Add support for custom log timestamps.

Closes #1121.

man/mosquitto.conf.5.xml

@@ -407,6 +407,21 @@
 					<para>Reloaded on reload signal.</para>
 				</listitem>
 			</varlistentry>
+			<varlistentry>
+				<term><option>log_timestamp_format</option> <replaceable>format</replaceable></term>
+				<listitem>
+					<para>Set the format of the log timestamp. If left unset,
+						this is the number of seconds since the Unix epoch.
+						This option is a free text string which will be passed
+						to the strftime function as the format specifier. To
+						get an ISO 8601 datetime, for example:</para>
+					<programlisting language="config">
+log_timestamp_format %Y-%m-%dT%H:%M:%S
+					</programlisting>
+					<para>Reloaded on reload signal.</para>
+				</listitem>
+			</varlistentry>
+
 			<varlistentry>
 				<term><option>log_type</option> <replaceable>types</replaceable></term>
 				<listitem>

mosquitto.conf

@@ -610,6 +610,13 @@
 # If set to true, add a timestamp value to each log message.
 #log_timestamp true
 
+# Set the format of the log timestamp. If left unset, this is the number of
+# seconds since the Unix epoch.
+# This is a free text string which will be passed to the strftime function. To
+# get an ISO 8601 datetime, for example:
+# log_timestamp_format %Y-%m-%dT%H:%M:%S
+#log_timestamp_format
+
 # =================================================================
 # Security
 # =================================================================

src/conf.c

@@ -213,6 +213,8 @@ static void config__init_reload(struct mosquitto_db *db, struct mosquitto__confi
 	}
 #endif
 	config->log_timestamp = true;
+	mosquitto__free(config->log_timestamp_format);
+	config->log_timestamp_format = NULL;
 	config->max_keepalive = 65535;
 	config->max_packet_size = 0;
 	config->max_inflight_messages = 20;
@@ -571,6 +573,9 @@ void config__copy(struct mosquitto__config *src, struct mosquitto__config *dest)
 	dest->log_type = src->log_type;
 	dest->log_timestamp = src->log_timestamp;
 
+	mosquitto__free(dest->log_timestamp_format);
+	dest->log_timestamp_format = src->log_timestamp_format;
+
 	mosquitto__free(dest->log_file);
 	dest->log_file = src->log_file;
 
@@ -1460,6 +1465,8 @@ int config__read_file_core(struct mosquitto__config *config, bool reload, struct
 #endif
 				}else if(!strcmp(token, "log_timestamp")){
 					if(conf__parse_bool(&token, token, &config->log_timestamp, saveptr)) return MOSQ_ERR_INVAL;
+				}else if(!strcmp(token, "log_timestamp_format")){
+					if(conf__parse_string(&token, token, &config->log_timestamp_format, saveptr)) return MOSQ_ERR_INVAL;
 				}else if(!strcmp(token, "log_type")){
 					token = strtok_r(NULL, " ", &saveptr);
 					if(token){

src/logging.c

@@ -56,6 +56,43 @@ static int log_priorities = MOSQ_LOG_ERR | MOSQ_LOG_WARNING | MOSQ_LOG_NOTICE |
 static DltContext dltContext;
 #endif
 
+static int get_time(struct tm **ti)
+{
+#ifdef WIN32
+	SYSTEMTIME st;
+#elif defined(__APPLE__)
+	struct timeval tv;
+#else
+	struct timespec ts;
+#endif
+	time_t s;
+
+#ifdef WIN32
+	s = time(NULL);
+
+	GetLocalTime(&st);
+	*ns = st.wMilliseconds*1000000L;
+#elif defined(__APPLE__)
+	gettimeofday(&tv, NULL);
+	s = tv.tv_sec;
+#else
+	if(clock_gettime(CLOCK_REALTIME, &ts) != 0){
+		fprintf(stderr, "Error obtaining system time.\n");
+		return 1;
+	}
+	s = ts.tv_sec;
+#endif
+
+	*ti = localtime(&s);
+	if(!(*ti)){
+		fprintf(stderr, "Error obtaining system time.\n");
+		return 1;
+	}
+
+	return 0;
+}
+
+
 int log__init(struct mosquitto__config *config)
 {
 	int rc = 0;
@@ -149,6 +186,7 @@ int log__vprintf(int priority, const char *fmt, va_list va)
 	int syslog_priority;
 	time_t now = time(NULL);
 	static time_t last_flush = 0;
+	char time_buf[50];
 
 	if((log_priorities & priority) && log_destinations != MQTT3_LOG_NONE){
 		switch(priority){
@@ -233,9 +271,20 @@ int log__vprintf(int priority, const char *fmt, va_list va)
 		vsnprintf(s, len, fmt, va);
 		s[len-1] = '\0'; /* Ensure string is null terminated. */
 
+		if(int_db.config && int_db.config->log_timestamp && int_db.config->log_timestamp_format){
+			struct tm *ti = NULL;
+			get_time(&ti);
+			if(strftime(time_buf, 50, int_db.config->log_timestamp_format, ti) == 0){
+				snprintf(time_buf, 50, "Time error");
+			}
+		}
 		if(log_destinations & MQTT3_LOG_STDOUT){
 			if(int_db.config && int_db.config->log_timestamp){
-				fprintf(stdout, "%d: %s\n", (int)now, s);
+				if(int_db.config->log_timestamp_format){
+					fprintf(stdout, "%s: %s\n", time_buf, s);
+				}else{
+					fprintf(stdout, "%d: %s\n", (int)now, s);
+				}
 			}else{
 				fprintf(stdout, "%s\n", s);
 			}
@@ -243,7 +292,11 @@ int log__vprintf(int priority, const char *fmt, va_list va)
 		}
 		if(log_destinations & MQTT3_LOG_STDERR){
 			if(int_db.config && int_db.config->log_timestamp){
-				fprintf(stderr, "%d: %s\n", (int)now, s);
+				if(int_db.config->log_timestamp_format){
+					fprintf(stderr, "%s: %s\n", time_buf, s);
+				}else{
+					fprintf(stderr, "%d: %s\n", (int)now, s);
+				}
 			}else{
 				fprintf(stderr, "%s\n", s);
 			}
@@ -251,7 +304,11 @@ int log__vprintf(int priority, const char *fmt, va_list va)
 		}
 		if(log_destinations & MQTT3_LOG_FILE && int_db.config->log_fptr){
 			if(int_db.config && int_db.config->log_timestamp){
-				fprintf(int_db.config->log_fptr, "%d: %s\n", (int)now, s);
+				if(int_db.config->log_timestamp_format){
+					fprintf(int_db.config->log_fptr, "%s: %s\n", time_buf, s);
+				}else{
+					fprintf(int_db.config->log_fptr, "%d: %s\n", (int)now, s);
+				}
 			}else{
 				fprintf(int_db.config->log_fptr, "%s\n", s);
 			}

src/mosquitto_broker_internal.h

@@ -255,6 +255,7 @@ struct mosquitto__config {
 	int log_facility;
 	int log_type;
 	bool log_timestamp;
+	char *log_timestamp_format;
 	char *log_file;
 	FILE *log_fptr;
 	uint16_t max_inflight_messages;