Light Client: No node available for call proof query.

[david9991]

I am encountering this error after starting the light client and committing a transaction immediately. The error message is:

2024-04-12T03:02:33.716878Z  WARN tx-service-ia-parachain: Failed to validate transaction 0xb812…7771: Error when retrieving the call proof: No node available for call proof query    
thread 'tests::test_light_client' panicked at src/tests.rs:166:10:
called `Result::unwrap()` on an `Err` value: Transaction(Dropped("Transaction was dropped"))

To workaround the issue, I have to add a 20 seconds delay between starting the light client and committing the first transaction. Anyone run into this?

[jsdw]

Is this when you start a light client pointed at a dev node, or when you're connecting to a chain that's been producing blocks for a while?

We have tests that run a light client against a brand new dev node, and IIRC for those we need to wait a few blocks before we can start interacting with it!

[david9991]

@jsdw I am connecting to a testnet has a relay chain with four validators and a para chain with two collators, they have been producing blocks for days. So how can we determine whether the light client is ready to process the transactions exactly (like some sort of Ready indicator or event)?

[jsdw]

Good question! @lexnv I think you've run into similar things before; do you know of any way we can wait for Smoldot to be ready?

[lexnv]

We ran into a similar TransactionDropped event when using the light-client for our testing in subxt.

There are a few things we could do about it in subxt:

• wait for more blocks to be produced (around 4 finalized blocks iirc)
• submit transaction with a backoff retry strategy when encountering a TransactionDropped event

Ideally, we'd need to reproduce this with logs enabled and raise the issue in smoldot