How to log into terminal in anchor program

Question

I'm debugging my program and I don't know where my code is dead. So is there any way to log strings and variables to the terminal?

Answer 1

If you're using Anchor then you can start the test suite with the detach option anchor test --detach to keep the local validator running after the tests pass/fail. This is useful if you want to look up failed transaction signatures and inspect the logs before the history gets reset.

Any msg!("logs"); will be visible in the logs

You can use an explorer with your localhost rpc url http://localhost:8899 to get a decent UI

https://solana.fm/?cluster=http%253A%252F%252Flocalhost%253A8899%252F

You might need to use skipPreFlight when sending your transaction or you might fail simulation which can mask the error.

Answer 2

To add to the answer, which is correct, you can use the solana logs to get live logging from your local validator ie:

$ solana logs -ul TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA
Streaming transaction logs mentioning TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA. Confirmed commitment

And if I do spl-token create-token in a different window, this first one will show:

Transaction executed in slot 93:
  Signature: 8MYopp3pedMs4655Ka5vyT3fw3bzmKuA4rsnbhEo2r8Mq71FwMNsmw5VL9bqabsJrKMnSkbDk29wr4Rx55T6dRU
  Status: Ok
  Log Messages:
    Program 11111111111111111111111111111111 invoke [1]
    Program 11111111111111111111111111111111 success
    Program TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA invoke [1]
    Program log: Instruction: InitializeMint
    Program TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA consumed 2919 of 400000 compute units
    Program TokenkegQfeZyiNwAJbNbGKPFXCWuBvf9Ss623VQ5DA success

Answer 3

your Anchor msg!() logs and Solana program logs will be saved inside your project in a file: [in 2023]: .anchor/validator-1700296750844.log

[2024 Anchor 0.30.1] .anchor/program-logs/YOUR_PROGRAM_ID.log