Add monitor parameters to enable multiple stanbys (#89)

This work introduces multi-standby configuration variables

formation.number_sync_standbys : integer, number of nodes in write quorum
node.candidate_priority : integer(1-100), priority of the candidate to be promoted, 0 if the node is never meant to be primary
node.replication_quorum : boolean, true if the node joins in write quorum
register_node and create_formation methods have those parameters to set them during creation time. I have also added set_formation_number_sync_standbys, set_node_candidate_priority,, and set_node_replication_quorum` UDFs with their corresponding get functions

node_active now also return candidate_priority and replication_quorum parameters.

.gitignore

@@ -41,3 +41,5 @@ lib*.pc
 
 # Exclude generated SQL files
 pgautofailover--?.?.sql
+!pgautofailover--1.0.sql
+

src/bin/pg_autoctl/cli_common.c

@@ -22,6 +22,7 @@
 #include "log.h"
 #include "monitor.h"
 #include "monitor_config.h"
+#include "parsing.h"
 #include "pgsetup.h"
 #include "pgsql.h"
 #include "state.h"
@@ -54,6 +55,8 @@ bool allowRemovingPgdata = false;
  *		{ "verbose", no_argument, NULL, 'v' },
  *		{ "quiet", no_argument, NULL, 'q' },
  *		{ "help", no_argument, NULL, 'h' },
+ *		{ "candidate-priority", required_argument, NULL, 'P'},
+ *		{ "replication-quorum", required_argument, NULL, 'r'},
  *		{ NULL, 0, NULL, 0 }
  *	};
  *
@@ -75,6 +78,9 @@ cli_create_node_getopts(int argc, char **argv,
 	LocalOptionConfig.prepare_promotion_walreceiver = -1;
 	LocalOptionConfig.postgresql_restart_failure_timeout = -1;
 	LocalOptionConfig.postgresql_restart_failure_max_retries = -1;
+	LocalOptionConfig.pgSetup.settings.candidatePriority = FAILOVER_NODE_CANDIDATE_PRIORITY;
+	LocalOptionConfig.pgSetup.settings.replicationQuorum = FAILOVER_NODE_REPLICATION_QUORUM;
+
 
 	optind = 0;
 
@@ -223,6 +229,37 @@ cli_create_node_getopts(int argc, char **argv,
 				log_trace("--allow-removing-pgdata");
 				break;
 			}
+			case 'P':
+			{
+				/* { "candidate-priority", required_argument, NULL, 'P'} */
+				int candidatePriority = strtol(optarg, NULL, 10);
+				if (errno == EINVAL || candidatePriority < 0 || candidatePriority > 100)
+				{
+					log_fatal("--candidate-priority argument is not valid."
+							  " Valid values are integers from 0 to 100. ");
+					exit(EXIT_CODE_BAD_ARGS);
+				}
+
+				LocalOptionConfig.pgSetup.settings.candidatePriority = candidatePriority;
+				log_trace("--candidate-priority %d", candidatePriority);
+				break;
+			}
+			case 'r':
+			{
+				/* { "replication-quorum", required_argument, NULL, 'r'} */
+				bool replicationQuorum = false;
+
+				if (!parse_bool(optarg, &replicationQuorum))
+				{
+					log_fatal("--replication-quorum argument is not valid."
+							  " Valid values are \"true\" or \"false\".");
+					exit(EXIT_CODE_BAD_ARGS);
+				}
+
+				LocalOptionConfig.pgSetup.settings.replicationQuorum = replicationQuorum;
+				log_trace("--replication-quorum %s", boolToString(replicationQuorum));
+				break;
+			}
 
 			case 'V':
 			{

src/bin/pg_autoctl/cli_common.h

@@ -67,6 +67,10 @@ extern CommandLine create_monitor_command;
 extern CommandLine create_postgres_command;
 extern CommandLine drop_node_command;
 
+/* cli_get_set_properties.c */
+extern CommandLine get_command;
+extern CommandLine set_command;
+
 /* cli_enable_disable.c */
 extern CommandLine enable_commands;
 extern CommandLine disable_commands;

src/bin/pg_autoctl/cli_create_drop_node.c

@@ -63,17 +63,19 @@ CommandLine create_postgres_command =
 	make_command("postgres",
 				 "Initialize a pg_auto_failover standalone postgres node",
 				 "",
-				 "  --pgctl       path to pg_ctl\n"
-				 "  --pgdata      path to data director\n"
-				 "  --pghost      PostgreSQL's hostname\n"
-				 "  --pgport      PostgreSQL's port number\n"
-				 "  --listen      PostgreSQL's listen_addresses\n"
-				 "  --username    PostgreSQL's username\n"
-				 "  --dbname      PostgreSQL's database name\n"
-				 "  --nodename    pg_auto_failover node\n"
-				 "  --formation   pg_auto_failover formation\n"
-				 "  --monitor     pg_auto_failover Monitor Postgres URL\n"
-				 "  --auth        authentication method for connections from monitor\n"
+				 "  --pgctl                       path to pg_ctl\n"
+				 "  --pgdata                      path to data director\n"
+				 "  --pghost                      PostgreSQL's hostname\n"
+				 "  --pgport                      PostgreSQL's port number\n"
+				 "  --listen                      PostgreSQL's listen_addresses\n"
+				 "  --username                    PostgreSQL's username\n"
+				 "  --dbname                      PostgreSQL's database name\n"
+				 "  --nodename                    pg_auto_failover node\n"
+				 "  --formation                   pg_auto_failover formation\n"
+				 "  --monitor                     pg_auto_failover Monitor Postgres URL\n"
+				 "  --auth                        authentication method for connections from monitor\n"
+				 "  --candidate-priority          priority of the node to be promoted to become primary\n"
+				 "  --replication-quorum          true if node participates in write quorum\n"
 				 KEEPER_CLI_ALLOW_RM_PGDATA_OPTION,
 				 cli_create_postgres_getopts,
 				 cli_create_postgres);
@@ -207,12 +209,14 @@ cli_create_postgres_getopts(int argc, char **argv)
 		{ "verbose", no_argument, NULL, 'v' },
 		{ "quiet", no_argument, NULL, 'q' },
  		{ "help", no_argument, NULL, 'h' },
+		{ "candidate-priority", required_argument, NULL, 'P'},
+		{ "replication-quorum", required_argument, NULL, 'r'},
 		{ NULL, 0, NULL, 0 }
 	};
 
 	int optind =
 		cli_create_node_getopts(argc, argv,
-								long_options, "C:D:H:p:l:U:A:d:n:f:m:RVvqh",
+								long_options, "C:D:H:p:l:U:A:d:n:f:m:RVvqhP:r:",
 								&options);
 
 	/* publish our option parsing in the global variable */

src/bin/pg_autoctl/cli_do_root.c

@@ -249,6 +249,8 @@ keeper_cli_keeper_setup_getopts(int argc, char **argv)
 		{ "verbose", no_argument, NULL, 'v' },
 		{ "quiet", no_argument, NULL, 'q' },
 		{ "help", no_argument, NULL, 'h' },
+		{ "candidate-priority", required_argument, NULL, 'P'},
+		{ "replication-quorum", required_argument, NULL, 'r'},
 		{ NULL, 0, NULL, 0 }
 	};
 
@@ -263,8 +265,7 @@ keeper_cli_keeper_setup_getopts(int argc, char **argv)
 	unsetenv("POSIXLY_CORRECT");
 
 	optind = cli_create_node_getopts(argc, argv,
-									 long_options,
-									 "C:D:H:p:l:y:U:A:d:n:f:g:m:RVvqh",
+									 long_options, "C:D:H:p:l:y:U:A:d:n:f:g:m:RVvqhP:r:",
 									 &options);
 
 	/* publish our option parsing in the global variable */

src/bin/pg_autoctl/cli_formation.c

@@ -32,13 +32,14 @@ CommandLine create_formation_command =
 				 "Create a new formation on the pg_auto_failover monitor",
 				 " [ --pgdata --formation --kind --dbname --with-secondary " \
 				 "--without-secondary ] ",
-				 "  --pgdata            path to data directory	 \n" \
-				 "  --formation         name of the formation to create \n" \
-				 "  --kind              formation kind, either \"pgsql\" or \"citus\" \n" \
-				 "  --dbname            name for postgres database to use in this formation \n" \
-				 "  --enable-secondary  create a formation that has multiple nodes that can be \n" \
-				 "                      used for fail over when others have issues \n" \
-				 "  --disable-secondary create a citus formation without nodes to fail over to \n",
+				 "  --pgdata               path to data directory	 \n" \
+				 "  --formation            name of the formation to create \n" \
+				 "  --kind                 formation kind, either \"pgsql\" or \"citus\" \n" \
+				 "  --dbname               name for postgres database to use in this formation \n" \
+				 "  --enable-secondary     create a formation that has multiple nodes that can be \n" \
+				 "                         used for fail over when others have issues \n" \
+				 "  --disable-secondary    create a citus formation without nodes to fail over to \n" \
+				 "  --number-sync-standbys minimum number of standbys to confirm write \n",
 				 keeper_cli_formation_create_getopts,
 				 keeper_cli_formation_create);
 
@@ -199,6 +200,7 @@ keeper_cli_formation_create_getopts(int argc, char **argv)
 		{ "verbose", no_argument, NULL, 'v' },
 		{ "quiet", no_argument, NULL, 'q' },
 		{ "help", no_argument, NULL, 'h' },
+		{ "number-sync-stanbys", required_argument, NULL, 'n' },
 		{ NULL, 0, NULL, 0 }
 	};
 
@@ -207,7 +209,7 @@ keeper_cli_formation_create_getopts(int argc, char **argv)
 	/* set defaults for formations */
 	options.formationHasSecondary = true;
 
-	while ((c = getopt_long(argc, argv, "D:f:k:sSVvqh",
+	while ((c = getopt_long(argc, argv, "D:f:k:sSVvqhn:",
 							long_options, &option_index)) != -1)
 	{
 		switch (c)
@@ -294,6 +296,22 @@ keeper_cli_formation_create_getopts(int argc, char **argv)
 				break;
 			}
 
+			case 'n':
+			{
+				/* { "number-sync-stanbys", required_argument, NULL, 'n'} */
+				int numberSyncStanbys = strtol(optarg, NULL, 10);
+
+				if (errno == EINVAL|| numberSyncStanbys < 0)
+				{
+					log_fatal("--number-sync-stanbys argument is not valid."
+							  " Use a non-negative integer value.");
+					exit(EXIT_CODE_BAD_ARGS);
+				}
+				options.numberSyncStandbys = numberSyncStanbys;
+				log_trace("--number-sync-stanbys %d", numberSyncStanbys);
+				break;
+			}
+
 			default:
 			{
 				/* getopt_long already wrote an error message */
@@ -365,7 +383,8 @@ keeper_cli_formation_create(int argc, char **argv)
 								  config.formation,
 								  config.formationKind,
 								  config.dbname,
-								  config.formationHasSecondary))
+								  config.formationHasSecondary,
+								  config.numberSyncStandbys))
 	{
 		/* errors have already been logged */
 		exit(EXIT_CODE_MONITOR);