Class: Dis::Layer

Inherits:
Object
  • Object
show all
Includes:
Logging
Defined in:
lib/dis/layer.rb

Overview

Dis Layer

Represents a layer of storage. It’s a wrapper around Fog::Storage, any provider supported by Fog should be usable.

Options

  • :delayed - Delayed layers will be processed outside of the request cycle by ActiveJob.

  • :readonly - Readonly layers can only be read from, not written to.

  • :public - Objects stored in public layers will have the public readable flag set if supported by the storage provider.

  • :path - Directory name to use for the store. For Amazon S3, this will be the name of the bucket.

Examples

This creates a local storage layer. It’s a good idea to have a local layer first, this provides you with a cache on disk that will be faster than reading from the cloud.

Dis::Layer.new(
  Fog::Storage.new({
    provider: 'Local',
    local_root: Rails.root.join('db', 'dis')
  }),
  path: Rails.env
)

This creates a delayed layer on Amazon S3. ActiveJob will kick in and and transfer content from one of the immediate layers later at it’s leisure.

Dis::Layer.new(
  Fog::Storage.new({
    provider:              'AWS',
    aws_access_key_id:     YOUR_AWS_ACCESS_KEY_ID,
    aws_secret_access_key: YOUR_AWS_SECRET_ACCESS_KEY
  }),
  path: "my_bucket",
  delayed: true
)

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Logging

#debug_log, #logger

Constructor Details

#initialize(connection, options = {}) ⇒ Layer

Returns a new instance of Layer.



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# File 'lib/dis/layer.rb', line 52

def initialize(connection, options = {})
  options     = default_options.merge(options)
  @connection = connection
  @delayed    = options[:delayed]
  @readonly   = options[:readonly]
  @public     = options[:public]
  @path       = options[:path]
end

Instance Attribute Details

#connection ⇒ Object (readonly)

Returns the value of attribute connection.



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# File 'lib/dis/layer.rb', line 50

def connection
  @connection
end

Instance Method Details

#delayed? ⇒ Boolean

Returns true if the layer is a delayed layer.

Returns:

  • (Boolean) 


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# File 'lib/dis/layer.rb', line 62

def delayed?
  @delayed
end

#delete(type, key) ⇒ Object

Deletes a file from the store.

layer.delete("documents", key)

Returns true if the file was deleted, or false if it could not be found. Raises an error if the layer is readonly.

Raises:



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# File 'lib/dis/layer.rb', line 148

def delete(type, key)
  raise Dis::Errors::ReadOnlyError if readonly?

  debug_log("Delete #{type}/#{key} from #{name}") do
    delete!(type, key)
  end
end

#existing(type, keys) ⇒ Object

Returns all the given keys that exist in the layer.

layer.existing("documents", keys)



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# File 'lib/dis/layer.rb', line 108

def existing(type, keys)
  return [] if keys.empty?

  list = []
  directory(type, keys.first).files.each do |file|
    list << file.key
  end

  keys.select { |key| list.include?(key_component(type, key)) }
end

#exists?(type, key) ⇒ Boolean

Returns true if a object with the given key exists.

layer.exists?("documents", key)

Returns:

  • (Boolean) 


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# File 'lib/dis/layer.rb', line 122

def exists?(type, key)
  if directory(type, key)&.files&.head(key_component(type, key))
    true
  else
    false
  end
end

#get(type, key) ⇒ Object

Retrieves a file from the store.

layer.get("documents", key)



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# File 'lib/dis/layer.rb', line 133

def get(type, key)
  dir = directory(type, key)
  return unless dir

  debug_log("Get #{type}/#{key} from #{name}") do
    dir.files.get(key_component(type, key))
  end
end

#immediate? ⇒ Boolean

Returns true if the layer isn’t a delayed layer.

Returns:

  • (Boolean) 


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# File 'lib/dis/layer.rb', line 67

def immediate?
  !delayed?
end

#name ⇒ Object

Returns a name for the layer.

layer.name # => "Fog::Storage::Local::Real/development"



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# File 'lib/dis/layer.rb', line 159

def name
  "#{connection.class.name}/#{path}"
end

#public? ⇒ Boolean

Returns true if the layer is public.

Returns:

  • (Boolean) 


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# File 'lib/dis/layer.rb', line 72

def public?
  @public
end

#readonly? ⇒ Boolean

Returns true if the layer is read only.

Returns:

  • (Boolean) 


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# File 'lib/dis/layer.rb', line 77

def readonly?
  @readonly
end

#store(type, key, file) ⇒ Object

Stores a file.

key = Digest::SHA1.file(file.path).hexdigest
layer.store("documents", key, path)

The key must be a hex digest of the file content. If an object with the supplied hash already exists, no action will be performed. In other words, no data will be overwritten if a hash collision occurs.

Returns an instance of Fog::Model, or raises an error if the layer is readonly.

Raises:



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# File 'lib/dis/layer.rb', line 97

def store(type, key, file)
  raise Dis::Errors::ReadOnlyError if readonly?

  debug_log("Store #{type}/#{key} to #{name}") do
    store!(type, key, file)
  end
end

#writeable? ⇒ Boolean

Returns true if the layer is writeable.

Returns:

  • (Boolean) 


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# File 'lib/dis/layer.rb', line 82

def writeable?
  !readonly?
end