with bash, is it possible to enter commands inside a docker container - linux

Question

i'm trying to see if i can run commands after "entering" into a container:
#!/bin/sh
# 1 - create a new user in the db for mautic
podman exec -it postal-mariadb mysql -h 127.0.0.1 -u root -p$1 <<EOF
CREATE DATABASE mauticdb;
CREATE USER 'mautic' IDENTIFIED BY /'$1/';
GRANT ALL PRIVILEGES ON mauticdb.* TO 'mautic';
FLUSH PRIVILEGES;
exit
EOF
this gives me an error: Error: container create failed (no logs from conmon): EOF
but im thinking maybe this is not a good use of HERE DOCS
something like this doesn't work either:
echo $1 | podman exec -it postal-mariadb mysql -h 127.0.0.1 -u root -p postal-server-1 -e 'select * from deliveries limit 10;'

Answer 1

That's a fine (and common) use of here docs, although you probably want to drop the -t from your podman command line. If I have a mariadb container running:
podman run -d --name mariadb -e MARIADB_ROOT_PASSWORD=secret docker.io/mariadb:10
Then if I put your shell script into a file named createdb.sh, modified to look like this for my environment:
podman exec -i mariadb mysql -u root -p$1 <<EOF
CREATE DATABASE mauticdb;
CREATE USER 'mautic' IDENTIFIED BY '$1';
GRANT ALL PRIVILEGES ON mauticdb.* TO 'mautic';
FLUSH PRIVILEGES;
EOF
I've made three changes:
I've removed the -t from the podman exec command line, since we're passing input on stdin rather than starting an interactive terminal;
I removed the unnecessary exit command (the interactive mysql shell will exit when it reaches end-of-file);
I removed the weird forward slashes around your quotes (/'$1/' -> '$1').
I can run it like this:
sh createdb.sh secret
And it runs without errors. The database exists:
$ podman exec mariadb mysql -u root -psecret -e 'show databases'
Database
information_schema
mauticdb <--- THERE IT IS
mysql
performance_schema
sys
And the user exists:
$ podman exec mariadb mysql -u root -psecret mysql -e 'select user from user where user="mautic"'
User
mautic