how to check if mongodb is up and ready to accept connections from bash script?

Question

I have a bash shell script which does a bunch of stuff before trying to mongorestore.

I want to make sure that not only MongoDB is up, but it is also ready to accept connections before i try restore.

Right now, what I am seeing is, mongo process is up but it take 45+ seconds to do the initial setup (setting up journal files etc) before it is ready to accept connections. Ideally I want to keep testing the connection in a loop and only when I am able to connect, I want to run mongorestore.

Can someone show me how to do this in Bash or point me in the right direction?

Answer 1

To test the connection in a loop like you suggest,

until nc -z localhost 27017
do
    sleep 1
done

Answer 2

A solution using MongoDB Tools. Useful in a docker container or something similiar where you do not want to install nc.

until mongo --eval "print(\"waited for connection\")"
  do
    sleep 60
  done

Based on that other guy's answer.