I need to periodically update a file that will host the Redis Latency values at certain time daily.
I am using the command redis-cli --latency -h 127.0.0.1 -p 6379. The issue is that this command works only in interactive mode and it cycles through the values. I want to get the latency values over a certain time period and then put the values in my file.
When I execute the following command with the timeout utility, it runs for the specified 20 seconds:
timeout 20 /usr/local/bin/redis-cli --latency -h 127.0.0.1 -p 6379
However, when I try to capture the output in a variable (to pass it int the file) like this:
Latency=$(timeout 20 /usr/local/bin/redis-cli --latency -h 127.0.0.1 -p 6379)
echo $Latency
The command stops immediately after running, rather than running for the intended 20 seconds.
How can I capture the Redis latency output for the full duration of 20 seconds into a variable?
When you try to capture Redis Latency output to a variable or file, by default Redis samples the latency for 1 second.
To customize the duration of the latency test, you can specify the interval between samples using the -i option like this
Latency=$(/usr/local/bin/redis-cli --latency -h 127.0.0.1 -p 6379 -i 20)
You can get also get this information using the help command for redis latency. Image from Redis help
redis-cli --latency --help