48 lines
1.3 KiB
Markdown
48 lines
1.3 KiB
Markdown
|
# Table of Contents
|
||
|
|
1. [Overview](#overview)
|
||
|
|
1. [Debug Logging](#debug-logging)
|
||
|
|
1. [Capturing pprof data with `lnd`](#capturing-pprof-data-with-lnd)
|
||
|
|
|
||
|
|
## Overview
|
||
|
|
|
||
|
|
`lnd` ships with a few useful features for debugging, such as a built-in
|
||
|
|
profiler and tunable logging levels. If you need to submit a bug report
|
||
|
|
for `lnd`, it may be helpful to capture debug logging and performance
|
||
|
|
data ahead of time.
|
||
|
|
|
||
|
|
## Debug Logging
|
||
|
|
|
||
|
|
You can enable debug logging in `lnd` by passing the `--debuglevel` flag. For
|
||
|
|
example, to increase the log level from `info` to `debug`:
|
||
|
|
|
||
|
|
```
|
||
|
|
$ lnd --debuglevel=debug
|
||
|
|
```
|
||
|
|
|
||
|
|
You may also specify logging per-subsystem, like this:
|
||
|
|
|
||
|
|
```
|
||
|
|
$ lnd --debuglevel=<subsystem>=<level>,<subsystem2>=<level>,...
|
||
|
|
```
|
||
|
|
|
||
|
|
## Capturing pprof data with `lnd`
|
||
|
|
|
||
|
|
`lnd` has a built-in feature which allows you to capture profiling data at
|
||
|
|
runtime using [pprof](https://golang.org/pkg/runtime/pprof/), a profiler for
|
||
|
|
Go. The profiler has negligible performance overhead during normal operations
|
||
|
|
(unless you have explictly enabled CPU profiling).
|
||
|
|
|
||
|
|
To enable this ability, start `lnd` with the `--profile` option using a free port.
|
||
|
|
|
||
|
|
```
|
||
|
|
$ lnd --profile=9736
|
||
|
|
```
|
||
|
|
|
||
|
|
Now, with `lnd` running, you can use the pprof endpoint on port 9736 to collect
|
||
|
|
runtime profiling data. You can fetch this data using `curl` like so:
|
||
|
|
|
||
|
|
```
|
||
|
|
$ curl http://localhost:9736/debug/pprof/goroutine?debug=1
|
||
|
|
...
|
||
|
|
```
|