Merge lp:~rcj/livecd-rootfs/trunk into lp:livecd-rootfs

[Robert C Jennings]

Add the server snap seed to the ubuntu-cpc project

This patch adds the server snap seed to the ubuntu-cpc project and
allows hooks to replace generic snap assertion.

The generic assertion will be put in place if there are preseeded snaps.
A hook that wants to add its own model should be able to overwrite
the generic assertion. This patch allows a hook to continue unchanged
calling snap_prepare_assertions with a custom brand/model. The patch
will replace the generic brand/model if a custom brand/model is specified.
Prior to this patch the generic brand/model would remain in place.

[Dan Watkins (oddbloke)]

review: Needs Information

[Francis Ginther (fginther)]

Looks good, just a follow up to Dan's comment.

review: Needs Fixing

[Robert C Jennings (rcj)]

Francis, updated.

[Robert C Jennings (rcj)]

This can be simplified to always overwrite the assertion if it exists. live-build/auto/build calls snap_prepare so we can drop the snap_prepare from snap_preseed. If a hook wants to specify a different model they can call snap_prepare with a custom brand/model.

Fixing...

[Robert C Jennings (rcj)]

I've tested these new changes and it works well. Doesn't break downstream cloud images. And it will allow subsequent hooks to overwrite non-generic assertions. Please review.

[Francis Ginther (fginther)]

Looks good, I have a couple of suggestions.

review: Needs Fixing

[Steve Langasek (vorlon)]

review: Needs Fixing

[Francis Ginther (fginther)]

Approve

review: Approve

[Robert C Jennings (rcj)]

This is ready for review again. I've inspected images built with this; downloads had generic models with lxd, aws had lxd, amazon-ssm-agent, and the amazon model. Tested that calling snap_preseed without snap_prepare emits an error and exits the build.

[Steve Langasek (vorlon)]

review: Approve

=== modified file 'debian/changelog'
--- debian/changelog	2018-09-26 00:43:50 +0000
+++ debian/changelog	2018-09-27 20:16:14 +0000
@@ -2,6 +2,10 @@
 
   * Remove device nodes from Docker images. (LP: #1645468) 
 
+  [ Robert C Jennings ]
+  * Add the server snap seed to the ubuntu-cpc project
+  * Allow hooks to replace generic snap assertion
+
  -- Michael Hudson-Doyle <[e-mail]>  Wed, 26 Sep 2018 12:43:23 +1200
 
 livecd-rootfs (2.540) cosmic; urgency=medium

=== modified file 'live-build/auto/config'
--- live-build/auto/config	2018-09-19 14:24:26 +0000
+++ live-build/auto/config	2018-09-27 20:16:14 +0000
@@ -696,6 +696,9 @@
 	ubuntu:*|kubuntu*:*|lubuntu*:*|xubuntu*:*|ubuntu-mate*:*|ubuntustudio*:*|ubuntukylin*:*|ubuntu-budgie*:*)
 		BASE_SEED='desktop'
 		;;
+	ubuntu-cpc:*)
+		BASE_SEED='server'
+		;;
 	ubuntu-server:live)
 		BASE_SEED='server'
 		# subiquity is seeded but in a separate squashfs via hooks; set HOOK_SNAPS and ALL_SNAPS.

=== modified file 'live-build/functions'
--- live-build/functions	2018-05-28 14:39:06 +0000
+++ live-build/functions	2018-09-27 20:16:14 +0000
@@ -427,6 +427,16 @@
     local brand="$(echo $CUSTOM_BRAND_MODEL | cut -d: -f 1)"
     local model="$(echo $CUSTOM_BRAND_MODEL | cut -d: -f 2)"
 
+    # Clear the assertions if they already exist
+    if [ -e "$model_assertion" ] ; then
+        existing_model=$(awk '/^model: / {print $2}' $model_assertion)
+        existing_brand=$(awk '/^brand-id: / {print $2}' $model_assertion)
+        echo "snap_prepare_assertions: replacing $existing_brand:$existing_model with $brand:$model"
+        rm "$model_assertion"
+        rm "$account_key_assertion"
+        rm "$account_assertion"
+    fi
+
     if ! [ -e "$model_assertion" ] ; then
         snap known --remote model series=16 \
             model=$model brand-id=$brand \
@@ -441,7 +451,6 @@
             > "$account_key_assertion"
     fi
 
-
     if ! [ -e "$account_assertion" ] ; then
         local account=$(sed -n -e's/account-id: //p' < "$account_key_assertion")
         snap known --remote account account-id=$account \
@@ -468,13 +477,16 @@
 }
 
 snap_preseed() {
-    # Preseed a snap in the image
+    # Preseed a snap in the image (snap_prepare must be called once prior)
     local CHROOT_ROOT=$1
     local SNAP=$2
     # Per Ubuntu policy, all seeded snaps (with the exception of the core
     # snap) must pull from stable/ubuntu-$(release_ver) as their channel.
     local CHANNEL=${3:-"stable/ubuntu-$(release_ver)"}
 
-    snap_prepare $CHROOT_ROOT
+    if [ ! -e "$CHROOT_ROOT/var/lib/snapd/seed/assertions/model" ]; then
+        echo "ERROR: Snap model assertion not present, snap_prepare must be called"
+        exit 1
+    fi
     _snap_preseed $CHROOT_ROOT $SNAP $CHANNEL
 }