Switch to regular expression for discovery by host

Use this to add expressions for compute nodes on Chrysalis,
Blues and Compy.

mache/discover.py

@@ -1,4 +1,5 @@
 import os
+import re
 import socket
 
 
@@ -18,29 +19,30 @@ def discover_machine(quiet=False):
     """
     hostname = socket.gethostname()
     machine = None
-    machines_by_hostname = {
-        'acme1': 'acme1',
-        'andes': 'andes',
-        'blueslogin': 'anvil',
-        'ch-fe': 'chicoma-cpu',
-        'chrlogin': 'chrysalis',
-        'compy': 'compy',
-        'cooley': 'cooley'
+    machines_by_host_re = {
+        r'^acme1': 'acme1',
+        r'^andes': 'andes',
+        r'^blueslogin': 'anvil',
+        r'^b\d{3}': 'anvil',
+        r'^ch-fe': 'chicoma-cpu',
+        r'^chrlogin': 'chrysalis',
+        r'^chr-\d{4}': 'chrysalis',
+        r'^compy': 'compy',
+        r'^n\d{4}': 'anvil',
+        r'^cooley': 'cooley'
     }
-    found = False
-    for host, mach in machines_by_hostname.items():
-        if hostname.startswith(host):
+    for host_re, mach in machines_by_host_re.items():
+        p = re.compile(host_re)
+        if p.match(hostname):
             machine = mach
-            found = True
             break
-    if not found and 'LMOD_SYSTEM_NAME' in os.environ:
+    if machine is None and 'LMOD_SYSTEM_NAME' in os.environ:
         hostname = os.environ['LMOD_SYSTEM_NAME']
         if hostname == 'frontier':
             # frontier's hostname is too generic to detect, so relying on
             # LMOD_SYSTEM_NAME
             machine = 'frontier'
-            found = True
-    if not found and 'NERSC_HOST' in os.environ:
+    if machine is None and 'NERSC_HOST' in os.environ:
         hostname = os.environ['NERSC_HOST']
         if hostname == 'perlmutter':
             # perlmutter's hostname is too generic to detect, so relying on