TIL awk patterns can be more than just regexes and can be combined with boolean operators. I've written a bit of awk and never realized this.
Logdy is more web-based and focuses on live tailing, structured log search, and quick filtering across multiple sources, also without requiring a centralized server. Not trying to compare directly, but if you're exploring this space, you might find it useful as a complementary approach or for different scenarios. Although we need to work more on adding ability to query multiple hosts.
Anyway, kudos on nerdlog—always great to see lean tools in the logging space that don’t require spinning up half a dozen services.
I do not want to store plaintext logs and use ancient workarounds like logrotate. journald itself has the built-in ability to receive logs from remote hosts (journald remote & gateway) and search them using --merge.
As mentioned in the article, my original use case was: having a fleet of hosts, each printing pretty sizeable amount of logs, e.g. having more than 1-2GB log file on every host on a single day was pretty common. My biggest problem with journalctl is that, during some intensive spikes of logs, it might drop logs; we were definitely observing this behavior that some messages are clearly missing from the journalctl output, but when we check the plain log files, the messages are there. I don't remember details now, but I've read about some kind of ratelimiting / buffer overflow going on there (and somehow the part which writes to the files enjoys not having these limits, or at least having more permissive limits). So that's the primary one; I definitely didn't want to deal with missing logs. Somehow, old school technology like plain log files keeps being more reliable.
Second, at least back then, journalctl was noticeably slower than simply using tail+head hacks to "select" the requested time range.
Third, having a dependency like journalctl it's just harder to test than plain log files.
Lastly, I wanted to be able to use any log files, not necessarily controlled by journalctl.
I think adding support for journalctl should be possible, but I still do have doubts on whether it's worth it. You mention that you don't want to store plaintext logs and using logrotate, but is it painful to simply install rsyslog? I think it takes care of all this without us having to worry about it.
Example: I'm running an Arch-based Linux desktop. Installing ryslog took several minutes to build and install. If I wasn't highly motivated to try out nerdlog, I would have canceled the install.
Also, can the SSH requirement for localhost be bypassed? Most users won't be running an SSH server on their desktop, and this would improve nerdlog's use-cases and make it easier for new users to give it a quick local test run.
Final suggestion: add `go get` support to your repo, so that I can install nerdlog from a single command and not have to clone the repo itself.
Just posting it in case you want to subscribe to it. Looks like it's a popular demand indeed, so I'll at least poke it and see what kind of performance we can get out of it.
But yes the bypass for localhost can definitely be implemented.
I did go get install ...nerdlog/cmd/nerdlog-tui@latest just fine.
Thanks for hacking in the open, and releasing early.
Not sure if that "Thanks" for releasing early is sarcastic, but regardless, I appreciate the feedback.
The `go get` one should be easy to solve though, and my bad for not thinking of it before, thanks. I'll look into it.
i use lnav in this way all the time: journalctl -f -u service | lnav
this is the ethos of unix tooling
In fact nerdlog doesn't even support anything like -f (realtime following) yet. The idea to implement it did cross my mind, but I never really needed it in practice, so I figured I'd spend my time on something else. Might do it some day if the demand is popular, but still, nerdlog in general is not about just reading a continuous stream of logs; it's rather about being able to query arbitrary time periods from remote logs, and being very fast at that.
Yeah it would be great, and I do want to support it, especially if the demand is popular. In fact, even if you ungzip them manually, as of today nerdlog doesn't support more than 2 files in a logstream, which needs to be fixed first.
Specifically about supporting gzipped logs though, the UX I'm thinking about is like this: if the requested time range goes beyond the earliest available ungzipped file, then warn the user that we'll have to ungzip the next file (that warning can be turned off in options though, but by default I don't want to just ungzip it silently, because it can consume a signficant amount of disk space). So if the user agrees, nerdlog ungzips it and places somewhere under tmp. It'll never delete it manually though, relying on the regular OS means of cleaning up /tmp, and will keep using it as long as it's available.
Does it make sense?
> In fact, even if you ungzip them manually, as of today nerdlog doesn't support more than 2 files in a logstream
Ah, interesting! I read the limitation as "we don't support zipped files," not "we only support two files!"
Best of luck, this is neat!
Does this work with runit (Void Linux)?
That's not hard to implement, however to make it persistent requires implementing some config / scriptability, which is a whole other thing and requires more thought.
Re: runit, I never tested it, but after looking around briefly, it sounds like there is no unified log file, and not even unified log format? I mean it's possible to make it work, treating every log file as a separate logstream, but I've no idea what these logs look like and whether supporting the formats would be easy.
It is a simple script: https://github.com/void-linux/socklog-void/blob/master/svlog...
I think everything is in /var/log/socklog/everything/current, so this could be considered united.
Before you add the timefmt, it may be better to add a configuration file if one does not already exist, but it seems like it does? You already have ~/.config/nerdlog/logstreams.yaml, so might as well have config.yaml?
For more about logging on Void: https://docs.voidlinux.org/config/services/logging.html
2025-04-21 12:34:56 myhostname myservice: Something happened
If so, then yeah it's totally doable to make this format supported.
Re: config.yaml, yeah I thought of that, but in the long term I rather wanted it to be nerdlogrc.lua, so a Lua script which nerdlog executes on startup. Similar to vim (or rather, more like neovim in this case since it's Lua). Certainly having config.yaml is easier to implement, but in the longer term it may make things more confusing if we also introduce the Lua scripting.
2025-04-21T19:18:15.09577 user.notice: Apr 21 21:18:15 root: ACPI group/action undefined: jack/lineout / LINEOUT
2025-04-21T19:18:15.98845 daemon.debug: Apr 21 19:18:15 rtkit-daemon[1368]: Supervising 0 threads of 0 processes of 1 users.
I went spelunking around in the codebase trying to get the actual answer to your question and it seems it's like many things: theoretically yes with enough energy expended but by default it seems to be ssh-ing into the target hosts and running a pseudo agent over its own protocol back through ssh. So, "no"
log_files:
mygroup:
- /var/log/syslog
- /var/log/foo
- /var/log/bar
log_streams:
myhost-01:
hostname: actualhost1.com
port: 1234
user: myuser
log_files: mygroup
myhost-02:
hostname: actualhost2.com
port: 7890
user: myuser
log_files: mygroup
myhost-03:
hostname: actualhost3.com
port: 8888
user: myuser
log_files: mygroupHowever, before we go there, I want to double check that we're on the same page: this `log_files` field specifies only files _in the same logstream_; meaning, these files need to have consecutive logs. So for example, it can be ["/var/log/syslog", "/var/log/syslog.1"], or it can be ["/var/log/auth.log", "/var/log/auth.log.1"], but it can NOT be something like ["/var/log/syslog", "/var/log/auth.log"].
https://docs.ansible.com/ansible/11/collections/ansible/buil...
e.g.
all:
children:
mygroup:
hosts:
myhost-01:
hostname: actualhost1.com
port: 1234
user: myuser
myhost-02:
hostname: actualhost2.com
port: 7890
user: myuser
myhost-03:
hostname: actualhost3.com
port: 8888
user: myuser
vars:
files:
- /var/log/syslog
- /var/log/foo
- /var/log/bar