Class: AWSDSL::CfnBuilder

Inherits:
Object
  • Object
show all
Includes:
CfnHelpers
Defined in:
lib/awsdsl/cfn_builder.rb

Class Method Summary collapse

Instance Method Summary collapse

Methods included from CfnHelpers

#format_block_devices, #format_listener, #format_policy_statement, #get_vpc_by_name, #get_zone_for_record, #health_check_defaults, #listener_defaults, #resolve_security_group, #resolve_security_groups, #resolve_subnet, #resolve_subnets, #resolve_vpc, #subnet_defined?, #subnet_refs, #update_policy_defaults, #vpc_defined?

Constructor Details

#initialize(stack) ⇒ CfnBuilder

Returns a new instance of CfnBuilder.



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# File 'lib/awsdsl/cfn_builder.rb', line 9

def initialize(stack)
  @stack = stack
end

Class Method Details

.build(stack) ⇒ Object 



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# File 'lib/awsdsl/cfn_builder.rb', line 13

def self.build(stack)
  CfnBuilder.new(stack).build
end

Instance Method Details

#build ⇒ Object 



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# File 'lib/awsdsl/cfn_builder.rb', line 17

def build
  @t = CfnDsl::CloudFormationTemplate.new
  stack = @stack
  @t.declare do
    Description stack.description
  end
  AWS.memoize do
    build_vpcs
    build_elasticaches
    build_buckets
    build_roles
  end
  @t
end

#build_buckets ⇒ Object 



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# File 'lib/awsdsl/cfn_builder.rb', line 374

def build_buckets
  stack = @stack
  stack.buckets.each do |bucket|
    @t.declare do
      Bucket "#{bucket.name.capitalize}Bucket" do
        BucketName bucket.bucket_name if bucket.bucket_name
        AccessControl bucket.access_control if bucket.access_control
      end
    end
  end
end

#build_elasticaches ⇒ Object 



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# File 'lib/awsdsl/cfn_builder.rb', line 231

def build_elasticaches
  default_ports = {
    'redis' => 6379,
    'memcached' => 11211
  }
  stack = @stack
  stack.elasticaches.each do |cache|
    # Default to Redis, also set default port if unset.
    engine ||= 'redis'
    port ||= default_ports[engine]
    num_nodes ||= 1
    cache_vpc = resolve_vpc(cache.vpc)
    cache_name = "#{cache.name.capitalize}Cache"

    # SG
    @t.declare do
      EC2_SecurityGroup "#{cache_name}SG" do
        GroupDescription "#{cache.name.capitalize} Cache Security Group"
        VpcId cache_vpc
        cache.allows.each do |rule|
          SecurityGroupIngress IpProtocol: 'tcp',
                               FromPort: port,
                               ToPort: port,
                               SourceSecurityGroupId: Ref("#{rule[:role].capitalize}SG")
        end
      end
    end

    # ElastiCacheSubnetGroup
    cache_subnets = resolve_subnets(cache.vpc, cache.subnets)
    @t.declare do
      ElastiCache_SubnetGroup "#{cache_name}SubnetGroup" do
        Description "SubnetGroup for #{cache_name}"
        SubnetIds cache_subnets
      end
    end

    # CacheCluster
    @t.declare do
      CacheCluster cache_name do
        CacheNodeType cache.node_type
        NumCacheNodes num_nodes
        Engine engine
        Port port
        CacheSubnetGroupName Ref("#{cache_name}SubnetGroup")
        VpcSecurityGroupIds [FnGetAtt("#{cache_name}SG", 'GroupId')]
      end
    end

    # Add additional policy to each Role that can access this Cache
    # This will allow said Role to discover the Cache nodes
    cache.allows.each do |rule|
      role = stack.roles.find { |r| r.name = rule[:role] }
      role.policy_statement effect: 'Allow',
                            action: 'elasticache:Describe*',
                            resource: '*'
    end
  end
end

#build_roles ⇒ Object 



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# File 'lib/awsdsl/cfn_builder.rb', line 32

def build_roles
  stack = @stack
  stack.roles.each do |role|
    role_name = role.name.capitalize
    role_vpc = resolve_vpc(role.vpc)

    # Create ELBs and appropriate security groups etc.
    role.load_balancers.each do |lb|
      listeners = lb.listeners.map { |l| format_listener(l) }
      health_check = health_check_defaults(lb.health_check) if lb.health_check

      lb_name = "#{role_name}#{lb.name.capitalize}ELB"
      subnets = lb.subnets.empty? ? role.subnets : lb.subnets
      lb_subnets = resolve_subnets(role.vpc, subnets)

      # ELB
      @t.declare do
        LoadBalancer lb_name do
          Listeners listeners
          ConnectionSettings lb.connection_settings if lb.connection_settings
          HealthCheck health_check if health_check
          CrossZone true
          Subnets lb_subnets
          SecurityGroups [Ref("#{lb_name}SG")]
        end
      end

      # ELB SG
      @t.declare do
        EC2_SecurityGroup "#{lb_name}SG" do
          GroupDescription "#{lb.name.capitalize} ELB Security Group"
          VpcId role_vpc
          listeners.map { |l| l[:LoadBalancerPort] }.each do |port|
            SecurityGroupIngress IpProtocol: 'tcp',
                                 FromPort: port,
                                 ToPort: port,
                                 CidrIp: '0.0.0.0/0'
          end
          lb.allows.each do |rule|
            ports = rule[:ports].is_a?(Array) ? rule[:ports] : [rule[:ports]]
            ports.each do |port|
              SecurityGroupIngress IpProtocol: rule[:proto] || 'tcp',
                                   FromPort: port,
                                   ToPort: port,
                                   SourceSecurityGroupId: Ref("#{rule[:role].capitalize}SG")
            end
          end
        end
      end

      # ELB DNS records
      lb.dns_records.each do |record|
        zone = record[:zone] || get_zone_for_record(record[:name]).id
        record_name = record[:name].split('.').map(&:capitalize).join
        @t.declare do
          RecordSet record_name do
            HostedZoneId zone
            Name record
            Type 'A'
            AliasTarget HostedZoneId: FnGetAtt(lb_name, 'CanonicalHostedZoneNameID'),
                        DNSName: FnGetAtt(lb_name, 'CanonicalHostedZoneName')
          end
        end
      end
    end # end load_balancers

    # IAM Role
    @t.declare do
      IAM_Role "#{role_name}Role" do
        AssumeRolePolicyDocument Statement: [{
          Effect: 'Allow',
          Principal: {
            Service: ['ec2.amazonaws.com']
          },
          Action: ['sts:AssumeRole']
        }]
        Path '/'
      end
    end

    # Policy
    statements = role.policy_statements.map { |s| format_policy_statement(s) }
    if statements.count > 1
      policy_name = "#{role_name}Policy"
      @t.declare do
        Policy policy_name do
          PolicyName policy_name
          PolicyDocument Statement: statements
          Roles [Ref("#{role_name}Role")]
        end
      end
    end

    # Instance Profile
    @t.declare do
      InstanceProfile "#{role_name}InstanceProfile" do
        Path '/'
        Roles [Ref("#{role_name}Role")]
      end
    end

    # Autoscaling Group
    update_policy = update_policy_defaults(role)
    lb_names = role.load_balancers.map { |lb| "#{role_name}#{lb.name.capitalize}ELB" }
    subnets = resolve_subnets(role.vpc, role.subnets)
    min = role.min_size || 0
    max = role.max_size || 1
    tgt = role.tgt_size || 1
    @t.declare do
      AutoScalingGroup "#{role_name}ASG" do
        LaunchConfigurationName Ref("#{role.name.capitalize}LaunchConfig")
        UpdatePolicy 'AutoScalingRollingUpdate', update_policy if update_policy
        MinSize min
        MaxSize max
        DesiredCapacity tgt
        LoadBalancerNames lb_names.map { |name| Ref(name) }
        VPCZoneIdentifier subnets
        AvailabiltityZones FnGetAZs('')
      end
    end

    # Launch Configuration
    security_groups = resolve_security_groups(role.vpc, role.security_groups)
    block_devices = format_block_devices(role.block_devices)
    vars = (stack.vars || {}).merge(role.vars || {})
    @t.declare do
      LaunchConfiguration "#{role_name}LaunchConfig" do
        ImageId role.ami
        # TODO(jpg): Should support NAT at some stage even though it's nasty on AWS
        AssociatePublicIpAddress true
        InstanceType role.instance_type
        # TODO(jpg): Need to resolve this to IDs or Refs as necessary
        SecurityGroups [Ref("#{role_name}SG")] + security_groups
        IamInstanceProfile Ref("#{role_name}InstanceProfile")
        BlockDeviceMappings block_devices
        KeyName role.key_pair if role.key_pair
        vars.each do |k,v|
          Metadata k.to_s, v
        end
      end
    end

    lb_ingress_rules = role.load_balancers.map do |lb|
      lb.listeners.map do |l|
        h = listener_defaults(l)
        h[:sg] = "#{role_name}#{lb.name.capitalize}ELBSG"
        h
      end
    end.flatten
    # Security Group
    @t.declare do
      EC2_SecurityGroup "#{role_name}SG" do
        GroupDescription "#{role_name} Security Group"
        VpcId role_vpc
        # TODO(jpg): Better way of offering up defaults
        SecurityGroupIngress IpProtocol: 'tcp',
                             FromPort: 22,
                             ToPort: 22,
                             CidrIp: '0.0.0.0/0'

        # Access from configured load_balancers
        lb_ingress_rules.each do |rule|
          SecurityGroupIngress IpProtocol: 'tcp',
                               FromPort: rule[:instance_port],
                               ToPort: rule[:instance_port],
                               SourceSecurityGroupId: Ref(rule[:sg])
        end

        # Access from other roles
        # TODO(jpg): catch undefined roles before template generation
        role.allows.select { |r| r[:role] != role.name }.each do |rule|
          ports = rule[:ports].is_a?(Array) ? rule[:ports] : [rule[:ports]]
          ports.each do |port|
            SecurityGroupIngress IpProtocol: rule[:proto] || 'tcp',
                                 FromPort: port,
                                 ToPort: port,
                                 SourceSecurityGroupId: Ref("#{rule[:role].capitalize}SG")
          end
        end
      end

      # Intracluster communication
      role.allows.select { |r| r[:role] == role.name }.each do |rule|
        ports = rule[:ports].is_a?(Array) ? rule[:ports] : [rule[:ports]]
        proto = rule[:proto] || 'tcp'
        ports.each do |port|
          EC2_SecurityGroupIngress "#{role_name}SG#{proto.upcase}#{port}" do
            GroupId Ref("#{role_name}SG")
            IpProtocol proto
            FromPort port
            ToPort port
            SourceSecurityGroupId Ref("#{role_name}SG")
          end
        end
      end
    end
  end
end

#build_vpcs ⇒ Object 



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# File 'lib/awsdsl/cfn_builder.rb', line 291

def build_vpcs
  stack = @stack
  stack.vpcs.each do |vpc|
    igw = vpc.igw || true
    dns = vpc.dns || true
    cidr = vpc.cidr || '10.0.0.0/16'
    subnet_bits = vpc.subnet_bits || 24
    dns_hostnames = vpc.dns_hostnames || true

    cidr = NetAddr::CIDR.create(cidr)
    subnets = cidr.subnet(Bits: subnet_bits).to_enum

    # VPC
    vpc_name = "#{vpc.name.capitalize}VPC"
    @t.declare do
      VPC vpc_name do
        CidrBlock cidr
        EnableDnsSupport dns
        EnableDnsHostnames dns_hostnames
      end
    end

    if igw # Don't create internet facing stuff if igw is not enabled
      igw_name = "#{vpc.name.capitalize}IGW"

      # IGW
      @t.declare do
        InternetGateway igw_name
      end

      # Attach to VPC
      @t.declare do
        VPCGatewayAttachment "#{vpc.name.capitalize}GWAttachment" do
          VpcId Ref(vpc_name)
          InternetGatewayId Ref(igw_name)
        end
      end

      # RouteTable
      rt_name = "#{vpc.name.capitalize}RouteTable"
      @t.declare do
        RouteTable rt_name do
          VpcId Ref(vpc_name)
        end
      end

      # Default route for RouteTable
      @t.declare do
        Route "#{vpc.name.capitalize}DefaultRoute" do
          RouteTableId Ref(rt_name)
          DestinationCidrBlock '0.0.0.0/0'
          GatewayId Ref(igw_name)
          # TODO(jpg): DependsOn rt_name
        end
      end
    end

    vpc.subnets.each do |subnet|
      subnet_igw = subnet.igw || igw
      azs = subnet.azs || fetch_availability_zones(vpc.region)
      subnet_name = "#{vpc.name.capitalize}#{subnet.name.capitalize}Subnet"
      azs.each do |az|
        subnet_name_az = "#{subnet_name}#{az.capitalize}"
        @t.declare do
          Subnet subnet_name_az do
            AvailabilityZone "#{vpc.region}#{az}"
            CidrBlock subnets.next
            VpcId Ref(vpc_name)
          end

          if subnet_igw
            SubnetRouteTableAssociation "#{subnet_name_az}DefaultRTAssoc" do
              SubnetId Ref(subnet_name_az)
              RouteTableId Ref(rt_name)
              # TODO(jpg): DependsOn rt_name
            end
          end
        end
      end
    end
  end
end