;
}
if (maxStalenessSecondsValue && maxStalenessSecondsValue < 0) {
return Status(ErrorCodes::BadValue,
str::stream() << kMaxStalenessSecondsFieldName
<< " must be a non-negative integer");
}
if (maxStalenessSecondsValue && maxStalenessSecondsValue >= Seconds::max().count()) {
return Status(ErrorCodes::BadValue,
str::stream() << kMaxStalenessSecondsFieldName << " value can not exceed "
<< Seconds::max().count());
}
if (maxStalenessSecondsValue && maxStalenessSecondsValue < kMinimalMaxStalenessValue.count()) {
return Status(ErrorCodes::MaxStalenessOutOfRange,
str::stream() << kMaxStalenessSecondsFieldName
<< " value can not be less than "
<< kMinimalMaxStalenessValue.count());
}
if ((mode == ReadPreference::PrimaryOnly) && maxStalenessSecondsValue) {
return Status(ErrorCodes::BadValue,
str::stream() << kMaxStalenessSecondsFieldName
<< " can not be set for the primary mode");
}
return ReadPreferenceSetting(mode, tags, Seconds(maxStalenessSecondsValue));
}
