From dc07eccd09458730dd29cda4210e66c03e40d89a Mon Sep 17 00:00:00 2001
From: Benjamin Renard <brenard@easter-eggs.com>
Date: Wed, 4 Nov 2020 15:01:57 +0100
Subject: [PATCH] Improve PostgreSQL installation parameters auto-detection

---
 check_pg_streaming_replication | 111 +++++++++++++++++++++++----------
 1 file changed, 79 insertions(+), 32 deletions(-)

diff --git a/check_pg_streaming_replication b/check_pg_streaming_replication
index b6bbfde..7b74cbf 100755
--- a/check_pg_streaming_replication
+++ b/check_pg_streaming_replication
@@ -19,22 +19,19 @@
 # Source : http://git.zionetrix.net/check_pg_streaming_replication
 #
 
-PG_USER=postgres
+DEFAULT_PG_USER=postgres
+DEFAULT_PG_VERSION=9.1
+DEFAULT_PG_MAIN=/var/lib/postgresql/$PG_VERSION/main
+DEFAULT_PG_PORT=5432
+PG_USER=""
+PG_VERSION=""
+PG_MAIN=""
 PG_MASTER_USER=""
 PSQL_BIN=/usr/bin/psql
-PG_MAIN=/var/lib/postgresql/9.1/main
-if [ -f /etc/debian_version ]
-then
-	AUTO_PG_MAIN=$( ls -1d /var/lib/postgresql/9*/main 2> /dev/null|sort -n|tail -n 1 )
-	[ -n "$AUTO_PG_MAIN" -a -d "$AUTO_PG_MAIN" ] && PG_MAIN=$AUTO_PG_MAIN
-elif [ -f /etc/redhat-release ]
-then
-	AUTO_PG_MAIN=$( ls -1d /var/lib/pgsql/9*/data 2> /dev/null|sort -n|tail -n 1 )
-	[ -n "$AUTO_PG_MAIN" -a -d "$AUTO_PG_MAIN" ] && PG_MAIN=$AUTO_PG_MAIN
-fi
+PG_LSCLUSTER_BIN=/usr/bin/pg_lsclusters
 RECOVERY_CONF_FILENAME=recovery.conf
 RECOVERY_CONF=""
-PG_DEFAULT_PORT=5432
+PG_DEFAULT_PORT=""
 PG_DEFAULT_APP_NAME=$( hostname )
 PG_DB=""
 CHECK_CUR_MASTER_XLOG=1
@@ -46,27 +43,30 @@ DEBUG=0
 function usage () {
 	cat << EOF
 Usage : $0 [-d] [-h] [options]
-	-u pg_user		Specify Postgres user (Default : $PG_USER)
-	-b psql_bin		Specify psql binary path (Default : $PSQL_BIN)
-	-m pg_main		Specify Postgres main directory path
-				(By default, try to auto-detect it, on your system it :
-                                $PG_MAIN)
+	-u pg_user		Specify local Postgres user (Default: try to auto-detect or use $DEFAULT_PG_USER)
+	-b psql_bin		Specify psql binary path (Default: $PSQL_BIN)
+	-B pg_lsclusters_bin	Specify pg_lsclusters binary path (Default: $PG_LSCLUSTER_BIN)
+	-V pg_version		Specify Postgres version (Default: try to auto-detect or use $DEFAULT_PG_VERSION)
+	-m pg_main		Specify Postgres main directory path (Default: try to auto-detect or use
+                                $DEFAULT_PG_MAIN)
 	-r recovery_conf	Specify Postgres recovery configuration file path
-				(Default : [PG_MAIN]/$RECOVERY_CONF_FILENAME)
-	-U pg_master_user	Specify Postgres user to use on master (Default : user from recovery.conf file)
-	-p pg_port		Specify default Postgres master TCP port (Default : $PG_DEFAULT_PORT)
-	-D dbname		Specify DB name on Postgres master/slave to connect on (Default : PG_USER)
+				(Default: [PG_MAIN]/$RECOVERY_CONF_FILENAME)
+	-U pg_master_user	Specify Postgres user to use on master (Default: user from recovery.conf file)
+	-p pg_port		Specify default Postgres master TCP port (Default: same as local PostgreSQL
+	                        port if detected or use $DEFAULT_PG_PORT)
+	-D dbname		Specify DB name on Postgres master/slave to connect on (Default: PG_USER, must
+	                        match with .pgpass one is used)
 	-C 1/0			Enable or disable check if the current XLOG file of the master host is the same
-				of the last replay XLOG file (Default : $CHECK_CUR_MASTER_XLOG)
-	-w replay_warn_delay	Specify the replay warning delay in second (Default : $REPLAY_WARNING_DELAY)
-	-c replay_crit_delay	Specify the replay critical delay in second (Default : $REPLAY_CRITICAL_DELAY)
+				of the last replay XLOG file (Default: $CHECK_CUR_MASTER_XLOG)
+	-w replay_warn_delay	Specify the replay warning delay in second (Default: $REPLAY_WARNING_DELAY)
+	-c replay_crit_delay	Specify the replay critical delay in second (Default: $REPLAY_CRITICAL_DELAY)
 	-d			Debug mode
 	-h 			Show this message
 EOF
 	exit 0
 }
 
-while getopts "hu:b:m:r:U:p:D:C:w:c:d" OPTION
+while getopts "hu:b:B:V:m:r:U:p:D:C:w:c:d" OPTION
 do
 	case $OPTION in
 		u)
@@ -75,6 +75,12 @@ do
 		b)
 			PSQL_BIN=$OPTARG
 		;;
+		B)
+			PG_LSCLUSTER_BIN=$OPTARG
+		;;
+		V)
+			PG_VERSION=$OPTARG
+		;;
 		m)
 			PG_MAIN=$OPTARG
 		;;
@@ -111,6 +117,52 @@ do
 	esac
 done
 
+function debug() {
+	if [ $DEBUG -eq 1 ]
+	then
+		>&2 echo -e "[DEBUG] $1"
+	fi
+}
+
+debug "Starting options (before handling auto-detection/default values) :
+PG_VERSION = $PG_VERSION
+PG_DB = $PG_DB
+PG_USER = $PG_USER
+PSQL_BIN = $PSQL_BIN
+PG_LSCLUSTER_BIN = $PG_LSCLUSTER_BIN
+PG_MAIN = $PG_MAIN
+RECOVERY_CONF = $RECOVERY_CONF
+PG_DEFAULT_PORT = $PG_DEFAULT_PORT
+PG_DEFAULT_APP_NAME = $PG_DEFAULT_APP_NAME
+CHECK_CUR_MASTER_XLOG = $CHECK_CUR_MASTER_XLOG
+REPLAY_WARNING_DELAY = $REPLAY_WARNING_DELAY
+REPLAY_CRITICAL_DELAY = $REPLAY_CRITICAL_DELAY
+"
+
+# Auto-detect PostgreSQL information using pg_lsclusters
+if [ -x "$PG_LSCLUSTER_BIN" ]
+then
+	PG_CLUSTER=$( $PG_LSCLUSTER_BIN -h 2>/dev/null|head -n1 )
+	if [ -n "$PG_CLUSTER" ]
+	then
+		debug "pg_lsclusters output:\n\t$PG_CLUSTER"
+		# Output example:
+		# 9.6 main    5432 online,recovery postgres /var/lib/postgresql/9.6/main /var/log/postgresql/postgresql-9.6-main.log
+		[ -z "$PG_VERSION" ] && PG_VERSION=$( echo "$PG_CLUSTER"|awk -F ' +' '{print $1}' )
+		[ -z "$PG_DEFAULT_PORT" ] && PG_DEFAULT_PORT=$( echo "$PG_CLUSTER"|awk -F ' +' '{print $3}' )
+		[ -z "$PG_USER" ] && PG_USER=$( echo "$PG_CLUSTER"|awk -F ' +' '{print $5}' )
+		[ -z "$PG_MAIN" ] && PG_MAIN=$( echo "$PG_CLUSTER"|awk -F ' +' '{print $6}' )
+	fi
+else
+	debug "pg_lsclusters not found ($PG_LSCLUSTER_BIN): parameters auto-detection disabled"
+fi
+
+# If auto-detection failed, use default values
+[ -z "$PG_USER" ] && PG_USER="$DEFAULT_PG_USER"
+[ -z "$PG_VERSION" ] && PG_VERSION="$DEFAULT_PG_VERSION"
+[ -z "$PG_MAIN" ] && PG_MAIN="$DEFAULT_PG_MAIN"
+[ -z "$PG_DEFAULT_PORT" ] && PG_DEFAULT_PORT="$DEFAULT_PG_PORT"
+
 # Check PG_USER
 [ -z "$PG_USER" ] && echo "UNKNOWN : Postgres user not specified" && exit 3
 id "$PG_USER" > /dev/null 2>&1
@@ -143,17 +195,12 @@ function psql_master_get () {
 	echo "$sql"|sudo -u $PG_USER $PSQL_BIN -U $M_USER -h $M_HOST -w -p $M_PORT -d $PG_DB -t -P format=unaligned
 }
 
-function debug() {
-	if [ $DEBUG -eq 1 ]
-	then
-		>&2 echo "[DEBUG] $1"
-	fi
-}
-
 debug "Running options :
+PG_VERSION = $PG_VERSION
 PG_DB = $PG_DB
 PG_USER = $PG_USER
 PSQL_BIN = $PSQL_BIN
+PG_LSCLUSTER_BIN = $PG_LSCLUSTER_BIN
 PG_MAIN = $PG_MAIN
 RECOVERY_CONF = $RECOVERY_CONF
 PG_DEFAULT_PORT = $PG_DEFAULT_PORT