DHT hourly key/value republish

Implementers and Contributors
1

The Kademlia spec states that

To store a <key,value> pair, a participant locates the k closest nodes to the key and sends them STORE RPCs. Additionally, each node re-publishes the <key,value> pairs that it has every hour.

Do our DHT implementations republish their <key,value> pairs every hour?

2

I don’t think go-libp2p-kad-dht does this automatically. IPFS does reprovide every N hours (can’t remember how many). Sorry for the vagueness.

3

I believe IPFS republishes IPNS records periodically. Are you saying it also reprovides all records periodically? I feel like this should really part of our Kademlia implementations, so as to comply with the spec (perhaps with an option to turn it off). But I wonder if there’s a good reason why it was left out?

4

This topic piques my interest.

go-ipfs doesn’t use dht.PutValue(key, value) to store content. Content is held locally, advertised via provider records (à la Coral), and exchanged via Bitswap, not via the DHT protocol. It is a pull model.

Since the availability of this data is not managed by the DHT, it cannot autonomously decide to reprovide.

OTOH, Kademlia’s STORE (= dht.PutValue(key, value)) is pertinent to a push model.

Usages I know of:

  • libp2p itself uses it to store public keys for peers.
  • IPNS uses it to publish name records.

go-libp2p deviates from Kademlia insofar we don’t expire content received via this pathway: it’s permanent. So republishing every hour is unnecessary.

This seems like a weakness worth addressing.

5

Opened an issue, thanks for reporting!