Extends info in os-release file (#5)

Extends the information in /etc/os-release file

meta-leda-distro/recipes-sdv-distro/os-release.bbappend

@@ -0,0 +1,69 @@
+# /********************************************************************************
+# * Copyright (c) 2022 Contributors to the Eclipse Foundation
+# *
+# * See the NOTICE file(s) distributed with this work for additional
+# * information regarding copyright ownership.
+# *
+# * This program and the accompanying materials are made available under the
+# * terms of the Apache License 2.0 which is available at
+# * https://www.apache.org/licenses/LICENSE-2.0
+# *
+# * SPDX-License-Identifier: Apache-2.0
+# ********************************************************************************/
+#
+# Adds additional fields to /etc/os-release
+# The fields are semantically defined by https://www.freedesktop.org/software/systemd/man/os-release.html
+#
+# Example output in ./tmp/sysroots-components/all/os-release/usr/lib/os-release:
+# 
+# ID=leda
+# NAME="Eclipse Leda"
+# VERSION="2022 (Hockenheim)"
+# VERSION_ID=v0.0.23-31-g64893dc
+# PRETTY_NAME="Eclipse Leda 2022 (Hockenheim)"
+# VERSION_CODENAME="Hockenheim"
+# IMAGE_ID="None"
+# IMAGE_MACHINE_ID="None"
+# IMAGE_VERSION="v0.0.23-31-g64893dc"
+# VERSION_ID=v0.0.23-31-g64893dc
+# BUILD_ID="20220901131248"
+#
+
+inherit features_check
+
+REQUIRED_DISTRO_FEATURES = "sdv"
+
+FILESEXTRAPATHS:prepend := "${THISDIR}/${BPN}:"
+
+DEPENDS = "git-native"
+
+# Always regenerate the /etc/os-release file to keep the metadata up to date
+do_compile[nostamp]="1"
+
+def exec_git_run(cmd, path):
+    (output, error) = bb.process.run(cmd, cwd=path)
+    return output.rstrip()
+
+python do_compile:prepend() {
+    if bb.utils.contains('DISTRO_FEATURES', 'sdv', True, False, d):
+        # Add additional fields to /etc/os-release
+        fields = set((d.getVar('OS_RELEASE_FIELDS') or "").split())
+        fields.add("VERSION_CODENAME")
+        fields.add("IMAGE_VERSION")
+        fields.add("VERSION_ID")
+        fields.add("BUILD_ID")
+        d.setVar('OS_RELEASE_FIELDS', ' '.join(sorted(fields)))
+
+        # Default fallback is just the version of the distro ("2022")
+        layerRev = d.getVar("DISTRO_VERSION")
+        path = d.getVar("TOPDIR") or d.getVar("BUILD_DIR")
+        try:
+            ver = exec_git_run("git describe --tags", path)
+            layerRev = ver
+        except Exception as exc:
+            bb.warn('Exception executing git, falling back to DISTRO_VERSION', exc)
+
+        d.setVar("VERSION_CODENAME", d.getVar("DISTRO_CODENAME"))
+        d.setVar("IMAGE_VERSION", layerRev)
+        d.setVar("VERSION_ID", layerRev)
+}