swarm services wait for start

swarm-services-lib.sh

#!/usr/bin/env bash

# This function checks if the service is in Running state
check_service_is_running() {
    local SERVICE_NAME=$1
    local STATE=$(docker service ps --format '{{json .CurrentState}}' $SERVICE_NAME)
    if [[ $STATE = \"Running* ]]; then
      echo 1
    else
      echo 0
    fi
}

# This function waits for the service to become available.
# Retries for 10 times and 3 second interval (hard coded for now)
wait_for_service_to_start() {
    local n=1
    local max=20
    local delay=3

    local SERVICE_NAME=$1
    local SERVICE_IS_RUNNING=0
    while [  "$SERVICE_IS_RUNNING" -eq 0 ]; do
      if [[ $n -gt $max ]]; then
        echo "ERROR: Retried $(($n-1)) times but $SERVICE_NAME didn't start. Exiting" >&2
        docker service ls

        echo "Logs for app_web:"
        docker service logs app_web

        echo "Logs for failed $SERVICE_NAME:"
        docker service logs $SERVICE_NAME
        exit 1
      fi
      SERVICE_IS_RUNNING=$(check_service_is_running $SERVICE_NAME)
      echo "Waiting for $SERVICE_NAME to start"
      n=$[$n+1]
      sleep $delay
    done
    echo "$SERVICE_NAME is Running"
}