Support to specify branch when building the image

- Explicity specify branch name for building non-dev image
- Use branch name for building dev image in devstack
- Update the doc

Candidate backport for stable/train

Change-Id: I4d2fe38fac34c75b42234fa7a20aba51e6dc1c4e

devstack/plugin.sh

@@ -447,7 +447,12 @@ function create_guest_image {
 
     echo "Starting to create guest image..."
 
-    $DEST/trove/integration/scripts/trovestack build-image ${TROVE_DATASTORE_TYPE} ${TROVE_IMAGE_OS} ${TROVE_IMAGE_OS_RELEASE} true
+    TROVE_BRANCH=${TROVE_BRANCH} $DEST/trove/integration/scripts/trovestack \
+      build-image \
+      ${TROVE_DATASTORE_TYPE} \
+      ${TROVE_IMAGE_OS} \
+      ${TROVE_IMAGE_OS_RELEASE} \
+      true
 
     image_name="trove-${TROVE_IMAGE_OS}-${TROVE_IMAGE_OS_RELEASE}-${TROVE_DATASTORE_TYPE}"
     image_file=$HOME/images/${image_name}.qcow2

doc/source/admin/trovestack.rst

@@ -80,6 +80,9 @@ The trove guest agent image could be created by running the following command:
     environment, it should be the ``stack`` user.
   * ``GUEST_WORKING_DIR``: The place to save the guest image, default value is
     ``$HOME/images``.
+  * ``TROVE_BRANCH``: only used in dev mode. The branch name of Trove code
+    repository, by default it's master, use other branches as needed such as
+    stable/train.
 
 For example, in order to build a MySQL image for Ubuntu Xenial operating
 system in development mode:

integration/scripts/files/elements/guest-agent/source-repository-guest-agent

@@ -1,3 +1,3 @@
 # This is used for source-based builds
-guest-agent git /opt/guest-agent https://opendev.org/openstack/trove
+guest-agent git /opt/guest-agent https://opendev.org/openstack/trove master
 upper-constraints file /opt/upper-constraints.txt https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt

integration/scripts/files/elements/ubuntu-guest/extra-data.d/15-trove-dep

@@ -8,7 +8,7 @@ set -o xtrace
 
 source $_LIB/die
 
-BRANCH_OVERRIDE=${BRANCH_OVERRIDE:-default}
+TROVE_BRANCH=${TROVE_BRANCH:-'master'}
 REQUIREMENTS_FILE=${TROVESTACK_SCRIPTS}/../../requirements.txt
 
 [ -n "$TMP_HOOKS_PATH" ] || die "Temp hook path not set"
@@ -30,13 +30,10 @@ if [ -f "${DEST}/requirements/${UC_FILE}" ]; then
         of="${TMP_HOOKS_PATH}/${UC_FILE}"
 else
     UC_DIR=$(pwd)
-    UC_BRANCH=${BRANCH_OVERRIDE}
-    if [ "${UC_BRANCH}" == "default" ]; then
-        UC_BRANCH=master
-    fi
+    UC_BRANCH=${TROVE_BRANCH##stable/}
 
     set +e
-    curl -o "${UC_DIR}/${UC_FILE}" "https://opendev.org/openstack/requirements/raw/branch/${UC_BRANCH}/${UC_FILE}"
+    curl -L -o "${UC_DIR}/${UC_FILE}" "https://releases.openstack.org/constraints/upper/${UC_BRANCH}"
     set -e
 
     if [ -f "${UC_DIR}/${UC_FILE}" ]; then

integration/scripts/functions_qemu

@@ -36,6 +36,8 @@ function build_vm() {
         export HOST_SCP_USERNAME=${HOST_SCP_USERNAME:-$(whoami)}
         export HOST_USERNAME=${HOST_SCP_USERNAME}
         export SSH_DIR=${SSH_DIR:-"$HOME/.ssh"}
+        export DEST=${DEST:-'/opt/stack'}
+        export TROVE_BRANCH=${TROVE_BRANCH:-'master'}
         manage_ssh_keys
     fi
 

integration/scripts/trovestack

@@ -827,7 +827,7 @@ function cmd_build_image() {
     local IMAGE_GUEST_OS=${2:-'ubuntu'}
     local IMAGE_GUEST_RELEASE=${3:-'xenial'}
     local DEV_MODE=${4:-'true'}
-    local guest_username=${5:-"ubuntu"}
+    local guest_username=${5:-'ubuntu'}
     local output=$6
 
     if [[ -z "$output" ]]; then