drain: rpcversion check for new format

drain/clnutils.py

@@ -0,0 +1,23 @@
+import re
+
+
+def cln_parse_rpcversion(string):
+    """
+    Parse cln version string to determine RPC version.
+
+    cln switched from 'semver' alike    `major.minor.sub[rcX][-mod]`
+    to ubuntu style with version 22.11  `yy.mm[.patch][-mod]`
+    make sure we can read all of them for (the next 80 years).
+    """
+    rpcversion = string
+    if rpcversion.startswith('v'):  # strip leading 'v'
+        rpcversion = rpcversion[1:]
+    if rpcversion.find('-') != -1:  # strip mods
+        rpcversion = rpcversion[:rpcversion.find('-')]
+    if re.search('.*(rc[\\d]*)$', rpcversion):  # strip release candidates
+        rpcversion = rpcversion[:rpcversion.find('rc')]
+    if rpcversion.count('.') == 1:  # imply patch version 0 if not given
+        rpcversion = rpcversion + '.0'
+
+    # split and convert numeric string parts to actual integers
+    return list(map(int, rpcversion.split('.')))