Add a feature to shtudown container after running init scripts

[mjpowersjr]

Sometimes I use a command like the following to initialize a mysql new database volume from a backup.

docker run --rm ... --volume /path/to/backup.sql:/docker-entrypoint-initdb.d/backup.sql mysql

It would be handy if I could (through a environment variable, alternative entrypoint, etc.) cause the docker container to stop running after the init process is complete, instead of listening for connections.

My current workaround (hack) is to build a new image based on the mysql image, that contains a shell script that waits for the init process to finish - and then kill the mysql service. This seems to work fine, but it would be nice if there was a baked in way to accomplish this behavior.

#!/bin/bash

set -e

# wait until init process is finished
until /docker-entrypoint.sh mysqld 2>&1 | \
    tee /dev/tty | \
    grep --silent --extended-regexp --max-count=1 "init process done|error";
do 
    sleep 1; 
done

# shutdown container
kill -s TERM $$

[yosifkit]

Why not just make your script alphabetically after your backup file in docker-entrypoint-initdb.d and then you can do something like the following:

#!/bin/bash
set -e

# you should have access to any vars from the entrypoint since scripts are sourced
kill -s TERM "$pid"
wait "$pid"
# or
killall -s TERM mysqld
sleep 10

# prevent entrypoint from continuing
exit 1

[davidroeca]

The solution documented in this issue no longer works ($pid is no longer an accessible variable). The solution mentioned in #423 (comment) works but will have to be manually updated every time the implementation changes.

Are there plans to support this now that #471 is merged?

[tianon]

You should be able to invoke docker_temp_server_stop to stop the temporary server, followed by exit in order to stop the execution of any further instructions (as above).

[tianon]

Also, with #471 you could more easily write your own script which just does the initialization followed by exiting (and thus be much less error-prone).

[davidroeca]

A script that copies _main from docker-entrypoint.sh becomes error-prone the moment a name used within _main changes, or a new (and necessary) command is added. What I'd like to do is just run _main without the last line.

[davidroeca]

Maybe I'm confused and there's an easier way to go about this?

[mjpowersjr]

I'm not sure if this works for everyone else interested - but I have since found a clean solution for my needs:

I simply append the SQL SHUTDOWN statement at the end of my bootstrap script!

https://dev.mysql.com/doc/refman/5.7/en/shutdown.html

As far as I'm concerned, this is a good solution. If there are no objections, I think it's safe to close this issue?

[davidroeca]

I try this one out today, thanks!

[davidroeca]

Works as intended for my use case; this should be the recommended solution

[marzigolbaz]

This is the command I run at the end of my bootstrap script:

 mysql -u root -A -e "SHUTDOWN;"

But, the container does not shut down and I see this error in the logs:

mysql: [Warning] Using a password on the command line interface can be insecure.
2020-03-18T19:48:31.974925Z 10 [System] [MY-013172] [Server] Received SHUTDOWN from user root. Shutting down mysqld (Version: 8.0.19).

2020-03-18 19:48:31+00:00 [Note] [Entrypoint]: Stopping temporary server
mysqladmin: connect to server at 'localhost' failed
error: 'Lost connection to MySQL server at 'reading initial communication packet', system error: 104'
2020-03-18 19:48:32+00:00 [ERROR] [Entrypoint]: Unable to shut down server.

What am I doing wrong?