bmsd/mqtt.c

/*****************************************************************************
 * Copyright (C) 2017-2018
 *   
 * Michiel Broek <mbroek at mbse dot eu>
 *
 * This file is part of the bms (Brewery Management System)
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2, or (at your option) any
 * later version.
 *
 * bms is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with ThermFerm; see the file COPYING.  If not, write to the Free
 * Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 *****************************************************************************/

#include "bms.h"
#include "xutil.h"
#include "mqtt.h"
#include "nodes.h"
#include "fermenters.h"


extern sys_config       Config;
extern int		debug;


/* Global variables for use in callbacks. */
int              	mqtt_qos = 0;
int              	mqtt_status = STATUS_CONNECTING;
int              	mqtt_mid_sent = 0;
int              	mqtt_last_mid = -1;
int              	mqtt_last_mid_sent = -1;
int              	mqtt_connected = TRUE;
int              	mqtt_disconnect_sent = FALSE;
int              	mqtt_connect_lost = FALSE;
int              	mqtt_my_shutdown = FALSE;
int              	mqtt_use = FALSE;
int			keepalive = 60;
unsigned int		max_inflight = 20;
struct mosquitto	*mosq = NULL;
char			*state = NULL;
char			my_hostname[256];
int			Sequence = 0;


char *payload_header(void)
{
    static char	*tmp;
    char	buf[128];

    tmp = xstrcpy((char *)"{\"timestamp\":");
    sprintf(buf, "%ld", time(NULL));
    tmp = xstrcat(tmp, buf);
    tmp = xstrcat(tmp, (char *)",\"seq\":");
    sprintf(buf, "%d", Sequence++);
    tmp = xstrcat(tmp, buf);
    tmp = xstrcat(tmp, (char *)",\"metric\":");
    return tmp;
}


char *topic_base(char *msgtype)
{
    static char	*tmp;

    tmp = xstrcpy((char *)"mbv1.0/brewery/");
    tmp = xstrcat(tmp, msgtype);
    tmp = xstrcat(tmp, (char *)"/");
    tmp = xstrcat(tmp, my_hostname);
    return tmp;
}


void my_connect_callback(struct mosquitto *my_mosq, void *obj, int result)
{
    char	*topic = NULL;

    if (mqtt_connect_lost) {
        mqtt_connect_lost = FALSE;
        syslog(LOG_NOTICE, "MQTT: reconnect: %s", mosquitto_connack_string(result));
    }

    if (!result) {
	topic = topic_base((char *)"NCMD");		// TODO: do we need this??
	topic = xstrcat(topic, (char *)"/#");
	mosquitto_subscribe(mosq, NULL, topic, 0);
	free(topic);
	topic = xstrcpy((char *)"mbv1.0/fermenters/#");		// Subscribe to fermenter messages.
	mosquitto_subscribe(mosq, NULL, topic, 0);
	free(topic);
	topic = NULL;
       	mqtt_status = STATUS_CONNACK_RECVD;
    } else {
       	syslog(LOG_NOTICE, "MQTT: my_connect_callback: %s\n", mosquitto_connack_string(result));
    }
}


void my_disconnect_callback(struct mosquitto *my_mosq, void *obj, int rc)
{
    if (mqtt_my_shutdown) {
       	syslog(LOG_NOTICE, "MQTT: acknowledged DISCONNECT from %s", Config.mqtt_host);
       	mqtt_connected = FALSE;
    } else {
       	/*
         * The remote server was brought down. We must keep running
         */
       	syslog(LOG_NOTICE, "MQTT: received DISCONNECT from %s, connection lost", Config.mqtt_host);
       	mqtt_connect_lost = TRUE;
    }
}


void my_publish_callback(struct mosquitto *my_mosq, void *obj, int mid)
{
    mqtt_last_mid_sent = mid;
}


void my_subscribe_callback(struct mosquitto *my_mosq, void *userdata, int mid, int qos_count, const int *granted_qos)
{
    int i;

    syslog(LOG_NOTICE, "Subscribed (mid: %d): %d", mid, granted_qos[0]);
    for (i = 1; i < qos_count; i++) {
	syslog(LOG_NOTICE, "     %d", granted_qos[i]);
    }
}


void my_log_callback(struct mosquitto *my_mosq, void *obj, int level, const char *str)
{
    syslog(LOG_NOTICE, "MQTT: %s", str);
    if (debug)
    	fprintf(stdout, "MQTT: %s\n", str);
}


void my_message_callback(struct mosquitto *my_mosq, void *userdata, const struct mosquitto_message *message)
{
    if (message->payloadlen) {
	// TODO: process subscribed topics here.
	if (strstr(message->topic, (char *)"NBIRTH") || strstr(message->topic, (char *)"NDATA")) {
	    node_birth_data(message->topic, (char *)message->payload);
	    return;
	}
	if (strstr(message->topic, (char *)"fermenters") &&  (strstr(message->topic, (char *)"DBIRTH") || strstr(message->topic, (char *)"DDATA"))) {
	    fermenter_birth_data(message->topic, (char *)message->payload);
	    return;
	}
	if (strstr(message->topic, (char *)"fermenters") && strstr(message->topic, (char *)"DLOG")) {
	    fermenter_log(message->topic, (char *)message->payload);
	    return;
	}
	syslog(LOG_NOTICE, "MQTT: message callback %s :: %d", message->topic, message->payloadlen);
    } else {
	if (strstr(message->topic, (char *)"NBIRTH")) {
	    // Ignore ??
	    fprintf(stdout, "MQTT: %s NULL\n", message->topic);
	    return;
	}
	if (strstr(message->topic, (char *)"NDEATH")) {
	    node_death(message->topic);
	    return;
	}
	if (strstr(message->topic, (char *)"fermenters") && strstr(message->topic, (char *)"DDEATH")) {
	    fermenter_death(message->topic);
	    return;
	}
	syslog(LOG_NOTICE, "MQTT: message callback %s (null)", message->topic);
    }
}


void publisher(struct mosquitto *my_mosq, char *topic, char *payload, bool retain) 
{
    // publish the data
    if (payload)
	mosquitto_publish(my_mosq, &mqtt_mid_sent, topic, strlen(payload), payload, mqtt_qos, retain);
    else
	mosquitto_publish(my_mosq, &mqtt_mid_sent, topic, 0, NULL, mqtt_qos, retain);
}


void publishNData(bool birth, int flag)
{
    char                *topic = NULL, *payload = NULL;
    struct utsname      ubuf;
    bool                comma = false;

    payload = payload_header();
    payload = xstrcat(payload, (char *)"{");
			        
    if (birth || flag & MQTT_NODE_CONTROL) {
	payload = xstrcat(payload, (char *)"\"nodecontrol\":{\"reboot\":false,\"rebirth\":false,\"nextserver\":false,\"scanrate\":3000}");
	comma = true;
    }

    if (birth) {
	if (comma)
	    payload = xstrcat(payload, (char *)",");
	payload = xstrcat(payload, (char *)"\"properties\":{\"hardwaremake\":\"Unknown\",\"hardwaremodel\":\"Unknown\"");
	if (uname(&ubuf) == 0) {
	    payload = xstrcat(payload, (char *)",\"os\":\"");
	    payload = xstrcat(payload, ubuf.sysname);
	    payload = xstrcat(payload, (char *)"\",\"os_version\":\"");
	    payload = xstrcat(payload, ubuf.release);
	    payload = xstrcat(payload, (char *)"\"");
	} else {
	    payload = xstrcat(payload, (char *)",\"os\":\"Unknown\",\"os_version\":\"Unknown\"");
	}

	payload = xstrcat(payload, (char *)",\"FW\":\"");
	payload = xstrcat(payload, (char *)VERSION);
	payload = xstrcat(payload, (char *)"\"}");
	comma = true;
    }
    payload = xstrcat(payload, (char *)"}}");

    if (birth) {
	topic = topic_base((char *)"NBIRTH");
	publisher(mosq, topic, payload, true);
    } else {
	topic = topic_base((char *)"NDATA");
	publisher(mosq, topic, payload, false);
    }

    free(payload);
    payload = NULL;
    free(topic);
    topic = NULL;
}


int mqtt_connect(void)
{
    char	*id = NULL, *topic = NULL;
    char	err[1024];
    int		rc;

    /*
     * Initialize mosquitto communication
     */
    gethostname(my_hostname, 255);
    mosquitto_lib_init();
    id = xstrcpy((char *)"bmsd/");
    id = xstrcat(id, my_hostname);
    if (strlen(id) > MOSQ_MQTT_ID_MAX_LENGTH) {
       /*
        * Enforce maximum client id length of 23 characters
        */
       id[MOSQ_MQTT_ID_MAX_LENGTH] = '\0';
    }

    mosq = mosquitto_new(id, TRUE, NULL);
    if (!mosq) {
       switch(errno) {
           case ENOMEM:
               syslog(LOG_NOTICE, "MQTT: mosquitto_new: Out of memory");
               break;
           case EINVAL:
               syslog(LOG_NOTICE, "MQTT: mosquitto_new: Invalid id");
               break;
       }
       mosquitto_lib_cleanup();
       return 1;
    }
    free(id);
    id = NULL;

    /*
     * Set our will
     */
    topic = topic_base((char *)"NDEATH");
    if ((rc = mosquitto_will_set(mosq, topic, 0, NULL, mqtt_qos, false))) {
	if (rc > MOSQ_ERR_SUCCESS)
	    syslog(LOG_NOTICE, "MQTT: mosquitto_will_set: %s", mosquitto_strerror(rc));
	mosquitto_lib_cleanup();
	return 2;
    }
    free(topic);
    topic = NULL;

    if (debug)
       mosquitto_log_callback_set(mosq, my_log_callback);

    /*
     * Username/Password
     */
    if (Config.mqtt_user) {
	if (Config.mqtt_pass) {
	    rc = mosquitto_username_pw_set(mosq, Config.mqtt_user, Config.mqtt_pass);
	} else {
	    rc = mosquitto_username_pw_set(mosq, Config.mqtt_user, NULL);
	}
	if (rc == MOSQ_ERR_INVAL) {
	    syslog(LOG_NOTICE, "MQTT: mosquitto_username_pw_set: input parameters invalid");
	} else if (rc == MOSQ_ERR_NOMEM) {
	    syslog(LOG_NOTICE, "MQTT: mosquitto_username_pw_set: Out of Memory");
	}
	if (rc != MOSQ_ERR_SUCCESS) {
	    mosquitto_lib_cleanup();
	    return 3;
	}
    }

    mosquitto_max_inflight_messages_set(mosq, max_inflight);
    mosquitto_connect_callback_set(mosq, my_connect_callback);
    mosquitto_disconnect_callback_set(mosq, my_disconnect_callback);
    mosquitto_publish_callback_set(mosq, my_publish_callback);
    mosquitto_message_callback_set(mosq, my_message_callback);
    mosquitto_subscribe_callback_set(mosq, my_subscribe_callback);

    if ((rc = mosquitto_connect(mosq, Config.mqtt_host, Config.mqtt_port, keepalive))) {
        if (rc == MOSQ_ERR_ERRNO) {
            strerror_r(errno, err, 1024);
            syslog(LOG_NOTICE, "MQTT: mosquitto_connect: error: %s", err);
        } else {
            syslog(LOG_NOTICE, "MQTT: mosquitto_connect: unable to connect (%d)", rc);
        }
        mosquitto_lib_cleanup();
	syslog(LOG_NOTICE, "MQTT: will run without an MQTT broker.");
	return 4;
    } else {
        mqtt_use = TRUE;
        syslog(LOG_NOTICE, "MQTT: connected with %s:%d", Config.mqtt_host, Config.mqtt_port);

        /*
         * Initialise is complete, report our presence state
         */
        mosquitto_loop_start(mosq);
	publishNData(true, 0);
    }

    return 0;
}


void mqtt_disconnect(void)
{
    int		rc;
    char	*topic = NULL;

    if (mqtt_use) {
        /*
         * Final publish 0 to clients/<hostname>/bmsd/state
	 * After that, remove the retained topic.
         */
        syslog(LOG_NOTICE, "MQTT disconnecting");
	topic = topic_base((char *)"NBIRTH");
	publisher(mosq, topic, NULL, true);
	free(topic);
	topic = topic_base((char *)"NDEATH");
	publisher(mosq, topic, NULL, true);
	free(topic);
	topic = NULL;
	mqtt_last_mid = mqtt_mid_sent;
        mqtt_status = STATUS_WAITING;
	mqtt_my_shutdown = TRUE;

        do {
            if (mqtt_status == STATUS_WAITING) {
                if (debug)
                    fprintf(stdout, (char *)"Waiting\n");
                if (mqtt_last_mid_sent == mqtt_last_mid && mqtt_disconnect_sent == FALSE) {
                    mosquitto_disconnect(mosq);
                    mqtt_disconnect_sent = TRUE;
                }
                usleep(100000);
            }
            rc = MOSQ_ERR_SUCCESS;
        } while (rc == MOSQ_ERR_SUCCESS && mqtt_connected);

        mosquitto_loop_stop(mosq, FALSE);
        mosquitto_destroy(mosq);
        mosquitto_lib_cleanup();
	mqtt_use = FALSE;
	mqtt_status = STATUS_CONNECTING;
	mqtt_mid_sent = 0;
	mqtt_last_mid = -1;
	mqtt_last_mid_sent = -1;
	mqtt_connected = TRUE;
	mqtt_disconnect_sent = FALSE;
	mqtt_connect_lost = FALSE;
	mqtt_my_shutdown = FALSE;
	syslog(LOG_NOTICE, "MQTT: disconnected");
    }
}