From f03e012c99be85c76bd41a1d214523ffdd15db07 Mon Sep 17 00:00:00 2001
From: Ian Barwick <barwick@gmail.com>
Date: Tue, 14 May 2019 15:56:00 +0900
Subject: [PATCH] cluster show/daemon status: report if node not attached to
 advertised upstream

---
 HISTORY                         |  6 ++-
 doc/appendix-release-notes.sgml |  8 ++++
 repmgr-client.c                 | 69 +++++++++++++++++++++++++++++++--
 3 files changed, 78 insertions(+), 5 deletions(-)

diff --git a/HISTORY b/HISTORY
index 1b285f41..320e8ade 100644
--- a/HISTORY
+++ b/HISTORY
@@ -4,8 +4,10 @@
         repmgr: add "--repmgrd-force-unpause" option to "standby switchover" (Ian)
         repmgr: improve "--dry-run" behaviour for "standby promote" and
           "standby switchover" (Ian)
-		repmgr: in "cluster show" and "daemon status", show upstream node name
-		  as reported by each individual node (Ian)
+        repmgr: in "cluster show" and "daemon status", show upstream node name
+          as reported by each individual node (Ian)
+        repmgr: in "cluster show" and "daemon status", check if a node is attached
+          to its advertised upstream node
         repmgrd: monitor standbys attached to primary (Ian)
         general: documentation converted to DocBook XML format (Ian)
 
diff --git a/doc/appendix-release-notes.sgml b/doc/appendix-release-notes.sgml
index f8512943..c2e3a39c 100644
--- a/doc/appendix-release-notes.sgml
+++ b/doc/appendix-release-notes.sgml
@@ -80,6 +80,14 @@
             </para>
           </listitem>
 
+		  <listitem>
+            <para>
+              <link linkend="repmgr-cluster-show"><command>repmgr cluster show</command></link>
+			  and <link linkend="repmgr-daemon-status"><command>repmgr daemon status</command></link>:
+			  check if a node is attached to its advertised upstream node, and issue a
+			  warning if the node is not attached.
+			</para>
+		  </listitem>
 		</itemizedlist>
 	  </para>
     </sect2>
diff --git a/repmgr-client.c b/repmgr-client.c
index 8bb71ad7..ef39414a 100644
--- a/repmgr-client.c
+++ b/repmgr-client.c
@@ -2007,6 +2007,10 @@ check_cli_parameters(const int action)
 }
 
 
+/*
+ * Generate formatted node status output for display by "cluster show" and
+ * "daemon status".
+ */
 bool
 format_node_status(t_node_info *node_info, PQExpBufferData *node_status, PQExpBufferData *upstream, ItemList *warnings)
 {
@@ -2264,15 +2268,73 @@ format_node_status(t_node_info *node_info, PQExpBufferData *node_status, PQExpBu
 	}
 	else
 	{
-		if (node_info->upstream_node_id == remote_node_rec.upstream_node_id)
+		if (node_info->upstream_node_id != NO_UPSTREAM_NODE && node_info->upstream_node_id == remote_node_rec.upstream_node_id)
 		{
+			/*
+			 * expected and reported upstreams match - check if node is actually
+			 * connected to the upstream
+			 */
+			NodeAttached attached_to_upstream = NODE_ATTACHED_UNKNOWN;
+			t_node_info upstream_node_rec = T_NODE_INFO_INITIALIZER;
+			RecordStatus upstream_node_rec_found = get_node_record(node_info->conn,
+																   node_info->upstream_node_id,
+																   &upstream_node_rec);
+
+			if (upstream_node_rec_found != RECORD_FOUND)
+			{
+				item_list_append_format(warnings,
+										"unable to find record for upstream node ID %i",
+										node_info->upstream_node_id);
+
+			}
+			else
+			{
+				PGconn *upstream_conn = establish_db_connection_quiet(upstream_node_rec.conninfo);
+
+				if (PQstatus(upstream_conn) != CONNECTION_OK)
+				{
+					item_list_append_format(warnings,
+											"unable to connect to node \"%s\" (ID: %i)'s upstream node \"%s\" (ID: %i)",
+											node_info->node_name,
+											node_info->node_id,
+											upstream_node_rec.node_name,
+											upstream_node_rec.node_id);
+				}
+				else
+				{
+					attached_to_upstream = is_downstream_node_attached(upstream_conn, node_info->node_name);
+				}
+
+				PQfinish(upstream_conn);
+			}
+
+			if (attached_to_upstream == NODE_ATTACHED_UNKNOWN)
+			{
+				appendPQExpBufferStr(upstream, "? ");
+				item_list_append_format(warnings,
+										"unable to determine if node \"%s\" (ID: %i) is attached to its upstream node \"%s\" (ID: %i)",
+										node_info->node_name,
+										node_info->node_id,
+										upstream_node_rec.node_name,
+										upstream_node_rec.node_id);
+			}
+			else if (attached_to_upstream == NODE_DETACHED)
+			{
+				appendPQExpBufferStr(upstream, "! ");
+				item_list_append_format(warnings,
+										"node \"%s\" (ID: %i) is not attached to its upstream node \"%s\" (ID: %i)",
+										node_info->node_name,
+										node_info->node_id,
+										upstream_node_rec.node_name,
+										upstream_node_rec.node_id);
+			}
 			appendPQExpBufferStr(upstream,
 								 node_info->upstream_node_name);
 
 		}
 		else
 		{
-			if (remote_node_rec.upstream_node_id == NO_UPSTREAM_NODE)
+			if (node_info->upstream_node_id != NO_UPSTREAM_NODE && remote_node_rec.upstream_node_id == NO_UPSTREAM_NODE)
 			{
 				appendPQExpBufferChar(upstream, '!');
 				item_list_append_format(warnings,
@@ -2281,7 +2343,8 @@ format_node_status(t_node_info *node_info, PQExpBufferData *node_status, PQExpBu
 										node_info->node_id,
 										node_info->upstream_node_name);
 			}
-			else
+			else if (node_info->upstream_node_id != NO_UPSTREAM_NODE && remote_node_rec.upstream_node_id != NO_UPSTREAM_NODE)
+
 			{
 				appendPQExpBuffer(upstream,
 								  "! %s", remote_node_rec.upstream_node_name);