run.sh

#!/usr/bin/env bash
set -mb
cd "$(dirname "$0")"

declare -ar CONFIG_PARAMS=(runas http_probe_headers python_virtualenv_params depends_grace_period system_packages package_manager_lock_wait probe_as_dependency probe_timeout probe_retries restart periodic_interval success_exit probe depends stop_signal reload_signal command probe_interval continous_probe probe_failure_action)
declare -A BACKGROUND_PIDS

for parameter in ${@}; do
  shift
  if [[ "$parameter" =~ (-d|--debug) ]]; then
    export debug=1
  else
    set -- "$@" "$parameter"
  fi
done

. _/defaults.config
. _/bash-init.config
. _/system.sh
. _/tools.sh

cleanup_bash_init

trap "exit" INT TERM
trap "exit_trap" EXIT

check_defaults

if [ $# -eq 0 ]; then
  text error "Missing service name/s in attribute"
  exit 1
fi

if command -v apk >/dev/null; then
  text info "Found apk, assuming an Alpine environment"
  export alpine=1
  export runas_helper="su-exec"
elif command -v apt >/dev/null; then
  text info "Found apt, assuming a Debian environment"
  export debian=1
  export runas_helper="gosu"
else
  text info "Found neither apt nor apk, unknown environment"
fi

text info "Spawned bash-init with PID $$"

#---------------------------#
#--------- Stage 1 ---------#
#---------------------------#
for i in {1..2}; do
  # On first loop, declare associative arrays
  if [ $i -eq 1 ]; then
    for raw_service in ${@}; do
      service="$(trim_string "$raw_service")"
      if ! is_regex_match "$service" '^[a-zA-Z0-9_]+$'; then
        text error "Invalid service name: ${service}"
        exit 1
      fi

      declare -A $service
    done

  else
    # On second loop source services and process
    . services.array
    for raw_service in ${@}; do
      service="$(trim_string "$raw_service")"
      declare -n "s=$service"

      if [ ${#s[@]} -eq 0 ]; then
        text error  "Service $service is not defined"
        exit 1
      elif [ ${#s[command]} -eq 0 ]; then
        text error "Service $service has no command defined"
        exit 1
      fi

      text info "$(stage info 1) Starting: $(text info $service color_only)"
      > /tmp/bash-init-svc_${service}
      for config in "${CONFIG_PARAMS[@]}"; do
        user_config=0
        for attr in "${!s[@]}"; do
          if [[ "$attr" == "$config" ]]; then
            user_config=1
            printf '%s="%s"\n' "$attr" "${s[$attr]}" >> /tmp/bash-init-svc_${service}
          fi
        done

        [ $user_config -eq 0 ] && printf '%s="%s"\n' "$config" "${!config}" >> /tmp/bash-init-svc_${service}
      done

      printf 'service_name="%s"\n' "$service" >> /tmp/bash-init-svc_${service}
      env_file=/tmp/bash-init-svc_${service} bash _/task.sh &
      pid=$!
      BACKGROUND_PIDS[$service]=$pid
      text success "$(stage success 1) Spawned service container $(text info $service color_only) with PID $pid"
    done
  fi
done

#---------------------------#
#--------- Stage 2 ---------#
#---------------------------#
declare -i pid
declare -i stage_2_loop=0
declare -A started_containers
declare -A awaiting_dependencies
while [ ${#started_containers[@]} -ne ${#BACKGROUND_PIDS[@]} ]; do
  for key in "${!BACKGROUND_PIDS[@]}"; do
    ((stage_2_loop++))
    service_dependency="$(env_ctrl "$key" "get" "depends")"

    if [ ! -z $service_dependency ]; then

      declare -n "sd=$service_dependency"

      if [ ${#sd[@]} -eq 0 ]; then
        text error \
        "Dependency $(text info $service_dependency color_only) of service \
        $(text info $key color_only) is not a defined service"
        exit 1

      elif [ "$service_dependency" == "$key" ]; then
        text error "Service $(text info $key color_only) depends on itself"
        exit 1

      else
        if [ $((stage_2_loop%3)) -eq 0 ]; then
          text info "$(stage info 2) \
            Trying service dependency $(text info $service_dependency color_only) of service $(text info $key color_only)"
        fi

        awaiting_dependencies[$key]=$service_dependency
        declare -i depends_grace_period=0
        depends_grace_period="$(env_ctrl "$key" "get" "depends_grace_period")"

        # Retries exceeded
        # OR Service is gone
        # OR Service is about to be terminated
        if [ $stage_2_loop -gt $depends_grace_period ] || \
           [ -z "$(env_ctrl "$service_dependency" "get" "service_name")" ] || \
           [ ! -z "$(env_ctrl "$service_dependency" "get" "pending_signal")" ]; then
          text error "$(stage error 2) Service $(text info $key color_only) will be configured to stop \
            after initialization due to unhealthy dependency $(text info $service_dependency color_only)"
          # Remove dependency to stop looping over it
          env_ctrl "$key" "set" "depends" ""
          # Tell service container to self-destroy
          env_ctrl "$key" "set" "pending_signal" "stop"
          unset health_check_loop[$key]
          unset awaiting_dependencies[$key]
          continue
        fi

        if [ ${#started_containers[$service_dependency]} -eq 0 ]; then
          if [ "${awaiting_dependencies[$service_dependency]}" == "$key" ]; then
            text error "FATAL: Dependency loop: Service $(text info $key color_only) depends on \
              $(text info $service_dependency color_only) which depends on $key"
            exit 1
          fi

        else
          if [ ! -z "$(env_ctrl "$service_dependency" "get" "probe")" ] && \
              [ "$(env_ctrl "$service_dependency" "get" "active_probe_status")" != "1" ]; then

            if [ $((health_check_loop[$key]%3)) -eq 0 ]; then
              text info "$(stage info 2) Service $(text info $key color_only) is awaiting \
                healthy state of service dependency $(text info $service_dependency color_only), delaying"
            fi

          else
            unset awaiting_dependencies[$key]
          fi
        fi
      fi
    fi

    #---------------------------#
    #-------- Stage 2.5 --------#
    #---------------------------#
    # This condition check will only be tried when dependencies were met
    # bash-init does now CONT the prepared service containers in stage 2
    # Stage 3 will ultimately be triggered by run_command() which also fires the probe inside the service container
    if [ ! -v awaiting_dependencies[$key] ] && [ ${#started_containers[$key]} -eq 0 ]; then
      pid=${BACKGROUND_PIDS[$key]}
      if await_stop $pid; then
        started_containers[$key]=1
        kill -CONT $pid
        [[ -z "$(env_ctrl "$key" "get" "pending_signal")" ]] && \
          text success "$(stage success 2) Service container $(text info $key color_only) was initialized"
      else
        text error "$(stage error 2) FATAL: Service container $(text info $key color_only) could not be initialized"
        exit 1
      fi
    fi
  done
  delay 1
done

declare -i run_loop=0
while true; do
  ((run_loop++))

  for key in ${!BACKGROUND_PIDS[@]}; do
    pid=${BACKGROUND_PIDS[$key]}

    if proc_exists $pid; then
      if [ $((run_loop%emit_stats_interval)) -eq 0 ]; then
        emit_service_stats $key
        run_loop=0
      fi

      pending_signal="$(env_ctrl "$key" "get" "pending_signal")"
      if [ ! -z "$pending_signal" ]; then
        env_ctrl "$key" "del" "pending_signal"
        stop_service "$key" "$pending_signal"
      fi

    else
      if [ -s /tmp/bash-init-svc_${key} ]; then
        while [ -s /tmp/env.lock ]; do
          delay 0.1
        done

        env_file=/tmp/bash-init-svc_${key} bash _/task.sh &
        _pid=$!
        BACKGROUND_PIDS[$key]=$_pid
        text warning "Restarting initialization of service container $(text info $key color_only) with PID $_pid"
        if await_stop $_pid; then
          kill -CONT $_pid
          text success "Service container $(text info $key color_only) was re-initialized"
        else
          text error "$(stage error 2) Service container $(text info $key color_only) could not be \
            re-initialized and will be removed"
          >/tmp/bash-init-svc_${key}
        fi

      else
        unset BACKGROUND_PIDS[$key]
        kill -$pid 2>/dev/null
        kill $pid 2>/dev/null
        >/tmp/bash-init-svc_${key}
        text info "Service $key has left the chat"
      fi
    fi
  done

  if [ ${#BACKGROUND_PIDS[@]} -eq 0 ]; then
    text info "No more running services to monitor"
    exit 0
  fi

  delay 1

done