Various improvements and fixes to the pg-backup-api restore section on the docs

I added a paragraph at the beginning of the section on where to look for
instructions on how to install the pg-backup-api rest API.

Fixed typos and some gramatical changes. Also reworded the first paragraph
(which is now the second one).

Signed-off-by: Martín Marqués <martin.marques@enterprisedb.com>

Makefile.global.in

@@ -22,7 +22,7 @@ GIT_WORK_TREE=${repmgr_abs_srcdir}
 GIT_DIR=${repmgr_abs_srcdir}/.git
 export GIT_DIR
 export GIT_WORK_TREE
-
+PG_LDFLAGS=-lcurl -ljson-c
 include $(PGXS)
 
 -include ${repmgr_abs_srcdir}/Makefile.custom

Makefile.in

@@ -30,7 +30,9 @@ DATA = \
   repmgr--5.1--5.2.sql \
   repmgr--5.2.sql \
   repmgr--5.2--5.3.sql \
-  repmgr--5.3.sql
+  repmgr--5.3.sql \
+  repmgr--5.3--5.4.sql \
+  repmgr--5.4.sql
 
 REGRESS = repmgr_extension
 
@@ -64,7 +66,7 @@ REPMGR_CLIENT_OBJS = repmgr-client.o \
 	repmgr-action-primary.o repmgr-action-standby.o repmgr-action-witness.o \
 	repmgr-action-cluster.o repmgr-action-node.o repmgr-action-service.o repmgr-action-daemon.o \
 	configdata.o configfile.o configfile-scan.o log.o strutil.o controldata.o dirutil.o compat.o \
-	dbutils.o sysutils.o
+	dbutils.o sysutils.o pgbackupapi.o
 REPMGRD_OBJS = repmgrd.o repmgrd-physical.o configdata.o configfile.o configfile-scan.o log.o \
 	dbutils.o strutil.o controldata.o compat.o sysutils.o
 

README.md

@@ -40,7 +40,6 @@ Directories
  - `contrib/`: additional utilities
  - `doc/`: DocBook-based documentation files
  - `expected/`: expected regression test output
- - `scripts/`: example scripts
  - `sql/`: regression test input
 
 
@@ -70,7 +69,6 @@ news are always welcome.
 
 Thanks from the repmgr core team.
 
-* Ian Barwick
 * Jaime Casanova
 * Abhijit Menon-Sen
 * Simon Riggs

configdata.c

@@ -291,6 +291,46 @@ struct ConfigFileSetting config_file_settings[] =
 		{},
 		{}
 	},
+	/* pg_backupapi_backup_id*/
+	{
+		"pg_backupapi_backup_id",
+		CONFIG_STRING,
+		{ .strptr = config_file_options.pg_backupapi_backup_id },
+		{ .strdefault = "" },
+		{},
+		{ .strmaxlen = sizeof(config_file_options.pg_backupapi_backup_id) },
+		{}
+	},
+	/* pg_backupapi_host*/
+	{
+		"pg_backupapi_host",
+		CONFIG_STRING,
+		{ .strptr = config_file_options.pg_backupapi_host },
+		{ .strdefault = "" },
+		{},
+		{ .strmaxlen = sizeof(config_file_options.pg_backupapi_host) },
+		{}
+	},
+	/* pg_backupapi_node_name */
+	{
+		"pg_backupapi_node_name",
+		CONFIG_STRING,
+		{ .strptr = config_file_options.pg_backupapi_node_name },
+		{ .strdefault = "" },
+		{},
+		{ .strmaxlen = sizeof(config_file_options.pg_backupapi_node_name) },
+		{}
+	},
+	/* pg_backupapi_remote_ssh_command */
+	{
+		"pg_backupapi_remote_ssh_command",
+		CONFIG_STRING,
+		{ .strptr = config_file_options.pg_backupapi_remote_ssh_command },
+		{ .strdefault = "" },
+		{},
+		{ .strmaxlen = sizeof(config_file_options.pg_backupapi_remote_ssh_command) },
+		{}
+	},
 
 	/* =======================
 	 * standby follow settings

configfile.h

@@ -164,6 +164,10 @@ typedef struct
 	char		archive_cleanup_command[MAXLEN];
 	bool		use_primary_conninfo_password;
 	char		passfile[MAXPGPATH];
+	char		pg_backupapi_backup_id[NAMEDATALEN];
+	char		pg_backupapi_host[NAMEDATALEN];
+	char		pg_backupapi_node_name[NAMEDATALEN];
+	char		pg_backupapi_remote_ssh_command[MAXLEN];
 
 	/* standby promote settings */
 	int			promote_check_timeout;

configure

@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.69 for repmgr 5.3.3.
+# Generated by GNU Autoconf 2.69 for repmgr 5.4.0.
 #
 # Report bugs to <repmgr@googlegroups.com>.
 #
@@ -11,7 +11,7 @@
 # This configure script is free software; the Free Software Foundation
 # gives unlimited permission to copy, distribute and modify it.
 #
-# Copyright (c) 2010-2022, EnterpriseDB Corporation
+# Copyright (c) 2010-2021, EnterpriseDB Corporation
 ## -------------------- ##
 ## M4sh Initialization. ##
 ## -------------------- ##
@@ -582,8 +582,8 @@ MAKEFLAGS=
 # Identity of this package.
 PACKAGE_NAME='repmgr'
 PACKAGE_TARNAME='repmgr'
-PACKAGE_VERSION='5.3.3'
-PACKAGE_STRING='repmgr 5.3.3'
+PACKAGE_VERSION='5.4.0'
+PACKAGE_STRING='repmgr 5.4.0'
 PACKAGE_BUGREPORT='repmgr@googlegroups.com'
 PACKAGE_URL='https://repmgr.org/'
 
@@ -1181,7 +1181,7 @@ if test "$ac_init_help" = "long"; then
   # Omit some internal or obsolete options to make the list less imposing.
   # This message is too long to be a string in the A/UX 3.1 sh.
   cat <<_ACEOF
-\`configure' configures repmgr 5.3.3 to adapt to many kinds of systems.
+\`configure' configures repmgr 5.4.0 to adapt to many kinds of systems.
 
 Usage: $0 [OPTION]... [VAR=VALUE]...
 
@@ -1242,7 +1242,7 @@ fi
 
 if test -n "$ac_init_help"; then
   case $ac_init_help in
-     short | recursive ) echo "Configuration of repmgr 5.3.3:";;
+     short | recursive ) echo "Configuration of repmgr 5.4.0:";;
    esac
   cat <<\_ACEOF
 
@@ -1316,14 +1316,14 @@ fi
 test -n "$ac_init_help" && exit $ac_status
 if $ac_init_version; then
   cat <<\_ACEOF
-repmgr configure 5.3.3
+repmgr configure 5.4.0
 generated by GNU Autoconf 2.69
 
 Copyright (C) 2012 Free Software Foundation, Inc.
 This configure script is free software; the Free Software Foundation
 gives unlimited permission to copy, distribute and modify it.
 
-Copyright (c) 2010-2022, EnterpriseDB Corporation
+Copyright (c) 2010-2021, EnterpriseDB Corporation
 _ACEOF
   exit
 fi
@@ -1335,7 +1335,7 @@ cat >config.log <<_ACEOF
 This file contains any messages produced by compilers while
 running configure, to aid debugging if configure makes a mistake.
 
-It was created by repmgr $as_me 5.3.3, which was
+It was created by repmgr $as_me 5.4.0, which was
 generated by GNU Autoconf 2.69.  Invocation command line was
 
   $ $0 $@
@@ -2487,7 +2487,7 @@ cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
 # report actual input values of CONFIG_FILES etc. instead of their
 # values after options handling.
 ac_log="
-This file was extended by repmgr $as_me 5.3.3, which was
+This file was extended by repmgr $as_me 5.4.0, which was
 generated by GNU Autoconf 2.69.  Invocation command line was
 
   CONFIG_FILES    = $CONFIG_FILES
@@ -2550,7 +2550,7 @@ _ACEOF
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 ac_cs_config="`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`"
 ac_cs_version="\\
-repmgr config.status 5.3.3
+repmgr config.status 5.4.0
 configured by $0, generated by GNU Autoconf 2.69,
   with options \\"\$ac_cs_config\\"
 

configure.in

@@ -1,6 +1,6 @@
-AC_INIT([repmgr], [5.3.3], [repmgr@googlegroups.com], [repmgr], [https://repmgr.org/])
+AC_INIT([repmgr], [5.4.0], [repmgr@googlegroups.com], [repmgr], [https://repmgr.org/])
 
-AC_COPYRIGHT([Copyright (c) 2010-2022, EnterpriseDB Corporation])
+AC_COPYRIGHT([Copyright (c) 2010-2021, EnterpriseDB Corporation])
 
 AC_CONFIG_HEADER(config.h)
 
@@ -60,6 +60,7 @@ AC_SUBST(vpath_build)
 AC_CHECK_PROG(HAVE_GNUSED,gnused,yes,no)
 AC_CHECK_PROG(HAVE_GSED,gsed,yes,no)
 AC_CHECK_PROG(HAVE_SED,sed,yes,no)
+AC_CHECK_PROG(HAVE_FLEX,flex,yes,no)
 
 if test "$HAVE_GNUSED" = yes; then
  SED=gnused
@@ -72,6 +73,25 @@ else
 fi
 AC_SUBST(SED)
 
+AS_IF([test x"$HAVE_FLEX" != x"yes"], AC_MSG_ERROR([flex should be installed first]))
+
+#Checking libraries
+GENERIC_LIB_FAILED_MSG="library should be installed"
+
+AC_CHECK_LIB(selinux, is_selinux_enabled, [],
+     [AC_MSG_ERROR(['selinux' $GENERIC_LIB_FAILED_MSG])])
+
+AC_CHECK_LIB(lz4, LZ4_compress_default, [],
+     [AC_MSG_ERROR(['Z4' $GENERIC_LIB_FAILED_MSG])])
+
+AC_CHECK_LIB(xslt, xsltCleanupGlobals, [],
+     [AC_MSG_ERROR(['xslt' $GENERIC_LIB_FAILED_MSG])])
+
+AC_CHECK_LIB(pam, pam_start, [],
+     [AC_MSG_ERROR(['pam' $GENERIC_LIB_FAILED_MSG])])
+
+AC_CHECK_LIB(gssapi_krb5, gss_init_sec_context, [],
+     [AC_MSG_ERROR([gssapi_krb5 $GENERIC_LIB_FAILED_MSG])])
 
 AC_CONFIG_FILES([Makefile])
 AC_CONFIG_FILES([Makefile.global])

doc/appendix-release-notes.xml

@@ -243,8 +243,7 @@
               risk of clashes with other shared libraries.
             </para>
             <para>
-              This does not affect user-facing SQL functions. However an upgrade
-              of the installed extension version is required.
+              This does not affect user-facing SQL functions. Howe
             </para>
           </listitem>
 

doc/cloning-standbys.xml

@@ -225,6 +225,109 @@ description = "Main cluster"
    </note>
 
   </sect2>
+
+  <sect2 id="cloning-from-barman-pg_backupapi-mode" xreflabel="Using Barman through its API (pg-backup-api)">
+    <title>Using Barman through its API (pg-backup-api)</title>
+    <indexterm>
+      <primary>cloning</primary>
+      <secondary>pg-backup-api</secondary>
+    </indexterm>
+
+    <para>
+      You can find information on how to install and setup pg-backup-api in
+      <ulink url="https://www.enterprisedb.com/docs/supported-open-source/barman/pg-backup-api/">the pg-backup-api
+      documentation</ulink>.
+    </para>
+
+    <para>
+      This mode (`pg-backupapi`) was introduced in v5.4.0 as a way to further integrate with Barman letting Barman
+      handle the restore. This also reduces the ssh keys that need to share between the backup and postgres nodes.
+      As long as you have access to the API service by HTTP calls, you could perform recoveries right away.
+      You just need to instruct Barman through the API which backup you need and on which node the backup needs to
+      to be restored on.
+    </para>
+
+    <para>
+      In order to enable <literal>pg_backupapi mode</literal> support for <command>repmgr standby clone</command>,
+      you need the following lines in repmgr.conf:
+      <itemizedlist spacing="compact" mark="bullet">
+        <listitem><para>pg_backupapi_host: Where pg-backup-api is hosted</para></listitem>
+        <listitem><para>pg_backupapi_node_name: Name of the server as understood by Barman</para></listitem>
+        <listitem><para>pg_backupapi_remote_ssh_command: How Barman will be connecting as to the node</para></listitem>
+        <listitem><para>pg_backupapi_backup_id: ID of the existing backup you need to restore</para></listitem>
+      </itemizedlist>
+
+      This is an example of how repmgr.conf would look like:
+
+      <programlisting>
+        pg_backupapi_host = '192.168.122.154'
+        pg_backupapi_node_name = 'burrito'
+        pg_backupapi_remote_ssh_command = 'ssh john_doe@192.168.122.1'
+        pg_backupapi_backup_id = '20230223T093201'
+      </programlisting>
+    </para>
+
+    <para>
+      <literal>pg_backupapi_host</literal> is the variable name that enables this mode, and when you set it,
+      all the rest of the above variables are required. Also, remember that this service is just an interface
+      between Barman and repmgr, hence if something fails during a recovery, you should check Barman's logs upon
+      why the process couldn't finish properly.
+    </para>
+
+    <note>
+      <simpara>
+        Despite in Barman you can define shortcuts like "lastest" or "oldest", they are not supported for the
+        time being in pg-backup-api. These shortcuts will be supported in a future release.
+      </simpara>
+     </note>
+
+    <para>
+      This is a real example of repmgr's output cloning with the API. Note that during this operation, we stopped
+      the service for a little while and repmgr had to retry but that doesn't affect the final outcome. The primary
+      is listening on localhost's port 6001:
+
+      <programlisting>
+$ repmgr -f ~/nodes/node_3/repmgr.conf standby clone -U repmgr -p 6001 -h localhost
+NOTICE: destination directory "/home/mario/nodes/node_3/data" provided
+INFO: Attempting to use `pg_backupapi` new restore mode
+INFO: connecting to source node
+DETAIL: connection string is: user=repmgr port=6001 host=localhost
+DETAIL: current installation size is 8541 MB
+DEBUG: 1 node records returned by source node
+DEBUG: connecting to: "user=repmgr dbname=repmgr host=localhost port=6001 connect_timeout=2 fallback_application_name=repmgr options=-csearch_path="
+DEBUG: upstream_node_id determined as 1
+INFO: Attempting to use `pg_backupapi` new restore mode
+INFO: replication slot usage not requested;  no replication slot will be set up for this standby
+NOTICE: starting backup (using pg_backupapi)...
+INFO: Success creating the task: operation id '20230309T150647'
+INFO: status IN_PROGRESS
+INFO: status IN_PROGRESS
+Incorrect reply received for that operation ID.
+INFO: Retrying...
+INFO: status IN_PROGRESS
+INFO: status IN_PROGRESS
+INFO: status IN_PROGRESS
+INFO: status IN_PROGRESS
+INFO: status IN_PROGRESS
+INFO: status IN_PROGRESS
+INFO: status IN_PROGRESS
+INFO: status IN_PROGRESS
+INFO: status IN_PROGRESS
+INFO: status IN_PROGRESS
+INFO: status IN_PROGRESS
+INFO: status IN_PROGRESS
+INFO: status IN_PROGRESS
+INFO: status IN_PROGRESS
+INFO: status IN_PROGRESS
+INFO: status DONE
+NOTICE: standby clone (from pg_backupapi) complete
+NOTICE: you can now start your PostgreSQL server
+HINT: for example: pg_ctl -D /home/mario/nodes/node_3/data start
+HINT: after starting the server, you need to register this standby with "repmgr standby register"
+      </programlisting>
+
+    </para>
+  </sect2> <!--END cloning-from-barman-pg_backupapi-mode !-->
  </sect1>
 
  <sect1 id="cloning-replication-slots" xreflabel="Cloning and replication slots">

doc/install-requirements.xml

@@ -115,6 +115,24 @@
         </thead>
 
         <tbody>
+          <row>
+            <entry>
+              &repmgr; 5.4
+            </entry>
+            <entry>
+              (dev)
+            </entry>
+            <entry>
+              <link linkend="release-current">&repmgrversion;</link> (&releasedate;)
+            </entry>
+            <entry>
+              9.4, 9.5, 9.6, 10, 11, 12, 13, 15
+            </entry>
+            <entry>
+              &nbsp;
+            </entry>
+          </row>
+
           <row>
             <entry>
               &repmgr; 5.3

doc/repmgr-node-rejoin.xml

@@ -73,16 +73,16 @@
       </varlistentry>
 
       <varlistentry>
-        <term><option>--force-rewind[=/path/to/pg_rewind]</option></term>
+        <term><option>--force-rewind</option></term>
         <listitem>
           <para>
             Execute <application>pg_rewind</application>.
           </para>
           <para>
-            It is only necessary to provide the <application>pg_rewind</application> path
-            if using PostgreSQL 9.4, and <application>pg_rewind</application>
-            is not installed in the PostgreSQL <filename>bin</filename> directory.
+            See <xref linkend="repmgr-node-rejoin-pg-rewind"/> for more details on using
+            <application>pg_rewind</application>.
           </para>
+
         </listitem>
       </varlistentry>
 
@@ -261,8 +261,6 @@
     <para>
       <command>repmgr node rejoin</command> can optionally use <command>pg_rewind</command> to re-integrate a
       node which has diverged from the rest of the cluster, typically a failed primary.
-      <command>pg_rewind</command> is available in PostgreSQL 9.5 and later as part of the core distribution,
-      and can be installed from external sources for PostgreSQL 9.4.
     </para>
     <note>
       <para>
@@ -386,6 +384,29 @@
     DETAIL: node 2 is now attached to node 3</programlisting>
       </para>
     </refsect2>
+
+    <refsect2 id="repmgr-node-rejoin-postgresql-94" xreflabel="pg_rewind and PostgreSQL 9.4">
+
+      <title><command>pg_rewind</command> and PostgreSQL 9.4</title>
+
+      <indexterm>
+        <primary>pg_rewind</primary>
+        <secondary>PostgreSQL 9.4</secondary>
+      </indexterm>
+
+      <para>
+        <application>pg_rewind</application> is available in PostgreSQL 9.5 and later as part of the core distribution.
+        Users of PostgreSQL 9.4 will need to manually install it; the source code is available here:
+        <ulink url="https://github.com/vmware/pg_rewind">https://github.com/vmware/pg_rewind</ulink>.
+        If the <application>pg_rewind</application>
+        binary is not installed in the PostgreSQL <filename>bin</filename> directory, provide
+        its full path  on the demotion candidate  with <option>--force-rewind</option>.
+      </para>
+      <para>
+        Note that building the 9.4 version of <application>pg_rewind</application> requires the PostgreSQL
+        source code.
+      </para>
+    </refsect2>
   </refsect1>
 
   <refsect1 id="repmgr-node-rejoin-caveats" xreflabel="Caveats">
@@ -478,7 +499,7 @@
   <refsect1>
     <title>See also</title>
     <para>
-     <xref linkend="repmgr-standby-follow"/>
+     <xref linkend="repmgr-standby-follow"/>, <xref linkend="repmgr-standby-switchover"/>
     </para>
   </refsect1>
 </refentry>

doc/repmgr-standby-switchover.xml

@@ -154,9 +154,12 @@
           <para>
             Use <application>pg_rewind</application> to reintegrate the old primary if necessary
             (and the prerequisites for using <application>pg_rewind</application> are met).
+          </para>
+          <para>
             If using PostgreSQL 9.4, and the <application>pg_rewind</application>
             binary is not installed in the PostgreSQL <filename>bin</filename> directory,
-            provide its full path. For more details see also <xref linkend="switchover-pg-rewind"/>.
+            provide its full path. For more details see also <xref linkend="switchover-pg-rewind"/>
+            and <xref linkend="repmgr-node-rejoin-pg-rewind"/>.
           </para>
         </listitem>
       </varlistentry>

doc/repmgrd-overview.xml

@@ -29,7 +29,7 @@
 
        <listitem>
          <simpara>
-           option to execute custom scripts (&quot;<link linkend="event-notifications">event notifications</link>
+           option to execute custom scripts (&quot;<link linkend="event-notifications">event notifications</link>&quot;)
            at different points in the failover sequence
          </simpara>
        </listitem>

doc/switchover.xml

@@ -242,21 +242,12 @@
       </simpara>
     </note>
     <para>
-      For more details on <application>pg_rewind</application>, see:
+      For more details on <application>pg_rewind</application>, see section <xref linkend="repmgr-node-rejoin-pg-rewind"/>
+      in the <link linkend="repmgr-node-rejoin"><command>repmgr node rejoin</command></link> documentation and
+      the PostgreSQL documentation at
       <ulink url="https://www.postgresql.org/docs/current/app-pgrewind.html">https://www.postgresql.org/docs/current/app-pgrewind.html</ulink>.
     </para>
-    <para>
-      <application>pg_rewind</application> has been part of the core PostgreSQL distribution since
-      version 9.5. Users of PostgreSQL 9.4 will need to manually install it; the source code is available here:
-      <ulink url="https://github.com/vmware/pg_rewind">https://github.com/vmware/pg_rewind</ulink>.
-      If the <application>pg_rewind</application>
-      binary is not installed in the PostgreSQL <filename>bin</filename> directory, provide
-      its full path  on the demotion candidate  with <option>--force-rewind</option>.
-    </para>
-    <para>
-      Note that building the 9.4 version of <application>pg_rewind</application> requires the PostgreSQL
-      source code.
-    </para>
+
   </sect2>
 
 

errcode.h

@@ -49,5 +49,6 @@
 #define ERR_NODE_STATUS 25
 #define ERR_REPMGRD_PAUSE 26
 #define ERR_REPMGRD_SERVICE 27
+#define ERR_PGBACKUPAPI_SERVICE 28
 
 #endif							/* _ERRCODE_H_ */

pgbackupapi.c

@@ -0,0 +1,147 @@
+/*
+ * pgbackupapi.c
+ * Copyright (c) EnterpriseDB Corporation, 2010-2021
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <string.h>
+
+#include <curl/curl.h>
+#include <json-c/json.h>
+
+#include "repmgr.h"
+#include "pgbackupapi.h"
+
+
+size_t receive_operations_cb(void *content, size_t size, size_t nmemb, char *buffer) {
+	short int max_chars_to_copy = MAX_BUFFER_LENGTH -2;
+	short int i = 0;
+	int operation_length = 0;
+	json_object *value;
+
+	json_object *root = json_tokener_parse(content);
+	json_object *operations = json_object_object_get(root, "operations");
+
+	operation_length = strlen(json_object_get_string(operations));
+	if (operation_length < max_chars_to_copy) {
+		max_chars_to_copy = operation_length;
+	}
+
+	strncpy(buffer, json_object_get_string(operations), max_chars_to_copy);
+
+	fprintf(stdout, "Success! The following operations were found\n");
+	for (i=0; i<json_object_array_length(operations); i++) {
+		value = json_object_array_get_idx(operations, i);
+		printf("%s\n", json_object_get_string(value));
+	}
+	return size * nmemb;
+}
+
+char * define_base_url(operation_task *task) {
+	char *format = "http://%s:7480/servers/%s/operations";
+	char *url = malloc(MAX_BUFFER_LENGTH);
+
+	snprintf(url, MAX_BUFFER_LENGTH-1, format, task->host, task->node_name);
+
+	//`url` is freed on the function that called this
+	return url;
+}
+
+CURLcode get_operations_on_server(CURL *curl, operation_task *task) {
+	char buffer[MAX_BUFFER_LENGTH];
+	char *url = define_base_url(task);
+	CURLcode ret;
+
+	curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, receive_operations_cb);
+	curl_easy_setopt(curl, CURLOPT_WRITEDATA, &buffer);
+	curl_easy_setopt(curl, CURLOPT_URL, url);
+
+	ret = curl_easy_perform(curl);
+	free(url);
+
+	return ret;
+}
+
+size_t receive_operation_id(void *content, size_t size, size_t nmemb, char *buffer) {
+	json_object *root = json_tokener_parse(content);
+	json_object *operation = json_object_object_get(root, "operation_id");
+
+	if (operation != NULL) {
+		strncpy(buffer, json_object_get_string(operation), MAX_BUFFER_LENGTH-2);
+	}
+
+	return size * nmemb;
+}
+
+
+CURLcode create_new_task(CURL *curl, operation_task *task) {
+	PQExpBufferData payload;
+	char *url = define_base_url(task);
+	CURLcode ret;
+	json_object *root = json_object_new_object();
+	struct curl_slist *chunk = NULL;
+
+	json_object_object_add(root, "operation_type", json_object_new_string(task->operation_type));
+	json_object_object_add(root, "backup_id", json_object_new_string(task->backup_id));
+	json_object_object_add(root, "remote_ssh_command", json_object_new_string(task->remote_ssh_command));
+	json_object_object_add(root, "destination_directory", json_object_new_string(task->destination_directory));
+
+	initPQExpBuffer(&payload);
+	appendPQExpBufferStr(&payload, json_object_to_json_string(root));
+
+	chunk = curl_slist_append(chunk, "Content-type: application/json");
+	curl_easy_setopt(curl, CURLOPT_HTTPHEADER, chunk);
+	curl_easy_setopt(curl, CURLOPT_URL, url);
+	curl_easy_setopt(curl, CURLOPT_POSTFIELDS, payload.data);
+	curl_easy_setopt(curl, CURLOPT_FAILONERROR, 1L);
+	//curl_easy_setopt(curl, CURLOPT_VERBOSE, 1L);
+	curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, receive_operation_id);
+	curl_easy_setopt(curl, CURLOPT_WRITEDATA, task->operation_id);
+	ret = curl_easy_perform(curl);
+	free(url);
+	termPQExpBuffer(&payload);
+
+	return ret;
+}
+
+
+size_t receive_operation_status(void *content, size_t size, size_t nmemb, char *buffer) {
+	json_object *root = json_tokener_parse(content);
+	json_object *status = json_object_object_get(root, "status");
+	if (status != NULL) {
+		strncpy(buffer, json_object_get_string(status), MAX_BUFFER_LENGTH-2);
+	}
+	else {
+		fprintf(stderr, "Incorrect reply received for that operation ID.\n");
+		strcpy(buffer, "\0");
+	}
+	return size * nmemb;
+}
+
+CURLcode get_status_of_operation(CURL *curl, operation_task *task) {
+	CURLcode ret;
+	char *url = define_base_url(task);
+
+	strcat(url, "/");
+	strcat(url, task->operation_id);
+	curl_easy_setopt(curl, CURLOPT_URL, url);
+	curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, receive_operation_status);
+	curl_easy_setopt(curl, CURLOPT_WRITEDATA, task->operation_status);
+
+	ret = curl_easy_perform(curl);
+	free(url);
+
+	return ret;
+}

pgbackupapi.h

@@ -0,0 +1,46 @@
+/*
+ * pgbackupapi.h
+ * Copyright (c) EnterpriseDB Corporation, 2010-2021
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <curl/curl.h>
+#include <json-c/json.h>
+
+typedef struct operation_task {
+        char *backup_id;
+        char *destination_directory;
+        char *operation_type;
+	char *operation_id;
+	char *operation_status;
+        char *remote_ssh_command;
+	char *host;
+	char *node_name;
+} operation_task;
+
+//Default simplebuffer size in most of operations
+#define MAX_BUFFER_LENGTH 72
+
+//Callbacks to send/receive data from pg-backup-api endpoints
+size_t receive_operations_cb(void *content, size_t size, size_t nmemb, char *buffer);
+size_t receive_operation_id(void *content, size_t size, size_t nmemb, char *buffer);
+size_t receive_operation_status(void *content, size_t size, size_t nmemb, char *buffer);
+
+//Functions that implement the logic and know what to do and how to comunnicate wuth the API
+CURLcode get_operations_on_server(CURL *curl, operation_task *task);
+CURLcode create_new_task(CURL *curl, operation_task *task);
+CURLcode get_status_of_operation(CURL *curl, operation_task *task);
+
+//Helper to make simpler to read the handler where we set the URL
+char * define_base_url(operation_task *task);

repmgr--5.3--5.4.sql

@@ -0,0 +1,2 @@
+-- complain if script is sourced in psql, rather than via CREAT EXTENSION
+\echo Use "CREATE EXTENSION repmgr" to load this file. \quit

repmgr--5.4.sql

@@ -0,0 +1,192 @@
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION repmgr" to load this file. \quit
+
+CREATE TABLE repmgr.nodes (
+  node_id          INTEGER     PRIMARY KEY,
+  upstream_node_id INTEGER     NULL REFERENCES nodes (node_id) DEFERRABLE,
+  active           BOOLEAN     NOT NULL DEFAULT TRUE,
+  node_name        TEXT        NOT NULL,
+  type             TEXT        NOT NULL CHECK (type IN('primary','standby','witness','bdr')),
+  location         TEXT        NOT NULL DEFAULT 'default',
+  priority         INT         NOT NULL DEFAULT 100,
+  conninfo         TEXT        NOT NULL,
+  repluser         VARCHAR(63) NOT NULL,
+  slot_name        TEXT        NULL,
+  config_file      TEXT        NOT NULL
+);
+
+SELECT pg_catalog.pg_extension_config_dump('repmgr.nodes', '');
+
+CREATE TABLE repmgr.events (
+  node_id          INTEGER NOT NULL,
+  event            TEXT NOT NULL,
+  successful       BOOLEAN NOT NULL DEFAULT TRUE,
+  event_timestamp  TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  details          TEXT NULL
+);
+
+SELECT pg_catalog.pg_extension_config_dump('repmgr.events', '');
+
+CREATE TABLE repmgr.monitoring_history (
+  primary_node_id                INTEGER NOT NULL,
+  standby_node_id                INTEGER NOT NULL,
+  last_monitor_time              TIMESTAMP WITH TIME ZONE NOT NULL,
+  last_apply_time                TIMESTAMP WITH TIME ZONE,
+  last_wal_primary_location      PG_LSN NOT NULL,
+  last_wal_standby_location      PG_LSN,
+  replication_lag                BIGINT NOT NULL,
+  apply_lag                      BIGINT NOT NULL
+);
+
+CREATE INDEX idx_monitoring_history_time
+          ON repmgr.monitoring_history (last_monitor_time, standby_node_id);
+
+SELECT pg_catalog.pg_extension_config_dump('repmgr.monitoring_history', '');
+
+CREATE VIEW repmgr.show_nodes AS
+   SELECT n.node_id,
+          n.node_name,
+          n.active,
+          n.upstream_node_id,
+          un.node_name AS upstream_node_name,
+          n.type,
+          n.priority,
+          n.conninfo
+     FROM repmgr.nodes n
+LEFT JOIN repmgr.nodes un
+       ON un.node_id = n.upstream_node_id;
+
+CREATE TABLE repmgr.voting_term (
+  term INT NOT NULL
+);
+
+CREATE UNIQUE INDEX voting_term_restrict
+ON repmgr.voting_term ((TRUE));
+
+CREATE RULE voting_term_delete AS
+   ON DELETE TO repmgr.voting_term
+   DO INSTEAD NOTHING;
+
+
+/* ================= */
+/* repmgrd functions */
+/* ================= */
+
+/* monitoring functions */
+
+CREATE FUNCTION set_local_node_id(INT)
+  RETURNS VOID
+  AS 'MODULE_PATHNAME', 'repmgr_set_local_node_id'
+  LANGUAGE C STRICT;
+
+CREATE FUNCTION get_local_node_id()
+  RETURNS INT
+  AS 'MODULE_PATHNAME', 'repmgr_get_local_node_id'
+  LANGUAGE C STRICT;
+
+CREATE FUNCTION standby_set_last_updated()
+  RETURNS TIMESTAMP WITH TIME ZONE
+  AS 'MODULE_PATHNAME', 'repmgr_standby_set_last_updated'
+  LANGUAGE C STRICT;
+
+CREATE FUNCTION standby_get_last_updated()
+  RETURNS TIMESTAMP WITH TIME ZONE
+  AS 'MODULE_PATHNAME', 'repmgr_standby_get_last_updated'
+  LANGUAGE C STRICT;
+
+CREATE FUNCTION set_upstream_last_seen(INT)
+  RETURNS VOID
+  AS 'MODULE_PATHNAME', 'repmgr_set_upstream_last_seen'
+  LANGUAGE C STRICT;
+
+CREATE FUNCTION get_upstream_last_seen()
+  RETURNS INT
+  AS 'MODULE_PATHNAME', 'repmgr_get_upstream_last_seen'
+  LANGUAGE C STRICT;
+
+CREATE FUNCTION get_upstream_node_id()
+  RETURNS INT
+  AS 'MODULE_PATHNAME', 'repmgr_get_upstream_node_id'
+  LANGUAGE C STRICT;
+
+CREATE FUNCTION set_upstream_node_id(INT)
+  RETURNS VOID
+  AS 'MODULE_PATHNAME', 'repmgr_set_upstream_node_id'
+  LANGUAGE C STRICT;
+
+/* failover functions */
+
+CREATE FUNCTION notify_follow_primary(INT)
+  RETURNS VOID
+  AS 'MODULE_PATHNAME', 'repmgr_notify_follow_primary'
+  LANGUAGE C STRICT;
+
+CREATE FUNCTION get_new_primary()
+  RETURNS INT
+  AS 'MODULE_PATHNAME', 'repmgr_get_new_primary'
+  LANGUAGE C STRICT;
+
+CREATE FUNCTION reset_voting_status()
+  RETURNS VOID
+  AS 'MODULE_PATHNAME', 'repmgr_reset_voting_status'
+  LANGUAGE C STRICT;
+
+CREATE FUNCTION get_repmgrd_pid()
+  RETURNS INT
+  AS 'MODULE_PATHNAME', 'get_repmgrd_pid'
+  LANGUAGE C STRICT;
+
+CREATE FUNCTION get_repmgrd_pidfile()
+  RETURNS TEXT
+  AS 'MODULE_PATHNAME', 'get_repmgrd_pidfile'
+  LANGUAGE C STRICT;
+
+CREATE FUNCTION set_repmgrd_pid(INT, TEXT)
+  RETURNS VOID
+  AS 'MODULE_PATHNAME', 'set_repmgrd_pid'
+  LANGUAGE C CALLED ON NULL INPUT;
+
+CREATE FUNCTION repmgrd_is_running()
+  RETURNS BOOL
+  AS 'MODULE_PATHNAME', 'repmgrd_is_running'
+  LANGUAGE C STRICT;
+
+CREATE FUNCTION repmgrd_pause(BOOL)
+  RETURNS VOID
+  AS 'MODULE_PATHNAME', 'repmgrd_pause'
+  LANGUAGE C STRICT;
+
+CREATE FUNCTION repmgrd_is_paused()
+  RETURNS BOOL
+  AS 'MODULE_PATHNAME', 'repmgrd_is_paused'
+  LANGUAGE C STRICT;
+
+CREATE FUNCTION get_wal_receiver_pid()
+  RETURNS INT
+  AS 'MODULE_PATHNAME', 'repmgr_get_wal_receiver_pid'
+  LANGUAGE C STRICT;
+
+
+
+
+/* views */
+
+CREATE VIEW repmgr.replication_status AS
+  SELECT m.primary_node_id, m.standby_node_id, n.node_name AS standby_name,
+ 	     n.type AS node_type, n.active, last_monitor_time,
+         CASE WHEN n.type='standby' THEN m.last_wal_primary_location ELSE NULL END AS last_wal_primary_location,
+         m.last_wal_standby_location,
+         CASE WHEN n.type='standby' THEN pg_catalog.pg_size_pretty(m.replication_lag) ELSE NULL END AS replication_lag,
+         CASE WHEN n.type='standby' THEN
+           CASE WHEN replication_lag > 0 THEN age(now(), m.last_apply_time) ELSE '0'::INTERVAL END
+           ELSE NULL
+         END AS replication_time_lag,
+         CASE WHEN n.type='standby' THEN pg_catalog.pg_size_pretty(m.apply_lag) ELSE NULL END AS apply_lag,
+         AGE(NOW(), CASE WHEN pg_catalog.pg_is_in_recovery() THEN repmgr.standby_get_last_updated() ELSE m.last_monitor_time END) AS communication_time_lag
+    FROM repmgr.monitoring_history m
+    JOIN repmgr.nodes n ON m.standby_node_id = n.node_id
+   WHERE (m.standby_node_id, m.last_monitor_time) IN (
+	          SELECT m1.standby_node_id, MAX(m1.last_monitor_time)
+			    FROM repmgr.monitoring_history m1 GROUP BY 1
+         );
+

repmgr-action-standby.c

@@ -21,6 +21,7 @@
 
 #include <sys/stat.h>
 #include <time.h>
+#include <unistd.h>
 
 #include "repmgr.h"
 #include "dirutil.h"
@@ -29,7 +30,7 @@
 
 #include "repmgr-client-global.h"
 #include "repmgr-action-standby.h"
-
+#include "pgbackupapi.h"
 
 typedef struct TablespaceDataListCell
 {
@@ -113,6 +114,7 @@ static void check_recovery_type(PGconn *conn);
 static void initialise_direct_clone(t_node_info *local_node_record, t_node_info *upstream_node_record);
 static int	run_basebackup(t_node_info *node_record);
 static int	run_file_backup(t_node_info *node_record);
+static int	run_pg_backupapi(t_node_info *node_record);
 
 static void copy_configuration_files(bool delete_after_copy);
 
@@ -687,19 +689,18 @@ do_standby_clone(void)
 		exit(SUCCESS);
 	}
 
-	if (mode != barman)
-	{
-		initialise_direct_clone(&local_node_record, &upstream_node_record);
-	}
-
 	switch (mode)
 	{
 		case pg_basebackup:
+			initialise_direct_clone(&local_node_record, &upstream_node_record);
 			log_notice(_("starting backup (using pg_basebackup)..."));
 			break;
 		case barman:
 			log_notice(_("retrieving backup from Barman..."));
 			break;
+		case pg_backupapi:
+			log_notice(_("starting backup (using pg_backupapi)..."));
+			break;
 		default:
 			/* should never reach here */
 			log_error(_("unknown clone mode"));
@@ -721,6 +722,9 @@ do_standby_clone(void)
 		case barman:
 			r = run_file_backup(&local_node_record);
 			break;
+		case pg_backupapi:
+			r = run_pg_backupapi(&local_node_record);
+			break;
 		default:
 			/* should never reach here */
 			log_error(_("unknown clone mode"));
@@ -814,7 +818,6 @@ do_standby_clone(void)
 	}
 
 	/* Write the recovery.conf file */
-
 	if (create_recovery_file(&local_node_record,
 							 &recovery_conninfo,
 							 source_server_version_num,
@@ -846,6 +849,9 @@ do_standby_clone(void)
 		case barman:
 			log_notice(_("standby clone (from Barman) complete"));
 			break;
+		case pg_backupapi:
+			log_notice(_("standby clone (from pg_backupapi) complete"));
+			break;
 	}
 
 	/*
@@ -937,6 +943,9 @@ do_standby_clone(void)
 		case barman:
 			appendPQExpBufferStr(&event_details, "barman");
 			break;
+		case pg_backupapi:
+			appendPQExpBufferStr(&event_details, "pg_backupapi");
+			break;
 	}
 
 	appendPQExpBuffer(&event_details,
@@ -7770,6 +7779,117 @@ stop_backup:
 }
 
 
+/*
+ * Perform a call to pg_backupapi endpoint to ask barman to write the backup
+ * for us. This will ensure that no matter the format on-disk of new backups,
+ * barman will always find a way how to read and write them.
+ * From repmgr 4 this is only used for Barman backups.
+ */
+static int
+run_pg_backupapi(t_node_info *local_node_record)
+{
+	int r = ERR_PGBACKUPAPI_SERVICE;
+	long http_return_code = 0;
+	short seconds_to_sleep = 3;
+	operation_task *task = malloc(sizeof(operation_task));
+	CURL *curl = curl_easy_init();
+	CURLcode ret;
+
+	check_pg_backupapi_standby_clone_options();
+
+	task->host = malloc(strlen(config_file_options.pg_backupapi_host)+1);
+	task->remote_ssh_command = malloc(strlen(config_file_options.pg_backupapi_remote_ssh_command)+1);
+	task->node_name = malloc(strlen(config_file_options.pg_backupapi_node_name)+1);
+	task->operation_type = malloc(strlen(DEFAULT_STANDBY_PG_BACKUPAPI_OP_TYPE)+1);
+	task->backup_id = malloc(strlen(config_file_options.pg_backupapi_backup_id)+1);
+	task->destination_directory = malloc(strlen(local_data_directory)+1);
+
+	task->operation_id = malloc(MAX_BUFFER_LENGTH);
+	task->operation_status = malloc(MAX_BUFFER_LENGTH);
+
+	strcpy(task->host, config_file_options.pg_backupapi_host);
+	strcpy(task->remote_ssh_command, config_file_options.pg_backupapi_remote_ssh_command);
+	strcpy(task->node_name, config_file_options.pg_backupapi_node_name);
+	strcpy(task->operation_type, DEFAULT_STANDBY_PG_BACKUPAPI_OP_TYPE);
+	strcpy(task->backup_id, config_file_options.pg_backupapi_backup_id);
+	strcpy(task->destination_directory, local_data_directory);
+	strcpy(task->operation_id, "\0");
+
+	ret = create_new_task(curl, task);
+
+	if ((ret != CURLE_OK) || (strlen(task->operation_id) == 0)) {
+		curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &http_return_code);
+		if (499 > http_return_code && http_return_code >= 400) {
+			log_error("Cannot find backup '%s' for node '%s'.", task->backup_id, task->node_name);
+		} else {
+			log_error("whilst reaching out pg_backup service: %s\n", curl_easy_strerror(ret));
+		}
+        }
+	else
+	{
+		log_info("Success creating the task: operation id '%s'", task->operation_id);
+
+		//We call init again because previous call included POST calls
+		curl_easy_cleanup(curl);
+		curl = curl_easy_init();
+		while (true)
+		{
+			ret = get_status_of_operation(curl, task);
+			if (strlen(task->operation_status) == 0) {
+				log_info("Retrying...");
+			}
+			else
+			{
+				log_info("status %s", task->operation_status);
+			}
+			if (strcmp(task->operation_status, "FAILED") == 0) {
+				break;
+			}
+			if (strcmp(task->operation_status, "DONE") == 0) {
+				r = SUCCESS;
+				break;
+			}
+
+			sleep(seconds_to_sleep);
+		}
+	}
+
+	curl_easy_cleanup(curl);
+	free(task);
+	return r;
+}
+
+/*
+ * pg_backupapi mode is enabled when config_file_options.pg_backupapi_host is set hence, we
+ * should also check the other required variables too.
+ */
+
+void check_pg_backupapi_standby_clone_options() {
+
+	bool error = false;
+
+	if (*config_file_options.pg_backupapi_remote_ssh_command == '\0') {
+		log_hint("Check config: remote ssh command is required");
+		error = true;
+	}
+	if (*config_file_options.pg_backupapi_node_name == '\0') {
+		log_hint("Check config: node name is required");
+		error = true;
+	}
+	if (*config_file_options.pg_backupapi_backup_id == '\0') {
+		log_hint("Check config: backup_id is required");
+		error = true;
+	}
+
+	if (error == true) {
+		log_error("Please fix the errors and try again");
+		exit(ERR_BAD_CONFIG);
+	}
+
+}
+
+
+
 static char *
 make_barman_ssh_command(char *buf)
 {

repmgr-action-standby.h

@@ -30,6 +30,6 @@ extern void do_standby_help(void);
 
 extern bool do_standby_follow_internal(PGconn *primary_conn, PGconn *follow_target_conn, t_node_info *follow_target_node_record, PQExpBufferData *output, int general_error_code, int *error_code);
 
-
+void check_pg_backupapi_standby_clone_options(void);
 
 #endif							/* _REPMGR_ACTION_STANDBY_H_ */

repmgr-client-global.h

@@ -193,7 +193,8 @@ typedef struct
 typedef enum
 {
 	barman,
-	pg_basebackup
+	pg_basebackup,
+	pg_backupapi
 } standy_clone_mode;
 
 typedef enum

repmgr-client.c

@@ -3096,9 +3096,14 @@ get_standby_clone_mode(void)
 
 	if (*config_file_options.barman_host != '\0' && runtime_options.without_barman == false)
 		mode = barman;
-	else
-		mode = pg_basebackup;
-
+	else {
+		if (*config_file_options.pg_backupapi_host != '\0') {
+			log_info("Attempting to use `pg_backupapi` new restore mode");
+			mode = pg_backupapi;
+		}
+		else
+			mode = pg_basebackup;
+	}
 	return mode;
 }
 

repmgr.control

@@ -1,6 +1,6 @@
 # repmgr extension
 comment = 'Replication manager for PostgreSQL'
-default_version = '5.3'
+default_version = '5.4'
 module_pathname = '$libdir/repmgr'
 relocatable = false
 schema = repmgr

repmgr.h

@@ -116,6 +116,7 @@
 #define DEFAULT_STANDBY_FOLLOW_TIMEOUT       30  /* seconds */
 #define DEFAULT_STANDBY_FOLLOW_RESTART       false
 #define DEFAULT_SHUTDOWN_CHECK_TIMEOUT       60  /* seconds */
+#define DEFAULT_STANDBY_PG_BACKUPAPI_OP_TYPE "recovery"
 #define DEFAULT_STANDBY_RECONNECT_TIMEOUT    60  /* seconds */
 #define DEFAULT_NODE_REJOIN_TIMEOUT          60  /* seconds */
 #define DEFAULT_ARCHIVE_READY_WARNING        16  /* WAL files */

repmgr_version.h.in

@@ -1,7 +1,7 @@
 #define REPMGR_VERSION_DATE ""
-#define REPMGR_VERSION "5.3.3"
-#define REPMGR_VERSION_NUM 50303
-#define REPMGR_EXTENSION_VERSION "5.3"
-#define REPMGR_EXTENSION_NUM 50300
-#define REPMGR_RELEASE_DATE "2022-10-17"
+#define REPMGR_VERSION "5.4dev"
+#define REPMGR_VERSION_NUM 50400
+#define REPMGR_EXTENSION_VERSION "5.4"
+#define REPMGR_EXTENSION_NUM 50400
+#define REPMGR_RELEASE_DATE "2022-XX-XX"
 #define PG_ACTUAL_VERSION_NUM