Merge ~jocave/plainbox-provider-resource:handle-track-info into plainbox-provider-resource:master

[Jonathan Cave]

With UC18 images model assertions have started appearing where the gadget and kernel snap fields specify a track that should be used. This breaks templates that were using this field to check details in the gadget snap of the system e.g. the job might try to query the path /snap/pc=18/current/...

Example resource unit produced on a UC18 device, note in this case the addition of the "gadget_track" key:
https://paste.ubuntu.com/p/pgXGCvscZ7/

[Sylvain Pineau (sylvain-pineau)]

+1

review: Approve

diff --git a/bin/snapd_resource b/bin/snapd_resource
index c65249c..d88ffa0 100755
--- a/bin/snapd_resource
+++ b/bin/snapd_resource
@@ -74,7 +74,8 @@ class AssertionQuery(SnapdQuery):
         """ Super naive Assertion parser
 
         No attempt to handle assertions with a body. Discards signatures based
-        on lack of colon characters.
+        on lack of colon characters. Update: need to be less naive about
+        gadget and kernel names on UC18
         """
         data = self.get(self.prefix + assertion)
         count = int(data.headers['X-Ubuntu-Assertions-Count'])
@@ -82,7 +83,14 @@ class AssertionQuery(SnapdQuery):
             for line in io.StringIO(data.text):
                 if line.strip() == "":
                     print()
-                if ':' in line:
+                if line.count(':') == 1:
+                    key, val = [x.strip() for x in line.split(':')]
+                    if key in ('gadget', 'kernel'):
+                        if '=' in val:
+                            snap, track = [x.strip() for x in val.split('=')]
+                            print('{}: {}'.format(key, snap))
+                            print('{}_track: {}'.format(key, track))
+                            continue
                     print(line.strip())
         return count