.circleci: test for specific Yocto branch

Up to now, all tests did simply check out any latest state of all layers
to perform testing. This is sufficient for master in most cases, but
will fail when attempting to test for other releases as it is required
for stable branch updates.

Unfortunately, despite this would be the best reference, currently there
is no way in circleci to determine the actual branch a pull request was
opened against. See also https://ideas.circleci.com/ideas/CCI-I-894

Thus for now, we define the targeted Yocto/poky branch and release
version with environment variables, named 'YOCTO_BRANCH' and
'YOCTO_VERSION'.

With them, the job now clones the exact branches required and also
writes the exact sstate mirror path required into local.conf.

By adapting the environment variable for different stable branches this
potentially allows running tests against the concrete poky version.

Signed-off-by: Enrico Jorns <[email protected]>

.circleci/config.yml

@@ -5,6 +5,8 @@ jobs:
     docker:
       - image: crops/yocto:ubuntu-19.04-builder
         environment:
+          YOCTO_BRANCH: master
+          YOCTO_VERSION: "3.1"
           LC_ALL: en_US.UTF-8
           LANG: en_US.UTF-8
           LANGUAGE: en_US.UTF-8
@@ -18,10 +20,10 @@ jobs:
             - sstate-test-
       - run:
           name: Clone poky
-          command: git clone git://git.yoctoproject.org/poky
+          command: git clone -b ${YOCTO_BRANCH} git://git.yoctoproject.org/poky
       - run:
           name: Clone meta-oe
-          command: git clone https://github.com/openembedded/meta-openembedded.git meta-oe
+          command: git clone -b ${YOCTO_BRANCH} https://github.com/openembedded/meta-openembedded.git meta-oe
       - run:
           name: Link meta-rauc
           command: ln -sf . meta-rauc
@@ -30,7 +32,7 @@ jobs:
           command: mkdir -p meta-this/conf/ && cp .circleci/*.sample meta-this/conf/.
       - run:
           name: Initialize build directory
-          command: TEMPLATECONF=../meta-this/conf source poky/oe-init-build-env build
+          command: TEMPLATECONF=../meta-this/conf source poky/oe-init-build-env build && sed -i s/YOCTO_VERSION/${YOCTO_VERSION}/g conf/local.conf && cat conf/local.conf
       - run:
           name: Build rauc
           command: source poky/oe-init-build-env build && bitbake rauc

.circleci/local.conf.sample

@@ -20,6 +20,5 @@ CONF_VERSION = "1"
 SSTATE_DIR ?= "${TOPDIR}/sstate-cache"
 SSTATE_MIRRORS = "\
 file://.* http://sstate.yoctoproject.org/dev/PATH;downloadfilename=PATH \n \
-file://.* http://sstate.yoctoproject.org/2.6/PATH;downloadfilename=PATH \n \
-file://.* http://sstate.yoctoproject.org/2.7/PATH;downloadfilename=PATH \n \
+file://.* http://sstate.yoctoproject.org/YOCTO_VERSION/PATH;downloadfilename=PATH \n \
 "