mirror of
https://github.com/tstack/lnav
synced 2024-11-08 01:10:29 +00:00
40 lines
2.0 KiB
Markdown
40 lines
2.0 KiB
Markdown
---
|
|
layout: post
|
|
title: "Pretty-print view in v0.7.3"
|
|
date: 2015-04-11 00:00:00
|
|
excerpt: Automatically reformat structured data with "SHIFT+P".
|
|
---
|
|
|
|
I wanted to call out the pretty-print feature in the latest release of lnav.
|
|
This idea came from a coworker of Suresh who was having a hard time trying to
|
|
read some unformatted XML in a log. They wanted the XML pretty-printed and were
|
|
hoping that could be done by just piping the message to xmlpp or the like. So,
|
|
first we implemented the 'pipe-to' and 'pipe-line-to' commands that will let you
|
|
pipe log messages to a command and then display the result inside of lnav. That
|
|
worked well enough, but pretty-printing is such a frequent operation that having
|
|
to execute a command was kind of a pain. It would also be nice if it worked for
|
|
a variety of text, like JSON or Python data. The solution we came up with was to
|
|
leverage the existing code for parsing log messages to create a simple
|
|
pretty-printer that should work for most data formats. Another benefit is that
|
|
the log message does not have to be well-formed for the printer to work, any
|
|
leading or trailing garbage shouldn't confuse things.
|
|
|
|
As an example, here is a screenshot of the log message with the unformatted XML
|
|
text with word-wrapping turned on:
|
|
|
|
|
|
|
|
That's not very easy to read and it's hard to figure out the structure of the
|
|
message. Now, here is that same message after pressing SHIFT+P to switch to the
|
|
pretty-print view of lnav:
|
|
|
|
|
|
|
|
The XML text is indented nicely and the usual syntax highlighting is applied.
|
|
Also notice that lnav will automatically try to lookup the DNS name for IP
|
|
addresses. Overall, I think it's a major improvement over the raw view.
|
|
|
|
This is a pretty simple feature but I have found it quite useful in the couple
|
|
weeks that it has been implemented. It's so useful that I'm kicking myself for
|
|
not having thought of it before.
|