Notify beacon for Debian/Ubuntu systems (#347)

Signed-off-by: Ricardo Mateus <rmateus@suse.com>
(cherry picked from commit 33d6baebba94cc7a66d5555de984ca98684157a0)

scripts/suse/dpkg/99dpkgnotify

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+DPkg::Post-Invoke {"/usr/bin/dpkgnotify";};

scripts/suse/dpkg/README.md

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+## What it is
+
+Debian base package to notify installation of new packages outside the control of salt.
+
+## Installation
+This script depends on python package, so python3 should be installed on the machine
+
+- The 99dpkgnotify file must be installed in /etc/apt/apt.conf.d/99dpkgnotify
+- The dpkgnotify file must be installed in /usr/bin/dpkgnotify

scripts/suse/dpkg/dpkgnotify

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+#!/usr/bin/python3
+
+import os
+import hashlib
+
+CK_PATH = "/var/cache/salt/minion/dpkg.cookie"
+DPKG_PATH = "/var/lib/dpkg/status"
+
+def _get_mtime():
+    """
+    Get the modified time of the Package Database.
+    Returns:
+        Unix ticks
+    """
+    return os.path.exists(DPKG_PATH) and int(os.path.getmtime(DPKG_PATH)) or 0
+
+
+def _get_checksum():
+    """
+    Get the checksum of the Package Database.
+    Returns:
+        hexdigest
+    """
+    digest = hashlib.sha256()
+    with open(DPKG_PATH, "rb") as pkg_db_fh:
+        while True:
+            buff = pkg_db_fh.read(0x1000)
+            if not buff:
+                break
+            digest.update(buff)
+    return digest.hexdigest()
+
+
+def dpkg_post_invoke():
+    """
+    Hook after the package installation transaction.
+    """
+    if 'SALT_RUNNING' not in os.environ:
+        with open(CK_PATH, 'w') as ck_fh:
+            ck_fh.write('{chksum} {mtime}\n'.format(chksum=_get_checksum(), mtime=_get_mtime()))
+
+
+if __name__ == "__main__":
+    dpkg_post_invoke()