bitbake-config-build: add a plugin for config fragments

This allows fine-tuning local configurations with pre-frabricated
configuration snippets in a structured, controlled way. It's also
an important building block for bitbake-setup.

The tool requires that each fragment contains a one-line summary, and one or more
lines of description, as BB_CONF_FRAGMENT_SUMMARY style metadata.

There are three (and a half) operations (list/enable/disable/disable all), and here's the 'list' output:

alex@Zen2:/srv/storage/alex/yocto/build-64$ bitbake-config-build list-fragments
NOTE: Starting bitbake server...
Available fragments in selftest layer located in /srv/work/alex/poky/meta-selftest:

Enabled fragments:
selftest/test-fragment	This is a configuration fragment intended for testing in oe-selftest context

Unused fragments:
selftest/more-fragments-here/test-another-fragment	This is a second configuration fragment intended for testing in oe-selftest context

(From OE-Core rev: fdb611e13bd7aa00360d3a68e4818ef5f05c8944)

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

4 files changed, 196 insertions, 0 deletions

diff --git a/meta-selftest/conf/fragments/more-fragments-here/test-another-fragment.conf b/meta-selftest/conf/fragments/more-fragments-here/test-another-fragment.conf
new file mode 100644
index 0000000000..3bf0459047
--- /dev/null
+++ b/meta-selftest/conf/fragments/more-fragments-here/test-another-fragment.conf
@@ -0,0 +1,3 @@
+BB_CONF_FRAGMENT_SUMMARY = "This is a second configuration fragment intended for testing in oe-selftest context"
+BB_CONF_FRAGMENT_DESCRIPTION = "It defines another variable that can be checked inside the test."
+SELFTEST_FRAGMENT_ANOTHER_VARIABLE = "someothervalue"
diff --git a/meta-selftest/conf/fragments/test-fragment.conf b/meta-selftest/conf/fragments/test-fragment.conf
new file mode 100644
index 0000000000..4c1d240945
--- /dev/null
+++ b/meta-selftest/conf/fragments/test-fragment.conf
@@ -0,0 +1,3 @@
+BB_CONF_FRAGMENT_SUMMARY = "This is a configuration fragment intended for testing in oe-selftest context"
+BB_CONF_FRAGMENT_DESCRIPTION = "It defines a variable that can be checked inside the test."
+SELFTEST_FRAGMENT_VARIABLE = "somevalue"
diff --git a/meta/lib/bbconfigbuild/configfragments.py b/meta/lib/bbconfigbuild/configfragments.py
new file mode 100644
index 0000000000..30cc5ece07
--- /dev/null
+++ b/meta/lib/bbconfigbuild/configfragments.py
@@ -0,0 +1,159 @@
+#
+# Copyright OpenEmbedded Contributors
+#
+# SPDX-License-Identifier: GPL-2.0-only
+#
+
+import logging
+import os
+import sys
+import os.path
+
+import bb.utils
+
+from bblayers.common import LayerPlugin
+
+logger = logging.getLogger('bitbake-config-layers')
+
+sys.path.insert(0, os.path.dirname(os.path.dirname(__file__)))
+
+def plugin_init(plugins):
+    return ConfigFragmentsPlugin()
+
+class ConfigFragmentsPlugin(LayerPlugin):
+    def get_fragment_info(self, path, name):
+        d = bb.data.init()
+        bb.parse.handle(path, d, True)
+        summary = d.getVar('BB_CONF_FRAGMENT_SUMMARY')
+        description = d.getVar('BB_CONF_FRAGMENT_DESCRIPTION')
+        if not summary:
+            raise Exception('Please add a one-line summary as BB_CONF_FRAGMENT_SUMMARY = \"...\" variable at the beginning of {}'.format(path))
+
+        if not description:
+            raise Exception('Please add a description as BB_CONF_FRAGMENT_DESCRIPTION = \"...\" variable at the beginning of {}'.format(path))
+
+        return summary, description
+
+    def discover_fragments(self):
+        fragments_path_prefix = self.tinfoil.config_data.getVar('OE_FRAGMENTS_PREFIX')
+        allfragments = {}
+        for layername in self.bbfile_collections:
+             layerdir = self.bbfile_collections[layername]
+             fragments = []
+             for topdir, dirs, files in os.walk(os.path.join(layerdir, fragments_path_prefix)):
+                 fragmentdir = os.path.relpath(topdir, os.path.join(layerdir, fragments_path_prefix))
+                 for fragmentfile in sorted(files):
+                     fragmentname = os.path.normpath("/".join((layername, fragmentdir, fragmentfile.split('.')[0])))
+                     fragmentpath = os.path.join(topdir, fragmentfile)
+                     fragmentsummary, fragmentdesc = self.get_fragment_info(fragmentpath, fragmentname)
+                     fragments.append({'path':fragmentpath, 'name':fragmentname, 'summary':fragmentsummary, 'description':fragmentdesc})
+             if fragments:
+                 allfragments[layername] = {'layerdir':layerdir,'fragments':fragments}
+        return allfragments
+
+    def do_list_fragments(self, args):
+        """ List available configuration fragments """
+        def print_fragment(f, verbose, is_enabled):
+            if not verbose:
+                print('{}\t{}'.format(f['name'], f['summary']))
+            else:
+                print('Name: {}\nPath: {}\nEnabled: {}\nSummary: {}\nDescription:\n{}\n'.format(f['name'], f['path'], 'yes' if is_enabled else 'no', f['summary'],''.join(f['description'])))
+
+        all_enabled_fragments = (self.tinfoil.config_data.getVar('OE_FRAGMENTS') or "").split()
+
+        for layername, layerdata in self.discover_fragments().items():
+            layerdir = layerdata['layerdir']
+            fragments = layerdata['fragments']
+            enabled_fragments = [f for f in fragments if f['name'] in all_enabled_fragments]
+            disabled_fragments = [f for f in fragments if f['name'] not in all_enabled_fragments]
+
+            print('Available fragments in {} layer located in {}:\n'.format(layername, layerdir))
+            if enabled_fragments:
+                print('Enabled fragments:')
+                for f in enabled_fragments:
+                    print_fragment(f, args.verbose, is_enabled=True)
+                print('')
+            if disabled_fragments:
+                print('Unused fragments:')
+                for f in disabled_fragments:
+                    print_fragment(f, args.verbose, is_enabled=False)
+            print('')
+
+    def fragment_exists(self, fragmentname):
+        for layername, layerdata in self.discover_fragments().items():
+            for f in layerdata['fragments']:
+              if f['name'] == fragmentname:
+                  return True
+        return False
+
+    def create_conf(self, confpath):
+        if not os.path.exists(confpath):
+            with open(confpath, 'w') as f:
+                f.write('')
+        with open(confpath, 'r') as f:
+            lines = f.read()
+        if "OE_FRAGMENTS += " not in lines:
+            lines += "\nOE_FRAGMENTS += \"\"\n"
+        with open(confpath, 'w') as f:
+            f.write(lines)
+
+    def do_enable_fragment(self, args):
+        """ Enable a fragment in the local build configuration """
+        def enable_helper(varname, origvalue, op, newlines):
+            enabled_fragments = origvalue.split()
+            if args.fragmentname in enabled_fragments:
+                print("Fragment {} already included in {}".format(args.fragmentname, args.confpath))
+            else:
+                enabled_fragments.append(args.fragmentname)
+            return " ".join(enabled_fragments), None, 0, True
+
+        if not self.fragment_exists(args.fragmentname):
+            raise Exception("Fragment {} does not exist; use 'list-fragments' to see the full list.".format(args.fragmentname))
+
+        self.create_conf(args.confpath)
+        modified = bb.utils.edit_metadata_file(args.confpath, ["OE_FRAGMENTS"], enable_helper)
+        if modified:
+            print("Fragment {} added to {}.".format(args.fragmentname, args.confpath))
+
+    def do_disable_fragment(self, args):
+        """ Disable a fragment in the local build configuration """
+        def disable_helper(varname, origvalue, op, newlines):
+            enabled_fragments = origvalue.split()
+            if args.fragmentname in enabled_fragments:
+                enabled_fragments.remove(args.fragmentname)
+            else:
+                print("Fragment {} not currently enabled in {}".format(args.fragmentname, args.confpath))
+            return " ".join(enabled_fragments), None, 0, True
+
+        self.create_conf(args.confpath)
+        modified = bb.utils.edit_metadata_file(args.confpath, ["OE_FRAGMENTS"], disable_helper)
+        if modified:
+            print("Fragment {} removed from {}.".format(args.fragmentname, args.confpath))
+
+    def do_disable_all_fragments(self, args):
+        """ Disable all fragments in the local build configuration """
+        def disable_all_helper(varname, origvalue, op, newlines):
+            return "", None, 0, True
+
+        self.create_conf(args.confpath)
+        modified = bb.utils.edit_metadata_file(args.confpath, ["OE_FRAGMENTS"], disable_all_helper)
+        if modified:
+            print("All fragments removed from {}.".format(args.confpath))
+
+    def register_commands(self, sp):
+        default_confpath = os.path.join(os.environ["BBPATH"], "conf/auto.conf")
+
+        parser_list_fragments = self.add_command(sp, 'list-fragments', self.do_list_fragments, parserecipes=False)
+        parser_list_fragments.add_argument("--confpath", default=default_confpath, help='Configuration file which contains a list of enabled fragments (default is {}).'.format(default_confpath))
+        parser_list_fragments.add_argument('--verbose', '-v', action='store_true', help='Print extended descriptions of the fragments')
+
+        parser_enable_fragment = self.add_command(sp, 'enable-fragment', self.do_enable_fragment, parserecipes=False)
+        parser_enable_fragment.add_argument("--confpath", default=default_confpath, help='Configuration file which contains a list of enabled fragments (default is {}).'.format(default_confpath))
+        parser_enable_fragment.add_argument('fragmentname', help='The name of the fragment (use list-fragments to see them)')
+
+        parser_disable_fragment = self.add_command(sp, 'disable-fragment', self.do_disable_fragment, parserecipes=False)
+        parser_disable_fragment.add_argument("--confpath", default=default_confpath, help='Configuration file which contains a list of enabled fragments (default is {}).'.format(default_confpath))
+        parser_disable_fragment.add_argument('fragmentname', help='The name of the fragment')
+
+        parser_disable_all = self.add_command(sp, 'disable-all-fragments', self.do_disable_all_fragments, parserecipes=False)
+        parser_disable_all.add_argument("--confpath", default=default_confpath, help='Configuration file which contains a list of enabled fragments (default is {}).'.format(default_confpath))
diff --git a/meta/lib/oeqa/selftest/cases/bblayers.py b/meta/lib/oeqa/selftest/cases/bblayers.py
index 695d17377d..68b0377720 100644
--- a/meta/lib/oeqa/selftest/cases/bblayers.py
+++ b/meta/lib/oeqa/selftest/cases/bblayers.py
@@ -240,3 +240,34 @@ class BitbakeLayers(OESelftestTestCase):
         self.assertEqual(first_desc_2, '', "Describe not cleared: '{}'".format(first_desc_2))
         self.assertEqual(second_rev_2, second_rev_1, "Revision should not be updated: '{}'".format(second_rev_2))
         self.assertEqual(second_desc_2, second_desc_1, "Describe should not be updated: '{}'".format(second_desc_2))
+
+class BitbakeConfigBuild(OESelftestTestCase):
+    def test_enable_disable_fragments(self):
+        self.assertEqual(get_bb_var('SELFTEST_FRAGMENT_VARIABLE'), None)
+        self.assertEqual(get_bb_var('SELFTEST_FRAGMENT_ANOTHER_VARIABLE'), None)
+
+        runCmd('bitbake-config-build enable-fragment selftest/test-fragment')
+        self.assertEqual(get_bb_var('SELFTEST_FRAGMENT_VARIABLE'), 'somevalue')
+        self.assertEqual(get_bb_var('SELFTEST_FRAGMENT_ANOTHER_VARIABLE'), None)
+
+        runCmd('bitbake-config-build enable-fragment selftest/more-fragments-here/test-another-fragment')
+        self.assertEqual(get_bb_var('SELFTEST_FRAGMENT_VARIABLE'), 'somevalue')
+        self.assertEqual(get_bb_var('SELFTEST_FRAGMENT_ANOTHER_VARIABLE'), 'someothervalue')
+
+        fragment_metadata_command = "bitbake-getvar -f {} --value {}"
+        result = runCmd(fragment_metadata_command.format("selftest/test-fragment", "BB_CONF_FRAGMENT_SUMMARY"))
+        self.assertIn("This is a configuration fragment intended for testing in oe-selftest context", result.output)
+        result = runCmd(fragment_metadata_command.format("selftest/test-fragment", "BB_CONF_FRAGMENT_DESCRIPTION"))
+        self.assertIn("It defines a variable that can be checked inside the test.", result.output)
+        result = runCmd(fragment_metadata_command.format("selftest/more-fragments-here/test-another-fragment", "BB_CONF_FRAGMENT_SUMMARY"))
+        self.assertIn("This is a second configuration fragment intended for testing in oe-selftest context", result.output)
+        result = runCmd(fragment_metadata_command.format("selftest/more-fragments-here/test-another-fragment", "BB_CONF_FRAGMENT_DESCRIPTION"))
+        self.assertIn("It defines another variable that can be checked inside the test.", result.output)
+
+        runCmd('bitbake-config-build disable-fragment selftest/test-fragment')
+        self.assertEqual(get_bb_var('SELFTEST_FRAGMENT_VARIABLE'), None)
+        self.assertEqual(get_bb_var('SELFTEST_FRAGMENT_ANOTHER_VARIABLE'), 'someothervalue')
+
+        runCmd('bitbake-config-build disable-fragment selftest/more-fragments-here/test-another-fragment')
+        self.assertEqual(get_bb_var('SELFTEST_FRAGMENT_VARIABLE'), None)
+        self.assertEqual(get_bb_var('SELFTEST_FRAGMENT_ANOTHER_VARIABLE'), None)