darpan 0.2.5

Linux developer service monitoring utility with auto-detection, real-time health checks, and interactive TUI for databases, APIs, Docker containers, and more
Documentation 
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use crate::health::HealthCheckerTrait;
use crate::models::{HealthResult, Service};
use async_trait::async_trait;
use std::time::{Duration, Instant};
use tokio::process::Command;
use tokio::time::timeout;
use tracing::debug;

/// Health checker that executes a script/command
pub struct ScriptHealthChecker {
    script: String,
    timeout: Duration,
    expected_exit_code: Option<i32>,
    parse_output: bool,
}

impl ScriptHealthChecker {
    pub fn new(script: String, timeout: Duration) -> Self {
        Self {
            script,
            timeout,
            expected_exit_code: Some(0),
            parse_output: false,
        }
    }

    pub fn with_exit_code(mut self, code: Option<i32>) -> Self {
        self.expected_exit_code = code;
        self
    }

    pub fn with_output_parsing(mut self, parse: bool) -> Self {
        self.parse_output = parse;
        self
    }

    async fn execute_script(&self, service: &Service) -> Result<(i32, String, String), String> {
        // Replace placeholders in script
        let script = self
            .script
            .replace("{name}", &service.name)
            .replace("{host}", &service.host)
            .replace("{port}", &service.port.to_string())
            .replace("{pid}", &service.pid.map(|p| p.to_string()).unwrap_or_default());

        // Parse command (simple shell parsing - split by spaces)
        let parts: Vec<&str> = script.trim().split_whitespace().collect();
        if parts.is_empty() {
            return Err("Empty script".to_string());
        }

        let command = parts[0];
        let args = &parts[1..];

        debug!("Executing health check script: {} {:?}", command, args);

        let start = Instant::now();

        // Execute command with timeout
        let output = timeout(
            self.timeout,
            Command::new(command).args(args).output(),
        )
        .await
        .map_err(|_| format!("Script timeout after {:?}", self.timeout))?
        .map_err(|e| format!("Failed to execute: {}", e))?;
        let elapsed = start.elapsed();

        let stdout = String::from_utf8_lossy(&output.stdout).to_string();
        let stderr = String::from_utf8_lossy(&output.stderr).to_string();
        let exit_code = output.status.code().unwrap_or(-1);

        debug!(
            "Script executed in {:?}, exit code: {}",
            elapsed, exit_code
        );

        Ok((exit_code, stdout, stderr))
    }
}

#[async_trait]
impl HealthCheckerTrait for ScriptHealthChecker {
    async fn check(&self, service: &Service) -> HealthResult {
        match self.execute_script(service).await {
            Ok((exit_code, stdout, stderr)) => {
                // Check exit code
                if let Some(expected) = self.expected_exit_code {
                    if exit_code != expected {
                        return HealthResult::unhealthy(
                            format!(
                                "Script exited with code {} (expected {})",
                                exit_code, expected
                            ),
                            Some(if !stderr.is_empty() {
                                stderr
                            } else {
                                stdout
                            }),
                        );
                    }
                }

                // Parse output if enabled
                if self.parse_output {
                    let output_lower = stdout.to_lowercase();
                    if output_lower.contains("healthy") || output_lower.contains("ok") {
                        return HealthResult::healthy(0);
                    } else if output_lower.contains("unhealthy")
                        || output_lower.contains("error")
                        || output_lower.contains("fail")
                    {
                        return HealthResult::unhealthy(
                            "Script reported unhealthy".to_string(),
                            Some(stdout),
                        );
                    }
                }

                // Success
                HealthResult::healthy(0)
            }
            Err(e) => HealthResult::unhealthy(
                format!("Script execution failed: {}", e),
                None,
            ),
        }
    }

    fn supports(&self, _service: &Service) -> bool {
        // Script checkers support all services (they're configured per-service)
        true
    }
}