C API for impersonation

libMapRClient also includes a new function in the connection.h header file: hb_connection_create_as_user(). This function provides support for impersonation, so that you can connect to a MapR cluster and access MapR-DB tables by using a specific username.

 * Creates an hb_connection_t instance for a specific user and initializes its
 * address into the passed pointer.
HBASE_API int32_t
    const char *zk_quorum,            /* [in] NULL terminated, comma separated
                                       *   string of CLDB servers. e.g.
                                       *   "<server1[:port]>,...". If set to
                                       *   NULL, IP addresses for CLDB nodes will be
                                       *   taken from mapr-clusters.conf */
    const char *zk_root,              /* [in] Ignored for MapR-DB. */
    const char *user,                 /* [in] The user who is being
                                       *   impersonated */
    hb_connection_t *connection_ptr); /* [out] pointer to hb_connection_t */

The user that is passed with the hb_connection_create_as_user() API must have permissions on the tables that the application accesses. For example, to read from a table, the user must have the readperm permission. To write to a table, the user must have the writeperm permission. See Enabling Table Authorizations with Access Control Expressions.

For hb_connection_create() and hb_connection_create_as_user(), the standard C APIs for HBase require a list of ZooKeeper nodes. For MapR-DB, this list is interpreted as a list of CLDB nodes. The zk_root parameter is ignored. If zk_quorum is NULL, then the connection will be created to the default cluster that is listed in the mapr-clusters.conf file.