Add the loadbalancer resource.

Some initial simplifications:
- only one Listener
- static (only use Instances)
- only http (no tcp or ssl)

Ref #164
Change-Id: Iaac06eff83a5c43049adc95a98ebe632e17b490c
Signed-off-by: Angus Salkeld <asalkeld@redhat.com>

heat/engine/loadbalancer.py

@@ -0,0 +1,295 @@
+# vim: tabstop=4 shiftwidth=4 softtabstop=4
+
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+import urllib2
+import json
+import logging
+
+from heat.common import exception
+from heat.engine.resources import Resource
+from heat.db import api as db_api
+from heat.engine import parser
+from novaclient.exceptions import NotFound
+
+logger = logging.getLogger(__file__)
+
+lb_template = '''
+{
+  "AWSTemplateFormatVersion": "2010-09-09",
+  "Description": "Built in HAProxy server",
+  "Parameters" : {
+    "KeyName" : {
+      "Type" : "String"
+    }
+  },
+  "Resources": {
+    "LoadBalancerInstance": {
+      "Type": "AWS::EC2::Instance",
+      "Metadata": {
+        "AWS::CloudFormation::Init": {
+          "config": {
+            "packages": {
+              "yum": {
+                "haproxy"        : []
+              }
+            },
+            "services": {
+              "systemd": {
+                "haproxy"   : { "enabled": "true", "ensureRunning": "true" }
+              }
+            },
+            "files": {
+              "/etc/haproxy/haproxy.cfg": {
+                "content": ""},
+                "mode": "000644",
+                "owner": "root",
+                "group": "root"
+            }
+          }
+        }
+      },
+      "Properties": {
+        "ImageId": "F16-x86_64-cfntools",
+        "InstanceType": "m1.small",
+        "KeyName": { "Ref": "KeyName" },
+        "UserData": { "Fn::Base64": { "Fn::Join": ["", [
+          "#!/bin/bash -v\\n",
+          "/opt/aws/bin/cfn-init -s ",
+          { "Ref": "AWS::StackName" },
+          "    --region ", { "Ref": "AWS::Region" }, "\\n"
+        ]]}}
+      }
+    }
+  },
+
+  "Outputs": {
+    "PublicIp": {
+      "Value": { "Fn::GetAtt": [ "LoadBalancerInstance", "PublicIp" ] },
+      "Description": "instance IP"
+    }
+  }
+}
+'''
+
+
+#
+# TODO(asalkeld) once we have done a couple of these composite
+# Resources we should probably make a generic CompositeResource class.
+# There will be plenty of scope for it. I resisted doing this initially
+# to see how what the other composites require.
+#
+# Also the above inline template _could_ be placed in an external file
+# at the moment this is because we will probably need to implement a
+# LoadBalancer based on keepalived as well (for for ssl support).
+#
+class LoadBalancer(Resource):
+
+    listeners_schema = {
+        'InstancePort': {'Type': 'Integer',
+                         'Required': True},
+        'LoadBalancerPort': {'Type': 'Integer',
+                             'Required': True},
+        'Protocol': {'Type': 'String',
+                     'Required': True,
+                     'AllowedValues': ['TCP', 'HTTP']},
+        'SSLCertificateId': {'Type': 'String',
+                             'Implemented': False},
+        'PolicyNames': {'Type': 'Map',
+                        'Implemented': False}
+    }
+    healthcheck_schema = {
+        'HealthyThreshold': {'Type': 'Integer',
+                             'Required': True},
+        'Interval': {'Type': 'Integer',
+                     'Required': True},
+        'Target': {'Type': 'String',
+                   'Required': True},
+        'Timeout': {'Type': 'Integer',
+                    'Required': True},
+        'UnHealthyTheshold': {'Type': 'Integer',
+                              'Required': True},
+    }
+
+    properties_schema = {
+        'AvailabilityZones': {'Type': 'List',
+                              'Required': True},
+        'HealthCheck': {'Type': 'Map',
+                        'Implemented': False,
+                        'Schema': healthcheck_schema},
+        'Instances': {'Type': 'List'},
+        'Listeners': {'Type': 'List',
+                      'Schema': listeners_schema},
+        'AppCookieStickinessPolicy': {'Type': 'String',
+                                      'Implemented': False},
+        'LBCookieStickinessPolicy': {'Type': 'String',
+                                     'Implemented': False},
+        'SecurityGroups': {'Type': 'String',
+                           'Implemented': False},
+        'Subnets': {'Type': 'List',
+                    'Implemented': False}
+    }
+
+    def __init__(self, name, json_snippet, stack):
+        Resource.__init__(self, name, json_snippet, stack)
+        self._nested = None
+
+    def _params(self):
+        # total hack - probably need an admin key here.
+        params = {'KeyName': {'Ref': 'KeyName'}}
+        p = self.stack.resolve_static_data(params)
+        return p
+
+    def nested(self):
+        if self._nested is None:
+            if self.instance_id is None:
+                return None
+
+            st = db_api.stack_get(self.stack.context, self.instance_id)
+            if not st:
+                raise exception.NotFound('Nested stack not found in DB')
+
+            n = parser.Stack(self.stack.context, st.name,
+                             st.raw_template.parsed_template.template,
+                             self.instance_id, self._params())
+            self._nested = n
+
+        return self._nested
+
+    def _instance_to_ipaddress(self, inst):
+        '''
+        Return the server's IP address, fetching it from Nova
+        '''
+        try:
+            server = self.nova().servers.get(inst)
+        except NotFound as ex:
+            logger.warn('Instance IP address not found (%s)' % str(ex))
+        else:
+            for n in server.networks:
+                return server.networks[n][0]
+
+        return '0.0.0.0'
+
+    def _haproxy_config(self, templ):
+        # initial simplifications:
+        # - only one Listener
+        # - static (only use Instances)
+        # - only http (no tcp or ssl)
+        #
+        # option httpchk HEAD /check.txt HTTP/1.0
+        gl = '''
+    global
+        daemon
+        maxconn 256
+
+    defaults
+        mode http
+        timeout connect 5000ms
+        timeout client 50000ms
+        timeout server 50000ms
+'''
+
+        listener = self.properties['Listeners'][0]
+        lb_port = listener['LoadBalancerPort']
+        inst_port = listener['InstancePort']
+        spaces = '            '
+        frontend = '''
+        frontend http
+            bind *:%s
+''' % (lb_port)
+
+        backend = '''
+        default_backend servers
+
+        backend servers
+            balance roundrobin
+            option http-server-close
+            option forwardfor
+'''
+        servers = []
+        n = 1
+        for i in self.properties['Instances']:
+            ip = self._instance_to_ipaddress(i)
+            servers.append('%sserver server%d %s:%s' % (spaces, n,
+                                                        ip, inst_port))
+            n = n + 1
+
+        return '%s%s%s%s\n' % (gl, frontend, backend, '\n'.join(servers))
+
+    def handle_create(self):
+        templ = json.loads(lb_template)
+
+        md = templ['Resources']['LoadBalancerInstance']['Metadata']
+        files = md['AWS::CloudFormation::Init']['config']['files']
+        cfg = self._haproxy_config(templ)
+        files['/etc/haproxy/haproxy.cfg']['content'] = cfg
+
+        self._nested = parser.Stack(self.stack.context,
+                                    self.name,
+                                    templ,
+                                    parms=self._params(),
+                                    metadata_server=self.stack.metadata_server)
+
+        rt = {'template': templ, 'stack_name': self.name}
+        new_rt = db_api.raw_template_create(None, rt)
+
+        parent_stack = db_api.stack_get(self.stack.context, self.stack.id)
+
+        s = {'name': self.name,
+             'owner_id': self.stack.id,
+             'raw_template_id': new_rt.id,
+             'user_creds_id': parent_stack.user_creds_id,
+             'username': self.stack.context.username}
+        new_s = db_api.stack_create(None, s)
+        self._nested.id = new_s.id
+
+        pt = {'template': self._nested.t, 'raw_template_id': new_rt.id}
+        new_pt = db_api.parsed_template_create(None, pt)
+
+        self._nested.parsed_template_id = new_pt.id
+
+        self._nested.create()
+        self.instance_id_set(self._nested.id)
+
+    def handle_delete(self):
+        try:
+            stack = self.nested()
+        except exception.NotFound:
+            logger.info("Stack not found to delete")
+        else:
+            if stack is not None:
+                stack.delete()
+
+    def FnGetAtt(self, key):
+        '''
+        We don't really support any of these yet.
+        '''
+        allow = ('CanonicalHostedZoneName',
+                 'CanonicalHostedZoneNameID',
+                 'DNSName',
+                 'SourceSecurityGroupName',
+                 'SourceSecurityGroupOwnerAlias')
+
+        if not key in allow:
+            raise exception.InvalidTemplateAttribute(resource=self.name,
+                                                     key=key)
+
+        stack = self.nested()
+        if stack is None:
+            # This seems like a hack, to get past validation
+            return ''
+        if key == 'DNSName':
+            return stack.output('PublicIp')
+        else:
+            return ''

heat/engine/resource_types.py

@@ -23,6 +23,7 @@ from heat.engine import resources
 from heat.engine import cloud_watch
 from heat.engine import eip
 from heat.engine import instance
+from heat.engine import loadbalancer
 from heat.engine import security_group
 from heat.engine import stack
 from heat.engine import user
@@ -42,6 +43,7 @@ _resource_classes = {
     'AWS::EC2::SecurityGroup': security_group.SecurityGroup,
     'AWS::EC2::Volume': volume.Volume,
     'AWS::EC2::VolumeAttachment': volume.VolumeAttachment,
+    'AWS::ElasticLoadBalancing::LoadBalancer': loadbalancer.LoadBalancer,
     'AWS::IAM::User': user.User,
     'AWS::IAM::AccessKey': user.AccessKey,
     'HEAT::HA::Restarter': instance.Restarter,

templates/WordPress_With_LB.template

@@ -109,39 +109,59 @@
     },
 
     "WikiServerOne": {
-      "Type": "AWS::CloudFormation::Stack",
+      "Type": "AWS::EC2::Instance",
-      "DependsOn": "DatabaseServer",
+      "DependsOn" : "DatabaseServer",
-      "Properties": {
+      "Metadata": {
-        "TemplateURL": "https://raw.github.com/heat-api/heat/master/templates/WordPress_And_Http.template",
+        "AWS::CloudFormation::Init": {
-        "Parameters": {
+          "config": {
-          "KeyName"          : { "Ref": "KeyName" },
+            "packages": {
-          "InstanceType"     : { "Ref": "InstanceType" },
+              "yum": {
-          "DBName"           : { "Ref": "DBName" },
+                "httpd"        : [],
-          "DBUsername"       : { "Ref": "DBUsername" },
+                "wordpress"    : []
-          "DBPassword"       : { "Ref": "DBPassword" },
+              }
-          "DBIpaddress"      : { "Fn::GetAtt": [ "DatabaseServer", "Outputs.PublicIp" ]},
+            },
-          "LinuxDistribution": { "Ref": "LinuxDistribution" }
+            "services": {
+              "systemd": {
+                "httpd"    : { "enabled": "true", "ensureRunning": "true" }
+              }
+            }
+          }
         }
+      },
+      "Properties": {
+        "ImageId": { "Fn::FindInMap": [ "DistroArch2AMI", { "Ref": "LinuxDistribution" },
+                          { "Fn::FindInMap": [ "AWSInstanceType2Arch", { "Ref": "InstanceType" }, "Arch" ] } ] },
+        "InstanceType"   : { "Ref": "InstanceType" },
+        "KeyName"        : { "Ref": "KeyName" },
+        "UserData"       : { "Fn::Base64": { "Fn::Join": ["", [
+          "#!/bin/bash -v\n",
+          "/opt/aws/bin/cfn-init\n",
+          "sed --in-place --e s/database_name_here/", { "Ref": "DBName" },
+          "/ --e s/username_here/", { "Ref": "DBUsername" },
+          "/ --e s/password_here/", { "Ref": "DBPassword" },
+          "/ --e s/localhost/", { "Fn::GetAtt": [ "DatabaseServer", "Outputs.PublicIp" ]},
+          "/ /usr/share/wordpress/wp-config.php\n"
+        ]]}}
       }
     },
 
-    "LoadBalancer": {
+    "LoadBalancer" : {
-      "Type": "AWS::CloudFormation::Stack",
+      "Type" : "AWS::ElasticLoadBalancing::LoadBalancer",
-      "DependsOn": "WikiServerOne",
+      "Properties" : {
-      "Properties": {
+        "AvailabilityZones" : { "Fn::GetAZs" : "" },
-        "TemplateURL": "https://raw.github.com/heat-api/heat/master/templates/HAProxy_Single_Instance.template",
+        "Instances" : [{"Ref": "WikiServerOne"}],
-        "Parameters": {
+        "Listeners" : [ {
-          "KeyName"          : { "Ref": "KeyName" },
+          "LoadBalancerPort" : "80",
-          "InstanceType"     : { "Ref": "InstanceType" },
+          "InstancePort" : "80",
-          "Server1"          : { "Fn::Join": ["", [{ "Fn::GetAtt": [ "WikiServerOne", "Outputs.PublicIp" ]}, ":80"]] }
+          "Protocol" : "HTTP"
-        }
+        }]
       }
     }
   },
 
   "Outputs": {
     "WebsiteURL": {
-      "Value": { "Fn::Join": ["", ["http://", { "Fn::GetAtt": [ "LoadBalancer", "Outputs.PublicIp" ]}, "/wordpress"]] },
+      "Value": { "Fn::Join": ["", ["http://", { "Fn::GetAtt": [ "LoadBalancer", "DNSName" ]}, "/wordpress"]] },
       "Description": "URL for Wordpress wiki"
     }
   }