public static UserGroupInformation loginIfNeeded()

in hbase-common/src/main/java/org/apache/omid/tools/hbase/HBaseLogin.java [44:78]
31 lines of code
11 McCabe index (conditional complexity)

    public static UserGroupInformation loginIfNeeded(SecureHBaseConfig config, Configuration hbaseConf) throws IOException {
        boolean credsProvided = null != config.getPrincipal() && null != config.getKeytab();
        if (UserGroupInformation.isSecurityEnabled()) {
            // Check if we need to authenticate with kerberos so that we cache the correct ConnectionInfo
            UserGroupInformation currentUser = UserGroupInformation.getCurrentUser();
            boolean hasKerberosCreds = currentUser.hasKerberosCredentials()
                    || (currentUser.getRealUser() != null
                            && currentUser.getRealUser().hasKerberosCredentials());
            if (credsProvided && (!hasKerberosCreds
                    || !isSameName(currentUser.getUserName(), config.getPrincipal()))) {
                synchronized (KERBEROS_LOGIN_LOCK) {
                    // Double check the current user, might have changed since we checked last. Don't want
                    // to re-login if it's the same user.
                    currentUser = UserGroupInformation.getCurrentUser();
                    if (!hasKerberosCreds || !isSameName(currentUser.getUserName(), config.getPrincipal())) {
                        final Configuration hbaseConfig = getConfiguration(hbaseConf, config.getPrincipal(), config.getKeytab());
                        LOG.info("Trying to connect to a secure cluster as {} with keytab {}",
                                hbaseConfig.get(SecureHBaseConfig.HBASE_CLIENT_PRINCIPAL_KEY),
                                hbaseConfig.get(SecureHBaseConfig.HBASE_CLIENT_KEYTAB_KEY));
                        UserGroupInformation.setConfiguration(hbaseConfig);
                        User.login(hbaseConfig, SecureHBaseConfig.HBASE_CLIENT_KEYTAB_KEY, SecureHBaseConfig.HBASE_CLIENT_PRINCIPAL_KEY, null);
                        LOG.info("Successful login to secure cluster");
                    }
                }
            } else {
                if (hasKerberosCreds) {
                    // The user already has Kerberos creds, so there isn't anything to change in the ConnectionInfo.
                    LOG.debug("Already logged in as {}", currentUser);
                } else {
                    LOG.warn("Security enabled but not logged in, and did not provide credentials. NULL UGI returned");
                }
            }
        }
        return ugi;
    }