REPORT_HOST no longer defaults to HOST

Cleanup of identity handling.  It is now possible to specify
a Tor identity and no clearnet identity.

docs/ENVIRONMENT.rst

@@ -215,6 +215,7 @@ raise them.
   functioning Electrum clients by default will send pings roughly
   every 60 seconds.
 
+
 Peer Discovery
 --------------
 
@@ -264,59 +265,69 @@ some of this.
   9150 (Tor browser bundle) and 1080 (socks).
 
 
-IRC
+Server Advertising
----
+------------------
 
-Use the following environment variables if you want to advertise
+These environment variables affect how your server is advertised, both
-connectivity on IRC:
+by peer discovery (if enabled) and IRC (if enabled).
-
-* **IRC**
-
-  Set to anything non-empty to advertise on IRC
-
-* **IRC_NICK**
-
-  The nick to use when connecting to IRC.  The default is a hash of
-  **REPORT_HOST**.  Either way a prefix will be prepended depending on
-  **COIN** and **NET**.
 
 * **REPORT_HOST**
 
-  The host to advertise.  Defaults to **HOST**.
+  The clearnet host to advertise.  If not set, no clearnet host is
+  advertised.
 
 * **REPORT_TCP_PORT**
 
-  The TCP port to advertise.  Defaults to **TCP_PORT**.  '0' disables
+  The clearnet TCP port to advertise if **REPORT_HOST** is set.
-  publishing the port.
+  Defaults to **TCP_PORT**.  '0' disables publishing a TCP port.
 
 * **REPORT_SSL_PORT**
 
-  The SSL port to advertise.  Defaults to **SSL_PORT**.  '0' disables
+  The clearnet SSL port to advertise if **REPORT_HOST** is set.
-  publishing the port.
+  Defaults to **SSL_PORT**.  '0' disables publishing an SSL port.
 
 * **REPORT_HOST_TOR**
 
-  The tor address to advertise; must end with `.onion`.  If set, an
+  If you wish run a Tor service, this is the Tor host name to
-  additional connection to IRC happens with '_tor' appended to
+  advertise and must end with `.onion`.
-  **IRC_NICK**.
 
 * **REPORT_TCP_PORT_TOR**
 
-  The TCP port to advertise for Tor.  Defaults to **REPORT_TCP_PORT**,
+  The Tor TCP port to advertise.  The default is the clearnet
-  unless it is '0', otherwise **TCP_PORT**.  '0' disables publishing
+  **REPORT_TCP_PORT**, unless disabled or it is '0', otherwise
-  the port.
+  **TCP_PORT**.  '0' disables publishing a Tor TCP port.
 
 * **REPORT_SSL_PORT_TOR**
 
-  The SSL port to advertise for Tor.  Defaults to **REPORT_SSL_PORT**,
+  The Tor SSL port to advertise.  The default is the clearnet
-  unless it is '0', otherwise **SSL_PORT**.  '0' disables publishing
+  **REPORT_SSL_PORT**, unless disabled or it is '0', otherwise
-  the port.
+  **SSL_PORT**.  '0' disables publishing a Tor SSL port.
 
   **NOTE**: Certificate-Authority signed certificates don't work over
   Tor, so you should set **REPORT_SSL_PORT_TOR** to 0 if yours is not
   self-signed.
 
 
+IRC
+---
+
+Use the following environment variables if you want to advertise
+connectivity on IRC:
+
+* **IRC**
+
+  Set to anything non-empty to advertise on IRC
+
+* **IRC_NICK**
+
+  The nick to use when connecting to IRC.  The default is a hash of
+  **REPORT_HOST**.  Either way a prefix will be prepended depending on
+  **COIN** and **NET**.
+
+  If **REPORT_HOST_TOR** is set, an additional connection to IRC
+  happens with '_tor' appended to **IRC_NICK**.
+
+
 Cache
 -----
 

server/env.py

@@ -70,33 +70,11 @@ class Env(LoggedClass):
         self.irc_nick = self.default('IRC_NICK', None)
 
         # Identities
-        report_host = self.default('REPORT_HOST', self.host)
+        clearnet_identity = self.clearnet_identity()
-        self.check_report_host(report_host)
+        tor_identity = self.tor_identity(clearnet_identity)
-        main_identity = NetIdentity(
+        self.identities = [identity
-            report_host,
+                           for identity in (clearnet_identity, tor_identity)
-            self.integer('REPORT_TCP_PORT', self.tcp_port) or None,
+                           if identity is not None]
-            self.integer('REPORT_SSL_PORT', self.ssl_port) or None,
-            ''
-        )
-        if main_identity.tcp_port == main_identity.ssl_port:
-            raise self.Error('REPORT_TCP_PORT and REPORT_SSL_PORT are both {}'
-                             .format(main_identity.tcp_port))
-
-        self.identities = [main_identity]
-        tor_host = self.default('REPORT_HOST_TOR', '')
-        if tor_host.endswith('.onion'):
-            self.identities.append(NetIdentity(
-                tor_host,
-                self.integer('REPORT_TCP_PORT_TOR',
-                             main_identity.tcp_port
-                             if main_identity.tcp_port else
-                             self.tcp_port) or None,
-                self.integer('REPORT_SSL_PORT_TOR',
-                             main_identity.ssl_port
-                             if main_identity.ssl_port else
-                             self.ssl_port) or None,
-                '_tor',
-            ))
 
     def default(self, envvar, default):
         return environ.get(envvar, default)
@@ -131,7 +109,16 @@ class Env(LoggedClass):
                              .format(env_value, value, nofile_limit))
         return value
 
-    def check_report_host(self, host):
+    def obsolete(self, envvars):
+        bad = [envvar for envvar in envvars if environ.get(envvar)]
+        if bad:
+            raise self.Error('remove obsolete environment variables {}'
+                             .format(bad))
+
+    def clearnet_identity(self):
+        host = self.default('REPORT_HOST', None)
+        if host is None:
+            return None
         try:
             ip = ip_address(host)
         except ValueError:
@@ -140,9 +127,43 @@ class Env(LoggedClass):
             bad = ip.is_multicast or ip.is_unspecified
         if bad:
             raise self.Error('"{}" is not a valid REPORT_HOST'.format(host))
+        tcp_port = self.integer('REPORT_TCP_PORT', self.tcp_port) or None
+        ssl_port = self.integer('REPORT_SSL_PORT', self.ssl_port) or None
+        if tcp_port == ssl_port:
+            raise self.Error('REPORT_TCP_PORT and REPORT_SSL_PORT '
+                             'both resolve to {}'.format(tcp_port))
+        return NetIdentity(
+            host,
+            tcp_port,
+            ssl_port,
+            ''
+        )
 
-    def obsolete(self, envvars):
+    def tor_identity(self, clearnet):
-        bad = [envvar for envvar in envvars if environ.get(envvar)]
+        host = self.default('REPORT_HOST_TOR', None)
-        if bad:
+        if host is None:
-            raise self.Error('remove obsolete environment variables {}'
+            return None
-                             .format(bad))
+        if not tor_host.endswith('.onion'):
+            raise self.Error('tor host "{}" must end with ".onion"'
+                             .format(host))
+
+        def port(port_kind):
+            '''Returns the clearnet identity port, if any and not zero,
+            otherwise the listening port.'''
+            result = 0
+            if clearnet:
+                result = getattr(clearnet, port_kind)
+            return result or getattr(self, port_kind)
+
+        tcp_port = self.integer('REPORT_TCP_PORT_TOR', port('tcp_port')) or None
+        ssl_port = self.integer('REPORT_SSL_PORT_TOR', port('ssl_port')) or None
+        if tcp_port == ssl_port:
+            raise self.Error('REPORT_TCP_PORT_TOR and REPORT_SSL_PORT_TOR '
+                             'both resolve to {}'.format(tcp_port))
+
+        return NetIdentity(
+            host,
+            tcp_port,
+            ssl_port,
+            '_tor',
+        )