From 9732f78565e98b29bd06d83d4f692eaa7374dc6e Mon Sep 17 00:00:00 2001
From: Ian Barwick <ian@2ndquadrant.com>
Date: Mon, 22 Jan 2018 16:06:16 +0900
Subject: [PATCH] repmgrd: check "repmgr" extension is installed before
 starting

Implements GitHub #361.
---
 repmgr-action-standby.c |  7 +++++--
 repmgrd.c               | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/repmgr-action-standby.c b/repmgr-action-standby.c
index a78b1fb4..ebcbbb8a 100644
--- a/repmgr-action-standby.c
+++ b/repmgr-action-standby.c
@@ -3430,8 +3430,11 @@ check_source_server()
 	{
 		if (!runtime_options.force)
 		{
+			/* this is unlikely to happen */
 			if (extension_status == REPMGR_UNKNOWN)
 			{
+				log_error(_("unable to determine status of \"repmgr\" extension"));
+				log_detail("%s", PQerrorMessage(primary_conn));
 				PQfinish(source_conn);
 				exit(ERR_DB_QUERY);
 			}
@@ -3446,10 +3449,10 @@ check_source_server()
 			}
 			else if (extension_status == REPMGR_UNAVAILABLE)
 			{
-				log_detail(_("repmgr extension is not available on the upstream server"));
+				log_detail(_("repmgr extension is not available on the upstream node"));
 			}
 
-			log_hint(_("check that the upstream server is part of a repmgr cluster"));
+			log_hint(_("check that the upstream node is part of a repmgr cluster"));
 			PQfinish(source_conn);
 			exit(ERR_BAD_CONFIG);
 		}
diff --git a/repmgrd.c b/repmgrd.c
index c4e293a2..5cccc92a 100644
--- a/repmgrd.c
+++ b/repmgrd.c
@@ -89,6 +89,7 @@ main(int argc, char **argv)
 	bool		cli_monitoring_history = false;
 
 	RecordStatus record_status;
+	ExtensionStatus extension_status = REPMGR_UNKNOWN;
 
 	FILE	   *fd;
 
@@ -318,6 +319,37 @@ main(int argc, char **argv)
 	 * repmgr has not been properly configured.
 	 */
 
+	/* Check "repmgr" the extension is installed */
+	extension_status = get_repmgr_extension_status(local_conn);
+
+	if (extension_status != REPMGR_INSTALLED)
+	{
+		/* this is unlikely to happen */
+		if (extension_status == REPMGR_UNKNOWN)
+		{
+			log_error(_("unable to determine status of \"repmgr\" extension"));
+			log_detail("%s", PQerrorMessage(local_conn));
+			PQfinish(local_conn);
+			exit(ERR_DB_QUERY);
+		}
+
+		log_error(_("repmgr extension not found on this node"));
+
+		if (extension_status == REPMGR_AVAILABLE)
+		{
+			log_detail(_("repmgr extension is available but not installed in database \"%s\""),
+					   PQdb(local_conn));
+		}
+		else if (extension_status == REPMGR_UNAVAILABLE)
+		{
+			log_detail(_("repmgr extension is not available on this node"));
+		}
+
+		log_hint(_("check that this node is part of a repmgr cluster"));
+		PQfinish(local_conn);
+		exit(ERR_BAD_CONFIG);
+	}
+
 	/* Retrieve record for this node from the local database */
 	record_status = get_node_record(local_conn, config_file_options.node_id, &local_node_info);