Class: Kiel::Cloud::AWS

Inherits:
Object
  • Object
show all
Includes:
AWSBase
Defined in:
lib/kiel/cloud/aws.rb

Overview

Implements the connection to the Amazon Web Services (AWS). The current implementation works for one configured region. The default server is a small EC2 instance.

Constant Summary collapse

RECOGNIZED_OPTIONS = 
[ :region, :credentials, :instance, :start_options ]

Constants included from AWSBase

Kiel::Cloud::AWSBase::INSTANCE_STARTUP_TIMEOUT

Instance Method Summary collapse

Methods included from AWSBase

#exists?

Constructor Details

#initialize(options = {}) ⇒ AWS

The contructor takes the following configuration options:

:region

A string naming the region to be used. If no region is given, the default region is used.

:credentials

A hash containing the fields ‘access_key_id’ and ‘secret_access_key’ with the credential information to your amazon account.

:instance

An instance of the AWS::EC2. If that instance is given, no credentials: should be given. Kiel::Cloud::AWS will instead use this instance.

:start_options

Options that are applied to EC2::InstanceCollection.create (siehe aws-sdk for more details). The aws_tests.rb uses the :key_name and :security_groups options to set the name of the used ssh key and a security group, where ssh is enabled.



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# File 'lib/kiel/cloud/aws.rb', line 26

def initialize options = {}
    require 'aws/ec2'

    options.each_key do | key |
        raise ArgumentError, "unrecognized option \'#{key}\'" unless RECOGNIZED_OPTIONS.include? key
    end
                        
    @ec2 = options[ :instance ]
    @start_options = options[ :start_options ] || {}
    
    if @ec2 
        puts "\'credentials\' ignored as an instance was given too" if options.key? :credentials
    else
        ::AWS.config( options[ :credentials ]  )
    
        @ec2 = ::AWS::EC2.new
        @ec2 = @ec2.regions[ options[ :region ] ] if options.key? :region
    end
end

Instance Method Details

#all_images_by_tags(tags) ⇒ Object

Finds all images where the given tags apply



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# File 'lib/kiel/cloud/aws.rb', line 47

def all_images_by_tags tags
    images = @ec2.images.with_owner('self').tagged( tags.first.first )
    
    images = images.select do | image |
        image_tags = image.tags.to_h
        image_tags.merge( tags ) == image_tags 
    end
    
    images
end

#delete_image(tags) ⇒ Object

deletes the given images by tags. For now this function is used just for cleanup during tests.



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# File 'lib/kiel/cloud/aws.rb', line 149

def delete_image tags
    all_images_by_tags( tags ).each { | image | image.deregister } 
end

#dns_name(instance) ⇒ Object

the public dns name of the given instance



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# File 'lib/kiel/cloud/aws.rb', line 144

def dns_name instance
    instance.dns_name
end

#start_instance(image_name) ⇒ Object

starts a server instance in the cloud, returning a handle to that instance. the image is either named by an image id :id => ‘image_id’ or by a set of tags that match for just one image :tags => { ‘image_type’ => ‘application’, ‘base’ => ‘34’ }



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# File 'lib/kiel/cloud/aws.rb', line 87

def start_instance image_name
    options = @start_options.merge( if image_name.key?( :id ) 
        { image_id: image_name[ :id ] }
    else
        tags  = image_name[ :tags ]
        image = image_by_tags tags
        raise RuntimeError, "no image with tags: \'#{tags}\' found to start an instance" unless image
        
        { image_id: image.id }
    end )
    
    instance = @ec2.instances.create( options )
    
    begin
        wait_for_ec2 instance
        puts "ec2 instance \'#{instance.dns_name}\' started."
    rescue 
        instance.terminate
        raise
    end 
    
    instance
end

#stop_instance(instance) ⇒ Object

stops the given instance.



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# File 'lib/kiel/cloud/aws.rb', line 136

def stop_instance instance
    begin
        instance.terminate
    rescue
    end                    
end

#store_image(instance, tags) ⇒ Object

store the given instance and add the hash of tags to the image.



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# File 'lib/kiel/cloud/aws.rb', line 112

def store_image instance, tags
    begin
    
        puts "waiting 2 minutes before starting to take the image..."
        sleep 120
        puts "creating image..."
    
        image = @ec2.images.create( 
            :instance_id => instance.id,
            :no_reboot => true,
            :description => "automaticaly created #{tags[ 'image_type' ]} image",
            :name => "#{tags[ 'image_type' ]} #{Digest::SHA1.hexdigest tags.inspect}" )
           
        wait_for_image image
    
        tags.each do | key, value |
            image.add_tag( key, :value => value )
        end               
    ensure
        stop_instance instance
    end
end