Allow specifying the docker network

Allow for the use of docker networks other than "bridge" and "none" for
for autograding containers. The network name can be specified in
config.py or via the preallocator. The network must exist on the target
docker host for the containers to run.

config.template.py

@@ -89,6 +89,8 @@ class Config(object):
     # Docker autograding container resource limits
     DOCKER_CORES_LIMIT = None
     DOCKER_MEMORY_LIMIT = None  # in MB
+    # Docker network to attach to (must already exist)
+    DOCKER_NETWORK = None
 
     # Maximum size for input files in bytes
     MAX_INPUT_FILE_SIZE = 10 * 1024 * 1024 * 1024  # 10GB

restful_tango/tangoREST.py

@@ -115,17 +115,22 @@ def createTangoMachine(self, image, vmms=Config.VMMS_NAME, vmObj=None):
         """createTangoMachine - Creates a tango machine object from image"""
         cores = getattr(Config, "DOCKER_CORES_LIMIT", None)
         memory = getattr(Config, "DOCKER_MEMORY_LIMIT", None)
+        docker_network = getattr(Config, "DOCKER_NETWORK", None)
+        if docker_network:
+            network = {"docker_attachment": docker_network}
         if vmObj and "cores" in vmObj and "memory" in vmObj:
             cores = vmObj["cores"]
             memory = vmObj["memory"]
+        if vmObj and "network" in vmObj:
+            network = vmObj["network"]
         return TangoMachine(
             name=image,
             vmms=vmms,
             image="%s" % (image),
             cores=cores,
             memory=memory,
             disk=None,
-            network=None,
+            network=network,
         )
 
     def convertJobObj(self, dirName, jobObj):

vmms/localDocker.py

@@ -11,6 +11,7 @@
 import os
 import sys
 import shutil
+from collections.abc import Mapping
 import config
 from tangoObjects import TangoMachine
 
@@ -163,6 +164,12 @@ def runJob(self, vm, runTimeout, maxOutputFileSize, disableNetwork):
             args = args + ["-m", f"{vm.memory}m"]
         if disableNetwork:
             args = args + ["--network", "none"]
+        elif (
+            vm.network
+            and isinstance(vm.network, Mapping)
+            and "docker_attachment" in vm.network
+        ):
+            args.append("--network", vm.network["docker_attachment"])
         args = args + [vm.image]
         args = args + ["sh", "-c"]