add normalize_uri instead of short_hostname

- use gethostbyaddr only in case of numeric IP
- hard wired reverse CNAME (network alias) for linse-c

normalizeuri.py

@@ -0,0 +1,35 @@
+import re
+import socket
+
+# sorry for hardwiring this ... there is no CNAME reverse lookup!
+# taking the original address as unique name would need a call to
+# gethostbyaddr, which might take some time - also not what we want
+reverse_alias = {
+    'pc15139': 'linse-c',
+    'pc16392': 'linse-a',
+}
+
+
+def normalizeuri(uri):
+    host, sep, port = uri.partition(':')
+    if host[0].isdigit():
+        try:
+            socket.setdefaulttimeout(1)
+            host = socket.gethostbyaddr(host)[0].split('.', 1)[0]
+        except socket.gaierror:
+            pass  # keep numbered IP
+        finally:
+            socket.setdefaulttimeout(None)
+    else:
+        host = host.split('.',1 )[0]
+    if host == 'localhost':
+        host = socket.gethostname()
+    else:
+        # this resolves CNAME entries (network aliases):
+        host = reverse_alias.get(host, host)
+    # strip appended IP when a host is registered twice (at PSI):
+    match = re.match(r'([^-]+)-129129\d{6}$', host)
+    host = match.group(1) if match else host
+    return f'{host}{sep}{port}'
+
+