From da49c0fa6cfeb5e2f61c2ed7fc2ac1a90af70b45 Mon Sep 17 00:00:00 2001
From: "Benjamin W. Smith" <benjaminwarfield@just-another.net>
Date: Mon, 26 Oct 2009 14:46:03 -0400
Subject: Add some thoughts about a possible Python based DSL for
 configuration..

---
 mrbelvedere_dsl_thoughts.py | 91 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 mrbelvedere_dsl_thoughts.py

diff --git a/mrbelvedere_dsl_thoughts.py b/mrbelvedere_dsl_thoughts.py
new file mode 100644
index 0000000..3310e65
--- /dev/null
+++ b/mrbelvedere_dsl_thoughts.py
@@ -0,0 +1,91 @@
+# Is this *too* flexible?
+# Am I being naive? Doing it wrong?
+
+from contextlib import contextmanager
+
+class MissingParameterError(Exception):
+
+    def __init__(self, value):
+        self.parameter = value
+
+    def __str__(self):
+        return repr(self.parameter)
+
+# Something like this for the template backend stuff
+class Template(object):
+    def __init__(self, template_name):
+        self.template_name = template_name
+        self.arguments = {}
+
+    def __setattr__(self, attr, value):
+        if attr in ("arguments", "template_name"):
+            object.__setattr__(self, attr, value)
+        else:
+            self.arguments[attr] = value
+
+    def build(self):
+        print "Building template %s with arguments: %s" % (self.template_name, self.arguments)
+
+        # Do some validation checking on certain arguments, execute code as needed
+        # Delete arbitrairy arguments that could be created (but inform the user)
+
+# Something like this for the service backend stuff
+class Service(object):                      
+    def __init__(self, service_name):       
+        self.service_name = service_name   
+        self.arguments = {}                  
+                                             
+    def __setattr__(self, attr, value):      
+        if attr in ("arguments", "service_name"):
+            object.__setattr__(self, attr, value)
+        else:                                
+            self.arguments[attr] = value     
+                                             
+    def build(self):                       
+        print "Building service %s with arguments: %s" % (self.service_name, self.arguments)
+
+        # Do some validation checking on certain arguments, execute code as needed
+        # Delete arbitrairy arguments that could be created (but inform the user)
+
+# Context manager to kick off the dirty work
+@contextmanager
+def create_template(name = None):
+
+    if not name:
+        raise MissingParameterError("Missing template name")
+
+    template = Template(name)
+    yield template
+    template.build()
+
+# Context manager to kick off the dirty work
+@contextmanager
+def create_service(name = None):
+
+    if not name:
+        raise MissingParameterError("Missing service name")
+
+    service = Service(name)
+    yield service
+    service.build()
+
+# Services/Templates would look something like this:
+
+with create_service(name = "network") as service:
+
+    service.description = "Define network stuff"
+
+    service.provides = ['network_guts']
+
+
+with create_template(name = "test_template") as webserver_template:
+
+    webserver_template.desciption = "Builds web server"
+
+    webserver_template.provides = ['webserver']
+
+    webserver_template.needs = ['services.network']
+
+    webserver_template.accounts = ['bsmith', 'mcrute']
+
+    
-- 
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