teemq pipes stdin to stdout and AMQP broker. It's also additionally buffers data in an internal queue to never stop input stream and be resilient to AMQP broker unavailabilty.

linegen | teemq --url amqp://guest:guest@rabbit:5672 --exchange logs --queue lines --key staging --declare > local.stream.txt

This will send stream of data from linegen to the stdout and also duplicate the data to the AMQP broker at host "rabbit", sending it to the queue "lines" with a routing key "logs". Queue will be declared if it's not existing (--declare option).

teemq can also connect to the RabbitMQ cluster by providing multiple hosts in URL

linegen \
| teemq \
    --url 'amqp://user:pass@rabbit1:5672;amqp://user:pass@rabbit2:5672;amqp://user:pass@rabbit3:5672' \
    --exchange logs
    --queue etl \
    --key prod \
> local.stream.txt

If the AMQP broker is not available teemq will buffer lines in the internal queue (its size is set with --limit option). While buffering messages for AMQP, piping to the stdout will not block and continue at usual pace because it's executed in a separate thread.

When the internal queue is filled up it will drop new lines from buffering for AMQP broker but piping to stdout will continue to work. In this case it will print the log message

$ linegen | teemq -e logs -q stream -k us-east > /dev/null
2017-11-19 00:38:04: [Tee]: Dropping line because QUEUE IS FULL
...