repmgr: make "node check" and "node status" return ERR_NODE_STATUS when appropriate

If any issue is detected (and "node check" is not being executed with a specific
individual check), "ERR_NODE_STATUS" is returned.

HISTORY

@@ -4,6 +4,8 @@
         repmgr: fix "standby register --wait-sync" when no timeout provided (Ian)
         repmgr: "cluster show" returns non-zero value if an issue encountered;
           GitHub #456 (Ian)
+        repmgr: "node check" and "node status" returns non-zero value if an issue
+           encountered (Ian)
         repmgr: "node status" returns non-zero value if an issue encountered (Ian)
         repmgrd: create a PID file by default; GitHub #457 (Ian)
 		repmgrd: daemonize process by default; GitHub #458 (Ian)

doc/appendix-release-notes.sgml

@@ -34,7 +34,7 @@
     </para>
 
     <sect2>
-      <title>repmgrd enhancements</title>
+      <title>repmgr enhancements</title>
       <para>
         <itemizedlist>
 
@@ -48,10 +48,20 @@
 
           <listitem>
             <para>
-              <command><link linkend="repmgr-cluster-show">repmgr cluster-show</link></command>
+              <command><link linkend="repmgr-cluster-show">repmgr cluster-show</link></command>,
-              returns non-zero exit code if node status issues detected (GitHub #456).
+              <command><link linkend="repmgr-node-check">repmgr node check</link></command> and
+              <command><link linkend="repmgr-node-status">repmgr node status</link></command>
+              return non-zero exit code if node status issues detected. (GitHub #456).
             </para>
           </listitem>
+        </itemizedlist>
+      </para>
+    </sect2>
+
+    <sect2>
+      <title>repmgrd enhancements</title>
+      <para>
+        <itemizedlist>
 
           <listitem>
             <para>

doc/repmgr-cluster-show.sgml

@@ -142,4 +142,11 @@
    </variablelist>
   </refsect1>
 
+  <refsect1>
+    <title>See also</title>
+    <para>
+     <xref linkend="repmgr-node-status">, <xref linkend="repmgr-node-check">
+    </para>
+  </refsect1>
+
 </refentry>

doc/repmgr-node-check.sgml

@@ -61,7 +61,9 @@
 
      <listitem>
       <simpara>
-        <literal>--archive-ready</literal>: checks for WAL files which have not yet been archived
+        <literal>--archive-ready</literal>: checks for WAL files which have not yet been archived,
+        and returns <literal>WARNING</literal> or <literal>CRITICAL</literal> if the number
+        exceeds <varname>archive_ready_warning</varname> or <varname>archive_ready_critical</varname> respectively.
       </simpara>
      </listitem>
 
@@ -107,4 +109,80 @@
       </itemizedlist>
     </para>
   </refsect1>
+
+  <refsect1>
+    <title>Exit codes</title>
+
+    <para>
+      When executing <command>repmgr node check</command> with one of the individual
+      checks listed above, &repmgr; will emit one of the following Nagios-style exit codes
+      (even if <literal>--nagios</literal> is not supplied):
+
+      <itemizedlist spacing="compact" mark="bullet">
+
+        <listitem>
+          <simpara>
+            <literal>0</literal>: OK
+          </simpara>
+        </listitem>
+
+        <listitem>
+          <simpara>
+            <literal>1</literal>: WARNING
+          </simpara>
+        </listitem>
+
+        <listitem>
+          <simpara>
+            <literal>2</literal>: ERROR
+          </simpara>
+        </listitem>
+
+        <listitem>
+          <simpara>
+            <literal>3</literal>: UNKNOWN
+          </simpara>
+        </listitem>
+
+      </itemizedlist>
+    </para>
+
+
+
+    <para>
+      Following exit codes can be emitted by <command>repmgr status check</command>
+      if no individual check was specified.
+    </para>
+    <variablelist>
+
+      <varlistentry>
+        <term><option>SUCCESS (0)</option></term>
+        <listitem>
+          <para>
+            No issues were detected.
+          </para>
+        </listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>ERR_NODE_STATUS (25)</option></term>
+        <listitem>
+          <para>
+            One or more issues were detected.
+          </para>
+        </listitem>
+      </varlistentry>
+
+   </variablelist>
+  </refsect1>
+
+
+
+  <refsect1>
+    <title>See also</title>
+    <para>
+     <xref linkend="repmgr-node-status">, <xref linkend="repmgr-cluster-show">
+    </para>
+  </refsect1>
+
 </refentry>

doc/repmgr-node-status.sgml

@@ -84,7 +84,8 @@
   <refsect1>
     <title>See also</title>
     <para>
-      See <xref linkend="repmgr-node-check"> to diagnose issues.
+      See <xref linkend="repmgr-node-check"> to diagnose issues and <xref linkend="repmgr-cluster-show">
+      for an overview of all nodes in the cluster.
     </para>
   </refsect1>
 </refentry>

repmgr-action-node.c

@@ -170,11 +170,17 @@ do_node_status(void)
 	}
 	else
 	{
+		/* "archive_mode" is not "off", i.e. one of "on", "always" */
 		bool		enabled = true;
 		PQExpBufferData archiving_status;
 		char		archive_command[MAXLEN] = "";
 
 		initPQExpBuffer(&archiving_status);
+
+		/*
+		 * if the node is a standby, and "archive_mode" is "on", archiving will
+		 * actually be disabled.
+		 */
 		if (recovery_type == RECTYPE_STANDBY)
 		{
 			if (guc_set(conn, "archive_mode", "=", "on"))
@@ -642,6 +648,7 @@ do_node_check(void)
 	CheckStatusList status_list = {NULL, NULL};
 	CheckStatusListCell *cell = NULL;
 
+	bool			issue_detected = false;
 
 	/* for internal use */
 	if (runtime_options.has_passfile == true)
@@ -750,12 +757,23 @@ do_node_check(void)
 	initPQExpBuffer(&output);
 
 	/* order functions are called is also output order */
-	(void) do_node_check_role(conn, runtime_options.output_mode, &node_info, &status_list);
+	if (do_node_check_role(conn, runtime_options.output_mode, &node_info, &status_list) != CHECK_STATUS_OK)
-	(void) do_node_check_replication_lag(conn, runtime_options.output_mode, &node_info, &status_list);
+		issue_detected = true;
-	(void) do_node_check_archive_ready(conn, runtime_options.output_mode, &status_list);
+
-	(void) do_node_check_downstream(conn, runtime_options.output_mode, &status_list);
+	if (do_node_check_replication_lag(conn, runtime_options.output_mode, &node_info, &status_list) != CHECK_STATUS_OK)
-	(void) do_node_check_slots(conn, runtime_options.output_mode, &node_info, &status_list);
+		issue_detected = true;
-	(void) do_node_check_missing_slots(conn, runtime_options.output_mode, &node_info, &status_list);
+
+	if (do_node_check_archive_ready(conn, runtime_options.output_mode, &status_list) != CHECK_STATUS_OK)
+		issue_detected = true;
+
+	if (do_node_check_downstream(conn, runtime_options.output_mode, &status_list) != CHECK_STATUS_OK)
+		issue_detected = true;
+
+	if (do_node_check_slots(conn, runtime_options.output_mode, &node_info, &status_list) != CHECK_STATUS_OK)
+		issue_detected = true;
+
+	if (do_node_check_missing_slots(conn, runtime_options.output_mode, &node_info, &status_list) != CHECK_STATUS_OK)
+		issue_detected = true;
 
 	if (runtime_options.output_mode == OM_CSV)
 	{
@@ -812,6 +830,11 @@ do_node_check(void)
 	check_status_list_free(&status_list);
 
 	PQfinish(conn);
+
+	if (issue_detected == true)
+	{
+		exit(ERR_NODE_STATUS);
+	}
 }