Auto run the start script + allow several workers

The Dockerfile now automatically run the `start.sh` script on startup by
default.

The `$NB_WORKERS` env variable now allows to customize the number of workers
created.

`start.sh` now sleeps infinitely at the end of its execution (to avoid stopping
the container at the end of its execution).

Dockerfile

@@ -68,4 +68,6 @@ RUN git clone https://github.com/kaldi-asr/kaldi && \
 COPY start.sh stop.sh /opt/
 
 RUN chmod +x /opt/start.sh && \
-    chmod +x /opt/stop.sh 
+    chmod +x /opt/stop.sh
+
+CMD /opt/start.sh

start.sh

@@ -36,7 +36,13 @@ if [ "$MASTER" == "localhost" ] ; then
   python /opt/kaldi-gstreamer-server/kaldigstserver/master_server.py --port=$PORT 2>> /opt/master.log &
 fi
 
-#start worker and connect it to the master
 export GST_PLUGIN_PATH=/opt/gst-kaldi-nnet2-online/src/:/opt/kaldi/src/gst-plugin/
 
-python /opt/kaldi-gstreamer-server/kaldigstserver/worker.py -c $YAML -u ws://$MASTER:$PORT/worker/ws/speech 2>> /opt/worker.log &
+NB_WORKERS=${NB_WORKERS:-1}
+for i in $(seq 1 $NB_WORKERS)
+do
+    #start worker and connect it to the master
+    python /opt/kaldi-gstreamer-server/kaldigstserver/worker.py -c $YAML -u ws://$MASTER:$PORT/worker/ws/speech 2>> /opt/worker-$i.log &
+done
+
+sleep infinity