Hi there! I wrote
wait-for-it in order to help me orchestrate containers I operate at my day job. I thought it was a neat little script, so I published it. I assumed I would be its only user, but that's not what happened!
wait-for-it has received more stars then all of my other public repositories put together. I had no idea this tool would solicit such an audience, and I was equally unprepared to carve out the time required to address my user's issues and patches. I would like to solicit a volunteer from the community who would be willing to be a co-maintainer of this repository. If this is something you might be interested in, please email me at
wait-for-it.sh is a pure bash script that will wait on the availability of a host and TCP port. It is useful for synchronizing the spin-up of interdependent services, such as linked docker containers. Since it is a pure bash script, it does not have any external dependencies.
wait-for-it.sh host:port [-s] [-t timeout] [-- command args] -h HOST | --host=HOST Host or IP under test -p PORT | --port=PORT TCP port under test Alternatively, you specify the host and port as host:port -s | --strict Only execute subcommand if the test succeeds -q | --quiet Don't output any status messages -t TIMEOUT | --timeout=TIMEOUT Timeout in seconds, zero for no timeout -- COMMAND ARGS Execute command with args after the test finishes
For example, let's test to see if we can access port 80 on www.google.com, and if it is available, echo the message
google is up.
$ ./wait-for-it.sh www.google.com:80 -- echo "google is up" wait-for-it.sh: waiting 15 seconds for www.google.com:80 wait-for-it.sh: www.google.com:80 is available after 0 seconds google is up
You can set your own timeout with the
--timeout= option. Setting the timeout value to 0 will disable the timeout:
$ ./wait-for-it.sh -t 0 www.google.com:80 -- echo "google is up" wait-for-it.sh: waiting for www.google.com:80 without a timeout wait-for-it.sh: www.google.com:80 is available after 0 seconds google is up
The subcommand will be executed regardless if the service is up or not. If you wish to execute the subcommand only if the service is up, add the
--strict argument. In this example, we will test port 81 on www.google.com which will fail:
$ ./wait-for-it.sh www.google.com:81 --timeout=1 --strict -- echo "google is up" wait-for-it.sh: waiting 1 seconds for www.google.com:81 wait-for-it.sh: timeout occurred after waiting 1 seconds for www.google.com:81 wait-for-it.sh: strict mode, refusing to execute subprocess
If you don't want to execute a subcommand, leave off the
-- argument. This way, you can test the exit condition of
wait-for-it.sh in your own scripts, and determine how to proceed:
$ ./wait-for-it.sh www.google.com:80 wait-for-it.sh: waiting 15 seconds for www.google.com:80 wait-for-it.sh: www.google.com:80 is available after 0 seconds $ echo $? 0 $ ./wait-for-it.sh www.google.com:81 wait-for-it.sh: waiting 15 seconds for www.google.com:81 wait-for-it.sh: timeout occurred after waiting 15 seconds for www.google.com:81 $ echo $? 124
I wrote this script for my employer, Ginkgo Bioworks, who was kind enough to let me release it as an open source tool. We are always looking to hire talented folks who are interested in working in the field of synthetic biology.