Adding drain after sessions flag (#1559)

[deploy]

NodeBase/Dockerfile.txt

@@ -165,6 +165,9 @@ ENV START_NO_VNC true
 # Path to the Configfile
 ENV CONFIG_FILE=/opt/selenium/config.toml
 ENV GENERATE_CONFIG true
+# Drain the Node after N sessions. 
+# A value higher than zero enables the feature
+ENV DRAIN_AFTER_SESSION_COUNT 0
 
 #========================
 # Selenium Configuration

NodeBase/generate_config

@@ -46,6 +46,7 @@ fi
 echo "session-timeout = \"${SE_NODE_SESSION_TIMEOUT}\"" >> "$FILENAME"
 echo "override-max-sessions = ${SE_NODE_OVERRIDE_MAX_SESSIONS}" >> "$FILENAME"
 echo "detect-drivers = false" >> "$FILENAME"
+echo "drain-after-session-count = ${DRAIN_AFTER_SESSION_COUNT}" >> "$FILENAME"
 echo "max-sessions = ${SE_NODE_MAX_SESSIONS}
 " >> "$FILENAME"
 

README.md

@@ -602,7 +602,8 @@ variables.
 Here is an example with the default values of these environment variables:
 
 ```bash
-$ docker run -d -e SE_EVENT_BUS_HOST=<event_bus_ip|event_bus_name> -e SE_EVENT_BUS_PUBLISH_PORT=4442 -e SE_EVENT_BUS_SUBSCRIBE_PORT=4443 --shm-size="2g" selenium/node-chrome:4.1.3-20220427
+$ docker run -d -e SE_EVENT_BUS_HOST=<event_bus_ip|event_bus_name> -e SE_EVENT_BUS_PUBLISH_PORT=4442 \ 
+  -e SE_EVENT_BUS_SUBSCRIBE_PORT=4443 --shm-size="2g" selenium/node-chrome:4.1.3-20220427
 ```
 
 ### Setting Screen Resolution
@@ -612,7 +613,7 @@ These settings can be adjusted by specifying `SCREEN_WIDTH`, `SCREEN_HEIGHT`, `S
 environmental variables when starting the container.
 
 ``` bash
-docker run -d -e SCREEN_WIDTH=1366 -e SCREEN_HEIGHT=768 -e SCREEN_DEPTH=24 -e SCREEN_DPI=74 selenium/standalone-firefox
+docker run -d -e SCREEN_WIDTH=1366 -e SCREEN_HEIGHT=768 -e SCREEN_DEPTH=24 -e SCREEN_DPI=74 selenium/standalone-firefox:4.1.3-20220427
 ```
 
 ### Grid Url and Session Timeout
@@ -661,10 +662,25 @@ To avoid starting the server you can set the `START_XVFB` environment variable t
 (or any other value than `true`), for example:
 
 ``` bash
-$ docker run -d --net grid -e SE_EVENT_BUS_HOST=selenium-hub -e SE_EVENT_BUS_PUBLISH_PORT=4442 -e SE_EVENT_BUS_SUBSCRIBE_PORT=4443 -e START_XVFB=false --shm-size="2g" selenium/node-chrome
+$ docker run -d --net grid -e SE_EVENT_BUS_HOST=selenium-hub -e SE_EVENT_BUS_PUBLISH_PORT=4442 \
+  -e SE_EVENT_BUS_SUBSCRIBE_PORT=4443 -e START_XVFB=false --shm-size="2g" selenium/node-chrome:4.1.3-20220427
 ```
 
 For more information, see this GitHub [issue](https://github.com/SeleniumHQ/docker-selenium/issues/567).
+
+### Stopping the Node/Standalone after N sessions have been executed
+
+In some environments, like Docker Swarm or Kubernetes, it is useful to shut down the Node or Standalone
+container after N tests have been executed. For example, this can be used in Kubernetes to terminate the
+pod and then scale a new one after N sessions. Set the environment variable `DRAIN_AFTER_SESSION_COUNT` to
+a value higher than zero to enable this behaviour. 
+
+``` bash
+$ docker run -e DRAIN_AFTER_SESSION_COUNT=5 --shm-size="2g" selenium/standalone-firefox:4.1.3-20220427
+```
+
+With the previous command, the Standalone container will shutdown after 5 sessions have been executed.
+
 ___
 
 ## Building the images

Standalone/generate_config

@@ -26,6 +26,7 @@ fi
 echo "session-timeout = \"${SE_NODE_SESSION_TIMEOUT}\"" >> "$FILENAME"
 echo "override-max-sessions = ${SE_NODE_OVERRIDE_MAX_SESSIONS}" >> "$FILENAME"
 echo "detect-drivers = false" >> "$FILENAME"
+echo "drain-after-session-count = ${DRAIN_AFTER_SESSION_COUNT}" >> "$FILENAME"
 echo "max-sessions = ${SE_NODE_MAX_SESSIONS}
 " >> "$FILENAME"