docker-entrypoint.sh

#!/usr/bin/env bash

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#
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COMMAND_STANDALONE="standalone-job"
COMMAND_HISTORY_SERVER="history-server"

# If unspecified, the hostname of the container is taken as the JobManager address
JOB_MANAGER_RPC_ADDRESS=${JOB_MANAGER_RPC_ADDRESS:-$(hostname -f)}
CONF_FILE="${FLINK_HOME}/conf/flink-conf.yaml"

drop_privs_cmd() {
    if [ $(id -u) != 0 ]; then
        # Don't need to drop privs if EUID != 0
        return
    elif [ -x /sbin/su-exec ]; then
        # Alpine
        echo su-exec flink
    else
        # Others
        echo gosu flink
    fi
}

copy_plugins_if_required() {
  if [ -z "$ENABLE_BUILT_IN_PLUGINS" ]; then
    return 0
  fi

  echo "Enabling required built-in plugins"
  for target_plugin in $(echo "$ENABLE_BUILT_IN_PLUGINS" | tr ';' ' '); do
    echo "Linking ${target_plugin} to plugin directory"
    plugin_name=${target_plugin%.jar}

    mkdir -p "${FLINK_HOME}/plugins/${plugin_name}"
    if [ ! -e "${FLINK_HOME}/opt/${target_plugin}" ]; then
      echo "Plugin ${target_plugin} does not exist. Exiting."
      exit 1
    else
      ln -fs "${FLINK_HOME}/opt/${target_plugin}" "${FLINK_HOME}/plugins/${plugin_name}"
      echo "Successfully enabled ${target_plugin}"
    fi
  done
}

set_config_option() {
  local option=$1
  local value=$2

  # escape periods for usage in regular expressions
  local escaped_option=$(echo ${option} | sed -e "s/\./\\\./g")

  # either override an existing entry, or append a new one
  if grep -E "^${escaped_option}:.*" "${CONF_FILE}" > /dev/null; then
        sed -i -e "s/${escaped_option}:.*/$option: $value/g" "${CONF_FILE}"
  else
        echo "${option}: ${value}" >> "${CONF_FILE}"
  fi
}

prepare_configuration() {
    set_config_option jobmanager.rpc.address ${JOB_MANAGER_RPC_ADDRESS}
    set_config_option blob.server.port 6124
    set_config_option query.server.port 6125

    if [ -n "${TASK_MANAGER_NUMBER_OF_TASK_SLOTS}" ]; then
        set_config_option taskmanager.numberOfTaskSlots ${TASK_MANAGER_NUMBER_OF_TASK_SLOTS}
    fi

    if [ -n "${FLINK_PROPERTIES}" ]; then
        echo "${FLINK_PROPERTIES}" >> "${CONF_FILE}"
    fi
    envsubst < "${CONF_FILE}" > "${CONF_FILE}.tmp" && mv "${CONF_FILE}.tmp" "${CONF_FILE}"
}

maybe_enable_jemalloc() {
    if [ "${DISABLE_JEMALLOC:-false}" == "false" ]; then
        JEMALLOC_PATH="/usr/lib/$(uname -m)-linux-gnu/libjemalloc.so"
        JEMALLOC_FALLBACK="/usr/lib/x86_64-linux-gnu/libjemalloc.so"
        if [ -f "$JEMALLOC_PATH" ]; then
            export LD_PRELOAD=$LD_PRELOAD:$JEMALLOC_PATH
        elif [ -f "$JEMALLOC_FALLBACK" ]; then
            export LD_PRELOAD=$LD_PRELOAD:$JEMALLOC_FALLBACK
        else
            if [ "$JEMALLOC_PATH" = "$JEMALLOC_FALLBACK" ]; then
                MSG_PATH=$JEMALLOC_PATH
            else
                MSG_PATH="$JEMALLOC_PATH and $JEMALLOC_FALLBACK"
            fi
            echo "WARNING: attempted to load jemalloc from $MSG_PATH but the library couldn't be found. glibc will be used instead."
        fi
    fi
}

maybe_enable_jemalloc

copy_plugins_if_required

prepare_configuration

args=("$@")
if [ "$1" = "help" ]; then
    printf "Usage: $(basename "$0") (jobmanager|${COMMAND_STANDALONE}|taskmanager|${COMMAND_HISTORY_SERVER})\n"
    printf "    Or $(basename "$0") help\n\n"
    printf "By default, Flink image adopts jemalloc as default memory allocator. This behavior can be disabled by setting the 'DISABLE_JEMALLOC' environment variable to 'true'.\n"
    exit 0
elif [ "$1" = "jobmanager" ]; then
    args=("${args[@]:1}")

    echo "Starting Job Manager"

    exec $(drop_privs_cmd) "$FLINK_HOME/bin/jobmanager.sh" start-foreground "${args[@]}"
elif [ "$1" = ${COMMAND_STANDALONE} ]; then
    args=("${args[@]:1}")

    echo "Starting Job Manager"

    exec $(drop_privs_cmd) "$FLINK_HOME/bin/standalone-job.sh" start-foreground "${args[@]}"
elif [ "$1" = ${COMMAND_HISTORY_SERVER} ]; then
    args=("${args[@]:1}")

    echo "Starting History Server"

    exec $(drop_privs_cmd) "$FLINK_HOME/bin/historyserver.sh" start-foreground "${args[@]}"
elif [ "$1" = "taskmanager" ]; then
    args=("${args[@]:1}")

    echo "Starting Task Manager"

    exec $(drop_privs_cmd) "$FLINK_HOME/bin/taskmanager.sh" start-foreground "${args[@]}"
fi

args=("${args[@]}")

# Running command in pass-through mode
exec $(drop_privs_cmd) "${args[@]}"