template.py - custom DSL for easier resource creation

example-riaks-template.py

@@ -1,9 +1,9 @@
-from solar.core import template
+from solar import template
 
 
 nodes = template.nodes_from('templates/riak_nodes.yml')
 
-riak_services = nodes.on_every(
+riak_services = nodes.on_each(
     'resources/riak_node',
     {
         'riak_self_name': 'riak{num}',
@@ -11,18 +11,16 @@ riak_services = nodes.on_every(
         'riak_name': 'riak{num}@riak_server{num}.solar',
 })
 
+slave_riak_services = riak_services.filter(lambda num: num > 0)
+
 riak_services.take(0).connect_list(
-    riak_services.filter(
-        lambda num: num > 0
-    ),
+    slave_riak_services,
     {
         'riak_name': 'join_to',
     }
 )
 
-hosts_files = nodes.on_every(
-    'resources/hosts_file'
-)
+hosts_files = nodes.on_each('resources/hosts_file')
 
 riak_services.connect_list_to_each(
     hosts_files,
@@ -31,3 +29,9 @@ riak_services.connect_list_to_each(
         'riak_hostname': 'hosts_names',
     }
 )
+
+
+hosts_files.add_deps('run/success', riak_services, 'run')
+slave_riak_services.add_reacts('run/success', slave_riak_services, 'join')
+slave_riak_services.add_reacts('leave/success', slave_riak_services, 'join')
+slave_riak_services.add_react('run/success', riak_services.take(0), 'commit')

solar/solar/template.py

@@ -0,0 +1,145 @@
+import os
+
+from solar.core.resource import virtual_resource as vr
+from solar.core import signals
+from solar.events.api import add_event
+from solar.events import controls
+
+
+class BaseTemplate(object):
+    @staticmethod
+    def args_fmt(args, kwargs):
+        return {
+            k.format(**kwargs): v.format(**kwargs) for k, v in args.items()
+        }
+
+    @staticmethod
+    def action_state_parse(action_state):
+        action, state = action_state.split('/')
+
+        return {
+            'action': action,
+            'state': state,
+        }
+
+
+class ResourceTemplate(BaseTemplate):
+    def __init__(self, resource):
+        self.resource = resource
+
+    def connect_list(self, resources, args={}):
+        for receiver_num, resource in enumerate(resources.resources):
+            kwargs = {
+                'receiver_num': receiver_num,
+            }
+
+            args_fmt = self.args_fmt(args, kwargs)
+
+            signals.connect(self.resource, resource, args_fmt)
+
+
+class ResourceListTemplate(BaseTemplate):
+    def __init__(self, resources):
+        self.resources = resources
+
+    @classmethod
+    def create(cls, count, resource_path, args={}):
+        created_resources = []
+
+        resource_path_name = os.path.split(resource_path)[-1]
+
+        for num in range(count):
+            kwargs = {
+                'num': num,
+                'resource_path_name': resource_path_name,
+                }
+            kwargs['name'] = '{resource_path_name}-{num}'.format(**kwargs)
+
+            args_fmt = cls.args_fmt(args, kwargs)
+
+            r = vr.create('{name}'.format(**kwargs),
+                          resource_path,
+                          args_fmt)[0]
+
+            created_resources.append(r)
+
+        return ResourceListTemplate(created_resources)
+
+    def add_deps(self, action_state, resources, action):
+        action_state = self.action_state_parse(action_state)
+
+        for r, dep_r in zip(self.resources, resources.resources):
+            add_event(
+                controls.Dep(
+                    r.name,
+                    action_state['action'],
+                    action_state['state'],
+                    dep_r.name,
+                    action
+                )
+            )
+
+    def add_react(self, action_state, resource, action):
+        action_state = self.action_state_parse(action_state)
+
+        for r in self.resources:
+            add_event(
+                controls.React(
+                    r.name,
+                    action_state['action'],
+                    action_state['state'],
+                    resource.resource.name,
+                    action
+                )
+            )
+
+    def add_reacts(self, action_state, resources, action):
+        action_state = self.action_state_parse(action_state)
+
+        for r, react_r in zip(self.resources, resources.resources):
+            add_event(
+                controls.React(
+                    r.name,
+                    action_state['action'],
+                    action_state['state'],
+                    react_r.name,
+                    action
+                )
+            )
+
+    def filter(self, func):
+        resources = filter(func, self.resources)
+
+        return ResourceListTemplate(resources)
+
+    def connect_list_to_each(self, resources, args={}):
+        for emitter_num, emitter in enumerate(self.resources):
+            for receiver_num, receiver in enumerate(resources.resources):
+                kwargs = {
+                    'emitter_num': emitter_num,
+                    'receiver_num': receiver_num,
+                }
+
+                args_fmt = self.args_fmt(args, kwargs)
+
+                signals.connect(emitter, receiver, args_fmt)
+
+    def on_each(self, resource_path, args={}):
+        created_resources = ResourceListTemplate.create(
+            len(self.resources),
+            resource_path,
+            args
+        )
+
+        for i, resource in enumerate(self.resources):
+            signals.connect(resource, created_resources.resources[i])
+
+        return created_resources
+
+    def take(self, i):
+        return ResourceTemplate(self.resources[i])
+
+
+def nodes_from(template_path):
+    nodes = vr.create('nodes', template_path, {})
+    return ResourceListTemplate(nodes)