node check: add option --db-connection

This is intended for diagnostic purposes, primarily when diagnosing
the connection parameters used when repmgr is being executed on a
remote node.

repmgr-action-node.c

@@ -53,6 +53,8 @@ static CheckStatus do_node_check_slots(PGconn *conn, OutputMode mode, t_node_inf
 static CheckStatus do_node_check_missing_slots(PGconn *conn, OutputMode mode, t_node_info *node_info, CheckStatusList *list_output);
 static CheckStatus do_node_check_data_directory(PGconn *conn, OutputMode mode, t_node_info *node_info, CheckStatusList *list_output);
 static CheckStatus do_node_check_replication_config_owner(PGconn *conn, OutputMode mode, t_node_info *node_info, CheckStatusList *list_output);
+static CheckStatus do_node_check_db_connection(PGconn *conn, OutputMode mode);
+
 /*
  * NODE STATUS
  *
@@ -734,12 +736,18 @@ do_node_check(void)
 		exit(return_code);
 	}
 
+	/* for use by "standby switchover" */
 	if (runtime_options.replication_connection == true)
 	{
 		do_node_check_replication_connection();
 		exit(SUCCESS);
 	}
 
+	if (runtime_options.db_connection == true)
+	{
+		exit_on_connection_error = false;
+	}
+
 	/*
 	 * If --optformat was provided, we'll assume this is a remote invocation
 	 * and instead of exiting with an error, we'll return an error string to
@@ -750,6 +758,7 @@ do_node_check(void)
 		exit_on_connection_error = false;
 	}
 
+
 	if (config_file_options.conninfo[0] != '\0')
 	{
 		t_conninfo_param_list node_conninfo = T_CONNINFO_PARAM_LIST_INITIALIZER;
@@ -799,6 +808,17 @@ do_node_check(void)
 		conn = establish_db_connection_by_params(&source_conninfo, exit_on_connection_error);
 	}
 
+
+	/*
+	 * --db-connection option provided
+	 */
+	if (runtime_options.db_connection == true)
+	{
+		return_code = do_node_check_db_connection(conn, runtime_options.output_mode);
+		PQfinish(conn);
+		exit(return_code);
+	}
+
 	/*
 	 * If we've reached here, and the connection is invalid, then --optformat was provided
 	 */
@@ -2152,6 +2172,72 @@ CheckStatus do_node_check_replication_config_owner(PGconn *conn, OutputMode mode
 }
 
 
+/*
+ * This is not included in the general list output
+ */
+static CheckStatus
+do_node_check_db_connection(PGconn *conn, OutputMode mode)
+{
+	CheckStatus status = CHECK_STATUS_OK;
+	PQExpBufferData details;
+
+	if (mode == OM_CSV)
+	{
+		log_error(_("--csv output not provided with --db-connection option"));
+		PQfinish(conn);
+		exit(ERR_BAD_CONFIG);
+	}
+
+	/* This check is for configuration diagnostics only */
+	if (mode == OM_NAGIOS)
+	{
+		log_error(_("--nagios output not provided with --db-connection option"));
+		PQfinish(conn);
+		exit(ERR_BAD_CONFIG);
+	}
+
+	initPQExpBuffer(&details);
+
+	if (PQstatus(conn) != CONNECTION_OK)
+	{
+		t_conninfo_param_list conninfo = T_CONNINFO_PARAM_LIST_INITIALIZER;
+		int c;
+
+		status = CHECK_STATUS_CRITICAL;
+		initialize_conninfo_params(&conninfo, false);
+		conn_to_param_list(conn, &conninfo);
+
+		appendPQExpBufferStr(&details,
+							 "connection parameters used:");
+		for (c = 0; c < conninfo.size && conninfo.keywords[c] != NULL; c++)
+		{
+			if (conninfo.values[c] != NULL && conninfo.values[c][0] != '\0')
+			{
+				appendPQExpBuffer(&details,
+								  " %s=%s",
+								  conninfo.keywords[c], conninfo.values[c]);
+			}
+		}
+
+	}
+
+	if (mode == OM_OPTFORMAT)
+	{
+		printf("--db-connection=%s\n",
+			   output_check_status(status));
+	}
+	else if (mode == OM_TEXT)
+	{
+		printf("%s (%s)\n",
+			   output_check_status(status),
+			   details.data);
+	}
+	termPQExpBuffer(&details);
+
+	return status;
+}
+
+
 void
 do_node_service(void)
 {

repmgr-client-global.h

@@ -120,6 +120,7 @@ typedef struct
 	bool		replication_connection;
 	bool		data_directory_config;
 	bool		replication_config_owner;
+	bool		db_connection;
 
 	/* "node rejoin" options */
 	char		config_files[MAXLEN];
@@ -172,7 +173,7 @@ typedef struct
 		/* "node status" options */ \
 		false, \
 		/* "node check" options */ \
-		false, false, false, false, false, false, false, false,	false, false, false, \
+		false, false, false, false, false, false, false, false,	false, false, false, false, \
 		/* "node rejoin" options */ \
 		"", \
 		/* "node service" options */ \

repmgr-client.c

@@ -541,6 +541,10 @@ main(int argc, char **argv)
 				runtime_options.replication_config_owner = true;
 				break;
 
+			case OPT_DB_CONNECTION:
+				runtime_options.db_connection = true;
+				break;
+
 				/*--------------------
 				 * "node rejoin" options
 				 *--------------------

repmgr-client.h

@@ -100,6 +100,7 @@
 #define OPT_DETAIL						   1047
 #define OPT_REPMGRD_FORCE_UNPAUSE		   1048
 #define OPT_REPLICATION_CONFIG_OWNER	   1049
+#define OPT_DB_CONNECTION				   1050
 
 /* deprecated since 4.0 */
 #define OPT_CHECK_UPSTREAM_CONFIG		    999
@@ -189,6 +190,7 @@ static struct option long_options[] =
 	{"replication-connection", no_argument, NULL, OPT_REPL_CONN},
 	{"data-directory-config", no_argument, NULL, OPT_DATA_DIRECTORY_CONFIG},
 	{"replication-config-owner", no_argument, NULL, OPT_REPLICATION_CONFIG_OWNER},
+	{"db-connection", no_argument, NULL, OPT_DB_CONNECTION},
 
 /* "node rejoin" options */
 	{"config-files", required_argument, NULL, OPT_CONFIG_FILES},