scheduling.py

"""
This file contains the database models
"""

import os
import logging
logger = logging.getLogger(__name__)

from datetime import datetime, timedelta

from django.db.models import Model, ForeignKey, OneToOneField, CharField, DateTimeField, BooleanField, IntegerField, BigIntegerField, \
    ManyToManyField, CASCADE, SET_NULL, PROTECT, QuerySet, BigAutoField, UniqueConstraint
from django.contrib.postgres.fields import ArrayField, JSONField
from .permissions import TMSSUser as User
from .common import AbstractChoice, BasicCommon, Template, NamedCommon, TemplateSchemaMixin, ProjectPropertyMixin
from enum import Enum
from django.db.models.expressions import RawSQL
from django.core.exceptions import ValidationError
from django.db.utils import InternalError
from lofar.sas.tmss.tmss.exceptions import SubtaskSchedulingException, SubtaskIllegalStateTransitionException
from django.conf import settings
from lofar.sas.resourceassignment.resourceassignmentservice.rpc import RADBRPC
import uuid

#
# I/O
#

#
# Choices
#

class SubtaskState(AbstractChoice):
    """Defines the model and predefined list of possible SubtaskStatusChoice's for Subtask.
    The items in the Choices class below are automagically populated into the database via a data migration."""
    class Choices(Enum):
        DEFINING = "defining"
        DEFINED = "defined"
        SCHEDULING = "scheduling"
        SCHEDULED = "scheduled"
        UNSCHEDULING = "unscheduling"
        QUEUEING = "queueing"
        QUEUED = "queued"
        STARTING = "starting"
        STARTED = "started"
        FINISHING = "finishing"
        FINISHED = "finished"
        CANCELLING = "cancelling"
        CANCELLED = "cancelled"
        ERROR = "error"
        UNSCHEDULABLE = "unschedulable"


class SubtaskType(AbstractChoice):
    """Defines the model and predefined list of possible SubtaskType's for Subtask.
    The items in the Choices class below are automagically populated into the database via a data migration."""
    class Choices(Enum):
        OBSERVATION = "observation"
        PIPELINE = "pipeline"
        INGEST = "ingest"
        COPY = "copy"
        INSPECTION = "inspection"
        QA_FILES = "qa_files" # task which creates "adder" QA h5 file(s) from a MeasurementSet of beamformed data
        QA_PLOTS = "qa_plots" # task which creates "adder" QA plots from an "adder" QA h5 file h5
        CLEANUP = "cleanup"
        MANUAL = 'manual'
        OTHER = 'other'


class StationType(AbstractChoice):
        """Defines the model and predefined list of possible StationType's for AntennaSet.
        The items in the Choices class below are automagically populated into the database via a data migration."""

        class Choices(Enum):
            CORE = "core"
            REMOTE = "remote"
            INTERNATIONAL = "international"


class HashAlgorithm(AbstractChoice):
    """Defines the model and predefined list of possible HashAlgorithm's for DataproductHash.
    The items in the Choices class below are automagically populated into the database via a data migration."""

    class Choices(Enum):
        MD5 = 'md5'
        AES256 = 'aes256'
        ADLER32 = 'adler32'


#
# Templates
#

class SubtaskTemplate(Template):
    type = ForeignKey('SubtaskType', null=False, on_delete=PROTECT)
    queue = BooleanField(default=False)
    realtime = BooleanField(default=False)


class DefaultSubtaskTemplate(BasicCommon):
    name = CharField(max_length=128, unique=True)
    template = ForeignKey('SubtaskTemplate', on_delete=PROTECT)


class DataproductSpecificationsTemplate(Template):
    pass


class DefaultDataproductSpecificationsTemplate(BasicCommon):
    name = CharField(max_length=128, unique=True)
    template = ForeignKey('DataproductSpecificationsTemplate', on_delete=PROTECT)


class DataproductFeedbackTemplate(Template):
    pass


class SAPTemplate(Template):
    pass

# todo: do we need to specify a default?


class SIPidentifier(Model):
    '''A SIPidentifier is a global unique id used to build provenance chains in the SIP for the LTA.
    It is derived from Model and not from BasicCommon to keep a small footprint.'''
    source = CharField(null=False, max_length=128, help_text='Source name')
    unique_identifier = BigAutoField(primary_key=True, help_text='Unique global identifier.')

    @staticmethod
    def assign_new_id_to_model(model):
        """
        Create an Unique Identifier for given model class if model is being created.
        """
        if model._state.adding:
            model.global_identifier = SIPidentifier.objects.create(source="TMSS")

#
# Instance Objects
#
class Subtask(BasicCommon, ProjectPropertyMixin, TemplateSchemaMixin):
    """
    Represents a low-level task, which is an atomic unit of execution, such as running an observation, running
    inspection plots on the observed data, etc. Each task has a specific configuration, will have resources allocated
    to it, and represents a single run.
    """
    start_time = DateTimeField(null=True, help_text='Start this subtask at the specified time (NULLable).')
    stop_time = DateTimeField(null=True, help_text='Stop this subtask at the specified time (NULLable).')
    state = ForeignKey('SubtaskState', null=False, on_delete=PROTECT, related_name='task_states', help_text='Subtask state (see Subtask State Machine).')
    specifications_doc = JSONField(help_text='Final specifications, as input for the controller.')
    task_blueprints = ManyToManyField('TaskBlueprint', related_name='subtasks', blank=True, help_text='Task Blueprint to which this Subtask belongs.')
    specifications_template = ForeignKey('SubtaskTemplate', null=False, on_delete=PROTECT, help_text='Schema used for specifications_doc.')
    cluster = ForeignKey('Cluster', null=True, on_delete=PROTECT, help_text='Where the Subtask is scheduled to run (NULLable).')
    # resource_claim = ForeignKey("ResourceClaim", null=False, on_delete=PROTECT) # todo <-- how is this external reference supposed to work?
    created_or_updated_by_user = ForeignKey(User, null=True, editable=False, on_delete=PROTECT, help_text='The user who created / updated the subtask.')
    raw_feedback = CharField(null=True, max_length=1048576, help_text='The raw feedback for this Subtask')
    global_identifier = OneToOneField('SIPidentifier', null=False, editable=False, on_delete=PROTECT, help_text='The global unique identifier for LTA SIP.')
    path_to_project = 'task_blueprints__scheduling_unit_blueprint__draft__scheduling_set__project'

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        # keep original state for logging
        self.__original_state_id = self.state_id

    @property
    def duration(self) -> timedelta:
        '''the duration of this subtask (stop-start), or 0 if start/stop are None'''
        if self.start_time is None or self.stop_time is None:
            return timedelta(seconds=0)
        return self.stop_time - self.start_time

    @property
    def specified_duration(self) -> timedelta:
        '''get the specified (or estimated) duration of this subtask based on the specified task duration and the subtask type'''
        if self.specifications_template.type.value == SubtaskType.Choices.OBSERVATION.value:
            # observations have a specified duration, so grab it from the spec.
            # In case we have several associated tasks: use the longest duration, since we assume that tasks will run in parallel (there would be no reason to combine them into a subtask).
            return timedelta(seconds=max([tb.specifications_doc.get('duration', 0) for tb in self.task_blueprints.all()]))

        if self.specifications_template.type.value == SubtaskType.Choices.PIPELINE.value:
            # pipelines usually do not have a specified duration, so make a guess (half the obs duration?).
            # In case we have several associated tasks: this guess is probably in no way accurate anyway, so we assume it does not really matter which task blueprint we refer to here
            return timedelta(seconds=self.task_blueprints.first().specifications_doc.get('duration', max(p.specified_duration.total_seconds() for p in self.predecessors)/2))

        # other subtasktypes usually depend on cpu/data/network etc. So, make a guess (for now)
        return timedelta(minutes=5)

    @staticmethod
    def independent_subtasks() -> QuerySet:
        '''return a QuerySet of all subtasks with no input (i.e. which are "independent" because they have no predecessors)
           If you want the result, add .all() like so: Subtask.independent_subtasks().all()
        '''
        return Subtask.objects.filter(inputs=None)

    @property
    def successors(self) -> QuerySet:
        '''return the connect successor subtask(s) as queryset (over which you can perform extended queries, or return via the serializers/viewsets)
           If you want the result, add .all() like so: my_subtask.successors.all()
        '''
        # JS, 20200528: I couldn't make django do a "self-reference" query from the subtask table to the subtask table (via input, output), so I used plain SQL.
        return Subtask.objects.filter(id__in=RawSQL("SELECT successor_st.id FROM tmssapp_subtask as successor_st\n"
                                                    "INNER JOIN tmssapp_subtaskinput as st_input on st_input.subtask_id = successor_st.id\n"
                                                    "INNER JOIN tmssapp_subtaskoutput as st_output on st_output.id = st_input.producer_id\n"
                                                    "WHERE st_output.subtask_id = %s", params=[self.id]))

    @property
    def predecessors(self) -> QuerySet:
        '''return the connect predecessor subtask(s) as queryset (over which you can perform extended queries, or return via the serializers/viewsets)
        If you want the result, add .all() like so: my_subtask.predecessors.all()
        '''
        # JS, 20200528: I couldn't make django do a "self-reference" query from the subtask table to the subtask table (via input, output), so I used plain SQL.
        return Subtask.objects.filter(id__in=RawSQL("SELECT predecessor_st.id FROM tmssapp_subtask as predecessor_st\n"
                                                    "INNER JOIN tmssapp_subtaskoutput as st_output on st_output.subtask_id = predecessor_st.id\n"
                                                    "INNER JOIN tmssapp_subtaskinput as st_input on st_input.producer_id = st_output.id\n"
                                                    "WHERE st_input.subtask_id = %s", params=[self.id]))

    @property
    def input_dataproducts(self) -> QuerySet:
        '''return the input dataproducts(s) as queryset (over which you can perform extended queries, or return via the serializers/viewsets)
        If you want the result, add .all() like so: my_subtask.input_dataproducts.all()
        '''
        return Dataproduct.objects.filter(subtaskinput__subtask_id=self.id)

    @property
    def output_dataproducts(self) -> QuerySet:
        '''return the output dataproducts(s) as queryset (over which you can perform extended queries, or return via the serializers/viewsets)
        If you want the result, add .all() like so: my_subtask.output_dataproducts.all()
        '''
        return Dataproduct.objects.filter(producer__subtask_id=self.id)

    @property
    def SAPs(self) -> QuerySet:
        '''return the SAP's (SubArrayPointings) as queryset (over which you can perform extended queries, or return via the serializers/viewsets)
        If you want the result, add .all() like so: my_subtask.SAPs.all()
        '''
        return SAP.objects.filter(dataproducts__producer__subtask_id=self.id).distinct()

    def get_transformed_input_dataproduct(self, output_dataproduct_id: int) -> 'Dataproduct':
        '''return the transformed input dataproduct for the given output_dataproduct_id.'''
        return self.input_dataproducts.get(consumers__output_id=output_dataproduct_id)

    def get_transformed_output_dataproduct(self, input_dataproduct_id: int) -> 'Dataproduct':
        '''return the transformed output dataproduct for the given input_dataproduct_id.'''
        return self.output_dataproducts.get(producers__input_id=input_dataproduct_id)

    @property
    def is_feedback_complete(self) -> bool:
        '''returns True if the feedback for all (>0) output dataproducts is filled in for a non-"empty"-template'''
        nr_of_output_dataproducts = self.output_dataproducts.count()
        return nr_of_output_dataproducts > 0 and self.output_dataproducts.filter(feedback_template__isnull=False).exclude(feedback_template__name="empty").count() == nr_of_output_dataproducts

    @property
    def progress(self) -> float:
        '''Get the progress of this subtask ranging from 0.0 before it is started, up to 1.0 when finished.'''
        if self.state.value in [SubtaskState.Choices.DEFINING.value, SubtaskState.Choices.DEFINING.value,
                                SubtaskState.Choices.SCHEDULING.value, SubtaskState.Choices.SCHEDULED.value,
                                SubtaskState.Choices.QUEUEING.value, SubtaskState.Choices.QUEUED.value,
                                SubtaskState.Choices.STARTING.value]:
            return 0.0

        if self.state.value == SubtaskState.Choices.FINISHED.value:
            return 1.0

        if self.state.value in [SubtaskState.Choices.STARTED.value, SubtaskState.Choices.FINISHING.value]:
            # subtask is running, compute progress if possible.
            if self.specifications_template.type.value == SubtaskType.Choices.INGEST.value:
                # progress for an ingest subtask is the ratio of archived output dataproducts over the total
                num_archived_dataproducts = self.output_dataproducts.filter(archive_info__isnull=False).distinct('id').count()
                num_dataproducts = self.output_dataproducts.count()
                return float(num_archived_dataproducts) / float(num_dataproducts)

            if self.specifications_template.type.value == SubtaskType.Choices.OBSERVATION.value:
                # progress for an observation is just how far we are into the duration
                num_seconds_running = max(0, (datetime.utcnow() - self.start_time).total_seconds())
                return min(1.0, float(num_seconds_running) / float(self.duration.total_seconds()))

            # TODO: add more progress computations for more subtask types if possible

        raise NotImplementedError("Could not get progress for subtask id=%s, type=%s state=%s" % (self.id,
                                                                                                  self.specifications_template.type.value,
                                                                                                  self.state))

    def save(self, force_insert=False, force_update=False, using=None, update_fields=None):
        creating = self._state.adding  # True on create, False on update

        self.annotate_validate_add_defaults_to_doc_using_template('specifications_doc', 'specifications_template')
        SIPidentifier.assign_new_id_to_model(self)

        # check for uniqueness of SAP names:
        # todo: this is a very specific check, that depends on the template. On the task level, we have a javascript
        #  field for complex validation on the template (I suspect that's for the frontend), so maybe we want to have
        #  a similar mechanism to describe complex validation on the backend?
        if self.specifications_doc and 'stations' in self.specifications_doc and 'digital_pointings' in self.specifications_doc['stations']:
            sap_names = [pointing['name'] for pointing in self.specifications_doc['stations']['digital_pointings']]
            duplicate_names = [name for name in set(sap_names) if sap_names.count(name) > 1]
            if duplicate_names:
                raise ValidationError("Pointings defined in the same Subtask must have unique names. Duplicate names %s in subtask id=%s." % (duplicate_names, self.pk))

        # check if we have a start time when scheduling
        if self.state.value == SubtaskState.Choices.SCHEDULED.value and self.__original_state_id == SubtaskState.Choices.SCHEDULING.value:
            if self.start_time is None:
                raise SubtaskSchedulingException("Cannot schedule subtask id=%s when start time is 'None'." % (self.pk, ))

        try:
            super().save(force_insert, force_update, using, update_fields)
        except InternalError as db_error:
            # wrap in TMSS SubtaskIllegalStateTransitionException if needed
            if 'ILLEGAL SUBTASK STATE TRANSITION' in str(db_error):
                raise SubtaskIllegalStateTransitionException(str(db_error))
            # else just reraise
            raise

        # log if either state update or new entry:
        if self.state_id != self.__original_state_id or creating == True:
            if self.created_or_updated_by_user is None:
                identifier = None
            else:
                identifier = self.created_or_updated_by_user.email
            log_entry = SubtaskStateLog(subtask=self, old_state=SubtaskState.objects.get(value=self.__original_state_id), new_state=self.state,
                                           user=self.created_or_updated_by_user, user_identifier=identifier)
            log_entry.save()

            # update the previous state value
            self.__original_state_id = self.state_id


class SubtaskAllowedStateTransitions(Model):
    """
    Table with the allowed subtask state transitions. See also the SQL trigger in populate which blocks any subtask state transitions which are not in this table, thus not allowed.
    """
    old_state = ForeignKey('SubtaskState', null=True, editable=False, on_delete=PROTECT, related_name='allowed_transition_from', help_text='Subtask state before update (see Subtask State Machine).')
    new_state = ForeignKey('SubtaskState', null=False, editable=False, on_delete=PROTECT, related_name='allowed_transition_to', help_text='Subtask state after update (see Subtask State Machine).')

    @staticmethod
    def allowed_new_states(old_state: SubtaskState) -> [SubtaskState]:
        '''get a list of all states we are allowed to transition to from the given old_state'''
        return [transition.new_state for transition in SubtaskAllowedStateTransitions.objects.filter(old_state=old_state).all()]

    @staticmethod
    def illegal_new_states(old_state: SubtaskState) -> [SubtaskState]:
        '''get a list of all states we are NOT allowed to transition to from the given old_state'''
        allowed_new_states = SubtaskAllowedStateTransitions.allowed_new_states(old_state)
        return list(SubtaskState.objects.exclude(value__in=[s.value for s in allowed_new_states]).exclude(pk=old_state.pk).all())


class SubtaskStateLog(BasicCommon):
    """
    History of state changes on subtasks
    This is now a very specific solution and based on what SOS communicated is what they are regularly interested in.
    Maybe one or two additional log tables for other models are benefitial and should be added at some point.

    Note that we could of course also log on the db level and there is also a variety of audit middlewares for Django
    available to keep track of changes more generally: https://djangopackages.org/grids/g/model-audit/
    This seems a bit overkill at the moment and we have to manage access to those logs etc., this needs tbd.
    """
    user = ForeignKey(User, null=True, editable=False, on_delete=PROTECT, help_text='The user who changed the state of the subtask.')
    user_identifier = CharField(null=True, editable=False, max_length=128, help_text='The ID of the user who changed the state of the subtask.')
    subtask = ForeignKey('Subtask', null=False,  editable=False, on_delete=CASCADE, help_text='Subtask to which this state change refers.')
    old_state = ForeignKey('SubtaskState', null=True,  editable=False, on_delete=PROTECT, related_name='is_old_state_of', help_text='Subtask state before update (see Subtask State Machine).')
    new_state = ForeignKey('SubtaskState', null=False, editable=False, on_delete=PROTECT, related_name='is_new_state_of', help_text='Subtask state after update (see Subtask State Machine).')


class SubtaskInput(BasicCommon, TemplateSchemaMixin):
    subtask = ForeignKey('Subtask', null=False, on_delete=CASCADE, related_name='inputs', help_text='Subtask to which this input specification refers.')
    task_relation_blueprint = ForeignKey('TaskRelationBlueprint', null=True, on_delete=SET_NULL, help_text='Task Relation Blueprint which this Subtask Input implements (NULLable).')
    producer = ForeignKey('SubtaskOutput', on_delete=PROTECT, related_name='consumers', help_text='The SubtaskOutput producing the input dataproducts for this SubtaskInput.')
    dataproducts = ManyToManyField('Dataproduct', help_text='The Dataproducts resulting from application of the filter at time of scheduling Although the dataproducts are simply the result of applying the filter on immutable data, the filter application could change over time. We thus store the result of this filtering directly to retain which input was specified for the task..')
    selection_doc = JSONField(help_text='Filter to apply to the dataproducts of the producer, to derive input dataproducts when scheduling.')
    selection_template = ForeignKey('TaskRelationSelectionTemplate', on_delete=PROTECT, help_text='Schema used for selection_doc.')

    def save(self, force_insert=False, force_update=False, using=None, update_fields=None):
        self.annotate_validate_add_defaults_to_doc_using_template('selection_doc', 'selection_template')
        super().save(force_insert, force_update, using, update_fields)


class SubtaskOutput(BasicCommon):
    subtask = ForeignKey('Subtask', null=False, on_delete=CASCADE, related_name='outputs', help_text='Subtask to which this output specification refers.')
    task_blueprint = ForeignKey('TaskBlueprint', null=False, on_delete=CASCADE, related_name='outputs', help_text='Task to which this output specification refers.')


class SAP(BasicCommon, TemplateSchemaMixin):
    specifications_doc = JSONField(help_text='SAP properties.')
    specifications_template = ForeignKey('SAPTemplate', null=False, on_delete=CASCADE, help_text='Schema used for specifications_doc.')
    global_identifier = OneToOneField('SIPidentifier', null=False, editable=False, on_delete=PROTECT, help_text='The global unique identifier for LTA SIP.')

    def save(self, force_insert=False, force_update=False, using=None, update_fields=None):
        self.annotate_validate_add_defaults_to_doc_using_template('specifications_doc', 'specifications_template')
        SIPidentifier.assign_new_id_to_model(self)

        super().save(force_insert, force_update, using, update_fields)


class Dataproduct(BasicCommon, TemplateSchemaMixin):
    """
    A data product represents an atomic dataset, produced and consumed by subtasks. The consumed dataproducts are those
    resulting from interpreting the Subtask Connector filters of the inputs. These links are explicitly saved, should
    the interpretation of the filter change over time. The produced dataproducts enumerate everything produced by a
    Subtask.
    """
    filename = CharField(max_length=128, help_text='Name of the file (or top-level directory) of the dataproduct. Adheres to a naming convention, but is not meant for parsing.')
    directory = CharField(max_length=1024, help_text='Directory where this dataproduct is (to be) stored.')
    dataformat = ForeignKey('Dataformat', null=False, on_delete=PROTECT)
    datatype = ForeignKey('Datatype', null=False, on_delete=PROTECT)
    deleted_since = DateTimeField(null=True, help_text='When this dataproduct was removed from disk, or NULL if not deleted (NULLable).')
    specifications_doc = JSONField(help_text='Dataproduct properties (f.e. beam, subband), to distinguish them when produced by the same task, and to act as input for selections in the Task Input and Work Request Relation Blueprint objects.')
    specifications_template = ForeignKey('DataproductSpecificationsTemplate', null=False, on_delete=CASCADE, help_text='Schema used for specifications_doc.')
    producer = ForeignKey('SubtaskOutput', on_delete=PROTECT, related_name="dataproducts", help_text='Subtask Output which generates this dataproduct.')
    expected_size = BigIntegerField(null=True, help_text='Expected size of dataproduct size, in bytes. Used for scheduling purposes. NULL if size is unknown (NULLable).')
    size = BigIntegerField(null=True, help_text='Dataproduct size, in bytes. Used for accounting purposes. NULL if size is (yet) unknown (NULLable).')
    feedback_doc = JSONField(help_text='Dataproduct properties, as reported by the producing process.')
    feedback_template = ForeignKey('DataproductFeedbackTemplate', on_delete=PROTECT, help_text='Schema used for feedback_doc.')
    sap = ForeignKey('SAP', on_delete=PROTECT, null=True, related_name="dataproducts", help_text='SAP this dataproduct was generated out of (NULLable).')
    global_identifier = OneToOneField('SIPidentifier', editable=False, null=False, on_delete=PROTECT, help_text='The global unique identifier for LTA SIP.')

    class Meta:
        constraints = [UniqueConstraint(fields=['directory', 'filename'], name='%(class)s_unique_path')]

    def save(self, force_insert=False, force_update=False, using=None, update_fields=None):
        self.annotate_validate_add_defaults_to_doc_using_template('specifications_doc', 'specifications_template')
        self.annotate_validate_add_defaults_to_doc_using_template('feedback_doc', 'feedback_template')
        SIPidentifier.assign_new_id_to_model(self)

        super().save(force_insert, force_update, using, update_fields)

    @property
    def filepath(self):
        '''return the full path of the dataproduct'''
        return os.path.join(self.directory, self.filename)

class AntennaSet(NamedCommon):
    station_type = ForeignKey('StationType', null=False, on_delete=PROTECT)
    rcus = ArrayField(IntegerField(), size=128, blank=False)
    inputs = ArrayField(CharField(max_length=128), size=128, blank=True)


class DataproductTransform(BasicCommon):
    """
    Each output dataproduct of a Subtask is linked to the input dataproducts that are used to produce it.
    These transforms encode the provenance information needed when tracking dependencies between dataproducts.
    """
    input = ForeignKey('Dataproduct', related_name='consumers', on_delete=PROTECT, help_text='A dataproduct that was the input of a transformation.')
    output = ForeignKey('Dataproduct',  related_name='producers', on_delete=PROTECT, help_text='A dataproduct that was produced from the input dataproduct.')
    identity = BooleanField(help_text='TRUE if this transform only copies, tars, or losslessly compresses its input, FALSE if the transform changes the data. Allows for efficient reasoning about data duplication.')


class Filesystem(NamedCommon):
    capacity = BigIntegerField(help_text='Capacity in bytes')
    cluster = ForeignKey('Cluster', on_delete=PROTECT, help_text='Cluster hosting this filesystem.')
    directory = CharField(max_length=1024, help_text='Root directory under which we are allowed to write our data.')

    def save(self, force_insert=False, force_update=False, using=None, update_fields=None):
        if self.directory and not self.directory.endswith('/'):
            self.directory += '/'

        super().save(force_insert, force_update, using, update_fields)


class Cluster(NamedCommon):
    location = CharField(max_length=128, help_text='Human-readable location of the cluster.')
    archive_site = BooleanField(default=False, null=False, help_text='TRUE if this cluster is an archive site, FALSE if not (f.e. a local cluster, or user-owned cluster).')


class DataproductArchiveInfo(BasicCommon):
    dataproduct = OneToOneField('Dataproduct', related_name='archive_info', on_delete=PROTECT, help_text='A dataproduct residing in the archive.')
    storage_ticket = CharField(max_length=128, help_text='Archive-system identifier.')
    public_since = DateTimeField(null=True, help_text='Dataproduct is available for public download since this moment, or NULL if dataproduct is not (NULLable).')
    corrupted_since = DateTimeField(null=True, help_text='Earliest timestamp from which this dataproduct is known to be partially or fully corrupt, or NULL if dataproduct is not known to be corrupt (NULLable).')


class DataproductHash(BasicCommon):
    dataproduct = ForeignKey('Dataproduct', related_name='hashes', on_delete=PROTECT, help_text='The dataproduct to which this hash refers.')
    hash_algorithm = ForeignKey('HashAlgorithm', null=False, on_delete=PROTECT, help_text='Algorithm used for hashing (MD5, AES256).')
    hash = CharField(max_length=128, help_text='Hash value.')