Avoid to corrupt project in case of error during loading

Fix #651

gns3server/controller/project.py

@@ -570,7 +570,10 @@ class Project:
         self._status = "opened"
 
         path = self._topology_file()
-        if os.path.exists(path):
+        if not os.path.exists(path):
+            return
+        shutil.copy(path, path + ".backup")
+        try:
             topology = load_topology(path)["topology"]
             for compute in topology.get("computes", []):
                 yield from self.controller.add_compute(**compute)
@@ -584,10 +587,22 @@ class Project:
                 for node_link in link_data["nodes"]:
                     node = self.get_node(node_link["node_id"])
                     yield from link.add_node(node, node_link["adapter_number"], node_link["port_number"], label=node_link.get("label"))
-
             for drawing_data in topology.get("drawings", []):
                 drawing = yield from self.add_drawing(**drawing_data)
 
+        # We catch all error to be able to rollback the .gns3 to the previous state
+        except Exception as e:
+            for compute in self._project_created_on_compute:
+                try:
+                    yield from compute.post("/projects/{}/close".format(self._id))
+                # We don't care if a compute is down at this step
+                except (aiohttp.errors.ClientOSError, aiohttp.web.HTTPNotFound, aiohttp.web.HTTPConflict):
+                    pass
+            shutil.copy(path + ".backup", path)
+            self._status = "closed"
+            raise e
+        os.remove(path + ".backup")
+
         # Should we start the nodes when project is open
         if self._auto_start:
             yield from self.start_all()

tests/controller/test_project_open.py

@@ -15,13 +15,16 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+
 import json
 import pytest
+import aiohttp
 
 from tests.utils import asyncio_patch, AsyncioMagicMock
 
 from gns3server.controller.compute import Compute
 
+
 @pytest.fixture
 def demo_topology():
     """
@@ -112,7 +115,7 @@ def demo_topology():
                     "z": 1
                 },
                 {
-                    "compute_id": "local",
+                    "compute_id": "vm",
                     "console": 5001,
                     "console_type": "telnet",
                     "height": 59,
@@ -148,6 +151,7 @@ def test_open(controller, tmpdir, demo_topology, async_run, http_server):
         json.dump(demo_topology, f)
 
     controller._computes["local"] = Compute("local", controller=controller, host=http_server[0], port=http_server[1])
+    controller._computes["vm"] = controller._computes["local"]
 
     project = async_run(controller.load_project(str(tmpdir / "demo.gns3")))
     assert project.status == "opened"
@@ -159,3 +163,21 @@ def test_open(controller, tmpdir, demo_topology, async_run, http_server):
     assert len(project.drawings) == 1
 
     assert project.name == "demo"
+
+
+def test_open_missing_compute(controller, tmpdir, demo_topology, async_run, http_server):
+    """
+    If a compute is missing the project should not be open and the .gns3 should
+    be the one before opening the project
+    """
+    with open(str(tmpdir / "demo.gns3"), "w+") as f:
+        json.dump(demo_topology, f)
+
+    controller._computes["local"] = Compute("local", controller=controller, host=http_server[0], port=http_server[1])
+
+    with pytest.raises(aiohttp.web_exceptions.HTTPNotFound):
+        project = async_run(controller.load_project(str(tmpdir / "demo.gns3")))
+    assert controller.get_project("3c1be6f9-b4ba-4737-b209-63c47c23359f").status == "closed"
+    with open(str(tmpdir / "demo.gns3"), "r") as f:
+        topo = json.load(f)
+        assert len(topo["topology"]["nodes"]) == 2