/* The algorithm works as follows: In case we have a read preference of
* primary, secondary or nearest the set will always contain a set of all nodes
* that should always be considered to be returned. With primary, there is only
* going to be one node, with primary the set contains only secondaries and
* with nearest we do not prefer a secondary over a primary or v.v.
*
* In case we have a read preference of primaryPreferred or
* secondaryPreferred, we need to do a bit more logic for selecting the node
* that we use. */
mongo_connection *mongo_pick_server_from_set(mongo_con_manager *manager, mcon_collection *col, mongo_read_preference *rp)
{
mongo_connection *con = NULL;
int entry;
/* If we prefer the primary, we check whether the first node is a primary
* (which it should be if it's available and sorted according to primary >
* secondary). If the first node in the list is no primary, we fall back
* to picking a random node from the set. */
if (rp->type == MONGO_RP_PRIMARY_PREFERRED) {
if (((mongo_connection*)col->data[0])->connection_type == MONGO_NODE_PRIMARY) {
mongo_manager_log(manager, MLOG_RS, MLOG_INFO, "pick server: the primary");
con = (mongo_connection*)col->data[0];
mongo_print_connection_info(manager, con, MLOG_INFO);
return con;
}
}
/* If we prefer a secondary, then we need to ignore the last item from the
* list, as this is the primary node - but only if there is more than one
* node in the list AND the last node in the list is a primary. */
if (rp->type == MONGO_RP_SECONDARY_PREFERRED) {
if (
(col->count > 1) &&
(((mongo_connection*)col->data[col->count - 1])->connection_type == MONGO_NODE_PRIMARY)
) {
entry = rand() % (col->count - 1);
mongo_manager_log(manager, MLOG_RS, MLOG_INFO, "pick server: random element %d while ignoring the primary", entry);
con = (mongo_connection*)col->data[entry];
mongo_print_connection_info(manager, con, MLOG_INFO);
return con;
}
}
/* For now, we just pick a random server from the set */
entry = rand() % col->count;
mongo_manager_log(manager, MLOG_RS, MLOG_INFO, "pick server: random element %d", entry);
con = (mongo_connection*)col->data[entry];
mongo_print_connection_info(manager, con, MLOG_INFO);
return con;
}
static mcon_collection *mongo_filter_candidates_by_credentials(mongo_con_manager *manager, mcon_collection *candidates, mongo_servers *servers)
{
int i;
char *db, *username, *auth_hash, *hashed = NULL;
mcon_collection *filtered;
mongo_manager_log(manager, MLOG_RS, MLOG_FINE, "limiting by credentials");
filtered = mcon_init_collection(sizeof(mongo_connection*));
for (i = 0; i < candidates->count; i++) {
db = username = auth_hash = hashed = NULL;
mongo_server_split_hash(((mongo_connection *) candidates->data[i])->hash, NULL, NULL, NULL, &db, &username, &auth_hash, NULL);
if (servers->server[0]->username && servers->server[0]->password && servers->server[0]->db) {
if (strcmp(db, servers->server[0]->db) != 0) {
mongo_manager_log(manager, MLOG_RS, MLOG_FINE, "- skipping '%s', database didn't match ('%s' vs '%s')", ((mongo_connection *) candidates->data[i])->hash, db, servers->server[0]->db);
goto skip;
}
if (strcmp(username, servers->server[0]->username) != 0) {
mongo_manager_log(manager, MLOG_RS, MLOG_FINE, "- skipping '%s', username didn't match ('%s' vs '%s')", ((mongo_connection *) candidates->data[i])->hash, username, servers->server[0]->username);
goto skip;
}
hashed = mongo_server_create_hashed_password(username, servers->server[0]->password);
if (strcmp(auth_hash, hashed) != 0) {
mongo_manager_log(manager, MLOG_RS, MLOG_FINE, "- skipping '%s', authentication hash didn't match ('%s' vs '%s')", ((mongo_connection *) candidates->data[i])->hash, auth_hash, hashed);
goto skip;
}
}
mcon_collection_add(filtered, (mongo_connection *) candidates->data[i]);
mongo_print_connection_info(manager, (mongo_connection *) candidates->data[i], MLOG_FINE);
skip:
if (db) {
free(db);
}
if (username) {
free(username);
}
if (auth_hash) {
free(auth_hash);
}
if (hashed) {
free(hashed);
}
}
mongo_manager_log(manager, MLOG_RS, MLOG_FINE, "limiting by credentials: done");
return filtered;
}
/* Collecting the correct servers */
static mcon_collection *filter_connections(mongo_con_manager *manager, int types, mongo_read_preference *rp)
{
mcon_collection *col;
mongo_con_manager_item *ptr = manager->connections;
col = mcon_init_collection(sizeof(mongo_connection*));
mongo_manager_log(manager, MLOG_RS, MLOG_FINE, "filter_connections: adding connections:");
while (ptr) {
if (ptr->connection->connection_type & types) {
mongo_print_connection_info(manager, ptr->connection, MLOG_FINE);
mcon_collection_add(col, ptr->connection);
}
ptr = ptr->next;
}
mongo_manager_log(manager, MLOG_RS, MLOG_FINE, "filter_connections: done");
return col;
}
static mcon_collection *mongo_filter_candidates_by_seed(mongo_con_manager *manager, mcon_collection *candidates, mongo_servers *servers)
{
int i, j;
mcon_collection *filtered;
char *server_hash;
mongo_manager_log(manager, MLOG_RS, MLOG_FINE, "limiting by seeded/discovered servers");
filtered = mcon_init_collection(sizeof(mongo_connection*));
for (j = 0; j < servers->count; j++) {
server_hash = mongo_server_create_hash(servers->server[j]);
for (i = 0; i < candidates->count; i++) {
if (strcmp(((mongo_connection *) candidates->data[i])->hash, server_hash) == 0) {
mongo_print_connection_info(manager, (mongo_connection *) candidates->data[i], MLOG_FINE);
mcon_collection_add(filtered, (mongo_connection *) candidates->data[i]);
}
}
free(server_hash);
}
mongo_manager_log(manager, MLOG_RS, MLOG_FINE, "limiting by seeded/discovered servers: done");
return filtered;
}
void mongo_print_connection_iterate_wrapper(mongo_con_manager *manager, void *elem)
{
mongo_connection *con = (mongo_connection*) elem;
mongo_print_connection_info(manager, con, MLOG_FINE);
}
