How to get Rust contract methods to output/print when running on substrate-contracts-node?

Question

I have tried following instructions from:

https://rustrepo.com/repo/paritytech-substrate-contracts-node

and

https://ink.substrate.io/faq/#how-do-i-print-something-to-the-console-from-the-runtime

My process:

1 - Add debug statements to the contract code:

#[ink(constructor)]
pub fn new() -> Self {
  ink_env::debug_println!("created new instance at {}", Self::env().block_number());
  Self {}
}

#[ink(message)]
pub fn sayhello(&self) {
  ink_env::debug_println!("Hello");
}

2 - build: cargo +nightly contract build.

OUTPUT:

Original wasm size: 32.7K, Optimized: 11.1K

The contract was built in DEBUG mode.

Your contract artifacts are ready. You can find them in:
/home/IamDeveloper/MySoftwareProjects/blockchain/rust/rust-substrate-blockchain-projects/my-first-substrate-projects/my-first-project-prep-lesson/my-first-smart-contracts/helloworld/target/ink

  - helloworld.contract (code + metadata)
  - helloworld.wasm (the contract's code)
  - metadata.json (the contract's metadata)

3 - In another terminal, run the node:

substrate-contracts-node --dev -lerror,runtime::contracts=debug

4 - In the original terminal, upload:

cargo contract upload --suri //Alice

5 - Get the code hash:

code_hash=0xfd548906549af08bbb8bdd436f46b457d2b6ea9f8b6610e9515b3c4e7fe22d9c

6 - Instantiate:

cargo contract instantiate \
  --gas 500000000000 \
  --constructor new \
  --suri //Alice \
  --code-hash $code_hash

7 - Get the Contract:

Contract=5E4V3mvaf2nYKLRJJMNhc6TXrM5GxNwsga4hESRPquCXEyu1

8 - Call:

cargo contract call \
  --gas 500000000000 \
  --message sayhello \
  --suri //Alice \
  --contract $Contract

RESULT: No output at all from the terminal running the node.

Answer 1

I have the following ink! message:

#[ink(message)]
pub fn say_hello(&self) {
    ink_env::debug_println!("Hello");
}

I run my node like this:

./target/release/substrate-contracts-node --dev -lerror,runtime::contracts=debug

If I call like this:

cargo contract call \
  --gas 500000000000 \
  --message say_hello \
  --suri //Alice \
  --contract 5HJSXhYLExB5KYCMXa95mKEUX4UXXsp8Up9rBLzR57PPwtkq

The following appears in my node logs:

2022-08-02 13:07:28.410 DEBUG tokio-runtime-worker runtime::contracts: Execution finished with debug buffer: Hello

Make sure your contract exists.

You should see it in https://polkadot.js.org/apps/#/contracts

Also, try deleting your contract and re-deploying. You may have an old contract there.