Extract consumer client.rack from /opt/strimzi/init/rack.id if present (#659)

Extract consumer client.rack from ${STRIMZI_HOME}/init/rack.id if present

Why:
To support rack awareness the strimzi kafka operator will mount in a file containing
the rack.id, this can be appended to the consumer configuration if it is present

Signed-off-by: Robert Young <[email protected]>

Signed-off-by: Robert Young <[email protected]>
Co-authored-by: Robert Young <[email protected]>

Author: robobario

bin/docker/kafka_bridge_config_generator.sh

@@ -117,6 +117,17 @@ EOF
 )
 done
 
+# Get broker rack if it's enabled from the file $KAFKA_HOME/init/rack.id (if it exists). This file is generated by the
+# init-container used when rack awareness is enabled.
+if [ -e "$STRIMZI_HOME/init/rack.id" ]; then
+  STRIMZI_RACK_ID=$(cat "$STRIMZI_HOME/init/rack.id")
+  CONSUMER_PROPERTIES=$(cat <<EOF
+$CONSUMER_PROPERTIES
+kafka.consumer.client.rack=${STRIMZI_RACK_ID}
+EOF
+)
+fi
+
 ADMIN_CLIENT_PROPERTIES="#Apache Kafka AdminClient"
 for i in $KAFKA_BRIDGE_ADMIN_CLIENT_CONFIG; do
         key="kafka.admin.$(echo $i | cut -d'=' -f1)"