From fcb7e7a29b617d60f02db6c1f14b7c02b92c5b1f Mon Sep 17 00:00:00 2001
From: Ian Barwick <ian@2ndquadrant.com>
Date: Thu, 4 Jan 2018 17:12:52 +0900
Subject: [PATCH] "repmgr bdr register": create missing connection replication
 set if needed

Previously the assumption was that the "repmgr" replication set would be
set up when the nodes are created, however no checks were implemented
and this was not well-documented.

Addresses GitHub #347.
---
 dbutils.c           | 68 +++++++++++++++++++++++++++++++++++++++++++++
 dbutils.h           |  2 ++
 repmgr-action-bdr.c |  6 +++-
 3 files changed, 75 insertions(+), 1 deletion(-)

diff --git a/dbutils.c b/dbutils.c
index 821d56e6..b631e031 100644
--- a/dbutils.c
+++ b/dbutils.c
@@ -4596,3 +4596,71 @@ unset_bdr_failover_handler(PGconn *conn)
 	PQclear(res);
 	return;
 }
+
+
+bool
+bdr_node_has_repmgr_set(PGconn *conn, const char *node_name)
+{
+	PQExpBufferData query;
+	PGresult   *res = NULL;
+	bool		has_repmgr_set = false;
+
+	initPQExpBuffer(&query);
+
+	appendPQExpBuffer(&query,
+					  " SELECT COUNT(*) "
+					  "   FROM UNNEST(bdr.connection_get_replication_sets('%s') AS repset "
+					  "  WHERE repset = 'repmgr'",
+					  node_name);
+
+	res = PQexec(conn, query.data);
+	termPQExpBuffer(&query);
+
+	if (PQresultStatus(res) != PGRES_TUPLES_OK || PQntuples(res) == 0)
+	{
+		has_repmgr_set = false;
+	}
+	else
+	{
+		has_repmgr_set = atoi(PQgetvalue(res, 0, 0)) == 1 ? true : false;
+	}
+
+	PQclear(res);
+
+	return has_repmgr_set;
+}
+
+
+bool
+bdr_node_set_repmgr_set(PGconn *conn, const char *node_name)
+{
+	PQExpBufferData query;
+	PGresult   *res = NULL;
+	bool		success = true;
+
+	initPQExpBuffer(&query);
+
+	appendPQExpBuffer(&query,
+					  " SELECT bdr.connection_set_replication_sets( "
+					  "   ARRAY( "
+					  "     SELECT repset::TEXT "
+					  "       FROM UNNEST(bdr.connection_get_replication_sets('node1')) AS repset "
+					  "         UNION "
+					  "     SELECT 'repmgr'::TEXT "
+					  "   ), "
+					  "   '%s' "
+					  " ) ",
+					  node_name);
+
+	res = PQexec(conn, query.data);
+	termPQExpBuffer(&query);
+
+	if (PQresultStatus(res) != PGRES_TUPLES_OK)
+	{
+		success = false;
+	}
+
+	PQclear(res);
+
+	return success;
+}
diff --git a/dbutils.h b/dbutils.h
index 4cf232c0..214cb0a8 100644
--- a/dbutils.h
+++ b/dbutils.h
@@ -504,5 +504,7 @@ void		get_bdr_other_node_name(PGconn *conn, int node_id, char *name_buf);
 
 bool		am_bdr_failover_handler(PGconn *conn, int node_id);
 void		unset_bdr_failover_handler(PGconn *conn);
+bool		bdr_node_has_repmgr_set(PGconn *conn, const char *node_name);
+bool		bdr_node_set_repmgr_set(PGconn *conn, const char *node_name);
 
 #endif							/* _REPMGR_DBUTILS_H_ */
diff --git a/repmgr-action-bdr.c b/repmgr-action-bdr.c
index 7677bd05..3c03d345 100644
--- a/repmgr-action-bdr.c
+++ b/repmgr-action-bdr.c
@@ -124,7 +124,7 @@ do_bdr_register(void)
 		termPQExpBuffer(&bdr_local_node_name);
 	}
 
-	/* check whether repmgr extension exists, and that any other nodes are BDR */
+	/* check whether repmgr extension exists, and there are no non-BDR nodes registered */
 	extension_status = get_repmgr_extension_status(conn);
 
 	if (extension_status == REPMGR_UNKNOWN)
@@ -174,6 +174,10 @@ do_bdr_register(void)
 
 	pfree(dbname);
 
+	if (bdr_node_has_repmgr_set(conn, config_file_options.node_name) == false)
+	{
+		bdr_node_set_repmgr_set(conn, config_file_options.node_name);
+	}
 
 	/*
 	 * before adding the extension tables to the replication set, if any other