Access, Admin Access & Error logs continue to write to `stdout`/`stderr` when specifying an override

When attempting to override the admin access, access & error log location/file names on a docker image you notice the logs are still being redirected to stdout and stderr. For example, you have set the below variables to use a path inside the container:

KONG_PROXY_ACCESS_LOG=/usr/local/kong/logs/access.log

KONG_PROXY_ERROR_LOG=/usr/local/kong/logs/error.log

docker exec kong ls -lart /usr/local/kong/logs
lrwxrwxrwx    1 kong     nogroup         11 Nov 29 15:05 error.log -> /dev/stderr
lrwxrwxrwx    1 kong     nogroup         11 Nov 29 15:05 access.log -> /dev/stdout

docker exec kong printenv | grep KONG_PROXY
KONG_PROXY_ACCESS_LOG=/usr/local/kong/logs/access.log
KONG_PROXY_ERROR_LOG=/usr/local/kong/logs/error.log

Why are the logs not being written in the container?

This will occur when you are using the default path and file names for the logs. Despite explicitly setting the variables, the values have not changed from their defaults. As seen in our docker-entrypoint, we explicitly define a symlink for the below logs:

ln -sf /dev/stdout $PREFIX/logs/access.log
ln -sf /dev/stdout $PREFIX/logs/admin_access.log
ln -sf /dev/stderr $PREFIX/logs/error.log

If you wish to redirect logging inside the container you will need to change the path and/or the filename for the logs.

i.e.

KONG_PROXY_ACCESS_LOG=/usr/local/kong/logs/gruber_access.log

KONG_PROXY_ERROR_LOG=/usr/local/kong/logs/gruber_error.log

docker exec kong ls -lart /usr/local/kong/logs
-rw-r--r--    1 kong     nogroup       2024 Nov 29 15:10 gruber_access.log
-rw-r--r--    1 kong     nogroup      77233 Nov 29 15:11 gruber_error.log

Note: Redirecting logs inside the container can be problematic and is not advised. If the container crashes the logs will be inaccessible.