Class: EC2VolumeSnapshoter

Inherits:
Object
  • Object
show all
Defined in:
lib/ec2_volume_snapshoter.rb

Constant Summary collapse

NAME_PREFIX = 
'Volume Snapshot'
KINDS =

Kind of snapshot and their expiration in days

{ 'test' => 1,
'snapshot' => 0,
'daily' => 7,
'weekly' => 31,
'monthly' => 300,
'yearly' => 0}

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(aki, sak, instance_id = open("http://169.254.169.254/latest/meta-data/instance-id").read) ⇒ EC2VolumeSnapshoter

Need access_key_id, secret_access_key and instance_id If not provided, attempt to fetch current instance_id



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# File 'lib/ec2_volume_snapshoter.rb', line 48

def initialize(aki, sak, instance_id = open("http://169.254.169.254/latest/meta-data/instance-id").read)

  @instance_id = instance_id

  @compute = Fog::Compute.new({:provider => 'AWS', :aws_access_key_id => aki, :aws_secret_access_key => sak})
end

Instance Attribute Details

#instance_id ⇒ Object (readonly)

Returns the value of attribute instance_id.



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# File 'lib/ec2_volume_snapshoter.rb', line 45

def instance_id
  @instance_id
end

Instance Method Details

#find_volume_for_device(device) ⇒ Object

Raises:



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# File 'lib/ec2_volume_snapshoter.rb', line 134

def find_volume_for_device(device)
  my = []
  @compute.volumes.all().each do |volume|
    if volume.server_id == @instance_id
      my << volume
      if volume.device == device
        return volume
      end
    end
  end
  raise NoSuchVolumeException.new(@instance_id, device, my)
end

#list_snapshots(devices, kind) ⇒ Object 



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# File 'lib/ec2_volume_snapshoter.rb', line 110

def list_snapshots(devices, kind)
  volume_map = []
  snapshots = {}

  tags = @compute.tags.all(:key => 'instance_id', :value => instance_id)
  tags.each do |tag|
    snap = @compute.snapshots.get(tag.resource_id)
    t =  snap.tags

    if devices.include?(t['device']) && 
      instance_id == t['instance_id'] &&
      NAME_PREFIX == t['application'] &&
      kind == t['kind']
      snapshots[t['date']] ||= []
      snapshots[t['date']] << snap
    end
  end

  # take out incomplete backups
  snapshots.delete_if{ |date, snaps| snaps.length != devices.length }
  snapshots
end

#snapshot_devices(devices, name = "#{instance_id}", kind = "test", limit = KINDS[kind]) ⇒ Object

Snapshots the list of devices devices is an array of device attached to the instance (/dev/foo) name if the name of the snapshot



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# File 'lib/ec2_volume_snapshoter.rb', line 57

def snapshot_devices(devices, name = "#{instance_id}", kind = "test", limit = KINDS[kind])
  log "Snapshot of kind #{kind}, limit set to #{limit} (0 means never purge)"
  ts = DateTime.now.to_s
  name = "#{NAME_PREFIX}:" + name
  volumes = {}
  devices.each do |device|
    volumes[device] = find_volume_for_device(device)
  end
  sn = []
  volumes.each do |device, volume|
    log "Creating volume snapshot for #{device} on instance #{instance_id}"
    snapshot = volume.snapshots.new
    snapshot.description = name+" #{device}"
    snapshot.save
    sn << snapshot
    snapshot.reload

    @compute.tags.create(:resource_id => snapshot.id, :key =>"application", :value => NAME_PREFIX)
    @compute.tags.create(:resource_id => snapshot.id, :key =>"device", :value => device)
    @compute.tags.create(:resource_id => snapshot.id, :key =>"instance_id", :value =>instance_id)
    @compute.tags.create(:resource_id => snapshot.id, :key =>"date", :value => ts)
    @compute.tags.create(:resource_id => snapshot.id, :key =>"kind", :value => kind)

  end
  log "Waiting for snapshots to complete."
  sn.each do |s|
    begin
      sleep(3)
      s.reload
    end while s.state == 'nil' || s.state == 'pending'
  end

  if limit != 0
    # populate data structure with updated information
    snapshots = list_snapshots(devices, kind)
    nsnaps = snapshots.keys.length
    if nsnaps-limit > 0
      dates = snapshots.keys.sort
      puts dates.inspect
      extra_snapshots = dates[0..-limit]
      remaining_snapshots = dates[-limit..-1]
      extra_snapshots.each do |date|
        snapshots[date].each do |snap|
          log "Destroying #{snap.description} #{snap.id}"
          snap.destroy
       end
      end
    end
  end
end