Looking for a good routine/class for purging Caché backups

Funny you should ask this as I was just looking at how to do this today.  

Most operating systems offer a way to search for files given a certain filter, such as being older than a certain date, and then piping that list to another command, such as delete.

Here is a class method I wrote to do this on a Windows 2012 R2 server running Cache

This method accepts a path and an integer indicating the number of days to keep files for.  It then uses constructs a command line which uses the "forfiles" command passing the path and a calculated date.  For each file it finds, it executes the command cmd /c del <path> which deletes the file.

There are probably more elegant ways to do this, cross platform compatible, but this is one solution that I had.

The article Recommendations on installing the InterSystems Caché DBMS for production environment  has some code that does this.

My comment  has a class that only deletes old backups as a scheduled task.

Kind regards,

Stephen

Class App.PurgeOldBackupFiles Extends %SYS.Task.Definition{Property BackupsToKeep As %Integer(MAXVAL = 30, MINVAL = 1) [ InitialExpression = 30, Required ];Property BackupFolder As %String [ Required ];Property BackupFileType As %String [ Required ];Method OnTask() As %Status{//s BackupsToKeep = 2//s Folder = "c:\backupfolder"//s BackupFileType = "FullAllDatabases" // or "FullDBList"s SortOrder = "DateModified"If ..BackupsToKeep<1 Quit $$$ERROR($$$GeneralError,"Invalid - Number of Backups to Keep must be greater than or equal to 1")If ..BackupFolder="" Quit $$$ERROR($$$GeneralError,"Invalid - BackupFolder - not supplied")if ..BackupFileType = "" Quit $$$ERROR($$$GeneralError,"Invalid - BackupFileType - not supplied")if (..BackupFileType '= "FullAllDatabases")&&(..BackupFileType '= "FullDBList") Quit $$$ERROR($$$GeneralError,"Invalid - BackupFileType")s BackupCount=0     k zPurgeOldBackupFiles(..BackupFileType)     Set rs=##class(%ResultSet).%New("%Library.File:FileSet")     w !,"backuplist",!     s BackupFileWildcard = ..BackupFileType _ "*.cbk"     set status=rs.Execute(..BackupFolder, BackupFileWildcard, SortOrder)     WHILE rs.Next() {          Set FullFileName=rs.Data("Name")          Set FName=##class(%File).GetFilename(FullFileName)          Set FDateTime=##class(%File).GetFileDateModified(FullFileName)          w "File "_FName_" "_FDateTime,!          Set FDate=$PIECE(FDateTime,",")          Set CDate=$PIECE($H,",")          s BackupCount=$I(BackupCount)          s zPurgeOldBackupFiles(..BackupFileType, BackupCount)=FullFileName      }     s zPurgeOldBackupFiles(..BackupFileType, "BackupCount")=BackupCount     do rs.Close()     if BackupCount > ..BackupsToKeep {          for i=1:1:BackupCount-..BackupsToKeep {               s FullFileName = zPurgeOldBackupFiles(..BackupFileType, i)               d ##class(%File).Delete(FullFileName)               w "File Purged "_FullFileName_" Purged",!          }     }     q status}}

You can schedule the following task which removes any file from a directory, based on its age, using Python:

Class admin.purge Extends%SYS.Task.Definition
{

Property Directory As%String(MAXLEN = 2000) [ InitialExpression = "/usr/irissys/mgr/Backup" ];Property DaysToKeep As%Integer(VALUELIST = ",0,1,2,3,4,5") [ InitialExpression = "1" ];

Method OnTask() As%Status
{
    set sc = $$$OKTry {
        do..purge(..Directory,..DaysToKeep)
    }
    Catch ex {
        Set sc=ex.AsStatus()
    }
    return sc
}

ClassMethod purge(path As%String, daysToKeep As%Integer) As%Status [ Language = python ]
{
import iris
import os
import time
from datetime import datetime, timedelta

event = "[TASK PURGE OLD BACKUP FILES]"class FileDeletionError(Exception):
    """Custom exception for file deletion errors."""
    pass

def delete_old_files(path, days_limit):
    limit_date = datetime.now() - timedelta(days=int(days_limit))

    for file in os.listdir(path):
        file_path = os.path.join(path, file)
        if os.path.isfile(file_path):
            creation_date = datetime.fromtimestamp(os.path.getctime(file_path))
            if creation_date < limit_date:
                try:
                    os.remove(file_path)
                    iris.cls("%SYS.System").WriteToConsoleLog(f"{event} Deleted: {str(file_path)}")
                except PermissionError:
                    raise FileDeletionError(f"Permission error: Unable to delete {file}")
                except FileNotFoundError:
                    raise FileDeletionError(f"File not found: {file}")
                except Exception as e:
                    raise FileDeletionError(f"Unexpected error while deleting {file}: {str(e)}")

try:
    iris.cls("%SYS.System").WriteToConsoleLog(f"{event} Executing task to delete backup files from directory {path} created more than {str(daysToKeep)} days ago")
    days_limit = daysToKeep
    delete_old_files(path, days_limit)
except FileDeletionError as e:
    iris.cls("%SYS.System").WriteToConsoleLog(f"{event} Error during deletion: {str(e)}",0,1)
except Exception as e:
    iris.cls("%SYS.System").WriteToConsoleLog(f"{event} Unexpected error: {str(e)}",0,1)
}

}

01/13/25-18:21:00:549 (35722) 0 [Utility.Event] [TASK PURGE OLD BACKUP FILES] Executing task to delete backup files from directory /usr/irissys/mgr/Backup created more than 0 days ago
01/13/25-18:21:00:550 (35722) 0 [Utility.Event] [TASK PURGE OLD BACKUP FILES] Deleted: /usr/irissys/mgr/Backup/FullAllDatabases_20250113_009.cbk
01/13/25-18:21:00:550 (35722) 0 [Utility.Event] [TASK PURGE OLD BACKUP FILES] Deleted: /usr/irissys/mgr/Backup/FullAllDatabases_20250113_008.log
01/13/25-18:21:00:598 (35722) 0 [Utility.Event] [TASK PURGE OLD BACKUP FILES] Deleted: /usr/irissys/mgr/Backup/FullAllDatabases_20250113_008.cbk
01/13/25-18:21:00:598 (35722) 0 [Utility.Event] [TASK PURGE OLD BACKUP FILES] Deleted: /usr/irissys/mgr/Backup/FullAllDatabases_20250113_009.log