Wait for Connection ready

docker-wait-for-mysql-alt.sh

#!/bin/sh

until docker-compose exec mysql mysql -h 127.0.0.1 -u $DB_USERNAME -p$DB_PASSWORD -D $DB_DATABASE --silent -e "show databases;"
do
  echo "Waiting for database connection..."
  sleep 5
done

docker-wait-for-mysql.sh

#!/bin/sh
failcounter=0
timeout_in_sec=120
until docker exec mysql mysqladmin --user=root --password=${MYSQL_ROOT_PASSWORD} --host "127.0.0.1" ping --silent &> /dev/null ; do
    let "failcounter += 1"
    echo "Waiting for database connection..."
     if [[ $failcounter -gt timeout_in_sec ]]; then
      echo "Timeout ($timeout_in_sec seconds) reached; failed to connect to database"
      exit 1
    fi
    sleep 2
done

docker-wait-for-postgres-alt.sh

#!/bin/sh

## reference https://starkandwayne.com/blog/how-to-know-when-your-postgres-service-is-ready/

pg_uri="postgres://postgres:postgres@postgrest-host:5432/shield"

# make sure pg is ready to accept connections
until pg_isready -h postgres-host -p 5432 -U postgres
do
  echo "Waiting for postgres at: $pg_uri"
  sleep 2;
done

# Now able to connect to postgres

docker-wait-for-postgres-alt2.sh

#!/bin/sh

#waiting for postgres
until psql --host=$KONG_PG_HOST --username=$POLLING_USER $POLLING_DATABASE -w &>/dev/null
do
  echo "Waiting for PostgreSQL..."
  sleep 1
done

docker-wait-for-postgres.sh

#!/bin/sh

failcounter=0
timeout_in_sec=120
until docker exec postgres pg_isready --username=root --host="127.0.0.1" --quiet &> /dev/null ; do
    let "failcounter += 1"
    echo "Waiting for database connection..."
     if [[ $failcounter -gt timeout_in_sec ]]; then
      echo "Timeout ($timeout_in_sec seconds) reached; failed to connect to database"
      exit 1
    fi
    sleep 2
done

thanks!!