outposts: rewrite state logic, use cache to expire old channels, support multiple instances

passbook/outposts/channels.py

@@ -1,17 +1,16 @@
 """Outpost websocket handler"""
 from dataclasses import asdict, dataclass, field
+from datetime import datetime
 from enum import IntEnum
-from time import time
 from typing import Any, Dict
 
 from dacite import from_dict
 from dacite.data import Data
-from django.core.cache import cache
 from guardian.shortcuts import get_objects_for_user
 from structlog import get_logger
 
 from passbook.core.channels import AuthJsonConsumer
-from passbook.outposts.models import Outpost
+from passbook.outposts.models import OUTPOST_HELLO_INTERVAL, Outpost, OutpostState
 
 LOGGER = get_logger()
 
@@ -54,24 +53,26 @@ class OutpostConsumer(AuthJsonConsumer):
             return
         self.accept()
         self.outpost = outpost.first()
-        self.outpost.channels.append(self.channel_name)
-        LOGGER.debug("added channel to outpost", channel_name=self.channel_name)
-        self.outpost.save()
+        OutpostState(
+            uid=self.channel_name, last_seen=datetime.now(), _outpost=self.outpost
+        ).save(timeout=OUTPOST_HELLO_INTERVAL * 2)
+        LOGGER.debug("added channel to cache", channel_name=self.channel_name)
 
     # pylint: disable=unused-argument
     def disconnect(self, close_code):
-        self.outpost.channels.remove(self.channel_name)
-        self.outpost.save()
-        LOGGER.debug("removed channel from outpost", channel_name=self.channel_name)
+        OutpostState.for_channel(self.outpost, self.channel_name).delete()
+        LOGGER.debug("removed channel from cache", channel_name=self.channel_name)
 
     def receive_json(self, content: Data):
         msg = from_dict(WebsocketMessage, content)
+        state = OutpostState(
+            uid=self.channel_name,
+            last_seen=datetime.now(),
+            _outpost=self.outpost,
+        )
         if msg.instruction == WebsocketMessageInstruction.HELLO:
-            cache.set(self.outpost.state_cache_prefix("health"), time(), timeout=60)
-            if "version" in msg.args:
-                cache.set(
-                    self.outpost.state_cache_prefix("version"), msg.args["version"]
-                )
+            state.version = msg.args.get("version", None)
+            state.save(timeout=OUTPOST_HELLO_INTERVAL * 2)
         elif msg.instruction == WebsocketMessageInstruction.ACK:
             return
 
@@ -80,7 +81,7 @@ class OutpostConsumer(AuthJsonConsumer):
 
     # pylint: disable=unused-argument
     def event_update(self, event):
-        """Event handler which is called by post_save signals"""
+        """Event handler which is called by post_save signals, Send update instruction"""
         self.send_json(
             asdict(
                 WebsocketMessage(instruction=WebsocketMessageInstruction.TRIGGER_UPDATE)

passbook/outposts/migrations/0007_remove_outpost_channels.py

@@ -0,0 +1,17 @@
+# Generated by Django 3.1.2 on 2020-10-14 08:32
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("passbook_outposts", "0006_auto_20201003_2239"),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name="outpost",
+            name="channels",
+        ),
+    ]

passbook/outposts/models.py

@@ -1,20 +1,18 @@
 """Outpost models"""
-from dataclasses import asdict, dataclass
+from dataclasses import asdict, dataclass, field
 from datetime import datetime
-from typing import Any, Dict, Iterable, Optional
+from typing import Iterable, List, Optional, Union
 from uuid import uuid4
 
 from dacite import from_dict
-from django.contrib.postgres.fields import ArrayField
 from django.core.cache import cache
 from django.db import models, transaction
 from django.db.models.base import Model
 from django.http import HttpRequest
-from django.utils import version
 from django.utils.translation import gettext_lazy as _
 from guardian.models import UserObjectPermission
 from guardian.shortcuts import assign_perm
-from packaging.version import InvalidVersion, parse
+from packaging.version import LegacyVersion, Version, parse
 
 from passbook import __version__
 from passbook.core.models import Provider, Token, TokenIntents, User
@@ -22,6 +20,7 @@ from passbook.lib.config import CONFIG
 from passbook.lib.utils.template import render_to_string
 
 OUR_VERSION = parse(__version__)
+OUTPOST_HELLO_INTERVAL = 10
 
 
 @dataclass
@@ -87,8 +86,6 @@ class Outpost(models.Model):
 
     providers = models.ManyToManyField(Provider)
 
-    channels = ArrayField(models.TextField(), default=list)
-
     @property
     def config(self) -> OutpostConfig:
         """Load config as OutpostConfig object"""
@@ -99,36 +96,15 @@ class Outpost(models.Model):
         """Dump config into json"""
         self._config = asdict(value)
 
-    def state_cache_prefix(self, suffix: str) -> str:
+    @property
+    def state_cache_prefix(self) -> str:
         """Key by which the outposts status is saved"""
-        return f"outpost_{self.uuid.hex}_state_{suffix}"
+        return f"outpost_{self.uuid.hex}_state"
 
     @property
-    def deployment_health(self) -> Optional[datetime]:
+    def state(self) -> List["OutpostState"]:
         """Get outpost's health status"""
-        key = self.state_cache_prefix("health")
-        value = cache.get(key, None)
-        if value:
-            return datetime.fromtimestamp(value)
-        return None
-
-    @property
-    def deployment_version(self) -> Dict[str, Any]:
-        """Get deployed outposts version, and if the version is behind ours.
-        Returns a dict with keys version and outdated."""
-        key = self.state_cache_prefix("version")
-        value = cache.get(key, None)
-        if not value:
-            return {"version": None, "outdated": False, "should": OUR_VERSION}
-        try:
-            outpost_version = parse(value)
-            return {
-                "version": value,
-                "outdated": outpost_version < OUR_VERSION,
-                "should": OUR_VERSION,
-            }
-        except InvalidVersion:
-            return {"version": version, "outdated": False, "should": OUR_VERSION}
+        return OutpostState.for_outpost(self)
 
     @property
     def user(self) -> User:
@@ -189,3 +165,53 @@ class Outpost(models.Model):
 
     def __str__(self) -> str:
         return f"Outpost {self.name}"
+
+
+@dataclass
+class OutpostState:
+    """Outpost instance state, last_seen and version"""
+
+    uid: str
+    last_seen: Optional[datetime] = field(default=None)
+    version: Optional[str] = field(default=None)
+    version_should: Union[Version, LegacyVersion] = field(default=OUR_VERSION)
+
+    _outpost: Optional[Outpost] = field(default=None)
+
+    @property
+    def version_outdated(self) -> bool:
+        """Check if outpost version matches our version"""
+        if not self.version:
+            return False
+        return parse(self.version) < OUR_VERSION
+
+    @staticmethod
+    def for_outpost(outpost: Outpost) -> List["OutpostState"]:
+        """Get all states for an outpost"""
+        keys = cache.keys(f"{outpost.state_cache_prefix}_*")
+        states = []
+        for key in keys:
+            channel = key.replace(f"{outpost.state_cache_prefix}_", "")
+            states.append(OutpostState.for_channel(outpost, channel))
+        return states
+
+    @staticmethod
+    def for_channel(outpost: Outpost, channel: str) -> "OutpostState":
+        """Get state for a single channel"""
+        key = f"{outpost.state_cache_prefix}_{channel}"
+        data = cache.get(key, {"uid": channel})
+        state = from_dict(OutpostState, data)
+        state.uid = channel
+        # pylint: disable=protected-access
+        state._outpost = outpost
+        return state
+
+    def save(self, timeout=OUTPOST_HELLO_INTERVAL):
+        """Save current state to cache"""
+        full_key = f"{self._outpost.state_cache_prefix}_{self.uid}"
+        return cache.set(full_key, asdict(self), timeout=timeout)
+
+    def delete(self):
+        """Manually delete from cache, used on channel disconnect"""
+        full_key = f"{self._outpost.state_cache_prefix}_{self.uid}"
+        cache.delete(full_key)

passbook/outposts/settings.py

@@ -2,9 +2,9 @@
 from celery.schedules import crontab
 
 CELERY_BEAT_SCHEDULE = {
-    "outposts_k8s": {
+    "outposts_controller": {
         "task": "passbook.outposts.tasks.outpost_controller",
-        "schedule": crontab(minute="*/5"),  # Run every 5 minutes
+        "schedule": crontab(minute="*/5"),
         "options": {"queue": "passbook_scheduled"},
-    }
+    },
 }

passbook/outposts/signals.py

@@ -23,8 +23,10 @@ def ensure_user_and_token(sender, instance: Model, **_):
 def post_save_update(sender, instance: Model, **_):
     """If an OutpostModel, or a model that is somehow connected to an OutpostModel is saved,
     we send a message down the relevant OutpostModels WS connection to trigger an update"""
-    if isinstance(instance, OutpostModel):
-        LOGGER.debug("triggering outpost update from outpostmodel", instance=instance)
+    if isinstance(instance, (OutpostModel, Outpost)):
+        LOGGER.debug(
+            "triggering outpost update from outpostmodel/outpost", instance=instance
+        )
         outpost_send_update.delay(class_to_path(instance.__class__), instance.pk)
         return
 

passbook/outposts/tasks.py

@@ -10,6 +10,7 @@ from passbook.outposts.models import (
     Outpost,
     OutpostDeploymentType,
     OutpostModel,
+    OutpostState,
     OutpostType,
 )
 from passbook.providers.proxy.controllers.docker import ProxyDockerController
@@ -19,9 +20,8 @@ from passbook.root.celery import CELERY_APP
 LOGGER = get_logger()
 
 
-@CELERY_APP.task(bind=True)
-# pylint: disable=unused-argument
-def outpost_controller(self):
+@CELERY_APP.task()
+def outpost_controller():
     """Launch Controller for all Outposts which support it"""
     for outpost in Outpost.objects.exclude(
         deployment_type=OutpostDeploymentType.CUSTOM
@@ -31,17 +31,14 @@ def outpost_controller(self):
         )
 
 
-@CELERY_APP.task(bind=True)
-# pylint: disable=unused-argument
-def outpost_controller_single(
-    self, outpost: str, deployment_type: str, outpost_type: str
-):
+@CELERY_APP.task()
+def outpost_controller_single(outpost_pk: str, deployment_type: str, outpost_type: str):
     """Launch controller and reconcile deployment/service/etc"""
     if outpost_type == OutpostType.PROXY:
         if deployment_type == OutpostDeploymentType.KUBERNETES:
-            ProxyKubernetesController(outpost).run()
+            ProxyKubernetesController(outpost_pk).run()
         if deployment_type == OutpostDeploymentType.DOCKER:
-            ProxyDockerController(outpost).run()
+            ProxyDockerController(outpost_pk).run()
 
 
 @CELERY_APP.task()
@@ -49,9 +46,19 @@ def outpost_send_update(model_class: str, model_pk: Any):
     """Send outpost update to all registered outposts, irregardless to which passbook
     instance they are connected"""
     model = path_to_class(model_class)
-    outpost_model: OutpostModel = model.objects.get(pk=model_pk)
-    for outpost in outpost_model.outpost_set.all():
-        channel_layer = get_channel_layer()
-        for channel in outpost.channels:
-            LOGGER.debug("sending update", channel=channel)
-            async_to_sync(channel_layer.send)(channel, {"type": "event.update"})
+    model_instace = model.objects.get(pk=model_pk)
+    channel_layer = get_channel_layer()
+    if isinstance(model_instace, OutpostModel):
+        for outpost in model_instace.outpost_set.all():
+            _outpost_single_update(outpost, channel_layer)
+    elif isinstance(model_instace, Outpost):
+        _outpost_single_update(model_instace, channel_layer)
+
+
+def _outpost_single_update(outpost: Outpost, layer=None):
+    """Update outpost instances connected to a single outpost"""
+    if not layer:  # pragma: no cover
+        layer = get_channel_layer()
+    for state in OutpostState.for_outpost(outpost):
+        LOGGER.debug("sending update", channel=state.uid, outpost=outpost)
+        async_to_sync(layer.send)(state.uid, {"type": "event.update"})