Class: BackupTool

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

Instance Method Summary collapse

Constructor Details

#initialize(cassandra, hadoop, logger) ⇒ BackupTool

Create a new BackupTool instance

  • Args :

    • cassandra -> Cassandra instance

    • hadoop -> HDFS instance

    • logger -> Logger



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# File 'lib/backuptool.rb', line 16

def initialize(cassandra, hadoop, logger)
  @cassandra = cassandra
  @hadoop = hadoop
  @logger = logger

  @metadir = META_DIR
end

Instance Method Details

#buffered_download(remote, local) ⇒ Object

Download a file from HDFS, buffered way

  • Args :

    • remote -> HDFS path

    • local -> local path



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# File 'lib/backuptool.rb', line 199

def buffered_download(remote, local)
  @logger.debug("#{remote} => #{local}")

  # Create the destination directory if not exists
  path = File.dirname(local)
  FileUtils.mkdir_p(path) unless File.exist?(path)

  file = open(local, 'wb')

  offset = 0
  length = BUFFER_SIZE
  print '['
  while length == BUFFER_SIZE
    print '#'
    content = @hadoop.read(remote, offset: offset, length: BUFFER_SIZE)
    file.write(content)
    length = content.length
    offset += length
  end
  print "]\n"

  file.close
end

#cleanup(days) ⇒ Object

Cleans up backups that are older than a number of days. This functions cleans data on all nodes.



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# File 'lib/backuptool.rb', line 148

def cleanup(days)
  retention_date = Date.today - days
  @logger.info("Cleaning backup data on all nodes before #{retention_date}.")

  all_snapshots = search_snapshots
  @logger.info("A total of #{all_snapshots.size} snapshots were found on Hadoop server.")

  snapshots_to_be_deleted = all_snapshots.select { |snapshot| snapshot.get_date < retention_date }
  @logger.info("A total of #{snapshots_to_be_deleted.size} snapshots will be deleted.")

  snapshots_to_be_deleted.each do |snapshot|
    delete_snapshots(node: snapshot.node, date: snapshot.date)
  end

  all_backup_flags = get_backup_flags
  @logger.info("A total of #{all_backup_flags.size} back up flags were found on Hadoop server.")

  backup_flags_to_be_delete = all_backup_flags.select { |flag| flag.date < retention_date }
  @logger.info("A total of #{backup_flags_to_be_delete.size} backup flags will be deleted.")

  backup_flags_location = @hadoop.base_dir + '/' + @metadir + '/' + @cassandra.cluster_name
  backup_flags_to_be_delete.each do |flag|
    file = backup_flags_location + '/' + flag.file
    @logger.info("Deleting #{file}")
    @hadoop.delete(file)
  end
end

#create_backup_flag(date) ⇒ Object

Method that creates a backup flag to signal that the backup is finished on all nodes This is an individual command that has to be called manually after snapshots have finished



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# File 'lib/backuptool.rb', line 178

def create_backup_flag(date)
  file_name = 'BACKUP_COMPLETED_' + date
  remote_file = @hadoop.base_dir + '/' + @metadir + '/' + @cassandra.cluster_name + '/' + file_name

  @logger.info('Setting backup completed flag : ' + remote_file)
  @hadoop.create(remote_file, '', overwrite: true)
end

#delete_snapshots(node: @cassandra.node_name, date: 'ALL') ⇒ Object 



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# File 'lib/backuptool.rb', line 118

def delete_snapshots(node: @cassandra.node_name, date: 'ALL')
  snapshots = search_snapshots(node: node, date: date)
  if snapshots.empty?
    raise('No snapshot found for deletion')
  else
    snapshots.each do |snapshot|
      @logger.info("Deleting snapshot #{snapshot}")
      node_snapshots = search_snapshots(node: snapshot.node)
      merged_metadata = Set.new
      node_snapshots.each do |s|
        merged_metadata += s.metadata if s != snapshot
      end
      files = snapshot.metadata - merged_metadata
      @logger.info("#{files.length} files to delete")
      files.each do |file|
        @logger.info("Deleting file #{file}")
        remote = @hadoop.base_dir + '/' + snapshot.cluster + '/' + snapshot.node + '/' + file
        @logger.debug("DELETE => #{remote}")
        @hadoop.delete(remote)
      end
      @logger.info('Deleting metadata in Hadoop')
      remote = @hadoop.base_dir + '/' + @metadir + '/' + snapshot.cluster + '/' + snapshot.node + '/cass_snap_' + snapshot.date
      @logger.debug("DELETE => #{remote}")
      @hadoop.delete(remote)
    end
  end
end

#get_backup_flags ⇒ Object 



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# File 'lib/backuptool.rb', line 186

def get_backup_flags
  backup_flags_location = @hadoop.base_dir + '/' + @metadir + '/' + @cassandra.cluster_name
  ls = @hadoop.list(backup_flags_location)
  backup_flags = ls.select { |item| item['pathSuffix'].include? 'BACKUP_COMPLETED_' }
  backup_flags.collect do |file|
    BackupFlag.new(@cassandra.cluster_name, file['pathSuffix'])
  end
end

#get_snapshot_metadata(node, date) ⇒ Object 



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# File 'lib/backuptool.rb', line 31

def get_snapshot_metadata(node, date)
  remote = @hadoop.base_dir + '/' + @metadir + '/' + @cassandra.cluster_name + '/' + node + '/cass_snap_' + date
  return @hadoop.read(remote).split("\n").to_set
rescue Exception => e
  raise("Could not read metadata : #{e.message}")
end

#get_snapshots_node(node, date) ⇒ Object 



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# File 'lib/backuptool.rb', line 38

def get_snapshots_node(node, date)
  result = []
  begin
    if date == 'ALL'
      ls = @hadoop.list("#{@hadoop.base_dir}/#{@metadir}/#{@cassandra.cluster_name}/#{node}")
      ls_metadata = ls.select { |item| item['pathSuffix'].include? 'cass_snap_' }
      ls_metadata.each do |item|
        date = item['pathSuffix'].gsub('cass_snap_', '')
        metadata = get_snapshot_metadata(node, date)
        snapshot = CassandraSnapshot.new(@cassandra.cluster_name, node, date, metadata)
        result.push(snapshot)
      end
    else
      metadata = get_snapshot_metadata(node, date)
      snapshot = CassandraSnapshot.new(@cassandra.cluster_name, node, date, metadata)
      result.push(snapshot)
    end
  rescue Exception => e
    @logger.warn("Could not get snapshots for node #{node} : #{e.message}")
  end
  result
end

#list_snapshots(node: @cassandra.node_name) ⇒ Object 



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# File 'lib/backuptool.rb', line 79

def list_snapshots(node: @cassandra.node_name)
  @logger.info('Listing available snapshots')
  snapshots = search_snapshots(node: node)
  tp(snapshots, 'cluster', 'node', 'date')
end

#new_snapshot ⇒ Object 



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# File 'lib/backuptool.rb', line 85

def new_snapshot
  @logger.info('Starting a new snapshot')
  snapshot = @cassandra.new_snapshot

  existing = search_snapshots(node: snapshot.node)
  last = if existing.empty?
           CassandraSnapshot.new(snapshot.cluster, snapshot.node, 'never')
         else
           existing[-1]
  end

  @logger.info('Uploading tables to Hadoop')
  files = snapshot.metadata - last.metadata
  @logger.info("#{files.length} files to upload")
  files.each do |file|
    @logger.info("Sending file #{file} to Hadoop")
    local = @cassandra.data_path + '/' + file
    remote = @hadoop.base_dir + '/' + snapshot.cluster + '/' + snapshot.node + '/' + file
    @logger.debug("#{local} => #{remote}")
    f = File.open(local, 'r')
    @hadoop.create(remote, f, overwrite: true)
    f.close
  end

  @logger.info('Sending metadata to Hadoop')
  remote = @hadoop.base_dir + '/' + @metadir + '/' + snapshot.cluster + '/' + snapshot.node + '/cass_snap_' + snapshot.date
  @logger.debug("metadata => #{remote}")
  @hadoop.create(remote, snapshot.metadata.to_a * "\n", overwrite: true)

  @cassandra.delete_snapshot(snapshot)
  @logger.info('Success !')
end

#restore_snapshot(node, date, destination) ⇒ Object

Restore a snapshot from HDFS

  • Args :

    • node -> node where the snapshot comes from

    • date -> snapshot date

    • destination -> local directory where to restore



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# File 'lib/backuptool.rb', line 228

def restore_snapshot(node, date, destination)
  # Search the snapshot matching node and date
  snapshots = search_snapshots(node: node, date: date)

  if snapshots.empty?
    raise('No snapshot found for restore')
  elsif snapshots.length > 1
    raise('More than one candidate snapshot to restore')
  else
    snapshot = snapshots[0]
    @logger.info("Restoring snapshot #{snapshot}")
    @logger.info("#{snapshot.metadata.length} files to restore")

    # For each file in metadata
    snapshot.metadata.each do |file|
      @logger.info("Restoring file #{file}")
      local = destination + '/' + file
      remote = @hadoop.base_dir + '/' + snapshot.cluster + '/' + snapshot.node + '/' + file
      # Download the file from hdfs
      buffered_download(remote, local)
    end
    @logger.info('Success !')
  end
end

#search_snapshots(node: 'ALL', date: 'ALL') ⇒ Object

Look for snapshots

  • Args :

    • node -> Cassandra node name

    • date -> HDFS instance



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# File 'lib/backuptool.rb', line 28

def search_snapshots(node: 'ALL', date: 'ALL')
  result = []

  def get_snapshot_metadata(node, date)
    remote = @hadoop.base_dir + '/' + @metadir + '/' + @cassandra.cluster_name + '/' + node + '/cass_snap_' + date
    return @hadoop.read(remote).split("\n").to_set
  rescue Exception => e
    raise("Could not read metadata : #{e.message}")
  end

  def get_snapshots_node(node, date)
    result = []
    begin
      if date == 'ALL'
        ls = @hadoop.list("#{@hadoop.base_dir}/#{@metadir}/#{@cassandra.cluster_name}/#{node}")
        ls_metadata = ls.select { |item| item['pathSuffix'].include? 'cass_snap_' }
        ls_metadata.each do |item|
          date = item['pathSuffix'].gsub('cass_snap_', '')
          metadata = get_snapshot_metadata(node, date)
          snapshot = CassandraSnapshot.new(@cassandra.cluster_name, node, date, metadata)
          result.push(snapshot)
        end
      else
        metadata = get_snapshot_metadata(node, date)
        snapshot = CassandraSnapshot.new(@cassandra.cluster_name, node, date, metadata)
        result.push(snapshot)
      end
    rescue Exception => e
      @logger.warn("Could not get snapshots for node #{node} : #{e.message}")
    end
    result
  end

  if node == 'ALL'
    begin
      ls = @hadoop.list("#{@hadoop.base_dir}/#{@metadir}/#{@cassandra.cluster_name}")
      ls_nodes = ls.select { |item| item['type'].casecmp('DIRECTORY') == 0 }
      ls_nodes.each do |item|
        n = item['pathSuffix']
        result += get_snapshots_node(n, date)
      end
    rescue Exception => e
      @logger.warn("Could not get snapshots for cluster #{@cassandra.cluster_name} : #{e.message}")
    end
  else
    result = get_snapshots_node(node, date)
  end

  result.sort
end