start-kafka.sh

#!/bin/bash

if [[ -z "$KAFKA_PORT" ]]; then
    export KAFKA_PORT=9092
fi

create-topics.sh &

if [[ -z "$KAFKA_ADVERTISED_PORT" && \
  -z "$KAFKA_LISTENERS" && \
  -z "$KAFKA_ADVERTISED_LISTENERS" && \
  -S /var/run/docker.sock ]]; then
    export KAFKA_ADVERTISED_PORT=$(docker port `hostname` $KAFKA_PORT | sed -r "s/.*:(.*)/\1/g")
fi
if [[ -z "$KAFKA_BROKER_ID" ]]; then
    if [[ -n "$BROKER_ID_COMMAND" ]]; then
        export KAFKA_BROKER_ID=$(eval $BROKER_ID_COMMAND)
    else
        # By default auto allocate broker ID
        export KAFKA_BROKER_ID=-1
    fi
fi
if [[ -z "$KAFKA_LOG_DIRS" ]]; then
    export KAFKA_LOG_DIRS="/kafka/kafka-logs-$HOSTNAME"
fi
if [[ -z "$KAFKA_ZOOKEEPER_CONNECT" ]]; then
    export KAFKA_ZOOKEEPER_CONNECT=$(env | grep ZK.*PORT_2181_TCP= | sed -e 's|.*tcp://||' | paste -sd ,)
fi

if [[ -n "$KAFKA_HEAP_OPTS" ]]; then
    sed -r -i "s/(export KAFKA_HEAP_OPTS)=\"(.*)\"/\1=\"$KAFKA_HEAP_OPTS\"/g" $KAFKA_HOME/bin/kafka-server-start.sh
    unset KAFKA_HEAP_OPTS
fi

if [[ -z "$KAFKA_ADVERTISED_HOST_NAME" && -n "$HOSTNAME_COMMAND" ]]; then
    export KAFKA_ADVERTISED_HOST_NAME=$(eval $HOSTNAME_COMMAND)
fi

if [[ -n "$KAFKA_LISTENER_SECURITY_PROTOCOL_MAP" ]]; then
  if [[ -n "$KAFKA_ADVERTISED_PORT" && -n "$KAFKA_ADVERTISED_PROTOCOL_NAME" ]]; then
    export KAFKA_ADVERTISED_LISTENERS="${KAFKA_ADVERTISED_PROTOCOL_NAME}://${KAFKA_ADVERTISED_HOST_NAME-}:${KAFKA_ADVERTISED_PORT}"
    export KAFKA_LISTENERS="$KAFKA_ADVERTISED_PROTOCOL_NAME://:$KAFKA_ADVERTISED_PORT"
  fi

  if [[ -z "$KAFKA_PROTOCOL_NAME" ]]; then
    export KAFKA_PROTOCOL_NAME="${KAFKA_ADVERTISED_PROTOCOL_NAME}"
  fi

  if [[ -n "$KAFKA_PORT" && -n "$KAFKA_PROTOCOL_NAME" ]]; then
    export ADD_LISTENER="${KAFKA_PROTOCOL_NAME}://${KAFKA_HOST_NAME-}:${KAFKA_PORT}"
  fi

  if [[ -z "$KAFKA_INTER_BROKER_LISTENER_NAME" ]]; then
    export KAFKA_INTER_BROKER_LISTENER_NAME=$KAFKA_PROTOCOL_NAME
  fi
else
   #DEFAULT LISTENERS 
   export KAFKA_ADVERTISED_LISTENERS="PLAINTEXT://${KAFKA_ADVERTISED_HOST_NAME-}:${KAFKA_ADVERTISED_PORT-$KAFKA_PORT}"
   export KAFKA_LISTENERS="PLAINTEXT://${KAFKA_HOST_NAME-}:${KAFKA_PORT-9092}"
fi

if [[ -n "$ADD_LISTENER" && -n "$KAFKA_LISTENERS" ]]; then
  export KAFKA_LISTENERS="${KAFKA_LISTENERS},${ADD_LISTENER}"
fi

if [[ -n "$ADD_LISTENER" && -z "$KAFKA_LISTENERS" ]]; then
  export KAFKA_LISTENERS="${ADD_LISTENER}"
fi

if [[ -n "$ADD_LISTENER" && -n "$KAFKA_ADVERTISED_LISTENERS" ]]; then
  export KAFKA_ADVERTISED_LISTENERS="${KAFKA_ADVERTISED_LISTENERS},${ADD_LISTENER}"
fi

if [[ -n "$ADD_LISTENER" && -z "$KAFKA_ADVERTISED_LISTENERS" ]]; then
  export KAFKA_ADVERTISED_LISTENERS="${ADD_LISTENER}"
fi

if [[ -n "$KAFKA_INTER_BROKER_LISTENER_NAME" && ! "$KAFKA_INTER_BROKER_LISTENER_NAME"X = "$KAFKA_PROTOCOL_NAME"X ]]; then
   if [[ -n "$KAFKA_INTER_BROKER_PORT" ]]; then
      export KAFKA_INTER_BROKER_PORT=$(( $KAFKA_PORT + 1 ))
   fi
   export INTER_BROKER_LISTENER="${KAFKA_INTER_BROKER_LISTENER_NAME}://:${KAFKA_INTER_BROKER_PORT}"
   export KAFKA_LISTENERS="${KAFKA_LISTENERS},${INTER_BROKER_LISTENER}"
   export KAFKA_ADVERTISED_LISTENERS="${KAFKA_ADVERTISED_LISTENERS},${INTER_BROKER_LISTENER}"
   unset KAFKA_INTER_BROKER_PORT
   unset KAFKA_SECURITY_INTER_BROKER_PROTOCOL
   unset INTER_BROKER_LISTENER
fi

if [[ -n "$RACK_COMMAND" && -z "$KAFKA_BROKER_RACK" ]]; then
    export KAFKA_BROKER_RACK=$(eval $RACK_COMMAND)
fi

#Issue newline to config file in case there is not one already
echo -e "\n" >> $KAFKA_HOME/config/server.properties

unset KAFKA_CREATE_TOPICS
unset KAFKA_ADVERTISED_PROTOCOL_NAME
unset KAFKA_PROTOCOL_NAME

if [[ -n "$KAFKA_ADVERTISED_LISTENERS" ]]; then
  unset KAFKA_ADVERTISED_PORT
  unset KAFKA_ADVERTISED_HOST_NAME
fi

if [[ -n "$KAFKA_LISTENERS" ]]; then
  unset KAFKA_PORT
  unset KAFKA_HOST_NAME
fi

for VAR in `env`
do
  if [[ $VAR =~ ^KAFKA_ && ! $VAR =~ ^KAFKA_HOME ]]; then
    kafka_name=`echo "$VAR" | sed -r "s/KAFKA_(.*)=.*/\1/g" | tr '[:upper:]' '[:lower:]' | tr _ .`
    env_var=`echo "$VAR" | sed -r "s/(.*)=.*/\1/g"`
    if egrep -q "(^|^#)$kafka_name=" $KAFKA_HOME/config/server.properties; then
        sed -r -i "s@(^|^#)($kafka_name)=(.*)@\2=${!env_var}@g" $KAFKA_HOME/config/server.properties #note that no config values may contain an '@' char
    else
        echo "$kafka_name=${!env_var}" >> $KAFKA_HOME/config/server.properties
    fi
  fi

  if [[ $VAR =~ ^LOG4J_ ]]; then
    log4j_name=`echo "$VAR" | sed -r "s/(LOG4J_.*)=.*/\1/g" | tr '[:upper:]' '[:lower:]' | tr _ .`
    log4j_env=`echo "$VAR" | sed -r "s/(.*)=.*/\1/g"`
    if egrep -q "(^|^#)$log4j_name=" $KAFKA_HOME/config/log4j.properties; then
        sed -r -i "s@(^|^#)($log4j_name)=(.*)@\2=${!log4j_env}@g" $KAFKA_HOME/config/log4j.properties #note that no config values may contain an '@' char
    else
        echo "$log4j_name=${!log4j_env}" >> $KAFKA_HOME/config/log4j.properties
    fi
  fi
done

if [[ -n "$CUSTOM_INIT_SCRIPT" ]] ; then
  eval $CUSTOM_INIT_SCRIPT
fi

exec $KAFKA_HOME/bin/kafka-server-start.sh $KAFKA_HOME/config/server.properties