How to decode output of cardano-cli query ledger-state?

Question

Running cardano-cli query ledger-state --mainnet --out-file out produces a binary file. What format is it in? How can I decode it? I cannot use the command without --out-file out because of memory limitations.

UPDATE

I tried:

pip install cbor2
cat ledger-state.cbor | python -m cbor2.tool --pretty > ledger-state.json

which gave me:

[
    320,
    {
        "\u0000\u0000\u00006\\xd5\u0015\\xe1.\u0018\\xcd<\\x88\\xc7O\t\\xa6y\\x84\\xc2\\xc2y\\xa5)j\\xa9n\\xfe\\x89": 58,
        "\u0000\u0000\u0000\\xf6n(\\xb0\\xf1\\x8a\\xef U_LIT#N2p߻\\xdc\\xc1?T\\xe7\\x99": 57,
[...]
    }
]

which does not seem to be decoded properly.

Answer 1

Pretty sure the binary format is CBOR and yes, the ledger state is HUGE.

I think that if you drop the --out-file command line option the output goes to stdout in JSON format but again the output on mainnet is so huge that for me cardano-cli is killed by the OOM killer on a machine with 16G of RAM.

Using the command you use, the output file is 1.4 Gigabytes (much more compact than the in-memory representation).

There is already a Github issue about that which is almost a year old.

Answer 2

If you're looking to create a readable snapshot of the Cardano ledger as of a given slot, might I suggest using ogmios.dev as a simpler solution. Ogmios allows one to read the entire state of the ledger via the chain sync mini-protocol. The ledger is exposed as a websocket api, reducing integration complexity.