From 768227f7aa31e2930e1ff2641c24fbf06fc339fe Mon Sep 17 00:00:00 2001
From: Ruben Beltran del Rio <git@r.bdr.sh>
Date: Sat, 25 Jan 2025 10:50:26 +0100
Subject: Add 1.0.0

---
 src/configuration.rs | 77 +++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 55 insertions(+), 22 deletions(-)

(limited to 'src/configuration.rs')

diff --git a/src/configuration.rs b/src/configuration.rs
index 1437594..af5c46d 100644
--- a/src/configuration.rs
+++ b/src/configuration.rs
@@ -1,45 +1,78 @@
+//! # Configuration
+//!
+//! This module defines the configuration used to initialize both proxies.
+
+use log::error;
 use std::env;
+use std::fmt::Debug;
 use std::sync::Arc;
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+pub enum ConfigurationError {
+    #[error("Environment variable {0} not set.")]
+    MissingEnvVar(String),
+    #[error("Failed to parse {0}.")]
+    ParseError(String),
+}
 
+/// Configuration for any proxy
+#[derive(Debug)]
 pub struct ProxyConfiguration {
     pub local_port: u16,
-    pub remote_domain: String,
+    pub bind_address: String,
+    pub remote_host: String,
     pub remote_port: u16,
     pub protocol: &'static str,
 }
 
+/// Aggregated configuration for both proxies, already in a reference counter.
 pub struct Configuration {
     pub imap_configuration: Arc<ProxyConfiguration>,
     pub smtp_configuration: Arc<ProxyConfiguration>,
 }
 
 impl Configuration {
-    pub fn new() -> Self {
-        Configuration {
+    /// Creates a new configuration object by reading the environment
+    /// variables. Exits if the right ones aren't found.
+    pub fn new() -> Result<Self, ConfigurationError> {
+        Ok(Configuration {
             imap_configuration: Arc::new(ProxyConfiguration {
-                local_port: env::var("LOCAL_IMAP_PORT")
-                    .expect("LOCAL_IMAP_PORT not set")
-                    .parse()
-                    .expect("Invalid LOCAL_IMAP_PORT"),
-                remote_domain: env::var("REMOTE_IMAP_DOMAIN").expect("REMOTE_IMAP_DOMAIN not set"),
-                remote_port: env::var("REMOTE_IMAP_PORT")
-                    .expect("REMOTE_IMAP_PORT not set")
-                    .parse()
-                    .expect("Invalid REMOTE_IMAP_PORT"),
+                local_port: get_env_number("LOCAL_IMAP_PORT", 143)?,
+                bind_address: get_env_var("LOCAL_IMAP_BIND_ADDRESS", Some("0.0.0.0".to_string()))?,
+                remote_host: get_env_var("REMOTE_IMAP_DOMAIN", None)?,
+                remote_port: get_env_number("REMOTE_IMAP_PORT", 993)?,
                 protocol: "IMAP",
             }),
             smtp_configuration: Arc::new(ProxyConfiguration {
-                local_port: env::var("LOCAL_SMTP_PORT")
-                    .expect("LOCAL_SMTP_PORT not set")
-                    .parse()
-                    .expect("Invalid LOCAL_SMTP_PORT"),
-                remote_domain: env::var("REMOTE_SMTP_DOMAIN").expect("REMOTE_SMTP_DOMAIN not set"),
-                remote_port: env::var("REMOTE_SMTP_PORT")
-                    .expect("REMOTE_SMTP_PORT not set")
-                    .parse()
-                    .expect("Invalid REMOTE_SMTP_PORT"),
+                local_port: get_env_number("LOCAL_SMTP_PORT", 25)?,
+                bind_address: get_env_var("LOCAL_SMTP_BIND_ADDRESS", Some("0.0.0.0".to_string()))?,
+                remote_host: get_env_var("REMOTE_SMTP_DOMAIN", None)?,
+                remote_port: get_env_number("REMOTE_SMTP_PORT", 993)?,
                 protocol: "SMTP",
             }),
-        }
+        })
+    }
+}
+
+/// Get an environment variable or return an error.
+fn get_env_var(name: &str, default: Option<String>) -> Result<String, ConfigurationError> {
+    match env::var(name) {
+        Ok(value) => Ok(value),
+        Err(_) => match default {
+            Some(default_value) => Ok(default_value),
+            None => Err(ConfigurationError::MissingEnvVar(name.to_string())),
+        },
+    }
+}
+
+/// Get an environment variable and parse it as a number. Return a default
+/// if not set.
+fn get_env_number(name: &str, default: u16) -> Result<u16, ConfigurationError> {
+    match env::var(name) {
+        Ok(value) => value
+            .parse()
+            .map_err(|_| ConfigurationError::ParseError(name.to_string())),
+        Err(_) => Ok(default),
     }
 }
-- 
cgit