Class: VCAP::Services::Base::SnapshotV2::SnapshotClient

Inherits:
Object
  • Object
show all
Includes:
Error
Defined in:
lib/base/snapshot_v2/snapshot_client.rb

Constant Summary collapse

SNAPSHOT_KEY_PREFIX = 
"vcap:snapshotv2".freeze
SNAPSHOT_ID = 
"maxid".freeze
FILTER_KEYS = 
%w(snapshot_id date size name).freeze
MAX_NAME_LENGTH = 
512

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Error

#failure, #internal_fail, #parse_msg, #success, #timeout_fail

Constructor Details

#initialize(redis_config) ⇒ SnapshotClient

Returns a new instance of SnapshotClient.



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# File 'lib/base/snapshot_v2/snapshot_client.rb', line 14

def initialize(redis_config)
  @redis = ::Redis.new(redis_config)
  # FIXME: use UUID?
  redis_init
end

Class Method Details

.filter_keys(snapshot) ⇒ Object

filter internal keys of a given snapshot object, return a new snapshot object in canonical format



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# File 'lib/base/snapshot_v2/snapshot_client.rb', line 57

def self.filter_keys(snapshot)
  return unless snapshot.is_a? Hash
  snapshot.select {|k,v| FILTER_KEYS.include? k.to_s}
end

.fmt_time ⇒ Object 



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# File 'lib/base/snapshot_v2/snapshot_client.rb', line 116

def self.fmt_time()
  # UTC time in ISO 8601 format.
  Time.now.utc.strftime("%FT%TZ")
end

.redis_key(key) ⇒ Object 



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# File 'lib/base/snapshot_v2/snapshot_client.rb', line 121

def self.redis_key(key)
  "#{SNAPSHOT_KEY_PREFIX}:#{key}"
end

.snapshot_filepath(base_dir, service_name, service_id, snapshot_id) ⇒ Object

Get the snapshot file path that service should save the dump file to. the snapshot path structure looks like <base_dir>snapshots<service-name><aa><bb><cc><aabbcc-rest-of-instance-guid>snapshot_id<service specific data>



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# File 'lib/base/snapshot_v2/snapshot_client.rb', line 69

def self.snapshot_filepath(base_dir, service_name, service_id, snapshot_id)
  File.join(base_dir, "snapshots", service_name, service_id[0,2], service_id[2,2], service_id[4,2], service_id, snapshot_id.to_s)
end

Instance Method Details

#create_empty_snapshot(service_id, name) ⇒ Object 



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# File 'lib/base/snapshot_v2/snapshot_client.rb', line 20

def create_empty_snapshot(service_id, name)
  snapshot = {
    'state' => 'empty',
    'size'  => 0,
    'name'  => name,
    'snapshot_id' => new_snapshot_id,
  }
  msg = Yajl::Encoder.encode(snapshot)
  client.hset(redis_key(service_id), snapshot['snapshot_id'], msg)
  snapshot
end

#delete_snapshot(service_id, snapshot_id) ⇒ Object 



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# File 'lib/base/snapshot_v2/snapshot_client.rb', line 110

def delete_snapshot(service_id , snapshot_id)
  return unless service_id && snapshot_id
  client.hdel(redis_key(service_id), snapshot_id)
end

#new_snapshot_id ⇒ Object

Generate a new unique id for a snapshot



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# File 'lib/base/snapshot_v2/snapshot_client.rb', line 63

def new_snapshot_id
  client.incr(redis_key(SNAPSHOT_ID)).to_s
end

#save_snapshot(service_id, snapshot) ⇒ Object 



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# File 'lib/base/snapshot_v2/snapshot_client.rb', line 101

def save_snapshot(service_id , snapshot)
  return unless service_id && snapshot
  # FIXME: srsly? where are we using symbols?
  sid = snapshot[:snapshot_id] || snapshot["snapshot_id"]
  return unless sid
  msg = Yajl::Encoder.encode(snapshot)
  client.hset(redis_key(service_id), sid, msg)
end

#service_snapshots(service_id) ⇒ Object

Get all snapshots related to a service instance



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# File 'lib/base/snapshot_v2/snapshot_client.rb', line 34

def service_snapshots(service_id)
  return unless service_id
  res = client.hgetall(redis_key(service_id))
  res.values.map{|v| Yajl::Parser.parse(v)}
end

#service_snapshots_count(service_id) ⇒ Object

Return total snapshots count



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# File 'lib/base/snapshot_v2/snapshot_client.rb', line 42

def service_snapshots_count(service_id)
  return unless service_id
  client.hlen(redis_key(service_id))
end

#snapshot_details(service_id, snapshot_id) ⇒ Object

Get detail information for a single snapshot

Raises:



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# File 'lib/base/snapshot_v2/snapshot_client.rb', line 49

def snapshot_details(service_id, snapshot_id)
  return unless service_id && snapshot_id
  res = client.hget(redis_key(service_id), snapshot_id)
  raise ServiceError.new(ServiceError::NOT_FOUND, "snapshot #{snapshot_id}") unless res
  Yajl::Parser.parse(res)
end

#update_name(service_id, snapshot_id, name) ⇒ Object

Update the name of given snapshot. This function is not protected by redis lock so a optimistic lock is applied to prevent concurrent update.



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# File 'lib/base/snapshot_v2/snapshot_client.rb', line 77

def update_name(service_id, snapshot_id, name)
  return unless service_id && snapshot_id && name
  verify_input_name(name)

  key = self.class.redis_key(service_id)
  # NOTE: idealy should watch on combination of (service_id, snapshot_id)
  # but current design doesn't support such fine-grained watching.
  client.watch(key)

  snapshot = client.hget(redis_key(service_id), snapshot_id)
  return nil unless snapshot
  snapshot = Yajl::Parser.parse(snapshot)
  snapshot["name"] = name

  res = client.multi do
    save_snapshot(service_id, snapshot)
  end

  unless res
    raise ServiceError.new(ServiceError::REDIS_CONCURRENT_UPDATE)
  end
  true
end