allow for customizing docker networking

cwltool/job.py

@@ -67,10 +67,11 @@ def run(self, dry_run=False, pull_image=True, rm_container=True, rm_tmpdir=True,
             runtime.append("--volume=%s:%s:rw" % (os.path.abspath(self.tmpdir), "/tmp"))
             runtime.append("--workdir=%s" % ("/var/spool/cwl"))
             runtime.append("--read-only=true")
-            if kwargs.get("enable_net", None) is None: 
+            if (kwargs.get("enable_net", None) is None and
+                    kwargs.get("custom_net", None) is not None):
                 runtime.append("--net=none")
-            else:
-                runtime.append("--net={0}".format(kwargs.get("enable_net")))
+            elif kwargs.get("custom_net", None) is not None:
+                runtime.append("--net={0}".format(kwargs.get("custom_net")))
 
             if self.stdout:
                 runtime.append("--log-driver=none")

cwltool/main.py

@@ -125,8 +125,12 @@ def arg_parser():
     parser.add_argument("--relative-deps", choices=['primary', 'cwd'], default="primary",
                          help="When using --print-deps, print paths relative to primary file or current working directory.")
 
-    parser.add_argument("--enable-net", help="Use the provided docker's network for container, default to disable network")
-
+    parser.add_argument("--enable-net", action="store_true",
+            help="Use docker's default networking for containers; the default is "
+            "to disable networking.")
+    parser.add_argument("--custom-net", type=str,
+            help="Will be passed to `docker run` as the '--net' parameter. "
+            "Implies '--enable-net'.")
     parser.add_argument("workflow", type=str, nargs="?", default=None)
     parser.add_argument("job_order", nargs=argparse.REMAINDER)