docker logs change tail default

[augnustin]

docker logs

outputs the whole container history, which is non-sense for a container that has been alive for some time.

Hence as far as I'm concerned, I always have type docker logs --tail=100 -f <container_name> which is crazy long for something that feels like a default behavior.

Whichever value different than all would work for me: eg. 10 ou 100.

But who wants to output 10k lines by default and block the process for 2/3mins?

[thaJeztah]

This would have to be implemented in the cli (github.com/docker/cli). While I understand the request, my concern is that changing the behaviour would likely be a breaking change (the behaviour has been like this for a long time (--tail was added in #6803, so the default was there before that).

@cpuguy83 wdyt?

[cpuguy83]

Current default is indeed silly, just that it's had a long long history.
It's probably fine to change the CLI's default.

Alternatively we could do something like what journalctl does and essentially pipe it through less when stdin is a TTY.

[cpuguy83]

We could also enforce a default max size so we don't spew gobs and gobs of logs.

[thaJeztah]

should the default driver be the local driver (which has a max by default)?

[cpuguy83]

Oh I was thinking max read size more than max store size.

[augnustin]

Great to read that this query is nicely welcomed.

I understand the backward-compatibility concern and can't tell how painful this could be to some users.

🤞 so that an acceptable solution is found.

[tao12345666333]

Current default is indeed silly, just that it's had a long long history.
It's probably fine to change the CLI's default.

+1

Usually I give it an alias

alias "dlt"="docker logs --tail=100"

[hammad13060]

@thaJeztah I've faced similar issue while using docker logs command. Sometimes it makes the debugging hard in Dev environments because debug logs are also enabled. I've completed the Dev environment setup of the moby package. I'd love to discuss the solution and contribute. Could you please assign this issue to me. Thanks.