# How do I run neptune-core in a way that is optimized for debugging?

**URL:** <https://talk.neptune.cash/t/how-do-i-run-neptune-core-in-a-way-that-is-optimized-for-debugging/37>\
**Category:** Development\
**Created:** [April 16, 2025, 10:57am UTC](https://talk.neptune.cash/t/how-do-i-run-neptune-core-in-a-way-that-is-optimized-for-debugging/37 "2025-04-16T10:57:35Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![aszepieniec](https://talk.neptune.cash/user_avatar/talk.neptune.cash/aszepieniec/32/5_2.png) [@aszepieniec](https://talk.neptune.cash/u/aszepieniec)\
**Post date:** [April 16, 2025, 10:57am UTC](https://talk.neptune.cash/t/how-do-i-run-neptune-core-in-a-way-that-is-optimized-for-debugging/37/1 "2025-04-16T10:57:35Z")

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_(This post supersedes [GitHub Issue #349](https://github.com/Neptune-Crypto/neptune-core/issues/349).)_

Here is a recipe for enabling all available debugging tools. You might want to pick and choose depending on the nature of the specific bug you are hunting.

1. Catch stack traces.

- Set the environment variable `RUST_BACKTRACE`, either run `export RUST_BACKTRACE=1` before invoking `neptune-core` or prepend the `neptune-core` with `RUST_BACKTRACE=1 `.

1. Choose informative log level.

- In principle there are four log levels, `ERROR`, `WARN`, `INFO`, and `DEBUG`, and by default everything up to and including `INFO` is enabled. Phrased differently, `DEBUG` messages are _disabled_ by default.
- To enable `DEBUG` messages, run `export RUST_LOG="debug"` or prepend the `neptune-core` command with `RUST_LOG="debug" `.

1. Trace locks.

- Lock tracing is another (non-standard) set of log messages. It requires nightly.
- Enable nightly: `rustup default nightly`, or alternatively add `+nightly` immediately after `cargo` in commands that use `cargo`.
- Set log level to `"debug,neptune_cash=trace"` with an `export` command or by prepending.
- Build and run with `--features log-slow-write-lock,log-slow-read-lock,log-lock_events` (immediately before the double dash (`--`) indicating the start of the command line arguments).

1. Use `tokio-console`.

- `tokio-console` is an `htop`-like tool to monitor which threads are doing what.
- Install `tokio-console`: `cargo install --locked tokio-console`
- To instruct `neptune-core` to support `tokio-console`, add `--tokio-console` as an extra CLI argument.
- Note that `tokio-console` uses port 6669 for communication, so that port had better not be in use by other processes.

1. Pipe output into a log file.

- `tee` can be used to put the console output into a file while preserving the console output.
- `sed` can be used to strip colors, making the file more reader-friendly.
- Use both: pipe the `neptune-core` output through `| tee >(sed -r "s/\x1B\[([0-9]{1,3}(;[0-9]{1,3})*)?[mGK]//g" > neptune-core.log)`
- This suffix will overwrite the log file `neptune-core.log`, so be sure to back it up if one exists already and you might need it.

1. All together.

- (Don’t forget to cherry pick!)
- (Don’t forget to `cargo install` dependencies.)
- (Don’t forget to replace `[other CLI arguments]` with the CLI arguments you would otherwise run `neptune-core` with, such as `--max-num-peers 5` or `--guess`.)
- `RUST_BACKTRACE=1 RUST_LOG="debug,neptune_cash=trace" cargo +nightly run neptune-core --features log-slow-write-lock,log-slow-read-lock,log-lock_events -- --tokio-console [other CLI arguments] | tee >(sed -r "s/\x1B\[([0-9]{1,3}(;[0-9]{1,3})*)?[mGK]//g" > neptune-core.log)`