record current and new versions of snap

examples/snaps/v2-snaps-subiquity.json

@@ -0,0 +1,62 @@
+{
+  "type": "sync",
+  "status-code": 200,
+  "status": "OK",
+  "result": {
+    "id": "ba2aj8guta0zSRlT3QM5aJNAUXPlBtf9",
+    "title": "subiquity",
+    "summary": "Ubuntu installer",
+    "description": "The Ubuntu server installer",
+    "installed-size": 51191808,
+    "name": "subiquity",
+    "publisher": {
+      "id": "canonical",
+      "username": "canonical",
+      "display-name": "Canonical",
+      "validation": "verified"
+    },
+    "developer": "canonical",
+    "status": "active",
+    "type": "app",
+    "version": "ubuntu-19.04.2",
+    "channel": "stable",
+    "ignore-validation": false,
+    "revision": "804",
+    "confinement": "classic",
+    "private": false,
+    "devmode": false,
+    "jailmode": false,
+    "apps": [
+      {
+        "snap": "subiquity",
+        "name": "console-conf"
+      },
+      {
+        "snap": "subiquity",
+        "name": "probert"
+      },
+      {
+        "snap": "subiquity",
+        "name": "subiquity"
+      },
+      {
+        "snap": "subiquity",
+        "name": "subiquity-configure-apt"
+      },
+      {
+        "snap": "subiquity",
+        "name": "subiquity-loadkeys"
+      },
+      {
+        "snap": "subiquity",
+        "name": "subiquity-service",
+        "daemon": "simple",
+        "enabled": true,
+        "active": true
+      }
+    ],
+    "contact": "mailto:mathieu.trudel-lapierre@canonical.com",
+    "mounted-from": "/var/lib/snapd/snaps/subiquity_804.snap",
+    "install-date": "2019-04-09T23:06:31.014843014+12:00"
+  }
+}

subiquity/controllers/refresh.py

@@ -56,12 +56,34 @@ class RefreshController(BaseController):
         self.check_state = CheckState.NOT_STARTED
         self.switch_state = SwitchState.NOT_STARTED
         self.network_state = "down"
+
+        self.current_snap_version = "unknown"
+        self.new_snap_version = ""
+
         self.view = None
         self.offered_first_time = False
         self.answers = self.all_answers.get("Refresh", {})
 
     def start(self):
         self.switch_state = SwitchState.SWITCHING
+        self.run_in_bg(self._bg_get_snap_details, self._got_snap_details)
+
+    def _bg_get_snap_details(self):
+        return self.snapd_connection.get(
+            'v2/snaps/{snap_name}'.format(snap_name=self.snap_name))
+
+    def _got_snap_details(self, fut):
+        try:
+            response = fut.result()
+            response.raise_for_status()
+        except requests.exceptions.RequestException:
+            log.exception("_got_snap_details")
+        else:
+            r = response.json()
+            self.current_snap_version = r['result']['version']
+            log.debug(
+                "current version of snap is: %r",
+                self.current_snap_version)
         channel = self.get_refresh_channel()
         self.run_in_bg(
             lambda: self._bg_switch_snap(channel),
@@ -172,6 +194,10 @@ class RefreshController(BaseController):
             for snap in result["result"]:
                 if snap["name"] == self.snap_name:
                     self.check_state = CheckState.AVAILABLE
+                    self.new_snap_version = snap["version"]
+                    log.debug(
+                        "new version of snap available: %r",
+                        self.new_snap_version)
                     break
             else:
                 self.check_state = CheckState.UNAVAILABLE