Docker container prints log messages to stdout

[jayhendren]

I am attempting to use the keeper/commander Docker container in order to fetch secrets in a non-interactive script. However, in addition to the output that I actually care about, the container also prints diagnostic log messages to stdout:

$ docker run --volume ~/.keeper:/home/commander/.keeper local/keeper-commander get --format password "$UID" 2>/dev/null
[2026-08-14 18:23:05] Config file found at /home/commander/.keeper/config.json, using config-based authentication
********
[2026-08-14 18:23:11] Performing cleanup on exit...
[2026-08-14 18:23:11] Cleanup completed
$

This makes it difficult to separate the output of the containerized keeper get command from the informational log messages.

By comparison, the non-containerized version of keeper get produces clean output that can be easily used in a script:

$ keeper get --format password "$UID"
********
$

I am not sure if I am using the container in an unintended way, or if there is some other method to get clean output from the container? I don't see any usage instructions/docs for the container anywhere.

FWIW, I was able to get the behavior I wanted by adding a stderr redirect to the log function in docker-entrypoint.sh. I changed the following line:

Commander/docker-entrypoint.sh

Line 27 in de8350d

echo "[$(date '+%Y-%m-%d %H:%M:%S')] $1"

to:

    echo "[$(date '+%Y-%m-%d %H:%M:%S')] $1" >&2

Then, after rebuilding the image, the same command as above returned clean output; I was able to use a stderr redirect to get rid of the unwanted log messages:

$ docker run --volume ~/.keeper:/home/commander/.keeper local/keeper-commander get --format password "$UID" 2>/dev/null
********
$