Source code for waeup.kofa.utils.batching

## $Id: batching.py 16012 2020-02-24 21:26:35Z henrik $
##
## Copyright (C) 2011 Uli Fouquet & Henrik Bettermann
## This program is free software; you can redistribute it and/or modify
## it under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 2 of the License, or
## (at your option) any later version.
##
## This program is distributed in the hope that it will be useful,
## but WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with this program; if not, write to the Free Software
## Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
##
"""Kofa components for batch processing.

Batch processors eat CSV files to add, update or remove large numbers
of certain kinds of objects at once.
"""
import grok
import datetime
import os
import shutil
import tempfile
import time
import unicodecsv
import zc.async.interfaces
from cStringIO import StringIO
from persistent.list import PersistentList
from zope.component import createObject, getUtility
from zope.component.hooks import setSite
from zope.interface import Interface, implementer
from zope.schema import getFields
from zope.schema.interfaces import ConstraintNotSatisfied, RequiredMissing
from zope.event import notify
from waeup.kofa.async import AsyncJob
from waeup.kofa.interfaces import (
    IBatchProcessor, FatalCSVError, IObjectConverter, IJobManager,
    ICSVExporter, IGNORE_MARKER, DuplicationError, JOB_STATUS_MAP,
    IExportJobContainer, IExportJob, IExportContainerFinder)

[docs]class BatchProcessor(grok.GlobalUtility): """A processor to add, update, or remove data. This is a non-active baseclass. """ grok.implements(IBatchProcessor) grok.context(Interface) grok.baseclass() # Name used in pages and forms... name = u'Non-registered base processor' # Internal name... util_name = '' # Items for this processor need an interface with zope.schema fields. iface = Interface # The name must be the same as the util_name attribute in order to # register this utility correctly. grok.name(util_name) # Headers needed to locate items... location_fields = [] # A factory with this name must be registered... factory_name = '' @property def required_fields(self): """Required fields that have no default. A list of names of field, whose value cannot be set if not given during creation. Therefore these fields must exist in input. Fields with a default != missing_value do not belong to this category. """ result = [] for key, field in getFields(self.iface).items(): if key in self.location_fields: continue if field.default is not field.missing_value: continue if field.required: result.append(key) return result @property def req(self): result = dict( create = self.location_fields + self.required_fields, update = self.location_fields, remove = self.location_fields, ) return result @property def available_fields(self): return sorted(list(set( self.location_fields + getFields(self.iface).keys())))
[docs] def getHeaders(self, mode='create'): return self.available_fields
[docs] def checkHeaders(self, headerfields, mode='create'): req = self.req[mode] # Check for required fields... for field in req: if not field in headerfields: raise FatalCSVError( "Need at least columns %s for import!" % ', '.join(["'%s'" % x for x in req])) # Check for double fields. Cannot happen because this error is # already catched in views not_ignored_fields = [x for x in headerfields if not x.startswith('--')] if len(set(not_ignored_fields)) < len(not_ignored_fields): raise FatalCSVError( "Double headers: each column name may only appear once.") return True
[docs] def applyMapping(self, row, mapping): """Apply mapping to a row of CSV data. """ result = dict() for key, replacement in mapping.items(): if replacement == u'--IGNORE--': # Skip ignored columns in failed and finished data files. continue result[replacement] = row[key] return result
[docs] def getMapping(self, path, headerfields, mode): """Get a mapping from CSV file headerfields to actually used fieldnames. """ result = dict() reader = unicodecsv.reader(open(path, 'rb')) raw_header = reader.next() for num, field in enumerate(headerfields): if field not in self.location_fields and mode == 'remove': # Skip non-location fields when removing. continue if field == u'--IGNORE--': # Skip ignored columns in failed and finished data files. continue result[raw_header[num]] = field return result
[docs] def stringFromErrs(self, errors, inv_errors): result = [] for err in errors: fieldname, message = err result.append("%s: %s" % (fieldname, message)) for err in inv_errors: result.append("invariant: %s" % err) return '; '.join(result)
[docs] def callFactory(self, *args, **kw): return createObject(self.factory_name)
[docs] def parentsExist(self, row, site): """Tell whether the parent object for data in ``row`` exists. """ raise NotImplementedError('method not implemented')
[docs] def entryExists(self, row, site): """Tell whether there already exists an entry for ``row`` data. """ raise NotImplementedError('method not implemented')
[docs] def getParent(self, row, site): """Get the parent object for the entry in ``row``. """ raise NotImplementedError('method not implemented')
[docs] def getEntry(self, row, site): """Get the object for the entry in ``row``. """ raise NotImplementedError('method not implemented')
[docs] def addEntry(self, obj, row, site): """Add the entry given given by ``row`` data. """ raise NotImplementedError('method not implemented')
[docs] def delEntry(self, row, site): """Delete entry given by ``row`` data. """ raise NotImplementedError('method not implemented')
[docs] def checkCreateRequirements(self, parent, row, site): """Checks requirements the parent object must fulfill when a new subobject is being created. This method is not used in case of updating or removing objects. Returns error messages as strings in case of requirement problems. """ return None
[docs] def checkUpdateRequirements(self, obj, row, site): """Checks requirements the object must fulfill when being updated. This method is not used in case of deleting or adding objects. Returns error messages as strings in case of requirement problems. """ return None
[docs] def checkRemoveRequirements(self, obj, row, site): """Checks requirements the object must fulfill when being removed. This method is not used in case of updating or adding objects. Returns error messages as strings in case of requirement problems. """ return None
[docs] def updateEntry(self, obj, row, site, filename): """Update obj to the values given in row. Returns a string describing the fields changed. """ changed = [] for key, value in row.items(): # Skip fields to be ignored. if value == IGNORE_MARKER: continue # Skip fields not declared in interface and which are # not yet attributes of existing objects. We can thus not # add non-existing attributes here. if not hasattr(obj, key): continue # DefaultObjectConverter.fromStringDict fails for # list-of-choices fields because we are using a different # widget for this combination. Thus the ListFieldConverter # returns a useless dictionary which causes getWidgetsData to # skip the field. The value in row remains unchanged. # We have to evaluate the string and replace the value here. try: evalvalue = eval(value) if isinstance(evalvalue, list): value = evalvalue except: pass try: setattr(obj, key, value) except AttributeError: # Computed attributes can't be set. continue log_value = getattr(value, 'code', value) changed.append('%s=%s' % (key, log_value)) # If any catalog is involved it must be updated. # # XXX: The event is also triggered when creating objects as # updateEntry is called also when creating entries resulting # in objectAdded and additional objectModified events. if len(changed): notify(grok.ObjectModifiedEvent(obj)) return ', '.join(changed)
[docs] def createLogfile(self, path, fail_path, num, warnings, mode, user, timedelta, logger=None): """Write to log file. """ if logger is None: return logger.info( "processed: %s, %s mode, %s lines (%s successful/ %s failed), " "%0.3f s (%0.4f s/item)" % ( path, mode, num, num - warnings, warnings, timedelta, timedelta/(num or 1))) return
[docs] def writeFailedRow(self, writer, row, warnings): """Write a row with error messages to error CSV. If warnings is a list of strings, they will be concatenated. """ error_col = warnings if isinstance(warnings, list): error_col = ' / '.join(warnings) row['--ERRORS--'] = error_col writer.writerow(row) return
[docs] def checkConversion(self, row, mode='ignore', ignore_empty=True): """Validates all values in row. """ converter = IObjectConverter(self.iface) errs, inv_errs, conv_dict = converter.fromStringDict( row, self.factory_name, mode=mode) return errs, inv_errs, conv_dict
[docs] def emptyRow(self, row): """Detect empty rows. """ for value in row.values(): if not value in (None, IGNORE_MARKER) and value.strip(): return False return True
[docs] def doImport(self, path, headerfields, mode='create', user='Unknown', logger=None, ignore_empty=True): """In contrast to most other methods, `doImport` is not supposed to be customized, neither in custom packages nor in derived batch processor classes. Therefore, this is the only place where we do import data. Before this method starts creating or updating persistent data, it prepares two more files in a temporary folder of the filesystem: (1) a file for pending data with file extension ``.pending`` and (2) a file for successfully processed data with file extension ``.finished``. Then the method starts iterating over all rows of the CSV file. Each row is treated as follows: 1. An empty row is skipped. 2. Empty strings or lists (``[]``) in the row are replaced by ignore markers. 3. The `BatchProcessor.checkConversion` method validates and converts all values in the row. Conversion means the transformation of strings into Python objects. For instance, number expressions have to be transformed into integers, dates into datetime objects, phone number expressions into phone number objects, etc. The converter returns a dictionary with converted values or, if the validation of one of the elements fails, an appropriate warning message. If the conversion fails a pending record is created and stored in the pending data file together with a warning message the converter has raised. 4. In **create mode** only: The parent object must be found and a child object with same object id must not exist. Otherwise the row is skipped, a corresponding warning message is raised and a record is stored in the pending data file. The `BatchProcessor.checkCreateRequirements` method checks additional requirements the parent object must fulfill before a new sububject is being added. These requirements are not imposed by the data type but the context of the object. For example, the course results of graduated students must not changed by import, neither by creating nor updating or removing course tickets. Now `doImport` tries to add the new object with the data from the conversion dictionary. In some cases this may fail and a `DuplicationError` is raised. For example, a new payment ticket is created but the same payment for same session has already been made. In this case the object id is unique, no other object with same id exists, but making the 'same' payment twice does not make sense. The import is skipped and a record is stored in the pending data file. 5. In **update mode** only: If the object can't be found, the row is skipped, a ``no such entry`` warning message is raised and a record is stored in the pending data file. The `BatchProcessor.checkUpdateRequirements` method checks additional requirements the object must fulfill before being updated. These requirements are not imposed by the data type but the context of the object. For example, post-graduate students have a different registration workflow. With this method we do forbid certain workflow transitions or states. Finally, `doImport` updates the existing object with the data from the conversion dictionary. 6. In **remove mode** only: If the object can't be found, the row is skipped, a ``no such entry`` warning message is raised and a record is stored in the pending data file. The `BatchProcessor.checkRemoveRequirements` method checks additional requirements the object must fulfill before being removed. These requirements are not imposed by the data type but the context of the object. For example, the course results of graduated students must not changed by import, neither by creating nor updating or removing course tickets. Finally, `doImport` removes the existing object. """ time_start = time.time() self.checkHeaders(headerfields, mode) mapping = self.getMapping(path, headerfields, mode) reader = unicodecsv.DictReader(open(path, 'rb')) temp_dir = tempfile.mkdtemp() base = os.path.basename(path) (base, ext) = os.path.splitext(base) failed_path = os.path.join(temp_dir, "%s.pending%s" % (base, ext)) failed_headers = mapping.values() failed_headers.append('--ERRORS--') failed_writer = unicodecsv.DictWriter(open(failed_path, 'wb'), failed_headers) os.chmod(failed_path, 0664) failed_writer.writerow(dict([(x,x) for x in failed_headers])) finished_path = os.path.join(temp_dir, "%s.finished%s" % (base, ext)) finished_headers = mapping.values() finished_writer = unicodecsv.DictWriter(open(finished_path, 'wb'), finished_headers) os.chmod(finished_path, 0664) finished_writer.writerow(dict([(x,x) for x in finished_headers])) num =0 num_warns = 0 site = grok.getSite() for raw_row in reader: num += 1 # Skip row if empty if self.emptyRow(raw_row): continue string_row = self.applyMapping(raw_row, mapping) if ignore_empty: # Replace empty strings and empty lists with ignore-markers for key, val in string_row.items(): if val == '' or val == '[]': string_row[key] = IGNORE_MARKER row = dict(string_row.items()) # create deep copy errs, inv_errs, conv_dict = self.checkConversion(string_row, mode) if errs or inv_errs: num_warns += 1 conv_warnings = self.stringFromErrs(errs, inv_errs) self.writeFailedRow( failed_writer, string_row, conv_warnings) continue row.update(conv_dict) if mode == 'create': if not self.parentsExist(row, site): num_warns += 1 self.writeFailedRow( failed_writer, string_row, "Not all parents do exist yet.") continue if self.entryExists(row, site): num_warns += 1 self.writeFailedRow( failed_writer, string_row, "This object already exists.") continue parent = self.getParent(row, site) create_errors = self.checkCreateRequirements(parent, row, site) if create_errors is not None: num_warns += 1 self.writeFailedRow( failed_writer, string_row, create_errors) continue obj = self.callFactory() # Override all values in row, also # student_ids and applicant_ids which have been # generated in the respective __init__ methods before. self.updateEntry(obj, row, site, base) try: self.addEntry(obj, row, site) except KeyError, error: num_warns += 1 self.writeFailedRow( failed_writer, string_row, error.message) continue except DuplicationError, error: num_warns += 1 self.writeFailedRow( failed_writer, string_row, error.msg) continue except FatalCSVError, error: num_warns += 1 self.writeFailedRow( failed_writer, string_row, error.message) continue elif mode == 'remove': if not self.entryExists(row, site): num_warns += 1 self.writeFailedRow( failed_writer, string_row, "Cannot remove: no such entry") continue obj = self.getEntry(row, site) remove_errors = self.checkRemoveRequirements(obj, row, site) if remove_errors is not None: num_warns += 1 self.writeFailedRow( failed_writer, string_row, remove_errors) continue self.delEntry(row, site) elif mode == 'update': obj = self.getEntry(row, site) if obj is None: num_warns += 1 self.writeFailedRow( failed_writer, string_row, "Cannot update: no such entry") continue update_errors = self.checkUpdateRequirements(obj, row, site) if update_errors is not None: num_warns += 1 self.writeFailedRow( failed_writer, string_row, update_errors) continue try: self.updateEntry(obj, row, site, base) except ConstraintNotSatisfied, err: num_warns += 1 self.writeFailedRow( failed_writer, string_row, "ConstraintNotSatisfied: %s" % err) continue except RequiredMissing, err: num_warns += 1 self.writeFailedRow( failed_writer, string_row, "RequiredMissing: %s" % err) continue finished_writer.writerow(string_row) time_end = time.time() timedelta = time_end - time_start self.createLogfile(path, failed_path, num, num_warns, mode, user, timedelta, logger=logger) failed_path = os.path.abspath(failed_path) if num_warns == 0: del failed_writer os.unlink(failed_path) failed_path = None return (num, num_warns, os.path.abspath(finished_path), failed_path)
[docs] def get_csv_skeleton(self): """Export CSV file only with a header of available fields. A raw string with CSV data should be returned. """ outfile = StringIO() writer = unicodecsv.DictWriter(outfile, self.available_fields) writer.writerow( dict(zip(self.available_fields, self.available_fields))) # header outfile.seek(0) return outfile.read()
[docs]class ExporterBase(object): """A base for exporters. """ grok.implements(ICSVExporter) #: Fieldnames considered by this exporter fields = ('code', 'title', 'title_prefix') #: The title under which this exporter will be displayed #: (if registered as a utility) title = 'Override this title'
[docs] def mangle_value(self, value, name, context=None): """Hook for mangling values in derived classes. """ if isinstance(value, bool): value = value and '1' or '0' elif isinstance(value, unicode): # CSV writers like byte streams better than unicode value = value.encode('utf-8') elif isinstance(value, datetime.datetime): #value = str(value) value = str('%s#' % value) # changed 2014-07-06, see ticket #941 elif isinstance(value, datetime.date): # Order is important here: check for date after datetime as # datetimes are also dates. # # Append hash '#' to dates to circumvent unwanted excel automatic value = str('%s#' % value) elif value is None: # None is not really representable in CSV files value = '' return value
[docs] def get_csv_writer(self, filepath=None): """Get a CSV dict writer instance open for writing. Returns a tuple (<writer>, <outfile>) where ``<writer>`` is a :class:`csv.DictWriter` instance and outfile is the real file which is written to. The latter is important when writing to StringIO and can normally be ignored otherwise. The returned file will already be filled with the header row. Please note that if you give a filepath, the returned outfile is open for writing only and you might have to close it before reopening it for reading. """ if filepath is None: outfile = StringIO() else: outfile = open(filepath, 'wb') writer = unicodecsv.DictWriter(outfile, self.fields) writer.writerow(dict(zip(self.fields, self.fields))) # header return writer, outfile
[docs] def write_item(self, obj, writer): """Write a row extracted from `obj` into CSV file using `writer`. """ row = {} for name in self.fields: value = getattr(obj, name, None) value = self.mangle_value(value, name, obj) row[name] = value writer.writerow(row) return
[docs] def close_outfile(self, filepath, outfile): """Close outfile. If filepath is None, the contents of outfile is returned. """ outfile.seek(0) if filepath is None: return outfile.read() outfile.close() return
[docs] def get_filtered(self, site, **kw): """Get datasets to export filtered by keyword arguments. Returns an iterable. """ raise NotImplementedError
[docs] def get_selected(self, site, selected): """Get datasets to export for selected items specified by a list of identifiers. Returns an iterable. """ raise NotImplementedError
[docs] def export(self, iterable, filepath=None): """Export `iterable` as CSV file. If `filepath` is ``None``, a raw string with CSV data should be returned. """ raise NotImplementedError
[docs] def export_all(self, site, filepath=None): """Export all appropriate objects in `site` into `filepath` as CSV data. If `filepath` is ``None``, a raw string with CSV data should be returned. """ raise NotImplementedError
[docs] def export_filtered(self, site, filepath=None, **kw): """Export items denoted by `kw`. If `filepath` is ``None``, a raw string with CSV data should be returned. """ data = self.get_filtered(site, **kw) return self.export(data, filepath=filepath)
[docs] def export_selected(self, site, filepath=None, **kw): """Export those items specified by a list of identifiers called `selected`. If `filepath` is ``None``, a raw string with CSV data should be returned. """ selected = kw.get('selected', []) data = self.get_selected(site, selected) return self.export(data, filepath=filepath)
[docs]def export_job(site, exporter_name, **kw): """Export all entries delivered by exporter and store it in a temp file. `site` gives the site to search. It will be passed to the exporter and also be set as 'current site' as the function is used in asynchronous jobs which run in their own threads and have no site set initially. Therefore `site` must also be a valid value for use with `zope.component.hooks.setSite()`. `exporter_name` is the utility name under which the desired exporter was registered with the ZCA. The resulting CSV file will be stored in a new temporary directory (using :func:`tempfile.mkdtemp`). It will be named after the exporter used with `.csv` filename extension. Returns the path to the created CSV file. .. note:: It is the callers responsibility to clean up the used file and its parent directory. """ setSite(site) exporter = getUtility(ICSVExporter, name=exporter_name) output_dir = tempfile.mkdtemp() filename = '%s.csv' % exporter_name output_path = os.path.join(output_dir, filename) if kw == {}: exporter.export_all(site, filepath=output_path) elif kw.has_key('selected'): exporter.export_selected(site, filepath=output_path, **kw) else: exporter.export_filtered(site, filepath=output_path, **kw) return output_path
[docs]class AsyncExportJob(AsyncJob): """An IJob that exports data to CSV files. `AsyncExportJob` instances are regular `AsyncJob` instances with a different constructor API. Instead of a callable to execute, you must pass a `site` and some `exporter_name` to trigger an export. The real work is done when an instance of this class is put into a queue. See :mod:`waeup.kofa.async` to learn more about asynchronous jobs. The `exporter_name` must be the name under which an ICSVExporter utility was registered with the ZCA. The `site` must be a valid site or ``None``. The result of an `AsyncExportJob` is the path to generated CSV file. The file will reside in a temporary directory that should be removed after being used. """ grok.implements(IExportJob)
[docs] def __init__(self, site, exporter_name, *args, **kwargs): super(AsyncExportJob, self).__init__( export_job, site, exporter_name, *args, **kwargs)
@property def finished(self): """A job is marked `finished` if it is completed. Please note: a finished report job does not neccessarily provide an IReport result. See meth:`failed`. """ return self.status == zc.async.interfaces.COMPLETED @property def failed(self): """A report job is marked failed iff it is finished and the result is None. While a job is unfinished, the `failed` status is ``None``. Failed jobs normally provide a `traceback` to examine reasons. """ if not self.finished: return None if getattr(self, 'result', None) is None: return True return False
[docs]class ExportJobContainer(object): """A mix-in that provides functionality for asynchronous export jobs. """ grok.implements(IExportJobContainer) running_exports = PersistentList()
[docs] def start_export_job(self, exporter_name, user_id, *args, **kwargs): """Start asynchronous export job. `exporter_name` is the name of an exporter utility to be used. `user_id` is the ID of the user that triggers the export. The job_id is stored along with exporter name and user id in a persistent list. The method supports additional positional and keyword arguments, which are passed as-is to the respective :class:`AsyncExportJob`. Returns the job ID of the job started. """ site = grok.getSite() manager = getUtility(IJobManager) job = AsyncExportJob(site, exporter_name, *args, **kwargs) job_id = manager.put(job) # Make sure that the persisted list is stored in ZODB self.running_exports = PersistentList(self.running_exports) self.running_exports.append((job_id, exporter_name, user_id)) return job_id
[docs] def get_running_export_jobs(self, user_id=None): """Get export jobs for user with `user_id` as list of tuples. Each tuples holds ``<job_id>, <exporter_name>, <user_id>`` in that order. The ``<exporter_name>`` is the utility name of the used exporter. If `user_id` is ``None``, all running jobs are returned. """ entries = [] to_delete = [] manager = getUtility(IJobManager) for entry in self.running_exports: if user_id is not None and entry[2] != user_id: continue if manager.get(entry[0]) is None: to_delete.append(entry) continue entries.append(entry) if to_delete: self.running_exports = PersistentList( [x for x in self.running_exports if x not in to_delete]) return entries
[docs] def get_export_jobs_status(self, user_id=None): """Get running/completed export jobs for `user_id` as list of tuples. Each tuple holds ``<raw status>, <status translated>, <exporter title>`` in that order, where ``<status translated>`` and ``<exporter title>`` are translated strings representing the status of the job and the human readable title of the exporter used. """ entries = self.get_running_export_jobs(user_id) result = [] manager = getUtility(IJobManager) for entry in entries: job = manager.get(entry[0]) if job is None: continue status, status_translated = JOB_STATUS_MAP[job.status] exporter_name = getUtility(ICSVExporter, name=entry[1]).title result.append((status, status_translated, exporter_name)) return result
[docs] def delete_export_entry(self, entry): """Delete the export denoted by `entry`. Removes given entry from the local `running_exports` list and also removes the regarding job via the local job manager. `entry` must be a tuple ``(<job id>, <exporter name>, <user id>)`` as created by :meth:`start_export_job` or returned by :meth:`get_running_export_jobs`. """ manager = getUtility(IJobManager) job = manager.get(entry[0]) if job is not None: # remove created export file if isinstance(job.result, basestring): if os.path.exists(os.path.dirname(job.result)): shutil.rmtree(os.path.dirname(job.result)) manager.remove(entry[0], self) new_entries = [x for x in self.running_exports if x != entry] self.running_exports = PersistentList(new_entries) return
[docs] def entry_from_job_id(self, job_id): """Get entry tuple for `job_id`. Returns ``None`` if no such entry can be found. """ for entry in self.running_exports: if entry[0] == job_id: return entry return None
[docs]class VirtualExportJobContainer(ExportJobContainer): """A virtual export job container. Virtual ExportJobContainers can be used as a mixin just like real ExportJobContainer. They retrieve and store data in the site-wide ExportJobContainer. Functionality is currently entirely as for regular ExportJobContainers, except that data is stored elsewhere. VirtualExportJobContainers need a registered IExportContainerFinder utility to find a suitable container for storing data. """ grok.implements(IExportJobContainer) @property def _site_container(self): return getUtility(IExportContainerFinder)() # The following is a simple trick. While ExportJobContainers store # only one attribute in ZODB, it is sufficient to replace this # attribute `running_exports` with a suitable manager to make the # whole virtual container work like the original but with the data # stored in the site-wide exports container. This way, virtual # export containers provide the whole functionality of a regular # exports container but store no data at all with themselves. @property def running_exports(self): """Exports stored in the site-wide exports container. """ return self._site_container.running_exports @running_exports.setter def running_exports(self, value): self._site_container.running_exports = value @running_exports.deleter def running_exports(self): del self._site_container.running_exports @property def logger(self): return self._site_container.logger
@implementer(IExportContainerFinder)
[docs]class ExportContainerFinder(grok.GlobalUtility): """Finder for local (site-wide) export container. """
[docs] def __call__(self): """Get the local export container- If no site can be determined or the site provides no export container, None is returned. """ site = grok.getSite() if site is None: return None return site.get('datacenter', None)