Move element-info to a standard entry-point

Move element-info from a wrapper script to a standard entry-point
console_script.

Update the documentation to explain how to run it for development.  I
don't think we should support the idea that you can check-out the code
and run ./bin/disk-image-create -- it has dependencies (dib-utils,
etc) and needs to be run from a virtualenv (this is what CI in the
gate does).  A follow-up can clean-up some of the path munging stuff
we have for this in disk-image-create.

Change-Id: Ic0c03995667f320a27ac30441279f3e6abb6bca8

MANIFEST.in

@@ -1,5 +1,4 @@
 include bin/disk-image-create
-include bin/element-info
 include bin/ramdisk-image-create
 graft lib
 graft elements

bin/element-info

@@ -1,21 +0,0 @@
-#!/usr/bin/env python
-# Copyright 2013 Hewlett-Packard Development Company, L.P.
-#
-# 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.
-
-import sys
-
-from diskimage_builder.element_dependencies import main
-
-
-sys.exit(main(sys.argv))

diskimage_builder/element_dependencies.py

@@ -179,7 +179,7 @@ def find_all_elements(paths=None):
     return all_elements
 
 
-def main(argv):
+def main():
     diskimage_builder.logging_config.setup()
 
     parser = argparse.ArgumentParser()
@@ -194,7 +194,7 @@ def main(argv):
                         help=('Output eval-able bash strings for '
                               'IMAGE_ELEMENT variables'))
 
-    args = parser.parse_args(argv[1:])
+    args = parser.parse_args(sys.argv[1:])
 
     all_elements = find_all_elements()
 
@@ -232,3 +232,6 @@ def main(argv):
         print(' '.join(elements))
 
     return 0
+
+if __name__ == "__main__":
+    main()

doc/source/developer/invocation.rst

@@ -1,3 +1,13 @@
+Installation
+============
+
+For general use, you can use distribution packages or install via
+``pip`` in a ``virtualenv``
+
+For development purposes, you can use ``pip -e`` to install into a
+local development/testing ``virtualenv``, or use ``tox -e venv --
+disk-image-create`` to run within a ``tox`` created environment.
+
 Invocation
 ==========
 

lib/common-functions

@@ -194,6 +194,7 @@ function arg_to_elements() {
     IMAGE_ELEMENT="$RAMDISK_ELEMENT $IMAGE_ELEMENT"
   fi
   echo "Building elements: $IMAGE_ELEMENT"
+  export IMAGE_ELEMENT
 
   # element-info will output bash code to create
   #  * IMAGE_ELEMENT
@@ -217,7 +218,7 @@ function arg_to_elements() {
   #        element=$i
   #        path=${image_elements[$i]
   #      done
-  eval "$($SCRIPT_HOME/element-info --env $IMAGE_ELEMENT)"
+  eval "$(element-info --env $IMAGE_ELEMENT)"
 
   echo "Expanded element dependencies to: $IMAGE_ELEMENT"
 }

releasenotes/notes/element-info-entry-point-448bf622be6061a0.yaml

@@ -0,0 +1,9 @@
+---
+deprecations:
+
+  - The ``element-info`` script is now provided by a standard python
+    entry-point, rather than an explicit wrapper script.  This may
+    affect you if you were running this script directly out of ``bin``
+    in the source directory without installing.  See developer notes
+    for details on using developer-installs with virtual environments
+    for testing.

setup.cfg

@@ -28,7 +28,6 @@ packages =
 scripts =
     bin/dib-lint
     bin/disk-image-create
-    bin/element-info
     bin/ramdisk-image-create
 data_files =
     share/diskimage-builder/elements = elements/*
@@ -57,4 +56,5 @@ universal = 1
 
 [entry_points]
 console_scripts =
+    element-info = diskimage_builder.element_dependencies:main
     dib-block-device = diskimage_builder.block_device:main