Docker stats for n seconds period

Question

I am running docker stats $CONTAINER_ID from a shell script to monitor my Docker container memory and CPU usage over a period of 1 hour. I have the below shell script.

#!/bin/sh

# First, start the container
CONTAINER_ID=abcadsasdasd

# Then start watching that it's running (with inspect)
while [ "$(docker inspect -f {{.State.Running}} $CONTAINER_ID 2>/dev/null)" = "true" ]; do
    # And while it's running, check stats
    #docker stats $CONTAINER_ID 2>&1 | tee "$1"
    docker stats --format "table {{.Container}}\t{{.CPUPerc}}\t{{.MemUsage}}\t{{.NetIO}}\t{{.BlockIO}}\t{{.PIDs}}" $CONTAINER_ID 2>&1 | tee "$1"
    sleep 5
done

It is running fine. But, it seems it is running at every second. I need that it outputs at every 5 seconds. I found that there is no such option like specifying timeperiod with docker stats command. Request some suggestions to achieve it. It seems sleep 5 is not having any effect.

Edit

Even with 1 second delay, I expected 60 lines in my log file, With 5 seconds, I expected 12 lines over 1 minute period. But, I am getting close to 150 lines for 1 minute.

Dabchick

Answer 1

docker stats $container won't exit when running, so your sleep 5 don't have chance to execute.

For you, you should use next:

--no-stream       Disable streaming stats and only pull the first result

Then, you could use something like next fake code to control the rate:

while xxx; do
    docker stats $container --no-stream
    sleep 5
done

Draconian

Answer 2

Easiest approach is to use watch:

watch -tn5 docker stats --no-stream $CONTAINER_NAME

Fledge

Answer 3

Without sleep, just read current values from the file ($1) and average them every period you choose:

#!/bin/bash

multiLine="";
format="table {{.Name}}\t{{.CPUPerc}}\t{{.MemUsage}}";
docker stats --all --format "$format" --no-trunc | (while read line; do
    sedLine=$(echo "$line" | sed "s/^.*name.*cpu.*mem.*$/_divider_/i")
    if [ "$sedLine" != "_divider_" ];
    then
        multiLine="${multiLine}"'\n'"${line}";
    else
        echo -e $multiLine > $1;
        multiLine="";
    fi;
done);

Diffractive