Class: FileStore::SimpleFileStore

Inherits:
Object
  • Object
show all
Includes:
Logger, OberservedSubject
Defined in:
lib/filestore/simple_store.rb

Overview

Main library class implementing a simple file store used for storing and managing arbitrary files

Constant Summary collapse

STORE_LOCK_FILE =

Name of the lock file

".locked"
META_FILE =

Name of the meta file describing the current file store

"filestore.yaml"
STORE_ROOT =

The base name of the file store directory

'filestore'
DELETED_ROOT =

The base name of the directory for storing deleted files

'deleted'
ROLLBACK_ROOT =

The base name of the directory storing files extracted from file store by a rollback action

'rollback'

Instance Attribute Summary collapse

Attributes included from OberservedSubject

#observers

Attributes included from Logger

#logger

Class Method Summary collapse

Instance Method Summary collapse

Methods included from OberservedSubject

included, #inform, #initialize_obs, #register, #unregister

Constructor Details

#initialize(metaManager, rootPath = '.', logger) ⇒ SimpleFileStore

Initializes a new instance of SimpleFileStore

Arguments: metaManager: The meta data manager instance to be used by this store rootPath: The path where the file store resides

Raises:



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# File 'lib/filestore/simple_store.rb', line 43

def initialize(metaManager, rootPath = '.', logger)
	raise FileStoreException, "Root path already locked" if SimpleFileStore.is_directory_locked?(rootPath)		
	raise FileStoreException, "FileStore root path #{rootPath} doesn't exist" if not File.directory?(rootPath)
	raise FileStoreException, "FileStore root path #{rootPath} isn't writable" if not File.writable?(rootPath)
	raise FileStoreException, "No meta data manager given" if metaManager.nil?
	raise FileStoreException, "Meta data manager must be of type FileStore::MetaManager" if not metaManager.is_a?(MetaManager)
	
	@metaManager = metaManager
	@rootPath = rootPath
	@storePath = File.join(@rootPath, STORE_ROOT)
	@deletedPath = File.join(@rootPath, DELETED_ROOT)
	@rollbackPath = File.join(@rootPath, ROLLBACK_ROOT)
	@metaFile = File.join(@rootPath, META_FILE)
	@locked = false
	@logger = logger
	
	self.initialize_obs
	
	begin
		# Try to recover existing store
		SimpleFileStore.recover_store(self)
	rescue FileStoreException => e
		# Recovery failed, trying to create the store
		SimpleFileStore.create_store(self)
	end
	
	lock
end

Instance Attribute Details

#deletedPath ⇒ Object (readonly)

Accessors for important properties



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# File 'lib/filestore/simple_store.rb', line 35

def deletedPath
  @deletedPath
end

#metaFile ⇒ Object (readonly)

Accessors for important properties



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# File 'lib/filestore/simple_store.rb', line 35

def metaFile
  @metaFile
end

#metaManager ⇒ Object (readonly)

Accessors for important properties



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# File 'lib/filestore/simple_store.rb', line 35

def metaManager
  @metaManager
end

#rollbackPath ⇒ Object (readonly)

Accessors for important properties



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# File 'lib/filestore/simple_store.rb', line 35

def rollbackPath
  @rollbackPath
end

#rootPath ⇒ Object (readonly)

Accessors for important properties



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# File 'lib/filestore/simple_store.rb', line 35

def rootPath
  @rootPath
end

#storePath ⇒ Object (readonly)

Accessors for important properties



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# File 'lib/filestore/simple_store.rb', line 35

def storePath
  @storePath
end

Class Method Details

.create_store(store) ⇒ Object

Setup for a new file store directory

Arguments: store: The file store instance to set up



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# File 'lib/filestore/simple_store.rb', line 277

def self.create_store(store)
	# Try to create needed directories
	begin
		FileUtils.mkdir [store.storePath, store.deletedPath, store.rollbackPath]
	rescue Errno::ENOENT => e
		raise FileStoreException, "One ore more system directories couldn't be created.\n#{e.message}"
	end
	# Try to create hidden meta file
	begin
		meta = { :created_at => Date.today.strftime('%d.%m.%Y %H:%M:%S:%L'), 
			:storePath => store.storePath,
			:deletedPath => store.deletedPath,
			:rollbackPath => store.rollbackPath,
			:created_by => Etc.getlogin
		}
		
		File.open(store.metaFile, "w+") do |fh|
			YAML.dump(meta, fh)
		end
		
		#
		# Creation was successful
		#
	rescue Exception => e
		raise FileStoreException, "Meta file #{store.metaFile} couldn't be created.\n#{e.message}"
	end
end

.get_daily_directory(base) ⇒ Object

Returns the currently used directory

Raises:



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# File 'lib/filestore/simple_store.rb', line 258

def self.get_daily_directory(base)
	date = Date.today
	dir = File.join(base, date.year.to_s, date.month.to_s, date.day.to_s)
	
	begin
		FileUtils.mkdir_p(dir) if not File.directory?(dir)
	rescue Exception => e
		raise FileStoreException, "Can't create daily directory #{dir}.\n#{e.message}"
	end
	
	raise FileStoreException, "Daily directory #{dir} isn't writable" if not File.writable?(dir)
	return dir
end

.get_id(store) ⇒ Object

Creates a new file ID

Returns: A string representing the file’s ID

Raises:



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# File 'lib/filestore/simple_store.rb', line 246

def self.get_id(store)
	for i in 0..2 do	
		id = UUIDTools::UUID.random_create.to_s
		
		return id if not store.metaManager.has_id?(id) 
	end
	
	raise FileStoreException, "Couldn't find unique ID"
end

.is_directory_locked?(rootPath) ⇒ Boolean

Determines wether the store path is already locked by another instance of SimpleFileStore

Returns:

  • (Boolean) 


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# File 'lib/filestore/simple_store.rb', line 237

def self.is_directory_locked?(rootPath)
	return File.exists?(File.join(rootPath, SimpleFileStore::STORE_LOCK_FILE))
end

.recover_store(store) ⇒ Object

Recover an existing file store

Arguments: store: The file store instance to recover



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# File 'lib/filestore/simple_store.rb', line 310

def self.recover_store(store)
	# trying to recover existing file store
	begin
		meta = YAML.load_file(store.metaFile)
		
		raise FileStoreException, "Store directory not found" if not File.directory?(meta[:storePath])
		raise FileStoreException, "Deleted directory not found" if not File.directory?(meta[:deletedPath])
		raise FileStoreException, "Rollback directory not found" if not File.directory?(meta[:rollbackPath])
		
		#
		# Recovery was successful
		#
	rescue Exception => e
		raise FileStoreException, "Unable to recover file store from path #{store.rootPath}.\n#{e.message}"
	end
end

Instance Method Details

#add(file, meta = {}, shouldMove = true) ⇒ Object

Adds a file to the store

Arguments: file: The file to be stored meta: Optional meta data to be stored along with the physical file shouldMove: Determines wether to original file should be deleted

Returns:

The newly created ID for the file

Raises:



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# File 'lib/filestore/simple_store.rb', line 82

def add(file, meta = {}, shouldMove = true)
	raise FileStoreException, "File #{file} not found" if not File.exists?(file)
	raise FileStoreException, "File #{file} isn't readable" if not File.readable?(file)
	raise FileStoreException, "File #{file} can't be removed" if not File.writable?(file)
	
	meta = {} if meta.nil?
	id = ""
	
	begin
		dir = SimpleFileStore.get_daily_directory(@storePath)
		@logger.info "Adding file #{file} to directory #{dir}"
		id = SimpleFileStore.get_id(self)
		@logger.info "Using file id #{id}"
		dstPath = File.join(dir, id)
		@logger.info "Created destination path #{dstPath}"
		
		shouldMove ? (@logger.info("Moving file"); FileUtils.mv(file, dstPath)) : 
			(@logger.info("Copying file"); FileUtils.copy_file(file, dstPath))
		
		self.inform ObserverAction.new(:type => ObserverAction::TYPE_STORE_ADD, 
        :objects => [file, meta], :msg => "Added file to file store")
	rescue Exception => e
		raise FileStoreException, "Couldn't add file #{file} to store.", e.backtrace
	end
	
	meta[:path] = dstPath
	@metaManager.add_or_update(id, meta)
	
	return id
end

#get(id) ⇒ Object

Retrieves a file identified by it’s ID

Arguments: id: The files ID to retrieve

Returns: A hash of file object (:path) and corresponding meta data (:data) representing the file in the store

Raises:



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# File 'lib/filestore/simple_store.rb', line 122

def get(id)
	raise FileStoreException, "No ID given" if id.nil? or id == ''
	raise FileStoreException, "No file for ID #{id} found" if not @metaManager.has_id?(id)
	
	md = @metaManager.get_data(id)
	path = md[:path]

	raise FileStoreException, "No valid meta data found for ID #{id}" if md.nil? or not File.exists?(path)
	
	self.inform ObserverAction.new :type => ObserverAction::TYPE_STORE_GET, 
      :objects => [id], :msg => "Returning file from file store"
	
	return { :path => File.new(path), :data => md }
end

#locked? ⇒ Boolean

Determines wether this store is locked

Returns:

  • (Boolean) 


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# File 'lib/filestore/simple_store.rb', line 204

def locked?
	return @locked
end

#remove(id) ⇒ Object

Moves a file from the current to the deleted store

Arguments: id: The ID identifying the file to be moved

Raises:



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# File 'lib/filestore/simple_store.rb', line 142

def remove(id)
	raise FileStoreException, "No file ID given for removal" if id == '' or id.nil?
	raise FileStoreException, "File ID for removal not found in store" if not @metaManager.has_id?(id)
	
	file = @metaManager.get_data(id)[:path]
	
	begin
		@metaManager.remove(id)
		
		dir = SimpleFileStore.get_daily_directory(@deletedPath)
		dstPath = File.join(dir, id)
		
		FileUtils.move(file, dstPath)
		
		self.inform ObserverAction.new :type => ObserverAction::TYPE_STORE_REMOVE, 
        :objects => [id], :msg => "Deleted file from store"
	rescue Exception => e
		raise FileStoreException, "Couldn't move file #{file} to deleted store.\n#{e.message}"
	end
end

#restore(id) ⇒ Object

Restores a file identified by it’s id

Arguments: id: The file ID

Raises:



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# File 'lib/filestore/simple_store.rb', line 168

def restore(id)
	raise FileStoreException, "No file ID given for restore" if id == '' or id.nil?
	
	begin
	  md = @metaManager.restore id
      @logger.debug "Restoring meta data #{md}"
      file = md[:path]
      
		dir = SimpleFileStore.get_daily_directory(@storePath)
		dstPath = File.join(dir, id)
		
		FileUtils.move(file, dstPath)
		
		self.inform ObserverAction.new :type => ObserverAction::TYPE_STORE_RESTORE, 
        :objects => [id], :msg => "Restored file from store"
	rescue Exception => e
		raise FileStoreException, "Couldn't restore file #{file} from deleted store.\n#{e.message}"
		#
		# Delete restored entry from metaManager
		@metaManager.delete(id)
	end
end

#shutdown ⇒ Object

Shuts down the file store



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# File 'lib/filestore/simple_store.rb', line 193

def shutdown
	@metaManager.shutdown
	
	release_lock
	
	self.inform ObserverAction.new :type => ObserverAction::TYPE_STORE_SHUTDOWN, 
      :msg => "File store shutdown"
end