build.rs

use std::fs::read_to_string;
use std::fs::remove_file;
use std::fs::File;
use std::path::{Path, PathBuf};
use std::process::Command;
use std::process::Stdio;

#[cfg(target_os = "windows")]
mod config {
    pub(crate) const CADDY_BIN_FILE: &'static str = "caddy.exe";
    pub(crate) const SHELL_TO_EXEC: &'static str = "powershell.exe";
    pub(crate) const DOWNLOAD_CADDY_SCRIPT: &'static str = "download_caddy.ps1";
}

#[cfg(not(target_os = "windows"))]
mod config {
    pub(crate) const CADDY_BIN_FILE: &'static str = "caddy";
    pub(crate) const SHELL_TO_EXEC: &'static str = "bash";
    pub(crate) const DOWNLOAD_CADDY_SCRIPT: &'static str = "download_caddy.bash";
}

fn main() {
    println!("cargo:rerun-if-changed=build.rs");
    println!("cargo:rerun-if-changed=bin/{}", config::DOWNLOAD_CADDY_SCRIPT);

    println!("cargo:rerun-if-changed=bin/{}", config::CADDY_BIN_FILE);

    let stdout_file_path = Path::new("build.log");
    if stdout_file_path.is_file() {
        remove_file(stdout_file_path).unwrap();
    }

    let stderr_file_path = Path::new("build.err");
    if stderr_file_path.is_file() {
        remove_file(stderr_file_path).unwrap();
    }

    let shell = which::which(config::SHELL_TO_EXEC).unwrap();

    let mut command = Command::new(shell);
    command
        .stdin(Stdio::null())
        .stdout(Stdio::from(File::create(stdout_file_path).unwrap()))
        .stderr(Stdio::from(File::create(stderr_file_path).unwrap()))
        .arg(format!("bin/{}", config::DOWNLOAD_CADDY_SCRIPT));

    match command.output() {
        Ok(output) => {
            let code = output.status.code().unwrap();
            if code != 0 {
                let error = read_to_string("build.err")
                    .expect("Could not retrieve error log after failing to download Caddy server.");
                caddy_download_error(format!(
                    " An error occured when downloading Caddy.\n Here is the error log:\n{}",
                    error
                ));
            }
        },
        Err(e) => {
            caddy_download_error(format!(" Could not download Caddy: {}", e));
        },
    };
}

fn caddy_download_error(message: String) {
    let caddy_bin = PathBuf::from("bin").join(config::CADDY_BIN_FILE);
    if caddy_bin.exists() {
        // Maybe network is disabled, but in the meantime, we'll reuse the existing Caddy.
        eprintln!(" /!\\ ==================== /!\\ ");
        eprintln!("{}", message);
        eprintln!(" /!\\ ==================== /!\\ ");
    } else {
        panic!("{}", message);
    }
}