מטא נתונים של פיד

אזהרה: nonce – יש לוודא שלשדה הזה יש ערך ייחודי בכל ההעלאות של הפיד. אחת מהשיטות הנפוצות היא ליצור אותה באמצעות חותמות זמן כדי להבטיח את הייחודיות שלה. הערך הזה צריך להיות זהה בכל הפיצולים בפיד. הוא מבטיח שפידים מלאים המקיפים מספר מקטעים יעובדו יחד.

message FeedMetadata {
  enum ProcessingInstruction {
    // Do not use.
    PROCESS_UNKNOWN = 0;

    // This Feed message is one shard of a complete feed. Anything previously
    // supplied by this partner will be deleted; the contents of this feed
    // represent the entire state of the world.
    PROCESS_AS_COMPLETE = 1;

    // Do not use. This value is deprecated.
    // Feed message is one shard of an incremental feed.
    // Existing entities will be left untouched except as modified in this feed.
    PROCESS_AS_INCREMENTAL = 2;
  }

  // Instructs us how to process the feed: either as a shard of a complete feed,
  // or as a shard of an incremental update. (required)
  ProcessingInstruction processing_instruction = 1;

  // The current shard and total number of shards for this feed.
  //
  // Shard number is assumed to be zero-based.
  //
  // There does not need to be any relationship to the file name.
  //
  // Shards do not need to be transferred in order, and they may not be
  // processed in order. (both required)
  int32 shard_number = 2;
  int32 total_shards = 3;

  // An identifier that must be consistent across all shards in a feed.
  // This value must be globally unique across each feed type.
  //
  // This value ensures that complete feeds spanning multiple shards are
  // processed together correctly.
  //
  // Clients only need to set this value when the processing_instruction is set
  // to PROCESS_AS_COMPLETE and the feed spans multiple shards (defined by
  // total_shards).
  //
  // Feeds that span multiple shards must set this nonce to the same value.
  // (required if total shards > 1)
  uint64 nonce = 5;

  // The timestamp at which this feed shard was generated.
  //
  // In Unix time format (seconds since the epoch). (required)
  int64 generation_timestamp = 4;
}