Merge branch 'pgsql-snapshot-fallback' into 'master'

Pgsql env variables to configure snapshot

See merge request !152

docs/30_Configuration/60_File_env.md

@@ -60,6 +60,19 @@ RESTIC_PARAMS=--no-scan
 
 You can override used parameters during backup. The parameters for mysqldump are in env_defaults. If you want to change them then put ``LD_MYSQL_DUMP_PARAMS=...`` into env file.
 
+### Localdump :: Pgsql
+
+Postgres backup supports backups with a snapshot database using `CREATE DATABASE snapshot_<SCHEMA> WITH TEMPLATE <SCHEMA>`.
+The backup script detects if a server is writable or readonly (slave). On a writable system the snapshot creation is activated.
+
+The creation of a snapshot database fails if a user is connected on the origin database. It is posible to disconnect all users but shouldn't be triggered during production times. You can configure a night time when to allow the disconnect (default: no disconnect).
+
+You can put these variables into env:
+
+* LD_PGSQL_SNAPSHOTS=0 - disable snapshot on a writable database server
+* LD_PGSQL_DISCONNECT_BEFORE - time in the morning until to allow disconnect; eg. "03:00"
+* LD_PGSQL_DISCONNECT_AFTER - time in the night when to allow disconnect; eg "22:00"
+
 ### Transfer :: Restic
 
 There are some environment variables for tuning

plugins/localdump/pgsql.sh

@@ -16,6 +16,7 @@
 # 2024-10-02  ah     v1.5  rename backup and restore function
 # 2024-12-13  ah     v1.6  backup uses a snapshot db
 # 2024-12-16  ah     v1.7  on snapshot mode it can fallback for single database to normal pg_dump of origin
+# 2024-12-17  ah     v1.8  handle env variables to disable snapshots or set times for disconnect
 # ================================================================================
 
 if [ -z "$BACKUP_TARGETDIR" ]; then
@@ -46,11 +47,21 @@ function pgsql.backup(){
   local bUseSnapshot
   local bUseSnapshot4DB
   local bDisconnect
-  local iHour; 
+  local mytime
 
   typeset -i bUseSnapshot=0
   typeset -i bDisconnect=0
-  typeset -i iHour; iHour=$( date +%H)
+
+  # handle config from jobs/env
+  LD_PGSQL_SNAPSHOTS="${LD_PGSQL_SNAPSHOTS:-1}"
+  LD_PGSQL_DISCONNECT_BEFORE="${LD_PGSQL_DISCONNECT_BEFORE:-00:00}"
+  LD_PGSQL_DISCONNECT_AFTER="${LD_PGSQL_DISCONNECT_AFTER:-24:00}"
+
+  echo "${LD_PGSQL_DISCONNECT_BEFORE}_${LD_PGSQL_DISCONNECT_AFTER}" \
+    | grep -q "[0-2][0-9]:[0-5][0-9]_[0-2][0-9]:[0-5][0-9]" \
+    || echo "ERROR: LD_PGSQL_DISCONNECT_BEFORE and LD_PGSQL_DISCONNECT_AFTER must be in the format HH:MM"
+
+  mytime="$( date +%H:%M)"
 
   create_targetdir
 
@@ -60,8 +71,13 @@ function pgsql.backup(){
   # ----- GO
 
   # prevent could not change directory to "/root": Permission denied
-  cd /tmp
+  cd /tmp || exit
 
+  # Enable snapshots?
+  if [ "$LD_PGSQL_SNAPSHOTS" = "0" ]; then
+    echo "INFO: Snapshots disabled by LD_PGSQL_SNAPSHOTS=0"
+    bUseSnapshot=0
+  else
     # Detect a readonly or writeable postgres host.
     TESTDB="imlbackup_createtest"
     su ${PGUSER} -c "dropdb ${TESTDB}" >/dev/null 2>&1
@@ -73,12 +89,15 @@ function pgsql.backup(){
     else
       echo "INFO: create database failed for snapshots - dumping databases directly"
     fi
+  fi
 
-  # disconnect after 21:00 and before 05:00
+  # enable disconnect?
   if [ $bUseSnapshot -eq 1 ]; then
-    if [ $iHour -ge 21 ] || [ $iHour -lt 5 ]; then
-      echo "INFO: clients will be disconnected for snapshot database creation"
+    if [ "$mytime" \< "$LD_PGSQL_DISCONNECT_BEFORE" ] || [ "$mytime" \> "$LD_PGSQL_DISCONNECT_AFTER" ]; then
+      echo "INFO: clients will be disconnected for snapshot database creation."
       bDisconnect=1
+    else
+      echo "INFO: clients will NOT be disconnected for snapshot database creation - which may fail then."
     fi
   fi