const BSONObj& ReadPreferenceSetting::secondaryPreferredMetadata() {
// This is a static method rather than a static member only because it is used by another TU
// during dynamic init.
static const auto bson =
ReadPreferenceSetting(ReadPreference::SecondaryPreferred).toContainingBSON();
return bson;
}
StatusWith<ReadPreferenceSetting> ReadPreferenceSetting::fromContainingBSON(
const BSONObj& obj, ReadPreference defaultReadPref) {
if (auto elem = obj["$readPreference"]) {
return fromInnerBSON(elem);
}
return ReadPreferenceSetting(defaultReadPref);
}
StatusWith<ReadPreferenceSetting> ClusterFind::extractUnwrappedReadPref(const BSONObj& cmdObj,
const bool isSlaveOk) {
BSONElement queryOptionsElt;
auto status = bsonExtractTypedField(
cmdObj, QueryRequest::kUnwrappedReadPrefField, BSONType::Object, &queryOptionsElt);
if (status.isOK()) {
// There must be a nested object containing the read preference if there is a queryOptions
// field.
BSONObj queryOptionsObj = queryOptionsElt.Obj();
invariant(queryOptionsObj[QueryRequest::kWrappedReadPrefField].type() == BSONType::Object);
BSONObj readPrefObj = queryOptionsObj[QueryRequest::kWrappedReadPrefField].Obj();
auto readPref = ReadPreferenceSetting::fromBSON(readPrefObj);
if (!readPref.isOK()) {
return readPref.getStatus();
}
return readPref.getValue();
} else if (status != ErrorCodes::NoSuchKey) {
return status;
}
// If there is no explicit read preference, the value we use depends on the setting of the slave
// ok bit.
ReadPreference pref =
isSlaveOk ? mongo::ReadPreference::SecondaryPreferred : mongo::ReadPreference::PrimaryOnly;
return ReadPreferenceSetting(pref, TagSet());
}
StatusWith<CachedDatabaseInfo> createShardDatabase(OperationContext* opCtx, StringData dbName) {
auto dbStatus = Grid::get(opCtx)->catalogCache()->getDatabase(opCtx, dbName);
if (dbStatus == ErrorCodes::NamespaceNotFound) {
ConfigsvrCreateDatabase configCreateDatabaseRequest(dbName.toString());
configCreateDatabaseRequest.setDbName(NamespaceString::kAdminDb);
auto configShard = Grid::get(opCtx)->shardRegistry()->getConfigShard();
auto createDbStatus =
uassertStatusOK(configShard->runCommandWithFixedRetryAttempts(
opCtx,
ReadPreferenceSetting(ReadPreference::PrimaryOnly),
"admin",
CommandHelpers::appendMajorityWriteConcern(
configCreateDatabaseRequest.toBSON({})),
Shard::RetryPolicy::kIdempotent))
.commandStatus;
if (createDbStatus.isOK() || createDbStatus == ErrorCodes::NamespaceExists) {
dbStatus = Grid::get(opCtx)->catalogCache()->getDatabase(opCtx, dbName);
} else {
dbStatus = createDbStatus;
}
}
if (dbStatus.isOK()) {
return dbStatus;
}
return dbStatus.getStatus().withContext(str::stream() << "Database " << dbName << " not found");
}
OpMsgRequest upconvertRequest(StringData db, BSONObj cmdObj, int queryFlags) {
cmdObj = cmdObj.getOwned(); // Usually this is a no-op since it is already owned.
auto readPrefContainer = BSONObj();
const StringData firstFieldName = cmdObj.firstElementFieldName();
if (firstFieldName == "$query" || firstFieldName == "query") {
// Commands sent over OP_QUERY specify read preference by putting it at the top level and
// putting the command in a nested field called either query or $query.
// Check if legacyCommand has an invalid $maxTimeMS option.
uassert(ErrorCodes::InvalidOptions,
"cannot use $maxTimeMS query option with commands; use maxTimeMS command option "
"instead",
!cmdObj.hasField("$maxTimeMS"));
if (auto readPref = cmdObj["$readPreference"])
readPrefContainer = readPref.wrap();
cmdObj = cmdObj.firstElement().Obj().shareOwnershipWith(cmdObj);
} else if (auto queryOptions = cmdObj["$queryOptions"]) {
// Mongos rewrites commands with $readPreference to put it in a field nested inside of
// $queryOptions. Its command implementations often forward commands in that format to
// shards. This function is responsible for rewriting it to a format that the shards
// understand.
readPrefContainer = queryOptions.Obj().shareOwnershipWith(cmdObj);
cmdObj = cmdObj.removeField("$queryOptions");
}
if (!readPrefContainer.isEmpty()) {
cmdObj = BSONObjBuilder(std::move(cmdObj)).appendElements(readPrefContainer).obj();
} else if (!cmdObj.hasField("$readPreference") && (queryFlags & QueryOption_SlaveOk)) {
BSONObjBuilder bodyBuilder(std::move(cmdObj));
ReadPreferenceSetting(ReadPreference::SecondaryPreferred).toContainingBSON(&bodyBuilder);
cmdObj = bodyBuilder.obj();
}
// Try to move supported array fields into document sequences.
auto docSequenceIt = docSequenceFieldsForCommands.find(cmdObj.firstElementFieldName());
auto docSequenceElem = docSequenceIt == docSequenceFieldsForCommands.end()
? BSONElement()
: cmdObj[docSequenceIt->second];
if (!isArrayOfObjects(docSequenceElem))
return OpMsgRequest::fromDBAndBody(db, std::move(cmdObj));
auto docSequenceName = docSequenceElem.fieldNameStringData();
// Note: removing field before adding "$db" to avoid the need to copy the potentially large
// array.
auto out = OpMsgRequest::fromDBAndBody(db, cmdObj.removeField(docSequenceName));
out.sequences.push_back({docSequenceName.toString()});
for (auto elem : docSequenceElem.Obj()) {
out.sequences[0].objs.push_back(elem.Obj().shareOwnershipWith(cmdObj));
}
return out;
}
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));
}
