Solana Debugger: Save input

To debug a Solana program, you need to specify its input. Unlike regular programs, the complete input to a Solana program is quite complex (transaction, signers, ledger state). Especially for more complex programs, this can be quite tedious to create.

This repo tries to make this easier by allowing you to create the input data directly from your integration tests.

How it works

1. Add the save_input.rs module to your test framework
2. At the point in your test framework where you send the transaction to Banks, you add a call to save_input (see the example below)
3. Run the integration test that contains the tx you want to debug
4. For each tx that is processed, this will generate a debug_input/program_input_N folder
5. To debug a tx, pass the respective folder to solana-debugger init

Example: How to include save_input.rs

The SPL governance program has its own test SDK. This SDK has a function that processes all transactions. We can use it as a hook to call save_input.

To do this, make these changes to governance/test-sdk/src/lib.rs:

// Declare it
mod save_input;

[...]

pub async fn process_transaction(
    &mut self,
    instructions: &[Instruction],
    signers: Option<&[&Keypair]>,
) -> Result<(), ProgramError> {
    let mut transaction = Transaction::new_with_payer(instructions, Some(&self.payer.pubkey()));

    let mut all_signers = vec![&self.payer];

    if let Some(signers) = signers {
        all_signers.extend_from_slice(signers);
    }

    let recent_blockhash = self
        .context
        .banks_client
        .get_latest_blockhash()
        .await
        .unwrap();

    // Call save_input
    save_input::save_input(&self.context.banks_client, &transaction, &all_signers).await.unwrap();

    transaction.sign(&all_signers, recent_blockhash);

    self.context
        .banks_client
        .process_transaction(transaction)
        .await
        .map_err(|e| map_transaction_error(e.into()))?;

    Ok(())
}

Now, you can run a test to generate the debug input:

cd solana-program-library/governance/program

cargo-test-sbf test_create_realm --test process_create_realm -- --exact --nocapture

# cargo-test-sbf test_refund_proposal_deposit --test process_refund_proposal_deposit -- --exact --nocapture

The output will be stored in solana-program-library/governance/program/debug_input, containing one subfolder per transaction.

Required dependencies

This module needs:

• base64
• solana-program-test
• solana-program

It suffices to add them as dev-dependencies since we only need them for the tests.

For example, you can add this to your Cargo.toml:

[dev-dependencies]
base64 = "0.22.1"
solana-program-test = "=2.1.9"
solana-sdk = "=2.1.9"

Examples

These are Solana programs where save_input.rs is already included. Running their integration tests will create inputs for the debugger.

• Delta counter program
• Governance program