Merge pull request #82 from DistributedSystemsGroup/eur/volumes-fix

Fix volume description and update docs

docs/zapps/zapp_format.rst

@@ -82,13 +82,13 @@ A number of special values can be used, these will be substituted by Zoe when th
 volumes
 ^^^^^^^
 
-array
+object
 
-A list of additional volumes to be mounted in this service container. Each volume is described by an array with three elements:
+A list of additional volumes to be mounted in this service container. Each volume is described by an object with three elements:
 
-* host path: the path on the host to mounted
-* container path: the path inside the container where host path should be mounted
-* read only: a boolean, if true the mountpoint will be read only
+* name: the name for this volume. In the container the volume will be mounted as ``/mnt/<name>``
+* path: the path on the host (usually on a shared filasystem) that should be mounted in this service container
+* read_only: a boolean, if true the volume will be read only
 
 Zoe will always mount the user workspace directory in ``$ZOE_WORKSPACE``.
 

tests/zapp.json

@@ -4,7 +4,13 @@
     "services": [
         {
             "image": "nginx:alpine",
-            "volumes": [],
+            "volumes": [
+                {
+                    "path": "/tmp",
+                    "name": "test",
+                    "read_only": true
+                }
+            ],
             "environment": [],
             "essential_count": 1,
             "monitor": true,

zoe_lib/state/__init__.py

@@ -18,5 +18,5 @@
 from zoe_lib.state.base import Base
 from zoe_lib.state.execution import Execution
 from zoe_lib.state.sql_manager import SQLManager
-from zoe_lib.state.service import Service, VolumeDescription
+from zoe_lib.state.service import Service, VolumeDescription, VolumeDescriptionHostPath
 from zoe_lib.state.port import Port

zoe_lib/state/service.py

@@ -63,11 +63,17 @@ class ResourceReservation:
 
 class VolumeDescription:
     """A generic description for container volumes."""
-    def __init__(self, data):
-        self.type = "host_directory"
-        self.path = data[0]
-        self.mount_point = data[1]
-        self.readonly = data[2]
+    def __init__(self, vtype: str):
+        self.type = vtype
+
+
+class VolumeDescriptionHostPath(VolumeDescription):
+    """Host-based volumes."""
+    def __init__(self, name: str, path: str, readonly: bool):
+        super().__init__("host_directory")
+        self.path = path
+        self.mount_point = '/mnt/' + name
+        self.readonly = readonly
 
 
 class Service:
@@ -113,7 +119,7 @@ class Service:
         self.environment = self.description['environment']
         self.command = self.description['command']
         self.resource_reservation = ResourceReservation(self.description['resources'])
-        self.volumes = [VolumeDescription(v) for v in self.description['volumes']]
+        self.volumes = [VolumeDescriptionHostPath(v['path'], v['name'], v['read_only']) for v in self.description['volumes']]
         self.replicas = self.description['replicas']
 
     def serialize(self):

zoe_master/backends/common.py

@@ -15,10 +15,10 @@
 
 """The high-level interface that Zoe uses to talk to the configured container backend."""
 
-from typing import Dict
+from typing import Dict, List
 
 from zoe_lib.config import get_conf
-from zoe_lib.state import Service, Execution
+from zoe_lib.state import Service, Execution, VolumeDescription
 from zoe_master.exceptions import ZoeStartExecutionFatalException
 from zoe_master.workspace.filesystem import ZoeFSWorkspace
 
@@ -43,14 +43,15 @@ def gen_environment(execution: Execution, service: Service, env_subst_dict: Dict
     env_list.append(('SERVICE_NAME', service.name))
     env_list.append(('PROXY_PATH', get_conf().proxy_path))
 
-    fswk = ZoeFSWorkspace()
-    env_list.append(('ZOE_WORKSPACE', fswk.get_mountpoint()))
+    wk_vol = ZoeFSWorkspace().get(execution.user_id)
+    env_list.append(('ZOE_WORKSPACE', wk_vol.mount_point))
     return env_list
 
 
-def gen_volumes(service_: Service, execution: Execution):
+def gen_volumes(service: Service, execution: Execution) -> List[VolumeDescription]:
     """Return the list of default volumes to be added to all containers."""
-    vol_list = []
+    vol_list = service.volumes
+
     fswk = ZoeFSWorkspace()
     wk_vol = fswk.get(execution.user_id)
 

zoe_master/backends/kubernetes/api_client.py

@@ -26,7 +26,7 @@ import pykube
 from zoe_master.stats import ClusterStats, NodeStats
 from zoe_master.backends.service_instance import ServiceInstance
 from zoe_lib.version import ZOE_VERSION
-from zoe_lib.state import VolumeDescription
+from zoe_lib.state import VolumeDescription, VolumeDescriptionHostPath
 from zoe_lib.config import get_conf
 
 log = logging.getLogger(__name__)
@@ -191,22 +191,29 @@ class KubernetesReplicationControllerConf:
         count = 0
 
         for vol in volumes:
-            if vol.type != "host_directory":
-                log.error('Swarm backend does not support volume type {}'.format(vol.type))
-
-            aux['spec']['containers'][0]['volumeMounts'][count]['mountPath'] = vol.mount_point
-            aux['spec']['containers'][0]['volumeMounts'][count]['name'] = name + "-" + str(count)
-            count += 1
+            if vol.type == "host_directory":
+                assert isinstance(vol, VolumeDescriptionHostPath)
+                aux['spec']['containers'][0]['volumeMounts'][count]['mountPath'] = vol.mount_point
+                aux['spec']['containers'][0]['volumeMounts'][count]['name'] = name + "-" + str(count)
+                count += 1
+            else:
+                log.error('Kubernetes backend does not support volume type {}'.format(vol.type))
+                continue
 
         aux['spec']['volumes'] = [{} for _ in range(len(volumes))]
         count = 0
 
         for vol in volumes:
-            aux['spec']['volumes'][count]['name'] = name + "-" + str(count)
-            aux['spec']['volumes'][count]['hostPath'] = {
-                'path': vol.path
-            }
-            count += 1
+            if vol.type == "host_directory":
+                assert isinstance(vol, VolumeDescriptionHostPath)
+                aux['spec']['volumes'][count]['name'] = name + "-" + str(count)
+                aux['spec']['volumes'][count]['hostPath'] = {
+                    'path': vol.path
+                }
+                count += 1
+            else:
+                log.error('Kubernetes backend does not support volume type {}'.format(vol.type))
+                continue
 
     def get_json(self):
         """Get json file"""

zoe_master/backends/service_instance.py

@@ -56,7 +56,7 @@ class ServiceInstance:
 
         self.labels = zoe_master.backends.common.gen_labels(service, execution)
         self.environment = service.environment + zoe_master.backends.common.gen_environment(execution, service, env_subst_dict)
-        self.volumes = service.volumes + zoe_master.backends.common.gen_volumes(service, execution)
+        self.volumes = zoe_master.backends.common.gen_volumes(service, execution)
 
         self.command = service.command
 

zoe_master/backends/swarm/api_client.py

@@ -40,7 +40,7 @@ import docker.models.containers
 import requests.exceptions
 
 from zoe_lib.config import get_conf
-from zoe_lib.state import Service
+from zoe_lib.state import Service, VolumeDescriptionHostPath
 from zoe_master.stats import ClusterStats, NodeStats
 from zoe_master.backends.service_instance import ServiceInstance
 from zoe_master.exceptions import ZoeException, ZoeNotEnoughResourcesException
@@ -169,9 +169,11 @@ class SwarmClient:
 
         volumes = {}
         for volume in service_instance.volumes:
-            if volume.type != "host_directory":
+            if volume.type == "host_directory":
+                assert isinstance(volume, VolumeDescriptionHostPath)
+                volumes[volume.path] = {'bind': volume.mount_point, 'mode': ("ro" if volume.readonly else "rw")}
+            else:
                 log.error('Swarm backend does not support volume type {}'.format(volume.type))
-            volumes[volume.path] = {'bind': volume.mount_point, 'mode': ("ro" if volume.readonly else "rw")}
 
         if service_instance.memory_limit is not None:
             mem_limit = service_instance.memory_limit.max

zoe_master/workspace/filesystem.py

@@ -19,7 +19,7 @@ import logging
 import os.path
 
 import zoe_lib.config as config
-from zoe_lib.state import VolumeDescription
+from zoe_lib.state import VolumeDescriptionHostPath
 import zoe_master.workspace.base
 
 log = logging.getLogger(__name__)
@@ -46,8 +46,8 @@ class ZoeFSWorkspace(zoe_master.workspace.base.ZoeWorkspaceBase):
     @classmethod
     def get_mountpoint(cls):
         """Get the volume mount point."""
-        return '/workspace'
+        return 'workspace'
 
     def get(self, user_id):
         """Return a VolumeDescription for the user workspace."""
-        return VolumeDescription((self.get_path(user_id), self.get_mountpoint(), False))
+        return VolumeDescriptionHostPath(path=self.get_path(user_id), name=self.get_mountpoint(), readonly=False)