Service Process Management

Service Process Management

Runy provides powerful process management capabilities through the ctx.process() method, allowing you to define long-running services with automatic restarts, file watching, and lifecycle management.

Basic Process Definition

Use ctx.process() to define a service process within your service’s run method:

await ctx.process({
  alias: "server",
  cmd: "python3",
  args: ["-m", "http.server", "8500"],
});

Process Configuration Options

Command and Arguments

• cmd: The executable command to run
• args: Array of command-line arguments
• alias: Unique identifier for the process

Restart Policies

Configure automatic restart behavior when the process exits. Runy supports four different restart strategies:

Never Restart

Prevents the process from restarting automatically:

restart: {
  kind: "never";
}

Always Restart

Restarts the process immediately after it exits (no delay):

restart: {
  kind: "always";
}

Fixed Restart

Restarts with a consistent delay between attempts:

restart: {
  kind: "fixed",
  delay: 1000,        // Milliseconds to wait before restart
  maxRestarts: 5      // Optional: maximum restart attempts
}

Exponential Backoff Restart

Increases the delay between restart attempts exponentially:

restart: {
  kind: "exponential",
  initialDelay: 1000,   // Starting delay in milliseconds
  maxDelay: 30000,      // Maximum delay cap in milliseconds
  multiplier: 2.0,      // Factor to multiply delay by each attempt
  maxRestarts: 10       // Optional: maximum restart attempts
}

Example exponential backoff sequence:

• 1st restart: 1 second delay
• 2nd restart: 2 seconds delay
• 3rd restart: 4 seconds delay
• 4th restart: 8 seconds delay
• …up to maxDelay

File Watching

Monitor files and restart the process when changes are detected:

watch: ["*.txt", "config.json", "src/**/*.py"];

Complete Example

s.run(async (ctx) => {
  await ctx.process({
    alias: "web-server",
    cmd: "python3",
    args: ["-m", "http.server", "8500"],
    restart: {
      kind: "exponential",
      initialDelay: 1000,
      maxDelay: 30000,
      multiplier: 2.0,
      maxRestarts: 10,
    },
    watch: ["*.py", "config/**/*.json"],
  });
});

This example creates a Python HTTP server that:

• Runs on port 8500
• Uses exponential backoff restart strategy (1s, 2s, 4s, 8s… up to 30s delays)
• Attempts up to 10 restarts before giving up
• Restarts when Python files or config JSON files change
• Can be referenced by the alias “web-server”