feat: allow adding custom external jars to classpath

Author: Trigtrig

ENV_VARIABLES.md

@@ -144,3 +144,4 @@
 | SE_NODE_REGISTER_SHUTDOWN_ON_FAILURE | true | If this flag is enabled, the Node will shut down after the register period is completed. This is useful for container environments to restart and register again. If restarted multiple times, the Node container status will be CrashLoopBackOff | --register-shutdown-on-failure |
 | SE_NODE_RELAY_BROWSER_VERSION |  |  |  |
 | SE_NODE_RELAY_ONLY | true |  |  |
+| SE_EXTRA_LIBS | | Extra jars to add to the classpath | --ext |

NodeBase/start-selenium-node.sh

@@ -129,13 +129,21 @@ if [ "$GENERATE_CONFIG" = true ]; then
 fi
 
 EXTRA_LIBS=""
+if [ -n "${SE_EXTRA_LIBS}" ]; then
+  echo "Adding external jars to classpath: ${SE_EXTRA_LIBS}"
+  EXTRA_LIBS="--ext ${SE_EXTRA_LIBS}"
+fi
 
 if [ "${SE_ENABLE_TRACING}" = "true" ] && [ -n "${SE_OTEL_EXPORTER_ENDPOINT}" ]; then
   EXTERNAL_JARS=$(</external_jars/.classpath.txt)
-  [ -n "$EXTRA_LIBS" ] && [ -n "${EXTERNAL_JARS}" ] && EXTRA_LIBS=${EXTRA_LIBS}:
-  EXTRA_LIBS="--ext "${EXTRA_LIBS}${EXTERNAL_JARS}
+  if [ -n "${EXTRA_LIBS}" ] && [ -n "${EXTERNAL_JARS}" ]; then
+    EXTRA_LIBS="${EXTRA_LIBS}:${EXTERNAL_JARS}"
+  elif [ -z "${EXTRA_LIBS}" ] && [ -n "${EXTERNAL_JARS}" ]; then
+    EXTRA_LIBS="--ext ${EXTERNAL_JARS}"
+  fi
   echo "Tracing is enabled"
-  echo "Classpath will be enriched with these external jars : " ${EXTRA_LIBS}
+  echo "Classpath will be enriched with these external jars : ${EXTRA_LIBS}"
+
   if [ -n "$SE_OTEL_SERVICE_NAME" ]; then
     SE_OTEL_JVM_ARGS="$SE_OTEL_JVM_ARGS -Dotel.resource.attributes=service.name=${SE_OTEL_SERVICE_NAME}"
   fi