Add configuration option "log_status_interval"

Normally (outside of log level DEBUG) repmgrd doesn't generate any
kind of log output, so examining the log file may give the impression
it's not working. Output an informational message at regular intervals
to show it's up and running.

config.c

@@ -219,6 +219,7 @@ _parse_config(t_configuration_options *options, ItemList *error_list, ItemList *
 	 */
 	memset(options->log_facility, 0, sizeof(options->log_facility));
 	memset(options->log_file, 0, sizeof(options->log_file));
+	options->log_status_interval = DEFAULT_LOG_STATUS_INTERVAL;
 
 	/* standby clone settings
 	 * ----------------------- */
@@ -354,6 +355,8 @@ _parse_config(t_configuration_options *options, ItemList *error_list, ItemList *
 			strncpy(options->log_level, value, MAXLEN);
 		else if (strcmp(name, "log_facility") == 0)
 			strncpy(options->log_facility, value, MAXLEN);
+		else if (strcmp(name, "log_status_interval") == 0)
+			options->log_status_interval = repmgr_atoi(value, name, error_list, 0);
 
 		/* standby clone settings */
 		else if (strcmp(name, "use_replication_slots") == 0)

config.h

@@ -62,6 +62,7 @@ typedef struct
 	char		log_level[MAXLEN];
 	char		log_facility[MAXLEN];
 	char		log_file[MAXLEN];
+	int			log_status_interval;
 
 	/* standby clone settings */
 	bool		use_replication_slots;
@@ -116,7 +117,7 @@ typedef struct
 		/* node information */ \
 		UNKNOWN_NODE_ID, NO_UPSTREAM_NODE, "", "", "", "", REPLICATION_TYPE_PHYSICAL, \
 		/* log settings */ \
-		"", "", "", \
+		"", "", "", DEFAULT_LOG_STATUS_INTERVAL,	\
 		/* standby clone settings */ \
 		false, "", "", "", "", { NULL, NULL },	\
 		/* repmgrd settings */ \

doc/changes-in-repmgr4.md

@@ -37,4 +37,5 @@ Logging changes
   - `logfile` has been renamed to `log_file`
   - `logfacility` has been renamed to `log_facility`
 - default value for `log_level` is `INFO` rather than `NOTICE`.
+- new parameter `log_status_interval`
 

log.h

@@ -14,6 +14,8 @@
 #define OM_COMMAND_LINE 1
 #define OM_DAEMON		2
 
+#define DEFAULT_LOG_STATUS_INTERVAL 300
+
 extern void
 stderr_log_with_level(const char *level_name, int level, const char *fmt,...)
 __attribute__((format(PG_PRINTF_ATTRIBUTE, 3, 4)));

repmgr.conf.sample

@@ -77,7 +77,8 @@
                                          # syslog integration, one of LOCAL0, LOCAL1, ..., LOCAL7, USER
 
 #log_file=''                             # stderr can be redirected to an arbitrary file:
-
+#log_status_interval=300                 # interval (in seconds) for repmgrd to log a message confirming
+                                         # its current status; setting to 0 disables this message
 
 #------------------------------------------------------------------------------
 # Event notification settings

repmgrd.c

@@ -10,6 +10,8 @@
 #include <sys/stat.h>
 #include <time.h>
 
+#include "portability/instr_time.h"
+
 #include "repmgr.h"
 #include "config.h"
 #include "voting.h"
@@ -449,7 +451,8 @@ start_monitoring(void)
 static void
 monitor_streaming_primary(void)
 {
-	NodeStatus node_status = NODE_STATUS_UP;
+	NodeStatus	node_status = NODE_STATUS_UP;
+	instr_time	log_status_interval_start;
 
 	/* Log startup event */
 	if (startup_event_logged == false)
@@ -467,11 +470,17 @@ monitor_streaming_primary(void)
 				   local_node_info.node_id);
 	}
 
+	INSTR_TIME_SET_CURRENT(log_status_interval_start);
+
 	while (true)
 	{
+		double		log_status_interval_elapsed = 0;
+		instr_time	log_status_interval_current;
+
 		// cache node list here, refresh at `node_list_refresh_interval`
 		if (is_server_available(local_node_info.conninfo) == false)
 		{
+
 			/* node is down, we were expecting it to be up */
 			if (node_status == NODE_STATUS_UP)
 			{
@@ -499,8 +508,22 @@ monitor_streaming_primary(void)
 			}
 		}
 
-
 	loop:
+		/* emit "still alive" log message at regular intervals, if requested */
+		if (config_file_options.log_status_interval > 0)
+		{
+			INSTR_TIME_SET_CURRENT(log_status_interval_current);
+			INSTR_TIME_SUBTRACT(log_status_interval_current, log_status_interval_start);
+			log_status_interval_elapsed = INSTR_TIME_GET_DOUBLE(log_status_interval_current);
+
+			if ((int) log_status_interval_elapsed >= config_file_options.log_status_interval)
+			{
+				log_info(_("monitoring primary node \"%s\" (node ID: %i)"),
+						 local_node_info.node_name,
+						 local_node_info.node_id);
+				INSTR_TIME_SET_CURRENT(log_status_interval_start);
+			}
+		}
 		sleep(1);
 	}
 }
@@ -509,7 +532,8 @@ monitor_streaming_primary(void)
 static void
 monitor_streaming_standby(void)
 {
-	NodeStatus upstream_node_status = NODE_STATUS_UP;
+	NodeStatus	upstream_node_status = NODE_STATUS_UP;
+	instr_time	log_status_interval_start;
 
 	// check result
 	(void) get_node_record(local_conn, local_node_info.upstream_node_id, &upstream_node_info);
@@ -531,16 +555,23 @@ monitor_streaming_standby(void)
 							NULL);
 		startup_event_logged = true;
 
-		log_notice(_("monitoring node \"%s\" (node ID: %i)"),
+		log_notice(_("repmgrd on node \"%s\" (node ID: %i) monitoring upstream node \"%s\" (node ID: %i)"),
+				   local_node_info.node_name,
+				   local_node_info.node_id,
 				   upstream_node_info.node_name,
 				   upstream_node_info.node_id);
 	}
 
+	INSTR_TIME_SET_CURRENT(log_status_interval_start);
 
 	while (true)
 	{
+		double		log_status_interval_elapsed = 0;
+		instr_time	log_status_interval_current;
+
 		if (is_server_available(upstream_node_info.conninfo) == false)
 		{
+
 			/* upstream node is down, we were expecting it to be up */
 			if (upstream_node_status == NODE_STATUS_UP)
 			{
@@ -615,6 +646,24 @@ monitor_streaming_standby(void)
 		}
 
 	loop:
+
+		/* emit "still alive" log message at regular intervals, if requested */
+		if (config_file_options.log_status_interval > 0)
+		{
+			INSTR_TIME_SET_CURRENT(log_status_interval_current);
+			INSTR_TIME_SUBTRACT(log_status_interval_current, log_status_interval_start);
+			log_status_interval_elapsed = INSTR_TIME_GET_DOUBLE(log_status_interval_current);
+			if ((int) log_status_interval_elapsed >= config_file_options.log_status_interval)
+			{
+				log_info(_("node \"%s\" (node ID: %i) monitoring upstream node \"%s\" (node ID: %i)"),
+						 local_node_info.node_name,
+						 local_node_info.node_id,
+						 upstream_node_info.node_name,
+						 upstream_node_info.node_id);
+
+				INSTR_TIME_SET_CURRENT(log_status_interval_start);
+			}
+		}
 		sleep(1);
 	}
 }
@@ -641,7 +690,7 @@ promote_self(void)
 	log_debug("promote command is:\n  \"%s\"",
 			  promote_command);
 
-	if (log_type == REPMGR_STDERR && *config_file_options.logfile)
+	if (log_type == REPMGR_STDERR && *config_file_options.log_file)
 	{
 		fflush(stderr);
 	}