How can I run script after starting process in docker? - docker

Question

I want to run this command in docker.
./kafka_2.12-2.2.1/bin/connect-distributed.sh","./kafka_2.12-2.2.1/config/connectdistributed.properties"
This command starts Kafka connect and connected to my azure event hub.
After the Kafka is connected then I want to run the script file in docker.
./script.sh
In this script checks if Kafka is connected successfully. If it is not connected then wait for connection. After the connection is done check if XYZ name connectors not available then create it otherwise script is terminated. I am able to do these things on a local machine but I' not in docker.

Answer 1

I needed to do something similar to wait for db to initialize before server starts otherwise it would fail/exit before whole compose process was done. I add an entrypoint script to the server with something like below.
I imagine there is a way to call your service and send the command to quit immediately. You might have to install the basic tools on that other image.
So, I have a db image. I need to install basic db connect (psql, sqlcmd) on server image to be able to contact my db container to ensure it is running.
host="$1"
shift
cmd="$#"
if [ "${PROVIDER}" == "postgres" ]; then
echo -e "Running under Postgres"
until PGPASSWORD=$POSTGRES_PASSWORD psql -h "$host" -U "$POSTGRES_USER" "$POSTGRES_DB" -c '\q'; do
>&2 echo -e "Postgres is unavailable - sleeping"
sleep 2
done
# https://learn.microsoft.com/en-us/sql/linux/sql-server-linux-configure-docker?view=sql-server-ver15
# The IP address in the connection string is the IP address of the host machine that is running the container.
else
echo -e "Running under Sql Server"
# sqlcmd -?
# sqlcmd -S db.mssql -U rust -P -d rust_test -q "Select * from rust.content_categories"
# sqlcmd -S 192.168.1.108 -U test -P -d shortpoetdb -q "Select * from vcc.admin_users"
until /opt/mssql-tools/bin/sqlcmd -S db.mssql -U "${MSSQL_USER}" -P "${MSSQL_PASSWORD}" -d "${MSSQL_DB}" -q ":exit"; do
>&2 echo -e "$Mssql is $unavailable - sleeping"
sleep 2
done
fi
>&2 echo -e "${PROVIDER} Database is up - executing command"
exec $cmd
docker docs wait
ms docs sql server linux setup

Answer 2

want to run this command in docker.
./kafka_2.12-2.2.1/bin/connect-distributed.sh
confluentinc/cp-kafka-connect images run this already
You should not run Connect and Brokers on the same machines or multiple processes in a container

Answer 3

Run your script as background process which will keep on checking Kafka is connected or not. Once connected it will run its commands and exit and your main command will keep on running and docker won't exit
Eg.
CMD nohup bash -c "script.sh &" && your-command