client.py

import itertools
import time

try:
    import json
except ImportError:
    import simplejson as json

import requests
import requests.exceptions
from requests_toolbelt.adapters import socket_options

import marathon
from .models import MarathonApp, MarathonDeployment, MarathonGroup, MarathonInfo, MarathonTask, MarathonEndpoint, MarathonQueueItem
from .exceptions import ConflictError, InternalServerError, NotFoundError, MarathonHttpError, MarathonError, NoResponseError
from .models.base import assert_valid_path
from .models.events import EventFactory, MarathonEvent
from .util import MarathonJsonEncoder, MarathonMinimalJsonEncoder


class MarathonClient:

    """Client interface for the Marathon REST API."""

    def __init__(self, servers, username=None, password=None, timeout=10, session=None,
                 auth_token=None, verify=True, sse_session=None):
        """Create a MarathonClient instance.

        If multiple servers are specified, each will be tried in succession until a non-"Connection Error"-type
        response is received. Servers are expected to have the same username and password.

        :param servers: One or a priority-ordered list of Marathon URLs (e.g., 'http://host:8080' or
        ['http://host1:8080','http://host2:8080'])
        :type servers: str or list[str]
        :param str username: Basic auth username
        :param str password: Basic auth password
        :param requests.session session: requests.session for reusing the connections
        :param int timeout: Timeout (in seconds) for requests to Marathon
        :param str auth_token: Token-based auth token, used with DCOS + Oauth
        :param bool verify: Enable SSL certificate verification
        :param requests.session sse_session: requests.session for event stream connections, which by default enables tcp keepalive
        """
        if session is None:
            self.session = requests.Session()
        else:
            self.session = session
        if sse_session is None:
            self.sse_session = requests.Session()
            keep_alive = socket_options.TCPKeepAliveAdapter()
            self.sse_session.mount('http://', keep_alive)
            self.sse_session.mount('https://', keep_alive)
        else:
            self.sse_session = sse_session
        self.servers = servers if isinstance(servers, list) else [servers]
        self.auth = (username, password) if username and password else None
        self.verify = verify
        self.timeout = timeout

        self.auth_token = auth_token
        if self.auth and self.auth_token:
            raise ValueError("Can't specify both auth token and username/password. Must select "
                             "one type of authentication.")

    def __repr__(self):
        return 'Connection:%s' % self.servers

    @staticmethod
    def _parse_response(response, clazz, is_list=False, resource_name=None):
        """Parse a Marathon response into an object or list of objects."""
        target = response.json()[
            resource_name] if resource_name else response.json()
        if is_list:
            return [clazz.from_json(resource) for resource in target]
        else:
            return clazz.from_json(target)

    def _do_request(self, method, path, params=None, data=None):
        """Query Marathon server."""
        headers = {
            'Content-Type': 'application/json', 'Accept': 'application/json'}

        if self.auth_token:
            headers['Authorization'] = f"token={self.auth_token}"

        response = None
        servers = list(self.servers)
        while servers and response is None:
            server = servers.pop(0)
            url = ''.join([server.rstrip('/'), path])
            try:
                response = self.session.request(
                    method, url, params=params, data=data, headers=headers,
                    auth=self.auth, timeout=self.timeout, verify=self.verify)
                marathon.log.info('Got response from %s', server)
            except requests.exceptions.RequestException as e:
                marathon.log.error(
                    'Error while calling %s: %s', url, str(e))

        if response is None:
            raise NoResponseError('No remaining Marathon servers to try')

        if response.status_code >= 500:
            marathon.log.error('Got HTTP {code}: {body}'.format(
                code=response.status_code, body=response.text.encode('utf-8')))
            raise InternalServerError(response)
        elif response.status_code >= 400:
            marathon.log.error('Got HTTP {code}: {body}'.format(
                code=response.status_code, body=response.text.encode('utf-8')))
            if response.status_code == 404:
                raise NotFoundError(response)
            elif response.status_code == 409:
                raise ConflictError(response)
            else:
                raise MarathonHttpError(response)
        elif response.status_code >= 300:
            marathon.log.warn('Got HTTP {code}: {body}'.format(
                code=response.status_code, body=response.text.encode('utf-8')))
        else:
            marathon.log.debug('Got HTTP {code}: {body}'.format(
                code=response.status_code, body=response.text.encode('utf-8')))

        return response

    def _do_sse_request(self, path, params=None):
        """Query Marathon server for events."""
        urls = [''.join([server.rstrip('/'), path]) for server in self.servers]
        while urls:
            url = urls.pop()
            try:
                # Requests does not set the original Authorization header on cross origin
                # redirects. If set allow_redirects=True we may get a 401 response.
                response = self.sse_session.get(
                    url,
                    params=params,
                    stream=True,
                    headers={'Accept': 'text/event-stream'},
                    auth=self.auth,
                    verify=self.verify,
                    allow_redirects=False
                )
            except Exception as e:
                marathon.log.error(
                    'Error while calling %s: %s', url, e.message)
            else:
                if response.is_redirect and response.next:
                    urls.append(response.next.url)
                    marathon.log.debug(f"Got redirect to {response.next.url}")
                elif response.ok:
                    return response.iter_lines()

        raise MarathonError('No remaining Marathon servers to try')

    def list_endpoints(self):
        """List the current endpoints for all applications

        :returns: list of endpoints
        :rtype: list[`MarathonEndpoint`]
        """
        return MarathonEndpoint.from_tasks(self.list_tasks())

    def create_app(self, app_id, app, minimal=True):
        """Create and start an app.

        :param str app_id: application ID
        :param :class:`marathon.models.app.MarathonApp` app: the application to create
        :param bool minimal: ignore nulls and empty collections

        :returns: the created app (on success)
        :rtype: :class:`marathon.models.app.MarathonApp` or False
        """
        app.id = assert_valid_path(app_id)
        data = app.to_json(minimal=minimal)
        marathon.log.debug('create app JSON sent: {}'.format(data))
        response = self._do_request('POST', '/v2/apps', data=data)
        if response.status_code == 201:
            return self._parse_response(response, MarathonApp)
        else:
            return False

    def list_apps(self, cmd=None, embed_tasks=False, embed_counts=False,
                  embed_deployments=False, embed_readiness=False,
                  embed_last_task_failure=False, embed_failures=False,
                  embed_task_stats=False, app_id=None, label=None, **kwargs):
        """List all apps.

        :param str cmd: if passed, only show apps with a matching `cmd`
        :param bool embed_tasks: embed tasks in result
        :param bool embed_counts: embed all task counts
        :param bool embed_deployments: embed all deployment identifier
        :param bool embed_readiness: embed all readiness check results
        :param bool embed_last_task_failure: embeds the last task failure
        :param bool embed_failures: shorthand for embed_last_task_failure
        :param bool embed_task_stats: embed task stats in result
        :param str app_id: if passed, only show apps with an 'id' that matches or contains this value
        :param str label: if passed, only show apps with the selected labels
        :param kwargs: arbitrary search filters

        :returns: list of applications
        :rtype: list[:class:`marathon.models.app.MarathonApp`]
        """
        params = {}
        if cmd:
            params['cmd'] = cmd
        if app_id:
            params['id'] = app_id
        if label:
            params['label'] = label

        embed_params = {
            'app.tasks': embed_tasks,
            'app.counts': embed_counts,
            'app.deployments': embed_deployments,
            'app.readiness': embed_readiness,
            'app.lastTaskFailure': embed_last_task_failure,
            'app.failures': embed_failures,
            'app.taskStats': embed_task_stats
        }
        filtered_embed_params = [k for (k, v) in embed_params.items() if v]
        if filtered_embed_params:
            params['embed'] = filtered_embed_params

        response = self._do_request('GET', '/v2/apps', params=params)
        apps = self._parse_response(
            response, MarathonApp, is_list=True, resource_name='apps')
        for k, v in kwargs.items():
            apps = [o for o in apps if getattr(o, k) == v]
        return apps

    def get_app(self, app_id, embed_tasks=False, embed_counts=False,
                embed_deployments=False, embed_readiness=False,
                embed_last_task_failure=False, embed_failures=False,
                embed_task_stats=False):
        """Get a single app.

        :param str app_id: application ID
        :param bool embed_tasks: embed tasks in result
        :param bool embed_counts: embed all task counts
        :param bool embed_deployments: embed all deployment identifier
        :param bool embed_readiness: embed all readiness check results
        :param bool embed_last_task_failure: embeds the last task failure
        :param bool embed_failures: shorthand for embed_last_task_failure
        :param bool embed_task_stats: embed task stats in result

        :returns: application
        :rtype: :class:`marathon.models.app.MarathonApp`
        """
        params = {}
        embed_params = {
            'app.tasks': embed_tasks,
            'app.counts': embed_counts,
            'app.deployments': embed_deployments,
            'app.readiness': embed_readiness,
            'app.lastTaskFailure': embed_last_task_failure,
            'app.failures': embed_failures,
            'app.taskStats': embed_task_stats
        }
        filtered_embed_params = [k for (k, v) in embed_params.items() if v]
        if filtered_embed_params:
            params['embed'] = filtered_embed_params

        response = self._do_request(
            'GET', f'/v2/apps/{app_id}', params=params)
        return self._parse_response(response, MarathonApp, resource_name='app')

    def restart_app(self, app_id, force=False):
        """
        Restarts given application by app_id
        :param str app_id: application ID
        :param bool force: apply even if a deployment is in progress
        :returns: a dict containing the deployment id and version
        :rtype: dict
        """
        params = {'force': force}
        response = self._do_request(
            'POST', f'/v2/apps/{app_id}/restart', params=params)
        return response.json()

    def update_app(self, app_id, app, force=False, minimal=True):
        """Update an app.

        Applies writable settings in `app` to `app_id`
        Note: this method can not be used to rename apps.

        :param str app_id: target application ID
        :param app: application settings
        :type app: :class:`marathon.models.app.MarathonApp`
        :param bool force: apply even if a deployment is in progress
        :param bool minimal: ignore nulls and empty collections

        :returns: a dict containing the deployment id and version
        :rtype: dict
        """
        # Changes won't take if version is set - blank it for convenience
        app.version = None

        params = {'force': force}
        data = app.to_json(minimal=minimal)

        response = self._do_request(
            'PUT', f'/v2/apps/{app_id}', params=params, data=data)
        return response.json()

    def update_apps(self, apps, force=False, minimal=True):
        """Update multiple apps.

        Applies writable settings in elements of apps either by upgrading existing ones or creating new ones

        :param apps: sequence of application settings
        :param bool force: apply even if a deployment is in progress
        :param bool minimal: ignore nulls and empty collections

        :returns: a dict containing the deployment id and version
        :rtype: dict
        """
        json_repr_apps = []
        for app in apps:
            # Changes won't take if version is set - blank it for convenience
            app.version = None
            json_repr_apps.append(app.json_repr(minimal=minimal))

        params = {'force': force}
        encoder = MarathonMinimalJsonEncoder if minimal else MarathonJsonEncoder
        data = json.dumps(json_repr_apps, cls=encoder, sort_keys=True)

        response = self._do_request(
            'PUT', '/v2/apps', params=params, data=data)
        return response.json()

    def rollback_app(self, app_id, version, force=False):
        """Roll an app back to a previous version.

        :param str app_id: application ID
        :param str version: application version
        :param bool force: apply even if a deployment is in progress

        :returns: a dict containing the deployment id and version
        :rtype: dict
        """
        params = {'force': force}
        data = json.dumps({'version': version})
        response = self._do_request(
            'PUT', f'/v2/apps/{app_id}', params=params, data=data)
        return response.json()

    def delete_app(self, app_id, force=False):
        """Stop and destroy an app.

        :param str app_id: application ID
        :param bool force: apply even if a deployment is in progress

        :returns: a dict containing the deployment id and version
        :rtype: dict
        """
        params = {'force': force}
        response = self._do_request(
            'DELETE', f'/v2/apps/{app_id}', params=params)
        return response.json()

    def scale_app(self, app_id, instances=None, delta=None, force=False):
        """Scale an app.

        Scale an app to a target number of instances (with `instances`), or scale the number of
        instances up or down by some delta (`delta`). If the resulting number of instances would be negative,
        desired instances will be set to zero.

        If both `instances` and `delta` are passed, use `instances`.

        :param str app_id: application ID
        :param int instances: [optional] the number of instances to scale to
        :param int delta: [optional] the number of instances to scale up or down by
        :param bool force: apply even if a deployment is in progress

        :returns: a dict containing the deployment id and version
        :rtype: dict
        """
        if instances is None and delta is None:
            marathon.log.error('instances or delta must be passed')
            return

        try:
            app = self.get_app(app_id)
        except NotFoundError:
            marathon.log.error(f'App "{app_id}" not found')
            return

        desired = instances if instances is not None else (
            app.instances + delta)
        return self.update_app(app.id, MarathonApp(instances=desired), force=force)

    def create_group(self, group):
        """Create and start a group.

        :param :class:`marathon.models.group.MarathonGroup` group: the group to create

        :returns: success
        :rtype: dict containing the version ID
        """
        data = group.to_json()
        response = self._do_request('POST', '/v2/groups', data=data)
        return response.json()

    def list_groups(self, **kwargs):
        """List all groups.

        :param kwargs: arbitrary search filters

        :returns: list of groups
        :rtype: list[:class:`marathon.models.group.MarathonGroup`]
        """
        response = self._do_request('GET', '/v2/groups')
        groups = self._parse_response(
            response, MarathonGroup, is_list=True, resource_name='groups')
        for k, v in kwargs.items():
            groups = [o for o in groups if getattr(o, k) == v]
        return groups

    def get_group(self, group_id):
        """Get a single group.

        :param str group_id: group ID

        :returns: group
        :rtype: :class:`marathon.models.group.MarathonGroup`
        """
        response = self._do_request(
            'GET', f'/v2/groups/{group_id}')
        return self._parse_response(response, MarathonGroup)

    def update_group(self, group_id, group, force=False, minimal=True):
        """Update a group.

        Applies writable settings in `group` to `group_id`
        Note: this method can not be used to rename groups.

        :param str group_id: target group ID
        :param group: group settings
        :type group: :class:`marathon.models.group.MarathonGroup`
        :param bool force: apply even if a deployment is in progress
        :param bool minimal: ignore nulls and empty collections

        :returns: a dict containing the deployment id and version
        :rtype: dict
        """
        # Changes won't take if version is set - blank it for convenience
        group.version = None

        params = {'force': force}
        data = group.to_json(minimal=minimal)

        response = self._do_request(
            'PUT', f'/v2/groups/{group_id}', data=data, params=params)
        return response.json()

    def rollback_group(self, group_id, version, force=False):
        """Roll a group back to a previous version.

        :param str group_id: group ID
        :param str version: group version
        :param bool force: apply even if a deployment is in progress

        :returns: a dict containing the deployment id and version
        :rtype: dict
        """
        params = {'force': force}
        response = self._do_request(
            'PUT',
            '/v2/groups/{group_id}/versions/{version}'.format(
                group_id=group_id, version=version),
            params=params)
        return response.json()

    def delete_group(self, group_id, force=False):
        """Stop and destroy a group.

        :param str group_id: group ID
        :param bool force: apply even if a deployment is in progress

        :returns: a dict containing the deleted version
        :rtype: dict
        """
        params = {'force': force}
        response = self._do_request(
            'DELETE', f'/v2/groups/{group_id}', params=params)
        return response.json()

    def scale_group(self, group_id, scale_by):
        """Scale a group by a factor.

        :param str group_id: group ID
        :param int scale_by: factor to scale by

        :returns: a dict containing the deployment id and version
        :rtype: dict
        """
        data = {'scaleBy': scale_by}
        response = self._do_request(
            'PUT', f'/v2/groups/{group_id}', data=json.dumps(data))
        return response.json()

    def list_tasks(self, app_id=None, **kwargs):
        """List running tasks, optionally filtered by app_id.

        :param str app_id: if passed, only show tasks for this application
        :param kwargs: arbitrary search filters

        :returns: list of tasks
        :rtype: list[:class:`marathon.models.task.MarathonTask`]
        """
        response = self._do_request(
            'GET', '/v2/apps/%s/tasks' % app_id if app_id else '/v2/tasks')
        tasks = self._parse_response(
            response, MarathonTask, is_list=True, resource_name='tasks')
        [setattr(t, 'app_id', app_id)
         for t in tasks if app_id and t.app_id is None]
        for k, v in kwargs.items():
            tasks = [o for o in tasks if getattr(o, k) == v]

        return tasks

    def kill_given_tasks(self, task_ids, scale=False, force=None):
        """Kill a list of given tasks.

        :param list[str] task_ids: tasks to kill
        :param bool scale: if true, scale down the app by the number of tasks killed
        :param bool force: if true, ignore any current running deployments

        :return: True on success
        :rtype: bool
        """
        params = {'scale': scale}
        if force is not None:
            params['force'] = force
        data = json.dumps({"ids": task_ids})
        response = self._do_request(
            'POST', '/v2/tasks/delete', params=params, data=data)
        return response.status_code == 200

    def kill_tasks(self, app_id, scale=False, wipe=False,
                   host=None, batch_size=0, batch_delay=0):
        """Kill all tasks belonging to app.

        :param str app_id: application ID
        :param bool scale: if true, scale down the app by the number of tasks killed
        :param str host: if provided, only terminate tasks on this Mesos slave
        :param int batch_size: if non-zero, terminate tasks in groups of this size
        :param int batch_delay: time (in seconds) to wait in between batched kills. If zero, automatically determine

        :returns: list of killed tasks
        :rtype: list[:class:`marathon.models.task.MarathonTask`]
        """
        def batch(iterable, size):
            sourceiter = iter(iterable)
            while True:
                batchiter = itertools.islice(sourceiter, size)
                yield itertools.chain([next(batchiter)], batchiter)

        if batch_size == 0:
            # Terminate all at once
            params = {'scale': scale, 'wipe': wipe}
            if host:
                params['host'] = host
            response = self._do_request(
                'DELETE', f'/v2/apps/{app_id}/tasks', params)
            # Marathon is inconsistent about what type of object it returns on the multi
            # task deletion endpoint, depending on the version of Marathon. See:
            # https://github.com/mesosphere/marathon/blob/06a6f763a75fb6d652b4f1660685ae234bd15387/src/main/scala/mesosphere/marathon/api/v2/AppTasksResource.scala#L88-L95
            if "tasks" in response.json():
                return self._parse_response(response, MarathonTask, is_list=True, resource_name='tasks')
            else:
                return response.json()
        else:
            # Terminate in batches
            tasks = self.list_tasks(
                app_id, host=host) if host else self.list_tasks(app_id)
            for tbatch in batch(tasks, batch_size):
                killed_tasks = [self.kill_task(app_id, t.id, scale=scale, wipe=wipe)
                                for t in tbatch]

                # Pause until the tasks have been killed to avoid race
                # conditions
                killed_task_ids = {t.id for t in killed_tasks}
                running_task_ids = killed_task_ids
                while killed_task_ids.intersection(running_task_ids):
                    time.sleep(1)
                    running_task_ids = {
                        t.id for t in self.get_app(app_id).tasks}

                if batch_delay == 0:
                    # Pause until the replacement tasks are healthy
                    desired_instances = self.get_app(app_id).instances
                    running_instances = 0
                    while running_instances < desired_instances:
                        time.sleep(1)
                        running_instances = sum(
                            t.started_at is None for t in self.get_app(app_id).tasks)
                else:
                    time.sleep(batch_delay)

            return tasks

    def kill_task(self, app_id, task_id, scale=False, wipe=False):
        """Kill a task.

        :param str app_id: application ID
        :param str task_id: the task to kill
        :param bool scale: if true, scale down the app by one if the task exists

        :returns: the killed task
        :rtype: :class:`marathon.models.task.MarathonTask`
        """
        params = {'scale': scale, 'wipe': wipe}
        response = self._do_request('DELETE', '/v2/apps/{app_id}/tasks/{task_id}'
                                    .format(app_id=app_id, task_id=task_id), params)
        # Marathon is inconsistent about what type of object it returns on the multi
        # task deletion endpoint, depending on the version of Marathon. See:
        # https://github.com/mesosphere/marathon/blob/06a6f763a75fb6d652b4f1660685ae234bd15387/src/main/scala/mesosphere/marathon/api/v2/AppTasksResource.scala#L88-L95
        if "task" in response.json():
            return self._parse_response(response, MarathonTask, is_list=False, resource_name='task')
        else:
            return response.json()

    def list_versions(self, app_id):
        """List the versions of an app.

        :param str app_id: application ID

        :returns: list of versions
        :rtype: list[str]
        """
        response = self._do_request(
            'GET', f'/v2/apps/{app_id}/versions')
        return [version for version in response.json()['versions']]

    def get_version(self, app_id, version):
        """Get the configuration of an app at a specific version.

        :param str app_id: application ID
        :param str version: application version

        :return: application configuration
        :rtype: :class:`marathon.models.app.MarathonApp`
        """
        response = self._do_request('GET', '/v2/apps/{app_id}/versions/{version}'
                                    .format(app_id=app_id, version=version))
        return MarathonApp.from_json(response.json())

    def list_event_subscriptions(self):
        """List the event subscriber callback URLs.

        :returns: list of callback URLs
        :rtype: list[str]
        """
        response = self._do_request('GET', '/v2/eventSubscriptions')
        return [url for url in response.json()['callbackUrls']]

    def create_event_subscription(self, url):
        """Register a callback URL as an event subscriber.

        :param str url: callback URL

        :returns: the created event subscription
        :rtype: dict
        """
        params = {'callbackUrl': url}
        response = self._do_request('POST', '/v2/eventSubscriptions', params)
        return response.json()

    def delete_event_subscription(self, url):
        """Deregister a callback URL as an event subscriber.

        :param str url: callback URL

        :returns: the deleted event subscription
        :rtype: dict
        """
        params = {'callbackUrl': url}
        response = self._do_request('DELETE', '/v2/eventSubscriptions', params)
        return response.json()

    def list_deployments(self):
        """List all running deployments.

        :returns: list of deployments
        :rtype: list[:class:`marathon.models.deployment.MarathonDeployment`]
        """
        response = self._do_request('GET', '/v2/deployments')
        return self._parse_response(response, MarathonDeployment, is_list=True)

    def list_queue(self, embed_last_unused_offers=False):
        """List all the tasks queued up or waiting to be scheduled.

        :returns: list of queue items
        :rtype: list[:class:`marathon.models.queue.MarathonQueueItem`]
        """
        if embed_last_unused_offers:
            params = {'embed': 'lastUnusedOffers'}
        else:
            params = {}
        response = self._do_request('GET', '/v2/queue', params=params)
        return self._parse_response(response, MarathonQueueItem, is_list=True, resource_name='queue')

    def delete_deployment(self, deployment_id, force=False):
        """Cancel a deployment.

        :param str deployment_id: deployment id
        :param bool force: if true, don't create a rollback deployment to restore the previous configuration

        :returns: a dict containing the deployment id and version (empty dict if force=True)
        :rtype: dict
        """
        if force:
            params = {'force': True}
            self._do_request('DELETE', '/v2/deployments/{deployment}'.format(
                deployment=deployment_id), params=params)
            # Successful DELETE with ?force=true returns empty text (and status
            # code 202). Client code should poll until deployment is removed.
            return {}
        else:
            response = self._do_request(
                'DELETE', f'/v2/deployments/{deployment_id}')
            return response.json()

    def reset_delay(self, app_id):
        self._do_request(
            "DELETE", f'/v2/queue/{app_id}/delay'
        )

    def get_info(self):
        """Get server configuration information.

        :returns: server config info
        :rtype: :class:`marathon.models.info.MarathonInfo`
        """
        response = self._do_request('GET', '/v2/info')
        return self._parse_response(response, MarathonInfo)

    def get_leader(self):
        """Get the current marathon leader.

        :returns: leader endpoint
        :rtype: dict
        """
        response = self._do_request('GET', '/v2/leader')
        return response.json()

    def delete_leader(self):
        """Causes the current leader to abdicate, triggers a new election.

        :returns: message saying leader abdicated
        :rtype: dict
        """
        response = self._do_request('DELETE', '/v2/leader')
        return response.json()

    def ping(self):
        """Ping the Marathon server.

        :returns: the text response
        :rtype: str
        """
        response = self._do_request('GET', '/ping')
        return response.text.encode('utf-8')

    def get_metrics(self):
        """Get server metrics

        :returns: metrics dict
        :rtype: dict
        """
        response = self._do_request('GET', '/metrics')
        return response.json()

    def event_stream(self, raw=False, event_types=None):
        """Polls event bus using /v2/events

        :param bool raw: if true, yield raw event text, else yield MarathonEvent object
        :param event_types: a list of event types to consume
        :type event_types: list[type] or list[str]
        :returns: iterator with events
        :rtype: iterator
        """

        ef = EventFactory()

        params = {
            'event_type': [
                EventFactory.class_to_event[et] if isinstance(
                    et, type) and issubclass(et, MarathonEvent) else et
                for et in event_types or []
            ]
        }

        for raw_message in self._do_sse_request('/v2/events', params=params):
            try:
                _data = raw_message.decode('utf8').split(':', 1)

                if _data[0] == 'data':
                    if raw:
                        yield _data[1]
                    else:
                        event_data = json.loads(_data[1].strip())
                        if 'eventType' not in event_data:
                            raise MarathonError('Invalid event data received.')
                        yield ef.process(event_data)
            except ValueError:
                raise MarathonError('Invalid event data received.')