display any error received when checking for updates

subiquity/controllers/refresh.py

@@ -74,16 +74,17 @@ class RefreshController(BaseController):
             response.raise_for_status()
         except requests.exceptions.RequestException as e:
             log.exception("checking for update")
+            self.check_error = e
             self.check_state = CheckState.FAILED
-            return
-        result = response.json()
-        log.debug("_check_result %s", result)
-        for snap in result["result"]:
-            if snap["name"] == self.snap_name:
-                self.check_state = CheckState.AVAILABLE
-                break
         else:
-            self.check_state = CheckState.UNAVAILABLE
+            result = response.json()
+            log.debug("_check_result %s", result)
+            for snap in result["result"]:
+                if snap["name"] == self.snap_name:
+                    self.check_state = CheckState.AVAILABLE
+                    break
+            else:
+                self.check_state = CheckState.UNAVAILABLE
         if self.view:
             self.view.update_check_state()
 

subiquity/ui/views/refresh.py

@@ -13,6 +13,7 @@
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+import json
 import logging
 
 from urwid import (
@@ -178,10 +179,19 @@ class RefreshView(BaseView):
     def check_state_failed(self):
         self.spinner.stop()
 
-        rows = [Text("<explanation goes here>")]
+        try:
+            result = self.controller.check_error.response.json()
+        except (AttributeError, json.decoder.JSONDecodeError):
+            message = None
+        else:
+            message = result.get("result", {}).get("message")
+        if message is None:
+            message = "Unknown error: {}".format(self.controller.check_error)
+
+        rows = [Text(message)]
 
         buttons = button_pile([
-            done_btn(_("Try again"), on_press=self.still_checking),
+            done_btn(_("Try again"), on_press=self.try_again),
             done_btn(_("Continue without updating"), on_press=self.done),
             other_btn(_("Back"), on_press=self.cancel),
             ])
@@ -190,6 +200,10 @@ class RefreshView(BaseView):
         self.title = self.failed_title
         self._w = screen(rows, buttons, excerpt=_(self.failed_excerpt))
 
+    def try_again(self, sender=None):
+        self.controller.snapd_network_changed()
+        self.check_state_checking()
+
     def update(self, sender=None):
         self.spinner.stop()
 

subiquitycore/core.py

@@ -284,7 +284,7 @@ class Application:
             "signal": Signal(),
             "prober": prober,
             "loop": None,
-            "pool": futures.ThreadPoolExecutor(4),
+            "pool": futures.ThreadPoolExecutor(10),
             "answers": answers,
             "input_filter": input_filter,
             "scale_factor": scale,