resource.py

import logging
from django.conf import settings
from django.db import models, transaction
from api.exceptions import DryccException, AlreadyExists, ServiceUnavailable
from api.models import UuidAuditedModel, validate_label
from scheduler import KubeException

logger = logging.getLogger(__name__)


class Resource(UuidAuditedModel):
    owner = models.ForeignKey(settings.AUTH_USER_MODEL,
                              on_delete=models.PROTECT)
    app = models.ForeignKey('App', on_delete=models.CASCADE)
    name = models.CharField(max_length=63, validators=[validate_label])
    plan = models.CharField(max_length=128)
    data = models.JSONField(default=dict, blank=True)
    status = models.TextField(blank=True, null=True)
    binding = models.TextField(blank=True, null=True)
    options = models.JSONField(default=dict, blank=True)

    class Meta:
        get_latest_by = 'created'
        unique_together = (('app', 'name'),)
        ordering = ['-created']

    def __str__(self):
        return self.name

    @transaction.atomic
    def save(self, *args, **kwargs):
        # Attach ServiceInstance, updates k8s
        if self.created == self.updated:
            self.attach(*args, **kwargs)
        # Save to DB
        return super(Resource, self).save(*args, **kwargs)

    def attach(self, *args, **kwargs):
        try:
            self._scheduler.svcat.get_instance(self.app.id, self.name)
            err = "Resource {} already exists in this namespace".format(self.name)  # noqa
            self.log(err, logging.INFO)
            raise AlreadyExists(err)
        except KubeException as e:
            logger.info(e)
            try:
                instance = self.plan.split(":")
                kwargs = {
                    "instance_class": instance[0],
                    "instance_plan": ":".join(instance[1:]),
                    "parameters": self.options,
                }
                self._scheduler.svcat.create_instance(
                    self.app.id, self.name, **kwargs
                )
            except KubeException as e:
                msg = 'There was a problem creating the resource ' \
                      '{} for {}'.format(self.name, self.app_id)
                raise ServiceUnavailable(msg) from e

    @transaction.atomic
    def delete(self, *args, **kwargs):
        if self.binding == "Ready":
            raise DryccException("the plan is still binding")
        # Deatch ServiceInstance, updates k8s
        self.detach(*args, **kwargs)
        # Delete from DB
        return super(Resource, self).delete(*args, **kwargs)

    def detach(self, *args, **kwargs):
        try:
            # We raise an exception when a resource doesn't exist
            self._scheduler.svcat.get_instance(self.app.id, self.name)
            self._scheduler.svcat.delete_instance(self.app.id, self.name)
        except KubeException as e:
            raise ServiceUnavailable("Could not delete resource {} for application {}".format(self.name, self.app_id)) from e  # noqa

    def log(self, message, level=logging.INFO):
        """Logs a message in the context of this service.

        This prefixes log messages with an application "tag" that the customized
        drycc-logspout will be on the lookout for.  When it's seen, the message-- usually
        an application event of some sort like releasing or scaling, will be considered
        as "belonging" to the application instead of the controller and will be handled
        accordingly.
        """
        logger.log(level, "[{}]: {}".format(self.uuid, message))

    def bind(self, *args, **kwargs):
        if self.status != "Ready":
            raise DryccException("the resource is not ready")
        if self.binding == "Ready":
            raise DryccException("the resource is binding")
        self.binding = "Binding"
        self.save()
        try:
            self._scheduler.svcat.get_binding(self.app.id, self.name)
            err = "Resource {} is binding".format(self.name)
            self.log(err, logging.INFO)
            raise AlreadyExists(err)
        except KubeException as e:
            logger.info(e)
            try:
                self._scheduler.svcat.create_binding(
                    self.app.id, self.name, **kwargs)
            except KubeException as e:
                msg = 'There was a problem binding the resource ' \
                      '{} for {}'.format(self.name, self.app_id)
                raise ServiceUnavailable(msg) from e

    def unbind(self, *args, **kwargs):
        if not self.binding:
            raise DryccException("the resource is not binding")
        try:
            # We raise an exception when a resource doesn't exist
            self._scheduler.svcat.get_binding(self.app.id, self.name)
            self._scheduler.svcat.delete_binding(self.app.id, self.name)
            self.binding = None
            self.data = {}
            self.save()
        except KubeException as e:
            raise ServiceUnavailable("Could not unbind resource {} for application {}".format(self.name, self.app_id)) from e  # noqa

    def attach_update(self, *args, **kwargs):
        try:
            data = self._scheduler.svcat.get_instance(
                self.app.id, self.name).json()
        except KubeException as e:
            logger.debug(e)
            self.DryccException("resource {} does not exist".format(self.name))
        try:
            version = data["metadata"]["resourceVersion"]
            instance = self.plan.split(":")
            kwargs = {
                "instance_class": instance[0],
                "instance_plan": ":".join(instance[1:]),
                "parameters": self.options,
                "external_id": data["spec"]["externalID"]
            }
            self._scheduler.svcat.put_instance(
                self.app.id, self.name, version, **kwargs
            )
        except KubeException as e:
            msg = 'There was a problem update the resource ' \
                  '{} for {}'.format(self.name, self.app_id)
            raise ServiceUnavailable(msg) from e

    def retrieve(self, *args, **kwargs):
        update_flag = False
        if self.status != "Ready":
            try:
                resp_i = self._scheduler.svcat.get_instance(
                    self.app.id, self.name).json()
                self.status = resp_i.get('status', {}).\
                    get('lastConditionState')
                self.options = resp_i.get('spec', {}).get('parameters', {})
                update_flag = True
            except KubeException as e:
                logger.info("retrieve instance info error: {}".format(e))
        if self.binding != "Ready":
            try:
                # We raise an exception when a resource doesn't exist
                resp_b = self._scheduler.svcat.get_binding(
                    self.app.id, self.name).json()
                self.binding = resp_b.get('status', {}).\
                    get('lastConditionState')
                update_flag = True
                secret_name = resp_b.get('spec', {}).get('secretName')
                if secret_name:
                    resp_s = self._scheduler.secret.get(
                        self.app.id, secret_name).json()
                    self.data = resp_s.get('data', {})
                    update_flag = True
            except KubeException as e:
                logger.info("retrieve binding info error: {}".format(e))
        if update_flag is True:
            self.save()
        if self.status == "Ready" and self.binding == "Ready":
            return True
        else:
            return False

    def detach_resource(self, *args, **kwargs):
        if self.binding != "Ready":
            try:
                resp_b = self._scheduler.svcat.get_binding(
                    self.app.id, self.name).json()
                secret_name = resp_b.get('spec', {}).get('secretName')
                if secret_name:
                    self._scheduler.secret.delete(self.app.id, secret_name)
                self._scheduler.svcat.delete_binding(
                    self.app.id, self.name)
            except KubeException as e:
                logger.info("delete binding info error: {}".format(e))
            self.binding = None

        if (self.status != "Ready") or (not self.binding):
            self.delete()

    def to_measurements(self, timestamp: float):
        return [{
            "name": self.name,
            "app_id": str(self.app_id),
            "owner_id": str(self.owner_id),
            "plan": self.plan,
            "timestamp": "%f" % timestamp
        }]