how to terminate server on watchman rebuild

When using watchman for project monitoring, there may be situations where you need to stop the server during rebuilds or other specific tasks. To achieve this goal, several methods are available. Here, I will introduce a more general approach: controlling the tasks triggered by watchman through scripts.

Step 1: Configure watchman

First, ensure that watchman is installed and configured in your project. You can create a watchman configuration file, such as watchman.json, to define which file changes trigger specific actions.

json
{
  "trigger": {
    "name": "rebuild-server",
    "expression": ["anyof", ["match", "*.js"], ["match", "*.css"]],
    "command": ["./rebuild_and_restart.sh"]
  }
}

In this configuration, we define a trigger rebuild-server that executes the rebuild_and_restart.sh script when any .js or .css file changes.

Step 2: Write the Control Script

In the rebuild_and_restart.sh script, we can write necessary commands to stop the currently running server, perform the required rebuild, and then restart the server.

bash
#!/bin/bash
# Stop the currently running server
echo "Stopping server..."
pkill -f my-server-process-name

# Perform the rebuild
echo "Rebuilding..."
npm run build

# Restart the server
echo "Restarting server..."
npm start

Step 3: Start watchman

Finally, ensure that watchman is running in the background and has loaded your configuration:

shell
watchman watch-project /path/to/your/project
watchman -- trigger /path/to/your/project rebuild-server 'rebuild_and_restart.sh'

Example

Suppose you are responsible for a Node.js project where the source code needs to be recompiled and restarted after every modification. You can set up watchman according to the above steps so that whenever JavaScript or CSS files are modified, the server automatically stops, the code is recompiled, and then the server restarts. This can significantly reduce the need for manual server restarts and improve development efficiency.

Summary

By leveraging watchman's trigger functionality combined with shell scripts, you can effectively manage complex automation tasks, such as automatically restarting the server when files change. This automation not only reduces repetitive work but also ensures efficiency and consistency during development.