Move install type enablement into base element

Move whether the package or source install type is enabled out of the
source-repositories element and into the base element.
source-repositories wasn't a great fit for this functionality to begin
with.

Specify the install type for an element via the
DIB_INSTALLTYPE_<install_dir_prefix> environment variable.

Additionally with this approach, any new install type can be added
in an element, without having to update source-repositories or anything
in dib.

You could just write your install type implementation under
nova-foo-install, then define DIB_INSTALLTYPE_nova=foo in your
environment, and the scripts under nova-foo-install would get run during
the image build.

Source installs (any scripts under <install_dir_prefix>-source-install)
is the default install type for all elements.

Change-Id: I9414aca360c41e030e27d3d0c0a52d9d8e13d8b1

README.md

@@ -107,6 +107,42 @@ source-repositories
 Git repositories and tarballs obtained via the source-repositories element will
 be cached.
 
+Install Types
+-------------
+
+Install types permit elements to be installed from different sources, such as
+git repositories, distribution packages, or pip.
+
+Many elements expose different install types. The different implementations
+live under <install-dir-prefix>-<install-type>-install directories under an
+element's install.d. The base element enables the chosen install type by
+symlinking the correct hook scripts under install.d directly.
+<install-dir-prefix> can be a string of alphanumeric and '-' characters, but
+typically corresponds to the element name.
+
+For example, the nova element would provide:
+
+    nova/install.d/nova-package-install/74-nova
+    nova/install.d/nova-source-install/74-nova
+
+The following symlink would be created for the package install type:
+
+    install.d/74-nova -> nova-package-install/74-nova
+
+Or, for the source install type:
+
+    install.d/74-nova -> nova-source-install/74-nova
+
+All other scripts that exist under install.d for an element will be executed as
+normal. This allows common install code to live in a script outside of
+<install-dir-prefix>-package-install or <install-dir-prefix>-source-install.
+
+To set the install type for an element define an environment variable
+DIB_INSTALLTYPE_<install_dir_prefx>. Note that if you used '-' characters in
+your install directory prefix, those need to be replaced with '_' in the
+environment variable.
+
+
 C and C++ compilation
 ---------------------
 

elements/base/extra-data.d/99-enable-install-types

@@ -0,0 +1,71 @@
+#!/bin/bash
+# Copyright 2014 Red Hat, Inc.
+# All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+
+set -eux
+
+declare -a SPECIFIED_ELEMS
+
+# Add a blank first element to the array, since we're running with -u, we don't
+# want an unbound variable error if no element install types were specified.
+SPECIFIED_ELEMS[0]=""
+
+# List of all env vars to set install types
+PREFIX="DIB_INSTALLTYPE_"
+INSTALL_TYPE_VARS=$(env | grep ^$PREFIX | cut -d'=' -f1)
+
+for _install_type_var in $INSTALL_TYPE_VARS; do
+
+    # Get the element name and its install type
+    INSTALLDIRPREFIX=${_install_type_var:${#PREFIX}}
+    INSTALLDIRPREFIX=${INSTALLDIRPREFIX//_/-}
+    eval INSTALLTYPE=\$$_install_type_var
+
+    # Create symlink for correct install type
+    pushd $TMP_HOOKS_PATH/install.d
+    if [ -d $INSTALLDIRPREFIX-$INSTALLTYPE-install ]; then
+        ln -sf $INSTALLDIRPREFIX-$INSTALLTYPE-install/* .
+    fi
+    popd
+
+    SPECIFIED_ELEMS+=($INSTALLDIRPREFIX)
+
+done
+
+# For any existing *-source-install directory under install.d, if an
+# environment variable setting a different install type was not seen, enable
+# the source install type.
+source_install_dirs=$(ls -d $TMP_HOOKS_PATH/install.d/*-source-install || true)
+for _source_install_dir in $source_install_dirs; do
+    SUFFIX="-source-install"
+    _source_install_dir=$(basename $_source_install_dir)
+    INSTALLDIRPREFIX=${_source_install_dir%$SUFFIX}
+
+    found=0
+    for specified in ${SPECIFIED_ELEMS[@]}; do
+        if [ "$specified" = "$INSTALLDIRPREFIX" ]; then
+            found=1
+            break
+        fi
+    done
+
+    # install type not specified, assume source
+    if [ "$found" = "0" ]; then
+        pushd $TMP_HOOKS_PATH/install.d
+        ln -sf $_source_install_dir/* .
+        popd
+    fi
+done

elements/source-repositories/extra-data.d/98-source-repositories

@@ -65,6 +65,14 @@ function get_repos_for_element(){
             CACHE_PATH=${CACHE_BASE}/$CACHE_NAME
             make_new_cache $OLD_CACHE_PATH $CACHE_PATH
 
+            # Return if install type is not source
+            local INSTALL_TYPE_VAR=DIB_INSTALLTYPE_${REPONAME//[^A-Za-z0-9]/_}
+            local INSTALL_TYPE=${!INSTALL_TYPE_VAR:-source}
+            if [ ! $INSTALL_TYPE = "source" ]; then
+                echo "$REPONAME install type not set to source"
+                continue
+            fi
+
             case $REPOTYPE in
             git)
                 if [ -z "${!REPOLOCATION_OVERRIDE:-""}" -a -n "${DIB_GITREPOBASE:-""}" ] ; then
@@ -136,9 +144,6 @@ function get_repos_for_element(){
                     sudo curl $REPOLOCATION -o $REPO_DEST
                 fi
                 ;;
-            package)
-                echo "$REPONAME set to package source type"
-                ;;
             *)
                 echo "Unsupported repository type: $REPOTYPE"
                 return 1
@@ -149,20 +154,6 @@ function get_repos_for_element(){
             # elements (like a pypi dependency cache).
             echo "$REPOPATH" | sudo dd of=$TMP_MOUNT_PATH/etc/dib-source-repositories oflag=append conv=notrunc
 
-            # Save the $REPOTYPE used so that it can be used later by install.d
-            if [ "$REPOTYPE" = "package" ]; then
-                REPOINSTALLTYPE="package"
-            else
-                REPOINSTALLTYPE="source"
-            fi
-
-            # Create symlink for correct install type
-            pushd $TMP_HOOKS_PATH/install.d
-            if [ -e $REPONAME-$REPOINSTALLTYPE-install ]; then
-                ln -sf $REPONAME-$REPOINSTALLTYPE-install/* .
-            fi
-            popd
-
         else
             echo "Couldn't parse '$line' as a source repository"
             return 1