facts: Simplify ssh key fetching

lib/ansible/module_utils/facts.py

@@ -471,36 +471,19 @@ class Facts(object):
                 pass
 
     def get_public_ssh_host_keys(self):
-        dsa_filename = '/etc/ssh/ssh_host_dsa_key.pub'
-        rsa_filename = '/etc/ssh/ssh_host_rsa_key.pub'
-        ecdsa_filename = '/etc/ssh/ssh_host_ecdsa_key.pub'
-        ed25519_filename = '/etc/ssh/ssh_host_ed25519_key.pub'
+        keytypes = ('dsa', 'rsa', 'ecdsa', 'ed25519')
 
         if self.facts['system'] == 'Darwin':
-            dsa_filename = '/etc/ssh_host_dsa_key.pub'
-            rsa_filename = '/etc/ssh_host_rsa_key.pub'
-            ecdsa_filename = '/etc/ssh_host_ecdsa_key.pub'
-            ed25519_filename = '/etc/ssh_host_ed25519_key.pub'
-        dsa = get_file_content(dsa_filename)
-        rsa = get_file_content(rsa_filename)
-        ecdsa = get_file_content(ecdsa_filename)
-        ed25519 = get_file_content(ed25519_filename)
-        if dsa is None:
-            dsa = 'NA'
+            keydir = '/etc'
         else:
-            self.facts['ssh_host_key_dsa_public'] = dsa.split()[1]
-        if rsa is None:
-            rsa = 'NA'
-        else:
-            self.facts['ssh_host_key_rsa_public'] = rsa.split()[1]
-        if ecdsa is None:
-            ecdsa = 'NA'
-        else:
-            self.facts['ssh_host_key_ecdsa_public'] = ecdsa.split()[1]
-        if ed25519 is None:
-            ed25519 = 'NA'
-        else:
-            self.facts['ssh_host_key_ed25519_public'] = ed25519.split()[1]
+            keydir = '/etc/ssh'
+
+        for type_ in keytypes:
+            key_filename = '%s/ssh_host_%s_key.pub' % (keydir, type_)
+            keydata = get_file_content(key_filename)
+            if keydata is not None:
+                factname = 'ssh_host_key_%s_public' % type_
+                self.facts[factname] = keydata.split()[1]
 
     def get_pkg_mgr_facts(self):
         self.facts['pkg_mgr'] = 'unknown'