Lines of
src/main.rs
from check-in 42ac4c7a9a
that are changed by the sequence of edits moving toward
check-in bdac638883:
1: //! Simple SMTP-to-Telegram gateway. Can parse email and send them as telegram
2: //! messages to specified chats, generally you specify which email address is
3: //! available in configuration, everything else is sent to default address.
4:
42ac4c7a9a 2026-10-28 5: use smol_macros::{
42ac4c7a9a 2026-10-28 6: LocalExecutor,
42ac4c7a9a 2026-10-28 7: main,
42ac4c7a9a 2026-10-28 8: };
42ac4c7a9a 2026-10-28 9:
10: use std::{
11: os::unix::fs::PermissionsExt,
12: path::Path,
13: };
14:
15: use clap::Parser;
16: use smol::fs::metadata;
17: use stacked_errors::{
18: Result,
19: StackableErr,
20: bail,
21: };
22:
23: use smtp2tg::mail::MailServer;
24:
25: /// SMTP-to-Telegram gateway
26: #[derive(Parser, Debug)]
27: #[command(name = "smtp2tg")]
28: #[command(about = format!("SMTP-to-Telegram gateway v{}, (C) 2024 - 2026", env!("CARGO_PKG_VERSION")), long_about = None)]
29: struct Args {
30: /// Set configuration file location
31: #[arg(short, long, default_value = "smtp2tg.toml")]
32: config: String,
33: }
34:
42ac4c7a9a 2026-10-28 35: main! {
36: /// Main asynchronous entry point for the application. Runs the gateway using
37: /// the configuration selected on the command line.
38: ///
39: /// The configuration file must use owner-only permissions. Once configured,
40: /// the SMTP server runs until it stops or encounters an error.
41: ///
42: /// # Errors
43: /// Returns an error if the configuration file is missing, inaccessible,
44: /// insecure, malformed, or contains invalid required settings.
45: /// Also returns an error if the system hostname cannot be read or is not
46: /// valid UTF-8, or if mail server initialisation fails.
47: ///
48: /// # Panics
49: /// Panics if configuring or serving the SMTP server fails.
42ac4c7a9a 2026-10-28 50: async fn main (ex: &LocalExecutor<'_>) -> Result<()> {
51: let args = Args::parse();
52: let settings = {
53: // Load configuration defaults and overrides after checking file permissions.
54: let config_file = Path::new(&args.config);
55: if !config_file.try_exists().stack()? {
56: bail!("Configuration file not found: {config_file:?}\n\
57: Hint: Ensure the file exists and the path is correct.");
58: };
59: {
60: let meta = metadata(config_file).await.stack()?;
61: if (!0o100600 & meta.permissions().mode()) > 0 {
62: bail!("Configuration file permissions are insecure {config_file:?}\n\
63: Current permissions: {:o}\n\
64: Required: 0600 (owner read/write only).\n\
65: Fix with: chmod 600 {config_file:?}",
66: meta.permissions().mode());
67: } }
68: config::Config::builder()
69: .set_default("api_gateway", "https://api.telegram.org").stack()?
70: .set_default("fields", vec!["date", "from", "subject"]).stack()?
71: .set_default("hostname", "smtp.2.tg").stack()?
72: .set_default("listen_on", "0.0.0.0:1025").stack()?
73: .set_default("domains", vec!["localhost",
74: hostname::get().context("Failed to get current hostname")?
75: .to_str().context("Can't convert hostname to string, bad UTF-8?")?]).stack()?
76: .add_source(config::File::from(config_file))
77: .build()
78: .with_context(|| format!(
79: "Failed to parse configuration file: {config_file:?}\n\
80: Check syntax against smtp2tg.toml.example.\n\
81: Common issues: missing quotes, trailing commas in inline tables, or invalid types."
82: ))?
83: };
84:
85: let listen_on = settings.get_string("listen_on").stack()?;
86: let server_name = settings.get_string("hostname").stack()?;
87: let core = MailServer::new(settings)?;
88: let mut server = mailin_embedded::Server::new(core);
89:
90: // TODO: remove unwraps when mailin-embedded bumps with better error handling
91: server.with_name(server_name)
92: .with_ssl(mailin_embedded::SslConfig::None).unwrap()
42ac4c7a9a 2026-10-28 93: .with_addr(listen_on).unwrap();
94: server.serve().unwrap();
95:
96: Ok(())
42ac4c7a9a 2026-10-28 97: } }