From 2c599f9c465ed3b88c3bf6f1852281a4847576d3 Mon Sep 17 00:00:00 2001
From: Michael Banck <michael.banck@credativ.de>
Date: Thu, 24 Mar 2022 15:43:10 +0100
Subject: [PATCH]   * debian/patches/pg_rewind_fix_get_guc_value.patch: New
 patch, changes the     pg_rewind calling behaviour so that it can deal with
 postgresql.conf not     being in the data directory; taken from upstream
 commit 7626b5f by Nick     Bluth.

---
 debian/changelog                              |  5 ++
 .../patches/pg_rewind_fix_get_guc_value.patch | 56 +++++++++++++++++++
 debian/patches/series                         |  1 +
 3 files changed, 62 insertions(+)
 create mode 100644 debian/patches/pg_rewind_fix_get_guc_value.patch

diff --git a/debian/changelog b/debian/changelog
index 0130503..dca1a3f 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,5 +1,10 @@
 patroni (2.1.3-2) UNRELEASED; urgency=medium
 
+  [ Michael Banck ]
+  * debian/patches/pg_rewind_fix_get_guc_value.patch: New patch, changes the
+    pg_rewind calling behaviour so that it can deal with postgresql.conf not
+    being in the data directory; taken from upstream commit 7626b5f by Nick
+    Bluth.
 
  -- Debian PostgreSQL Maintainers <team+postgresql@tracker.debian.org>  Fri, 18 Feb 2022 22:16:47 +0100
 
diff --git a/debian/patches/pg_rewind_fix_get_guc_value.patch b/debian/patches/pg_rewind_fix_get_guc_value.patch
new file mode 100644
index 0000000..560e3ba
--- /dev/null
+++ b/debian/patches/pg_rewind_fix_get_guc_value.patch
@@ -0,0 +1,56 @@
+commit 7626b5fef8ef18feab477354006a56b46a47436e
+Author: Gunnar "Nick" Bluth <gunnar.bluth@pro-open.de>
+Date:   Thu Mar 24 13:56:16 2022 +0100
+
+    Fix pg_rewind on typical Debian/Ubuntu systems (#2225)
+    
+    On Debian/Ubuntu systems it is common to keep Postgres config files outside of the data directory.
+    It created a couple of problems for pg_rewind support in Patroni.
+    1. The `--config_file` argument must be supplied while figuring out the `restore_command` GUC value on Postgres v12+
+    2. With Postgres v13+ pg_rewind by itself can't find postgresql.conf in order to figure out `restore_command` and therefore we have to use Patroni as a fallback for fetching missing WAL's that are required for rewind.
+    
+    This commit addresses both problems.
+
+diff --git a/patroni/postgresql/__init__.py b/patroni/postgresql/__init__.py
+index aeadc3e..3b9f250 100644
+--- a/patroni/postgresql/__init__.py
++++ b/patroni/postgresql/__init__.py
+@@ -798,7 +798,8 @@ class Postgresql(object):
+         return True
+ 
+     def get_guc_value(self, name):
+-        cmd = [self.pgcommand('postgres'), '-D', self._data_dir, '-C', name]
++        cmd = [self.pgcommand('postgres'), '-D', self._data_dir, '-C', name,
++               '--config-file={}'.format(self.config.postgresql_conf)]
+         try:
+             data = subprocess.check_output(cmd)
+             if data:
+diff --git a/patroni/postgresql/rewind.py b/patroni/postgresql/rewind.py
+index fb754f5..5a2e4a3 100644
+--- a/patroni/postgresql/rewind.py
++++ b/patroni/postgresql/rewind.py
+@@ -311,8 +311,14 @@ class Rewind(object):
+         restore_command = self._postgresql.config.get('recovery_conf', {}).get('restore_command') \
+             if self._postgresql.major_version < 120000 else self._postgresql.get_guc_value('restore_command')
+ 
++        # currently, pg_rewind expects postgresql.conf to be inside $PGDATA, which is not the case on e.g. Debian
++        # Fix this logic if e.g. PG15 receives an update for pg_rewind:
++        pg_rewind_can_restore = self._postgresql.major_version >= 130000 \
++            and restore_command \
++            and self._postgresql.config._config_dir == self._postgresql.data_dir
++
+         cmd = [self._postgresql.pgcommand('pg_rewind')]
+-        if self._postgresql.major_version >= 130000 and restore_command:
++        if pg_rewind_can_restore:
+             cmd.append('--restore-target-wal')
+         cmd.extend(['-D', self._postgresql.data_dir, '--source-server', dsn])
+ 
+@@ -329,7 +335,7 @@ class Rewind(object):
+             if ret == 0:
+                 return True
+ 
+-            if not restore_command or self._postgresql.major_version >= 130000:
++            if not restore_command or pg_rewind_can_restore:
+                 return False
+ 
+             missing_wal = self._find_missing_wal(results['stderr']) or self._find_missing_wal(results['stdout'])
diff --git a/debian/patches/series b/debian/patches/series
index 5c3bdd8..49a4f6b 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -4,3 +4,4 @@ requirements_setuptools.patch
 offline_intersphinx.patch
 requirements_cdiff.patch
 regression_tests_disable_raft_tests.py
+pg_rewind_fix_get_guc_value.patch