Script to follow or purge a docker container log by id or name.

docker-log-util.sh

#!/bin/bash
set -e
set -u
set -o pipefail

debug=0
purge=0
follow=0

while getopts 'c:fpn:v' OPTION; do
  case "$OPTION" in
    c)
      container_id="$OPTARG"
      ;;

    f)
      follow=1
      ;;

    p)
      purge=1
      ;;

    n)
      echo "The container name provided is $OPTARG"
      container_id=$(docker ps -aqf "name=^$OPTARG$")
      ;;

    v)
      verbose=1
      ;;

    ?)
      echo "script usage: $(basename $0) [-c container_id] [-n container_name] [-v] [-p] [-f]" >&2
      echo "-v (verbose)" >&2
      echo "-c container_id" >&2
      echo "-n container_name" >&2
      echo "-p (purge)" >&2
      echo "-f (follow)" >&2
      exit 1
      ;;
  esac
done
shift "$(($OPTIND -1))"

if [[ -z $container_id ]]; then
    echo "No container specified"
    exit 1
fi

echo "The container id provided is [$container_id]"

if [[ "$(docker ps -aq -f id=$container_id 2> /dev/null)" == "" ]]; then
    echo "Container \"$container_id\" does not exist, exiting."
    exit 1
fi

log=$(docker inspect -f '{{.LogPath}}' $container_id 2> /dev/null)
if [[ $log == "" ]]
then
  echo "No log file found.  Exiting."
  exit 0
fi

if [[ $purge -gt 0 ]]
then
  echo "Purging log file."
  truncate -s 0 $log
fi

if [[ $follow -gt 0 ]]
then
  docker logs -f "$container_id"
fi