kubectl-demo

kubectl-demo

#!/bin/bash
trap ctrl_c INT
function ctrl_c() {
echo "**************************************** Bye Bye ****************************************"
for pid in ${PIDS[@]}
do
kill -TERM $pid 
done
rm $NAMED_PIPE
rm $sync
exit 0
}
function colorize() {
pod=$1
counter=$2
# colors from 31 to 39
pre_colour="\033[3${counter}m"
post_colour="\033[0m"
if [ "$colorize_output" = true ]
then
colour_pod="${pre_colour}[${pod}]${post_colour}"
else
colour_pod="[${pod}]"
fi
}
function show_logs() {
local sync="$1"
grep -E -f $sync $NAMED_PIPE &
}
function banner() {
echo ""
echo "==================================================="
echo "+ Showing logs for:"
echo "+ $1"
echo "==================================================="
echo ""
}
function start_log() {
show_logs $sync 
shl_pid=$!
disown $shl_pid
PIDS+=$shl_pid" "  
}
function usage() {
echo "~~~~~~~~~~~"
echo " U S A G E"
echo "~~~~~~~~~~~"
echo "Usage: kubectl demo [option]"
echo "  options:"
echo "    --no-colorize: no colorize [default: colorize]"
echo "    -h: Show this help"
echo ""
echo "When running you can use the numbers 1 to N to filter N-pod and only show it's output."
echo "0 resets and shows all outputs again"
echo ""
}
NAMED_PIPE="/tmp/my_named_pipe"
PODS=$(kubectl get pods --no-headers=true -o=custom-columns=NAME:.metadata.name)
TOTAL_PODS=$(echo $PODS | sed -s 's/ /n/g' | wc -l)
colorize_output=true
if [[ $@ ]]; then
case "$@" in
"--no-colorize")
colorize_output=false
;;
"-h")
usage
exit 1
;;
*) echo "Invalid option"
exit 1
;;
esac
fi
# create named pipe
if [ ! -p $NAMED_PIPE ]
then
mkfifo $NAMED_PIPE
chmod a+rw $NAMED_PIPE
fi
PIDS=()
declare -A pods_index
counter=1
for pod in $(echo $PODS)
do
colour_pod=""
colorize $pod $counter
kubectl logs -f $pod | awk -v pod_name=$colour_pod '{print pod_name" "$0}' > $NAMED_PIPE &
PIDS+=$!" " # save all PIDs
pods_index[$counter]=$pod
counter=$((counter+1))
done
# Trick: Shared memory segment for inter process comunication. 
sync=/dev/shm/syntest-$$  # allocate a shared memory segment name for this pid
echo '' > $sync           # init the shm
start_log
input="*"
re='^[0-9]+$' # we match only numbers
while true
do
read -t 0.25 -N 1 input
if  [[ $input =~ $re ]]  && [ "$input" -ge "0" ] && [ "$input" -le "$TOTAL_PODS" ]
then
if [ "$input" -eq "0" ]
then
banner "All Pods"
echo $ > $sync    # grep everything
else
banner ${pods_index[$input]}
echo ${pods_index[$input]} > $sync  # grep only pod name
fi
kill -SIGTERM $shl_pid
PIDS=$(echo $PID | sed -e "s/$shl_pid//g" | tr -s " ")  # remove unused pid
start_log
fi
done