Class: Longleaf::MetadataSerializer

Inherits:
Object
  • Object
show all
Extended by:
Logging
Defined in:
lib/longleaf/services/metadata_serializer.rb

Overview

Service which serializes MetadataRecord objects

Class Method Summary collapse

Methods included from Logging

initialize_logger, initialize_logger, logger, logger

Class Method Details

.metadata_suffix(format: 'yaml') ⇒ String

Returns the suffix used to indicate that a file is a metadata file in the provided encoding.

Parameters:

  • format (String) (defaults to: 'yaml') —

    encoding format used for metadata file

Returns:

  • (String) —

    the suffix used to indicate that a file is a metadata file in the provided encoding

Raises:

  • (ArgumentError) —

    raised if the provided format is not a supported metadata encoding format


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# File 'lib/longleaf/services/metadata_serializer.rb', line 79

def self.metadata_suffix(format: 'yaml')
  case format
  when 'yaml'
    '-llmd.yaml'
  else
    raise ArgumentError.new("Invalid serialization format #{format} specified")
  end
end

.to_hash(metadata) ⇒ Object

Create a hash representation of the given MetadataRecord file

Parameters:

  • metadata (MetadataRecord) —

    metadata record to transform into a hash


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# File 'lib/longleaf/services/metadata_serializer.rb', line 50

def self.to_hash(metadata)
  props = Hash.new

  data = Hash.new.merge(metadata.properties)
  data[MDF::REGISTERED_TIMESTAMP] = metadata.registered if metadata.registered
  data[MDF::DEREGISTERED_TIMESTAMP] = metadata.deregistered if metadata.deregistered
  data[MDF::CHECKSUMS] = metadata.checksums unless metadata.checksums && metadata.checksums.empty?
  data[MDF::FILE_SIZE] = metadata.file_size unless metadata.file_size.nil?
  data[MDF::LAST_MODIFIED] = metadata.last_modified if metadata.last_modified

  props[MDF::DATA] = data

  services = Hash.new
  metadata.list_services.each do |name|
    service = metadata.service(name)
    service[MDF::STALE_REPLICAS] = service.stale_replicas if service.stale_replicas
    service[MDF::SERVICE_TIMESTAMP] = service.timestamp unless service.timestamp.nil?
    service[MDF::RUN_NEEDED] = service.run_needed if service.run_needed
    services[name] = service.properties unless service.properties.empty?
  end

  props[MDF::SERVICES] = services

  props
end

.to_yaml(metadata) ⇒ String

Returns a yaml representation of the provided MetadataRecord.

Parameters:

Returns:

  • (String) —

    a yaml representation of the provided MetadataRecord


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# File 'lib/longleaf/services/metadata_serializer.rb', line 43

def self.to_yaml(metadata)
  props = to_hash(metadata)
  props.to_yaml
end

.write(metadata:, file_path:, format: 'yaml', digest_algs: []) ⇒ Object

Serialize the contents of the provided metadata record to the specified path

Parameters:

  • metadata (MetadataRecord) —

    metadata record to serialize. Required.

  • file_path (String) —

    path to write the file to. Required.

  • format (String) (defaults to: 'yaml') —

    format to serialize the metadata in. Default is ‘yaml’.

  • digest_algs (Array) (defaults to: []) —

    if provided, sidecar digest files for the metadata file will be generated for each algorithm.

Raises:

  • (ArgumentError) 

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# File 'lib/longleaf/services/metadata_serializer.rb', line 22

def self.write(metadata:, file_path:, format: 'yaml', digest_algs: [])
  raise ArgumentError.new('metadata parameter must be a MetadataRecord') \
      unless metadata.class == MetadataRecord

  case format
  when 'yaml'
    content = to_yaml(metadata)
  else
    raise ArgumentError.new("Invalid serialization format #{format} specified")
  end

  # Fill in parent directories if they do not exist
  parent_dir = Pathname(file_path).parent
  parent_dir.mkpath unless parent_dir.exist?

  File.write(file_path, content)
  write_digests(file_path, content, digest_algs)
end