Turn some of this into an object so it can be extended (slightly).

It may be reasonable to change this more, but the benefits aren't clear.
(These changes will be used from the new-install-branch.)

src/ZEO/mkzeoinst.py

@@ -113,48 +113,60 @@ exec %(zdctl)s -C "$INSTANCE/etc/%(package)sctl.conf" ${1+"$@"}
 """
 
 def main():
-    try:
-        opts, args = getopt.getopt(sys.argv[1:], "h", ["help"])
-    except getopt.error, msg:
-        print msg
-        sys.exit(2)
-    program = os.path.basename(sys.argv[0])
-    if opts:
-        # There's only the help options, so just dump some help:
-        msg = __doc__ % {"program": program}
-        print msg
-        sys.exit()
-    if len(args) not in [1, 2]:
-        print "Usage: %s home [port]" % program
-        sys.exit(2)
-    home = args[0]
-    if not os.path.isabs(home):
-        home = os.path.abspath(home)
-    if args[1:]:
-        port = int(args[1])
-    else:
-        port = 9999
-    checkport(port)
-    params = {
-        "package": "zeo",
-        "PACKAGE": "ZEO",
-        "home": home,
-        "port": port,
-        "python": sys.executable,
-        "server": which("runzeo.py"),
-        "zdrun": which("zdrun.py"),
-        "zdctl": which("zdctl.py"),
-        }
-    makedir(home)
-    makedir(home, "etc")
-    makedir(home, "var")
-    makedir(home, "log")
-    makedir(home, "bin")
-    makefile(zeo_conf_template, home, "etc", "zeo.conf", **params)
-    makefile(runner_conf_template, home, "etc", "zeoctl.conf", **params)
-    makexfile(zdctl_template, home, "bin", "zeoctl", **params)
+    ZEOInstanceBuilder().run()
     print "All done."
 
+
+class ZEOInstanceBuilder:
+    def run(self):
+        try:
+            opts, args = getopt.getopt(sys.argv[1:], "h", ["help"])
+        except getopt.error, msg:
+            print msg
+            sys.exit(2)
+        program = os.path.basename(sys.argv[0])
+        if opts:
+            # There's only the help options, so just dump some help:
+            msg = __doc__ % {"program": program}
+            print msg
+            sys.exit()
+        if len(args) not in [1, 2]:
+            print "Usage: %s home [port]" % program
+            sys.exit(2)
+        home = args[0]
+        if not os.path.isabs(home):
+            home = os.path.abspath(home)
+        if args[1:]:
+            port = int(args[1])
+        else:
+            port = 9999
+        checkport(port)
+        params = self.get_params(home, port)
+        self.create(home, params)
+
+    def get_params(self, home, port):
+        return {
+            "package": "zeo",
+            "PACKAGE": "ZEO",
+            "home": home,
+            "port": port,
+            "python": sys.executable,
+            "server": which("runzeo.py"),
+            "zdrun": which("zdrun.py"),
+            "zdctl": which("zdctl.py"),
+            }
+
+    def create(self, home, params):
+        makedir(home)
+        makedir(home, "etc")
+        makedir(home, "var")
+        makedir(home, "log")
+        makedir(home, "bin")
+        makefile(zeo_conf_template, home, "etc", "zeo.conf", **params)
+        makefile(runner_conf_template, home, "etc", "zeoctl.conf", **params)
+        makexfile(zdctl_template, home, "bin", "zeoctl", **params)
+
+
 def checkport(port):
     import socket
     s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)