knot knot

knot.healthcheck

The knot.healthcheck library provides functions for space health monitoring. It is only available in agent-side health check scripts. The check functions (http_head, tcp_port, program) return True or False so you can combine them, then call check_result() to report the final status and exit.

Functions

Function Description
http_head(url, skip_ssl_verify=False, timeout=10) HTTP HEAD check — returns True if status 200
tcp_port(port, timeout=10) TCP port check — returns True if port is open
program(command, timeout=10) Run a command — returns True if exit code 0
check_result(healthy) Report the health result and exit

Usage

import knot.healthcheck as hc

# Simple HTTP check
hc.check_result(hc.http_head("http://localhost:8080/health"))

# Simple TCP check
hc.check_result(hc.tcp_port(8080))

# Combine multiple checks
ok = hc.http_head("http://localhost:8080/health") and hc.tcp_port(6379)
hc.check_result(ok)

# Custom logic
ok = hc.tcp_port(5432) and hc.program("pg_isready -q")
hc.check_result(ok)

Function Details

http_head(url, skip_ssl_verify=False, timeout=10)

Perform an HTTP HEAD request. Returns True if the response status code is 200, False for any other status or connection error.

Parameters:

  • url (string): The URL to check
  • skip_ssl_verify (bool, optional): Skip TLS certificate verification (default: False)
  • timeout (int, optional): Request timeout in seconds (default: 10)

Returns: bool — True if healthy

tcp_port(port, timeout=10)

Attempt a TCP connection to 127.0.0.1 on the given port. Returns True if the connection succeeds.

Parameters:

  • port (int): The port number to check
  • timeout (int, optional): Connection timeout in seconds (default: 10)

Returns: bool — True if healthy

program(command, timeout=10)

Execute a shell command. Returns True if the command exits with code 0, False for any non-zero exit code or error.

Parameters:

  • command (string): The command to execute
  • timeout (int, optional): Execution timeout in seconds (default: 10)

Returns: bool — True if healthy

check_result(healthy)

Report the final health check result and exit the script immediately.

Parameters:

  • healthy (bool): True for healthy, False for unhealthy

Environment Compatibility

The knot.healthcheck library is only available in agent-side health check scripts. It is not available in local, MCP, or remote execution environments.

When a template configures a health check type (HTTP, TCP, or Program), the agent automatically generates and runs a script using these functions. For the custom health check type, you write a script that imports knot.healthcheck directly, combines check functions as needed, and calls check_result() with the final result.