lava-dispatcher: fix the version parsing

The build script is currently failing with:
invalid argument "linaro/lava-dispatcher-debian-stretch-amd64:Source:" for --tag=linaro/lava-dispatcher-debian-stretch-amd64:Source:: Error parsing reference: "linaro/lava-dispatcher-debian-stretch-amd64:Source:" is not a valid repository/tag

Change the parsing of the Packages file:
1. extract the lava-dispatcher package section and print 5 lines,
   which should be more than enough to contain the version.
2. extract the version line from the previous strings extraction, ensuring
   the version belongs to the lava-dispatcher package.
3. get only the value of the Version field.
4. filter out unwanted characters with sed.

Change-Id: Ic15a4f9ebc9d90ee3cb3daedfff7cb39ebecce68
Signed-off-by: Fathi Boudra <fathi.boudra@linaro.org>

1 files changed, 4 insertions, 4 deletions

diff --git a/lava/dispatcher/production/stretch-amd64/build.sh b/lava/dispatcher/production/stretch-amd64/build.sh
index cdf52809..d7f69b33 100755
--- a/lava/dispatcher/production/stretch-amd64/build.sh
+++ b/lava/dispatcher/production/stretch-amd64/build.sh
@@ -9,10 +9,10 @@ ARCHITECTURE=$(basename ${PWD} | cut -f2 -d '-')
 REPO=$(basename $(dirname ${PWD}))
 
 # Get version by parsing Packages file from respective repo.
-VERSION=$(wget -qO - \
-               http://images.validation.linaro.org/${REPO}-repo/dists/${DISTRIBUTION}-backports/main/binary-${ARCHITECTURE}/Packages | \
-                 sed -n '/Package: lava-dispatcher/{n;p}' | \
-                 sed 's/Version: //' | sed 's/[~|+].*//')
+VERSION=$(wget -qO - http://images.validation.linaro.org/${REPO}-repo/dists/${DISTRIBUTION}-backports/main/binary-${ARCHITECTURE}/Packages \
+            | grep -A5 '^Package: lava-dispatcher' | grep '^Version: ' \
+            | awk '{ print $2 }' \
+            | sed 's/[~|+].*//')
 
 image=linaro/lava-dispatcher-debian-${DISTRIBUTION}-${ARCHITECTURE}:${VERSION}
 docker build --no-cache --pull --tag=$image .