#!/usr/bin/env python

import os, sys, logging

new_path = [ os.path.join( os.getcwd(), "lib" ) ]
new_path.extend( sys.path[1:] ) # remove scripts/ from the path
sys.path = new_path

log = logging.getLogger()
log.setLevel( 10 )
log.addHandler( logging.StreamHandler( sys.stdout ) )

from galaxy import eggs
import pkg_resources  
pkg_resources.require( "SQLAlchemy >= 0.4" )

import time, ConfigParser, shutil
from datetime import datetime, timedelta
from time import strftime
from optparse import OptionParser

import galaxy.config
import galaxy.model.mapping
import sqlalchemy as sa
from galaxy.model.orm import and_, eagerload
from galaxy.objectstore import build_object_store_from_config
from galaxy.exceptions import ObjectNotFound

assert sys.version_info[:2] >= ( 2, 4 )

def main():
    """
    Managing library datasets is a bit complex, so here is a scenario that hopefully provides clarification.  The complexities
    of handling library datasets is mostly contained in the delete_datasets() method in this script.
    
    Assume we have 1 library dataset with: LibraryDatasetDatasetAssociation -> LibraryDataset and Dataset
    At this point, we have the following database column values:

    LibraryDatasetDatasetAssociation deleted: False
    LibraryDataset deleted: False, purged: False
    Dataset deleted: False purged: False

    1. A user deletes the assumed dataset above from a data library via a UI menu option.
    This action results in the following database column values (changes from previous step marked with *):

    LibraryDatasetDatasetAssociation deleted: False
    LibraryDataset deleted: True*, purged: False
    Dataset deleted: False, purged: False
    
    2. After the number of days configured for the delete_datasets() method (option -6 below) have passed, execution
    of the delete_datasets() method results in the following database column values (changes from previous step marked with *):

    LibraryDatasetDatasetAssociation deleted: True*
    LibraryDataset deleted: True, purged: True*
    Dataset deleted: True*, purged: False
    
    3. After the number of days configured for the purge_datasets() method (option -3 below) have passed, execution
    of the purge_datasets() method results in the following database column values (changes from previous step marked with *):

    LibraryDatasetDatasetAssociation deleted: True
    LibraryDataset deleted: True, purged: True
    Dataset deleted: True, purged: True* (dataset file removed from disk if -r flag is used)

    This scenario is about as simple as it gets.  Keep in mind that a Dataset object can have many HistoryDatasetAssociations
    and many LibraryDatasetDatasetAssociations, and a LibraryDataset can have many LibraryDatasetDatasetAssociations.
    Another way of stating it is: LibraryDatasetDatasetAssociation objects map LibraryDataset objects to Dataset objects,
    and Dataset objects may be mapped to History objects via HistoryDatasetAssociation objects.  
    """
    parser = OptionParser()
    parser.add_option( "-d", "--days", dest="days", action="store", type="int", help="number of days (60)", default=60 )
    parser.add_option( "-r", "--remove_from_disk", action="store_true", dest="remove_from_disk", help="remove datasets from disk when purged", default=False )
    parser.add_option( "-i", "--info_only", action="store_true", dest="info_only", help="info about the requested action", default=False )
    parser.add_option( "-f", "--force_retry", action="store_true", dest="force_retry", help="performs the requested actions, but ignores whether it might have been done before. Useful when -r wasn't used, but should have been", default=False )
    parser.add_option( "-1", "--delete_userless_histories", action="store_true", dest="delete_userless_histories", default=False, help="delete userless histories and datasets" )
    parser.add_option( "-2", "--purge_histories", action="store_true", dest="purge_histories", default=False, help="purge deleted histories" )
    parser.add_option( "-3", "--purge_datasets", action="store_true", dest="purge_datasets", default=False, help="purge deleted datasets" )
    parser.add_option( "-4", "--purge_libraries", action="store_true", dest="purge_libraries", default=False, help="purge deleted libraries" )
    parser.add_option( "-5", "--purge_folders", action="store_true", dest="purge_folders", default=False, help="purge deleted library folders" )
    parser.add_option( "-6", "--delete_datasets", action="store_true", dest="delete_datasets", default=False, help="mark deletable datasets as deleted and purge associated dataset instances" )

    ( options, args ) = parser.parse_args()
    ini_file = args[0]
    
    if not ( options.purge_folders ^ options.delete_userless_histories ^ \
             options.purge_libraries ^ options.purge_histories ^ \
             options.purge_datasets ^ options.delete_datasets ):
        parser.print_help()
        sys.exit(0)
    
    if options.remove_from_disk and options.info_only:
        parser.error( "remove_from_disk and info_only are mutually exclusive" )
    
    config_parser = ConfigParser.ConfigParser( {'here':os.getcwd()} )
    config_parser.read( ini_file )
    config_dict = {}
    for key, value in config_parser.items( "app:main" ):
        config_dict[key] = value

    config = galaxy.config.Configuration( **config_dict )
    
    app = CleanupDatasetsApplication( config )
    cutoff_time = datetime.utcnow() - timedelta( days=options.days )
    now = strftime( "%Y-%m-%d %H:%M:%S" )
    
    print "##########################################"
    print "\n# %s - Handling stuff older than %i days" % ( now, options.days )
    
    if options.info_only:
        print "# Displaying info only ( --info_only )\n"
    elif options.remove_from_disk:
        print "Datasets will be removed from disk.\n"
    else:
        print "Datasets will NOT be removed from disk.\n"
    
    if options.delete_userless_histories:
        delete_userless_histories( app, cutoff_time, info_only = options.info_only, force_retry = options.force_retry )
    elif options.purge_histories:
        purge_histories( app, cutoff_time, options.remove_from_disk, info_only = options.info_only, force_retry = options.force_retry )
    elif options.purge_datasets:
        purge_datasets( app, cutoff_time, options.remove_from_disk, info_only = options.info_only, force_retry = options.force_retry )
    elif options.purge_libraries:
        purge_libraries( app, cutoff_time, options.remove_from_disk, info_only = options.info_only, force_retry = options.force_retry )
    elif options.purge_folders:
        purge_folders( app, cutoff_time, options.remove_from_disk, info_only = options.info_only, force_retry = options.force_retry )
    elif options.delete_datasets:
        delete_datasets( app, cutoff_time, options.remove_from_disk, info_only = options.info_only, force_retry = options.force_retry )
    
    app.shutdown()
    sys.exit(0)

def delete_userless_histories( app, cutoff_time, info_only = False, force_retry = False ):
    # Deletes userless histories whose update_time value is older than the cutoff_time.
    # The purge history script will handle marking DatasetInstances as deleted. 
    # Nothing is removed from disk yet.
    history_count = 0
    start = time.time()
    if force_retry:
        histories = app.sa_session.query( app.model.History ) \
                                  .filter( and_( app.model.History.table.c.user_id==None,
                                                 app.model.History.table.c.update_time < cutoff_time ) )
    else:
        histories = app.sa_session.query( app.model.History ) \
                                  .filter( and_( app.model.History.table.c.user_id==None,
                                                 app.model.History.table.c.deleted==False,
                                                 app.model.History.table.c.update_time < cutoff_time ) )
    for history in histories:
        if not info_only:
            print "Deleting history id ", history.id
            history.deleted = True
            app.sa_session.add( history )
            app.sa_session.flush()
        history_count += 1
    stop = time.time()
    print "Deleted %d histories" % history_count
    print "Elapsed time: ", stop - start
    print "##########################################" 

def purge_histories( app, cutoff_time, remove_from_disk, info_only = False, force_retry = False ):
    # Purges deleted histories whose update_time is older than the cutoff_time.
    # The dataset associations of each history are also marked as deleted.
    # The Purge Dataset method will purge each Dataset as necessary
    # history.purged == True simply means that it can no longer be undeleted
    # i.e. all associated datasets are marked as deleted
    history_count = 0
    start = time.time()
    if force_retry:
        histories = app.sa_session.query( app.model.History ) \
                                  .filter( and_( app.model.History.table.c.deleted==True,
                                                 app.model.History.table.c.update_time < cutoff_time ) ) \
                                  .options( eagerload( 'datasets' ) )
    else:
        histories = app.sa_session.query( app.model.History ) \
                                  .filter( and_( app.model.History.table.c.deleted==True,
                                                 app.model.History.table.c.purged==False,
                                                 app.model.History.table.c.update_time < cutoff_time ) ) \
                                  .options( eagerload( 'datasets' ) )
    for history in histories:
        print ("### Processing history id %d (%s)" % (history.id, history.name)).encode('utf-8')
        for dataset_assoc in history.datasets:
            _purge_dataset_instance( dataset_assoc, app, remove_from_disk, info_only = info_only ) #mark a DatasetInstance as deleted, clear associated files, and mark the Dataset as deleted if it is deletable
        if not info_only:
            # TODO: should the Delete DefaultHistoryPermissions be deleted here?  This was incorrectly
            # done in the _list_delete() method of the history controller, so copied it here.  Not sure 
            # if we should ever delete info like this from the db though, so commented out for now...
            #for dhp in history.default_permissions:
            #    dhp.delete()
            print "Purging history id ", history.id
            history.purged = True
            app.sa_session.add( history )
            app.sa_session.flush()
        else:
            print "History id %d will be purged (without 'info_only' mode)" % history.id
        history_count += 1
    stop = time.time()
    print 'Purged %d histories.' % history_count
    print "Elapsed time: ", stop - start
    print "##########################################" 

def purge_libraries( app, cutoff_time, remove_from_disk, info_only = False, force_retry = False ):
    # Purges deleted libraries whose update_time is older than the cutoff_time.
    # The dataset associations of each library are also marked as deleted.
    # The Purge Dataset method will purge each Dataset as necessary
    # library.purged == True simply means that it can no longer be undeleted
    # i.e. all associated LibraryDatasets/folders are marked as deleted
    library_count = 0
    start = time.time()
    if force_retry:
        libraries = app.sa_session.query( app.model.Library ) \
                                  .filter( and_( app.model.Library.table.c.deleted==True,
                                                 app.model.Library.table.c.update_time < cutoff_time ) )
    else:
        libraries = app.sa_session.query( app.model.Library ) \
                                  .filter( and_( app.model.Library.table.c.deleted==True,
                                                 app.model.Library.table.c.purged==False,
                                                 app.model.Library.table.c.update_time < cutoff_time ) )
    for library in libraries:
        _purge_folder( library.root_folder, app, remove_from_disk, info_only = info_only )
        if not info_only:
            print "Purging library id ", library.id
            library.purged = True
            app.sa_session.add( library )
            app.sa_session.flush()
        library_count += 1
    stop = time.time()
    print '# Purged %d libraries .' % library_count
    print "Elapsed time: ", stop - start
    print "##########################################" 

def purge_folders( app, cutoff_time, remove_from_disk, info_only = False, force_retry = False ):
    # Purges deleted folders whose update_time is older than the cutoff_time.
    # The dataset associations of each folder are also marked as deleted.
    # The Purge Dataset method will purge each Dataset as necessary
    # libraryFolder.purged == True simply means that it can no longer be undeleted
    # i.e. all associated LibraryDatasets/folders are marked as deleted
    folder_count = 0
    start = time.time()
    if force_retry:
        folders = app.sa_session.query( app.model.LibraryFolder ) \
                                .filter( and_( app.model.LibraryFolder.table.c.deleted==True,
                                               app.model.LibraryFolder.table.c.update_time < cutoff_time ) )
    else:
        folders = app.sa_session.query( app.model.LibraryFolder ) \
                                .filter( and_( app.model.LibraryFolder.table.c.deleted==True,
                                               app.model.LibraryFolder.table.c.purged==False,
                                               app.model.LibraryFolder.table.c.update_time < cutoff_time ) )
    for folder in folders:
        _purge_folder( folder, app, remove_from_disk, info_only = info_only )
        folder_count += 1
    stop = time.time()
    print '# Purged %d folders.' % folder_count
    print "Elapsed time: ", stop - start
    print "##########################################" 

def delete_datasets( app, cutoff_time, remove_from_disk, info_only = False, force_retry = False ):
    # Marks datasets as deleted if associated items are all deleted.
    start = time.time()
    if force_retry:
        history_dataset_ids_query = sa.select( ( app.model.Dataset.table.c.id,
                                                 app.model.Dataset.table.c.state ),
                                               whereclause = app.model.HistoryDatasetAssociation.table.c.update_time < cutoff_time,
                                               from_obj = [ sa.outerjoin( app.model.Dataset.table,
                                                                          app.model.HistoryDatasetAssociation.table ) ] )
        library_dataset_ids_query = sa.select( ( app.model.LibraryDataset.table.c.id,
                                                 app.model.LibraryDataset.table.c.deleted ),
                                                whereclause = app.model.LibraryDataset.table.c.update_time < cutoff_time,
                                                from_obj = [ app.model.LibraryDataset.table ] )
    else:                                  
        # We really only need the id column here, but sqlalchemy barfs when trying to select only 1 column
        history_dataset_ids_query = sa.select( ( app.model.Dataset.table.c.id,
                                                 app.model.Dataset.table.c.state ),
                                               whereclause = and_( app.model.Dataset.table.c.deleted == False,
                                                                   app.model.HistoryDatasetAssociation.table.c.update_time < cutoff_time,
                                                                   app.model.HistoryDatasetAssociation.table.c.deleted == True ),
                                               from_obj = [ sa.outerjoin( app.model.Dataset.table,
                                                                          app.model.HistoryDatasetAssociation.table ) ] )
        library_dataset_ids_query = sa.select( ( app.model.LibraryDataset.table.c.id,
                                                 app.model.LibraryDataset.table.c.deleted ),
                                                whereclause = and_( app.model.LibraryDataset.table.c.deleted == True,
                                                                    app.model.LibraryDataset.table.c.purged == False,
                                                                    app.model.LibraryDataset.table.c.update_time < cutoff_time ),
                                                from_obj = [ app.model.LibraryDataset.table ] )
    deleted_dataset_count = 0
    deleted_instance_count = 0
    skip = []
    # Handle library datasets.  This is a bit tricky, so here's some clarification.  We have a list of all
    # LibraryDatasets that were marked deleted before our cutoff_time, but have not yet been marked purged.
    # A LibraryDataset object is marked purged when all of its LibraryDatasetDatasetAssociations have been
    # marked deleted.  When a LibraryDataset has been marked purged, it can never be undeleted in the data
    # library.  We have several steps to complete here.  For each LibraryDataset, get its associated Dataset
    # and add it to our accrued list of Datasets for later processing.  We mark  as deleted all of its
    # LibraryDatasetDatasetAssociations.  Then we mark the LibraryDataset as purged.  We then process our
    # list of Datasets.
    library_dataset_ids = [ row.id for row in library_dataset_ids_query.execute() ]
    dataset_ids = []
    for library_dataset_id in library_dataset_ids:
        print "######### Processing LibraryDataset id:", library_dataset_id
        # Get the LibraryDataset and the current LibraryDatasetDatasetAssociation objects
        ld = app.sa_session.query( app.model.LibraryDataset ).get( library_dataset_id )
        ldda =  ld.library_dataset_dataset_association
        # Append the associated Dataset object's id to our list of dataset_ids
        dataset_ids.append( ldda.dataset_id )
        # Mark all of the LibraryDataset's associated LibraryDatasetDatasetAssociation objects' as deleted
        if not ldda.deleted:
            ldda.deleted = True
            app.sa_session.add( ldda )
            print "Marked associated LibraryDatasetDatasetAssociation id %d as deleted" % ldda.id
        for expired_ldda in ld.expired_datasets:
            if not expired_ldda.deleted:
                expired_ldda.deleted = True
                app.sa_session.add( expired_ldda )
                print "Marked associated expired LibraryDatasetDatasetAssociation id %d as deleted" % ldda.id
        # Mark the LibraryDataset as purged
        ld.purged = True
        app.sa_session.add( ld )
        print "Marked LibraryDataset id %d as purged" % ld.id
        app.sa_session.flush()
    # Add all datasets associated with Histories to our list
    dataset_ids.extend( [ row.id for row in history_dataset_ids_query.execute() ] )
    # Process each of the Dataset objects
    for dataset_id in dataset_ids:
        dataset = app.sa_session.query( app.model.Dataset ).get( dataset_id )
        if dataset.id in skip:
            continue
        skip.append( dataset.id )
        print "######### Processing dataset id:", dataset_id
        if not _dataset_is_deletable( dataset ):
            print "Dataset is not deletable (shared between multiple histories/libraries, at least one is not deleted)"
            continue
        deleted_dataset_count += 1
        for dataset_instance in dataset.history_associations + dataset.library_associations:
            # Mark each associated HDA as deleted
            _purge_dataset_instance( dataset_instance, app, remove_from_disk, include_children=True, info_only=info_only, is_deletable=True )
            deleted_instance_count += 1
    stop = time.time()
    print "Examined %d datasets, marked %d datasets and %d dataset instances (HDA) as deleted" % ( len( skip ), deleted_dataset_count, deleted_instance_count )
    print "Total elapsed time: ", stop - start
    print "##########################################" 

def purge_datasets( app, cutoff_time, remove_from_disk, info_only = False, force_retry = False ):
    # Purges deleted datasets whose update_time is older than cutoff_time.  Files may or may
    # not be removed from disk.
    dataset_count = 0
    disk_space = 0
    start = time.time()
    if force_retry:
        datasets = app.sa_session.query( app.model.Dataset ) \
                                 .filter( and_( app.model.Dataset.table.c.deleted==True,
                                                app.model.Dataset.table.c.purgable==True,
                                                app.model.Dataset.table.c.update_time < cutoff_time ) )
    else:
        datasets = app.sa_session.query( app.model.Dataset ) \
                                 .filter( and_( app.model.Dataset.table.c.deleted==True,
                                                app.model.Dataset.table.c.purgable==True,
                                                app.model.Dataset.table.c.purged==False,
                                                app.model.Dataset.table.c.update_time < cutoff_time ) )
    for dataset in datasets:
        file_size = dataset.file_size
        _purge_dataset( app, dataset, remove_from_disk, info_only = info_only )
        dataset_count += 1
        try:
            disk_space += file_size
        except:
            pass
    stop = time.time()
    print 'Purged %d datasets' % dataset_count
    if remove_from_disk:
        print 'Freed disk space: ', disk_space
    print "Elapsed time: ", stop - start
    print "##########################################" 

def _purge_dataset_instance( dataset_instance, app, remove_from_disk, include_children=True, info_only=False, is_deletable=False ):
    # A dataset_instance is either a HDA or an LDDA.  Purging a dataset instance marks the instance as deleted, 
    # and marks the associated dataset as deleted if it is not associated with another active DatsetInstance.
    if not info_only:
        print "Marking as deleted: %s id %d (for dataset id %d)" % \
            ( dataset_instance.__class__.__name__, dataset_instance.id, dataset_instance.dataset.id )
        dataset_instance.mark_deleted( include_children = include_children )
        dataset_instance.clear_associated_files()
        app.sa_session.add( dataset_instance )
        app.sa_session.flush()
        app.sa_session.refresh( dataset_instance.dataset )
    else:
        print "%s id %d (for dataset id %d) will be marked as deleted (without 'info_only' mode)" % \
            ( dataset_instance.__class__.__name__, dataset_instance.id, dataset_instance.dataset.id )
    if is_deletable or _dataset_is_deletable( dataset_instance.dataset ):
        # Calling methods may have already checked _dataset_is_deletable, if so, is_deletable should be True
        _delete_dataset( dataset_instance.dataset, app, remove_from_disk, info_only=info_only, is_deletable=is_deletable )
    else:
        if info_only:
            print "Not deleting dataset ", dataset_instance.dataset.id, " (will be possibly deleted without 'info_only' mode)"
        else:
            print "Not deleting dataset %d (shared between multiple histories/libraries, at least one not deleted)" % dataset_instance.dataset.id
    #need to purge children here
    if include_children:
        for child in dataset_instance.children:
            _purge_dataset_instance( child, app, remove_from_disk, include_children = include_children, info_only = info_only )

def _dataset_is_deletable( dataset ):
    #a dataset is deletable when it no longer has any non-deleted associations
    return not bool( dataset.active_history_associations or dataset.active_library_associations )

def _delete_dataset( dataset, app, remove_from_disk, info_only=False, is_deletable=False ):
    # Marks a base dataset as deleted, hdas/lddas associated with dataset can no longer be undeleted.
    # Metadata files attached to associated dataset Instances is removed now.
    if not is_deletable and not _dataset_is_deletable( dataset ):
        print "This Dataset (%i) is not deletable, associated Metadata Files will not be removed.\n" % ( dataset.id )
    else:
        # Mark all associated MetadataFiles as deleted and purged and remove them from disk
        metadata_files = []
        #lets create a list of metadata files, then perform actions on them
        for hda in dataset.history_associations:
            for metadata_file in app.sa_session.query( app.model.MetadataFile ) \
                                               .filter( app.model.MetadataFile.table.c.hda_id==hda.id ):
                metadata_files.append( metadata_file )
        for ldda in dataset.library_associations:
            for metadata_file in app.sa_session.query( app.model.MetadataFile ) \
                                               .filter( app.model.MetadataFile.table.c.lda_id==ldda.id ):
                metadata_files.append( metadata_file )
        for metadata_file in metadata_files:
            op_description = "marked as deleted"
            if remove_from_disk:
                op_description = op_description + " and purged from disk"
            if info_only:
                print "The following metadata files attached to associations of Dataset '%s' will be %s (without 'info_only' mode):" % ( dataset.id, op_description )
            else:
                print "The following metadata files attached to associations of Dataset '%s' have been %s:" % ( dataset.id, op_description )
                if remove_from_disk:
                    try:
                        print "Removing disk file ", metadata_file.file_name
                        os.unlink( metadata_file.file_name )
                    except Exception, e:
                        print "Error, exception: %s caught attempting to purge metadata file %s\n" %( str( e ), metadata_file.file_name )
                    metadata_file.purged = True
                    app.sa_session.add( metadata_file )
                    app.sa_session.flush()
                metadata_file.deleted = True
                app.sa_session.add( metadata_file )
                app.sa_session.flush()
            print "%s" % metadata_file.file_name
        if not info_only:
            print "Deleting dataset id", dataset.id
            dataset.deleted = True
            app.sa_session.add( dataset )
            app.sa_session.flush()
        else:
            print "Dataset %i will be deleted (without 'info_only' mode)" % ( dataset.id )

def _purge_dataset( app, dataset, remove_from_disk, info_only = False ):
    if dataset.deleted:
        try:
            if dataset.purgable and _dataset_is_deletable( dataset ):
                if not info_only:
                    # Remove files from disk and update the database
                    if remove_from_disk:
                        # TODO: should permissions on the dataset be deleted here?
                        print "Removing disk, file ", dataset.file_name
                        os.unlink( dataset.file_name )
                        # Remove associated extra files from disk if they exist
                        if dataset.extra_files_path and os.path.exists( dataset.extra_files_path ):
                            shutil.rmtree( dataset.extra_files_path ) #we need to delete the directory and its contents; os.unlink would always fail on a directory
                        usage_users = []
                        for hda in dataset.history_associations:
                            if not hda.purged and hda.history.user is not None and hda.history.user not in usage_users:
                                usage_users.append( hda.history.user )
                        for user in usage_users:
                            user.total_disk_usage -= dataset.total_size
                            app.sa_session.add( user )
                    print "Purging dataset id", dataset.id
                    dataset.purged = True
                    app.sa_session.add( dataset )
                    app.sa_session.flush()
                else:
                    print "Dataset %i will be purged (without 'info_only' mode)" % (dataset.id)
            else:
                print "This dataset (%i) is not purgable, the file (%s) will not be removed.\n" % ( dataset.id, dataset.file_name )
        except OSError, exc:
            print "Error, dataset file has already been removed: %s" % str( exc )
            print "Purging dataset id", dataset.id
            dataset.purged = True
            app.sa_session.add( dataset )
            app.sa_session.flush()
        except ObjectNotFound:
            print "Dataset %i cannot be found in the object store" % dataset.id
        except Exception, exc:
            print "Error attempting to purge data file: ", dataset.file_name, " error: ", str( exc )
    else:
        print "Error: '%s' has not previously been deleted, so it cannot be purged\n" % dataset.file_name

def _purge_folder( folder, app, remove_from_disk, info_only = False ):
    """Purges a folder and its contents, recursively"""
    for ld in folder.datasets:
        print "Deleting library dataset id ", ld.id
        ld.deleted = True
        for ldda in [ld.library_dataset_dataset_association] + ld.expired_datasets:
            _purge_dataset_instance( ldda, app, remove_from_disk, info_only = info_only ) #mark a DatasetInstance as deleted, clear associated files, and mark the Dataset as deleted if it is deletable
    for sub_folder in folder.folders:
        _purge_folder( sub_folder, app, remove_from_disk, info_only = info_only )
    if not info_only:
        # TODO: should the folder permissions be deleted here?
        print "Purging folder id ", folder.id
        folder.purged = True
        app.sa_session.add( folder )
        app.sa_session.flush()

class CleanupDatasetsApplication( object ):
    """Encapsulates the state of a Universe application"""
    def __init__( self, config ):
        if config.database_connection is False:
            config.database_connection = "sqlite:///%s?isolation_level=IMMEDIATE" % config.database
        self.object_store = build_object_store_from_config( config )
        # Setup the database engine and ORM
        self.model = galaxy.model.mapping.init( config.file_path, config.database_connection, engine_options={}, create_tables=False, object_store=self.object_store )
    @property
    def sa_session( self ):
        """
        Returns a SQLAlchemy session -- currently just gets the current
        session from the threadlocal session context, but this is provided
        to allow migration toward a more SQLAlchemy 0.4 style of use.
        """
        return self.model.context.current
    def shutdown( self ):
        self.object_store.shutdown()

if __name__ == "__main__": main()