[isar] rootfs: Add new ROOTFS_FEATURE 'slimfy' to minimize the footprint

[venkata.pyla@toshiba-tsip.com]

From: venkata pyla <venkata.pyla@toshiba-tsip.com>

 This Adds new ROOTFS_FEATURE 'slimify' that deletes unnecessary files
 in the rootfs and contributes to minimal footprint in the rootfs and
 also avoids the reproducible failures due to non-deterministic data in
 the log files and temporary files.

 It deletes the following files
  - /var/log/*
  - /tmp/*

 To enable this feature
   ROOTFS_FEATURE += slimify

Signed-off-by: venkata pyla <venkata.pyla@toshiba-tsip.com>
---
 meta/classes/rootfs.bbclass | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/meta/classes/rootfs.bbclass b/meta/classes/rootfs.bbclass
index f9151c5..d01a9d1 100644
--- a/meta/classes/rootfs.bbclass
+++ b/meta/classes/rootfs.bbclass
@@ -12,6 +12,7 @@ ROOTFS_PACKAGES ?= ""
 # 'clean-package-cache' - delete package cache from rootfs
 # 'generate-manifest' - generate a package manifest of the rootfs into ${ROOTFS_MANIFEST_DEPLOY_DIR}
 # 'export-dpkg-status' - exports /var/lib/dpkg/status file to ${ROOTFS_DPKGSTATUS_DEPLOY_DIR}
+# 'slimify'            - delete unnecessary files in rootfs like /var/log/*, /tmp/*
 ROOTFS_FEATURES ?= ""
 
 ROOTFS_APT_ARGS="install --yes -o Debug::pkgProblemResolver=yes"
@@ -229,6 +230,12 @@ rootfs_export_dpkg_status() {
        '${ROOTFS_DPKGSTATUS_DEPLOY_DIR}'/'${PF}'.dpkg_status
 }
 
+ROOTFS_POSTPROCESS_COMMAND += "${@bb.utils.contains('ROOTFS_FEATURES', 'slimify', 'rootfs_slimify', '', d)}"
+rootfs_slimify() {
+    sudo rm -rf "${ROOTFSDIR}/var/log/"*
+    sudo rm -rf "${ROOTFSDIR}/tmp/"*
+}
+
 do_rootfs_postprocess[vardeps] = "${ROOTFS_POSTPROCESS_COMMAND}"
 python do_rootfs_postprocess() {
     # Take care that its correctly mounted:
-- 
2.20.1