gop2plibp2pgo-libp2p

Can I keep the same ID in libp2p across restarts?

I am writing a test app. For this, it would be ideal if my libp2p nodes would keep their IDs across restarts - otherwise I need to think of some intermediate service which keeps track of NodeIDs for the nodes to connect during a test.

Can I do this?

Currently, if I just run the https://docs.libp2p.io/guides/getting-started/go/ tutorial, after each restart, it prints a different Node ID.

❯ go run ./main.go
Listen addresses: /ip4/127.0.0.1/tcp/9436/p2p/12D3KooWNK774CCm9b48H84qZu3mp2Jq4wvDBh9813omB712qqLW
^CReceived signal, shutting down...
❯ go run ./main.go
Listen addresses: /ip4/127.0.0.1/tcp/9436/p2p/12D3KooWGLgDLUaNiuruX5umaExyFQJQBsf3yyXgC9MPy7cGS99F
^CReceived signal, shutting down...
Solution

  • This comment seems to provide the answer: https://github.com/libp2p/go-libp2p/issues/1040#issuecomment-767695679

    Quoting from there:

    A libp2p peer can't connect to a remote peer without it's peerId.

    You can configure a libp2p node to use a persisted secret key to derive the same peerId as before by using the Identity option.

    libp2p.New(context.Background(), libp2p.Identity(//secret key here))

    To get a hosts's secret key and then marshal it, you can use:

    sk := h.Peerstore().PrivKey(h.ID())     
bz, _ := crypto.MarshalPrivateKey(sk)