remote/exporter: add poll tracking override

The poll() function tracks whether the local information has changed vs
the previous state and only takes the availability into account. Since
we now poll() the resource on creation, the local state is immediately
updated with the information on the resource. This also means that
instead of a "clear" by sending an unavailable resource, we don't send an
update to the exporter in case the resource is still available.

Previously:
Create Resource -> unavailable
poll() -> update to coordinator

Now:
create resource, poll() -> availability stays the same and we skip the
information update.

Add an explicit override to the poll function to mark the state as dirty
for the first poll().

Signed-off-by: Rouven Czerwinski <[email protected]>

labgrid/remote/exporter.py

@@ -135,7 +135,7 @@ def stop(self):
             raise
         self.start_params = None
 
-    def poll(self):
+    def poll(self, dirty=False):
         # poll and check for updated params/avail
         self.local.poll()
 
@@ -154,7 +154,6 @@ def poll(self):
                 self.stop()
 
         # check if resulting information has changed
-        dirty = False
         if self.avail != (self.local.avail and not self.broken):
             self.data["avail"] = self.local.avail and not self.broken
             dirty = True
@@ -1003,7 +1002,7 @@ async def add_resource(self, group_name, resource_name, cls, params):
             res = group[resource_name] = export_cls(
                 config, host=self.hostname, proxy=getfqdn(), proxy_required=proxy_req
             )
-            res.poll()
+            res.poll(dirty=True)
         else:
             config["params"]["extra"] = {
                 "proxy": getfqdn(),