[RFC,2/3] bitbake-layers: add ability to save current layer repository configuration into a json file

diff --git a/meta/lib/bblayers/makesetup.py b/meta/lib/bblayers/makesetup.py
new file mode 100644
index 0000000000..36de32b6f9
--- /dev/null
+++ b/meta/lib/bblayers/makesetup.py
@@ -0,0 +1,135 @@ 
+#
+# SPDX-License-Identifier: GPL-2.0-only
+#
+
+import logging
+import os
+import stat
+import sys
+import shutil
+import json
+
+import bb.utils
+import bb.process
+
+from bblayers.common import LayerPlugin
+
+logger = logging.getLogger('bitbake-layers')
+
+sys.path.insert(0, os.path.dirname(os.path.dirname(__file__)))
+
+import oe.buildcfg
+
+def plugin_init(plugins):
+    return MakeSetupPlugin()
+
+class MakeSetupPlugin(LayerPlugin):
+
+    def _write_python(self, input, output):
+        with open(input) as f:
+            script = f.read()
+        with open(output, 'w') as f:
+            f.write(script)
+        st = os.stat(output)
+        os.chmod(output, st.st_mode | stat.S_IEXEC | stat.S_IXGRP | stat.S_IXOTH)
+
+    def _write_json(self, repos, output):
+        with open(output, 'w') as f:
+            json.dump(repos, f, sort_keys=True, indent=4)
+
+    def _get_repo_path(self, layer_path):
+        repo_path, _ = bb.process.run('git rev-parse --show-toplevel', cwd=layer_path)
+        return repo_path.strip()
+
+    def _get_remotes(self, repo_path):
+        remotes = {}
+        remotes_list,_ = bb.process.run('git remote', cwd=repo_path)
+        for r in remotes_list.split():
+            uri,_ = bb.process.run('git remote get-url {r}'.format(r=r), cwd=repo_path)
+            remotes[r] = {'uri':uri.strip()}
+        return remotes
+
+    def _get_describe(self, repo_path):
+        try:
+            describe,_ = bb.process.run('git describe --tags', cwd=repo_path)
+        except bb.process.ExecutionError:
+            return ""
+        return describe.strip()
+
+    def _get_confs(self, conf_path):
+        try:
+           files = os.listdir(conf_path)
+        except:
+           return []
+        return {f.replace(".conf",""):{} for f in files if f.endswith(".conf")}
+
+    def _get_distros(self, layer_path):
+        return self._get_confs(os.path.join(layer_path, "conf/distro"))
+
+    def _get_machines(self, layer_path):
+        return self._get_confs(os.path.join(layer_path, "conf/machine"))
+
+    def _get_buildconfigs(self, layerpath):
+        return {os.path.relpath(dir, start=layerpath):{} for (dir, subdirs, files) in os.walk(layerpath) if 'local.conf.sample' in files and 'bblayers.conf.sample' in files}
+
+    def _make_repo_config(self, destdir):
+        repos = {}
+        layers = oe.buildcfg.get_layer_revisions(self.tinfoil.config_data)
+        for (l_path, l_name, l_branch, l_rev, l_ismodified) in layers:
+            if l_name == 'workspace':
+                continue
+            if l_ismodified:
+                logger.error("Layer {name} in {path} has uncommitted modifications or is not in a git repository.".format(name=l_name,path=l_path))
+                return
+            repo_path = self._get_repo_path(l_path)
+            if repo_path not in repos.keys():
+                repos[repo_path] = {'path':os.path.basename(repo_path),'layers':{},'git-remote':{'rev':l_rev, 'branch':l_branch, 'remotes':self._get_remotes(repo_path), 'describe':self._get_describe(repo_path)}}
+                if not repos[repo_path]['git-remote']['remotes']:
+                    logger.error("Layer repository in {path} does not have any remotes configured. Please add at least one with 'git remote add'.".format(path=repo_path))
+                    return
+                if repo_path in os.path.abspath(destdir):
+                    repos[repo_path]['contains_this_file'] = True
+            repos[repo_path]['layers'][l_name] = {'subpath':l_path.replace(repo_path,'')[1:]}
+            distros = self._get_distros(l_path)
+            machines = self._get_machines(l_path)
+            buildconfigs = self._get_buildconfigs(l_path)
+            if distros:
+                repos[repo_path]['layers'][l_name]['distros'] = distros
+            if machines:
+                repos[repo_path]['layers'][l_name]['machines'] = machines
+            if buildconfigs:
+                repos[repo_path]['layers'][l_name]['buildconfigs'] = buildconfigs
+
+        repo_dirs = set([os.path.dirname(p) for p in repos.keys()])
+        if len(repo_dirs) > 1:
+            logger.error("Layer repositories are not all in the same parent directory: {repo_dirs}. They need to be relocated into the same directory.".format(repo_dirs=repo_dirs))
+            return
+
+        repos_nopaths = {}
+        for r in repos.keys():
+            r_nopath = os.path.basename(r)
+            repos_nopaths[r_nopath] = repos[r]
+        return repos_nopaths
+
+    def do_make_setup(self, args):
+        """ Writes out a python script and a json config that replicate the directory structure and revisions of the layers in a current build. """
+        repos = self._make_repo_config(args.destdir)
+        json = {"version":"1.0","sources":repos}
+        if not repos:
+            return
+        output = args.output_prefix or "setup-layers"
+        output = os.path.join(os.path.abspath(args.destdir),output)
+        self._write_json(json, output + ".json")
+        logger.info('Created {}.json'.format(output))
+        if not args.json_only:
+            self._write_python(os.path.join(os.path.dirname(__file__),'../../../scripts/oe-setup-layers'), output)
+        logger.info('Created {}'.format(output))
+
+    def register_commands(self, sp):
+        parser_setup_layers = self.add_command(sp, 'create-layers-setup', self.do_make_setup, parserecipes=False)
+        parser_setup_layers.add_argument('destdir',
+            help='Directory where to write the output\n(if it is inside one of the layers, the layer becomes a bootstrap repository and thus will be excluded from fetching by the script).')
+        parser_setup_layers.add_argument('--output-prefix', '-o',
+            help='File name prefix for the output files, if the default (setup-layers) is undesirable.')
+        parser_setup_layers.add_argument('--json-only', action='store_true',
+            help='Write only the layer configuruation in json format. Otherwise, also a copy of poky/scripts/oe-setup-layers is provided, which is a self contained python script that fetches all the needed layers and sets them to correct revisions using the data from the json.')