scripts/oe-setup-layers: write a list of layer paths into the checkout's top dir

This is beneficial for setting up builds, as this list can be used
to determine reliably where the actual layers are, and discover
available configurations from them.

Also adjust the selftest to check the presence of that file rather
than any specific layer in a hardcoded location.

Sample output (paths are written relative to the file for relocatability
and ease of reading):

{
    "layers": [
        "meta-openembedded/meta-filesystems",
        "meta-openembedded/meta-gnome",
        "meta-openembedded/meta-initramfs",
        "meta-openembedded/meta-multimedia",
        "meta-openembedded/meta-networking",
        "meta-openembedded/meta-oe",
        "meta-openembedded/meta-perl",
        "meta-openembedded/meta-python",
        "meta-openembedded/meta-webserver",
        "meta-openembedded/meta-xfce",
        "poky/bitbake/lib/layerindexlib/tests/testdata/layer1",
        "poky/bitbake/lib/layerindexlib/tests/testdata/layer2",
        "poky/bitbake/lib/layerindexlib/tests/testdata/layer3",
        "poky/bitbake/lib/layerindexlib/tests/testdata/layer4",
        "poky/meta-poky",
        "poky/meta-selftest",
        "poky/meta-skeleton",
        "poky/meta-yocto-bsp",
        "poky/meta"
    ],
    "version": "1.0"
}

(From OE-Core rev: 82743f4f767f8016564be0d9d6c0d8fe9e067740)

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

2 files changed, 17 insertions, 4 deletions

diff --git a/meta/lib/oeqa/selftest/cases/bblayers.py b/meta/lib/oeqa/selftest/cases/bblayers.py
index 2475a79468..34363cd791 100644
--- a/meta/lib/oeqa/selftest/cases/bblayers.py
+++ b/meta/lib/oeqa/selftest/cases/bblayers.py
@@ -163,7 +163,5 @@ class BitbakeLayers(OESelftestTestCase):
 
         testcheckoutdir = os.path.join(self.builddir, 'test-layer-checkout')
         result = runCmd('{}/setup-layers --destdir {}'.format(self.testlayer_path, testcheckoutdir))
-        # May not necessarily be named 'poky' or 'openembedded-core'
-        oecoredir = os.listdir(testcheckoutdir)[0]
-        testcheckoutfile = os.path.join(testcheckoutdir, oecoredir, "oe-init-build-env")
-        self.assertTrue(os.path.exists(testcheckoutfile), "File {} not found in test layer checkout".format(testcheckoutfile))
+        layers_json = os.path.join(testcheckoutdir, ".oe-layers.json")
+        self.assertTrue(os.path.exists(layers_json), "File {} not found in test layer checkout".format(layers_json))
diff --git a/scripts/oe-setup-layers b/scripts/oe-setup-layers
index 6d49688a32..bee4ef0fec 100755
--- a/scripts/oe-setup-layers
+++ b/scripts/oe-setup-layers
@@ -49,11 +49,24 @@ def _is_repo_at_remote_uri(repodir, remote, uri):
 def _contains_submodules(repodir):
     return os.path.exists(os.path.join(repodir,".gitmodules"))
 
+def _write_layer_list(dest, repodirs):
+    layers = []
+    for r in repodirs:
+        for root, dirs, files in os.walk(r):
+            if os.path.basename(root) == 'conf' and 'layer.conf' in files:
+                layers.append(os.path.relpath(os.path.dirname(root), dest))
+    layers_f = os.path.join(dest, ".oe-layers.json")
+    print("Writing list of layers into {}".format(layers_f))
+    with open(layers_f, 'w') as f:
+        json.dump({"version":"1.0","layers":layers}, f, sort_keys=True, indent=4)
+
 def _do_checkout(args, json):
     repos = json['sources']
+    repodirs = []
     for r_name in repos:
         r_data = repos[r_name]
         repodir = os.path.abspath(os.path.join(args['destdir'], r_data['path']))
+        repodirs.append(repodir)
 
         if 'contains_this_file' in r_data.keys():
             force_arg = 'force_bootstraplayer_checkout'
@@ -96,6 +109,8 @@ def _do_checkout(args, json):
             if _contains_submodules(repodir):
                 print("Repo {} contains submodules, use 'git submodule update' to ensure they are up to date".format(repodir))
 
+    _write_layer_list(args['destdir'], repodirs)
+
 parser = argparse.ArgumentParser(description="A self contained python script that fetches all the needed layers and sets them to correct revisions using data in a json format from a separate file. The json data can be created from an active build directory with 'bitbake-layers create-layers-setup destdir' and there's a sample file and a schema in meta/files/")
 
 parser.add_argument('--force-bootstraplayer-checkout', action='store_true',