detect broken htpasswd files during startup

1 files changed, 22 insertions, 11 deletions

diff --git a/src/api/auth.rs b/src/api/auth.rs
index de4220c..c07db74 100644
--- a/src/api/auth.rs
+++ b/src/api/auth.rs
@@ -1,3 +1,4 @@
+use anyhow::Context;
 use argon2::{Argon2, password_hash::PasswordVerifier};
 use axum::extract::State;
 use axum::{
@@ -21,18 +22,28 @@ use std::{
 use tokio::sync::Semaphore;
 use tokio::time::sleep;
 
-fn load_users(path: &str) -> std::io::Result<HashMap<String, String>> {
-    let file = File::open(path)?;
+/// The users of an htpasswd file (`user:hash` lines; empty lines and `#` comments are
+/// skipped). A line that is neither, or a file without users, is an error: every request
+/// would be refused, which is better told at startup.
+fn load_users(path: &str) -> anyhow::Result<HashMap<String, String>> {
+    let file = File::open(path).with_context(|| format!("Opening the htpasswd file {path}"))?;
     let reader = BufReader::new(file);
 
     let mut users = HashMap::new();
 
-    for line in reader.lines() {
-        let line = line?;
-
-        if let Some((user, hash)) = line.split_once(':') {
-            users.insert(user.to_owned(), hash.to_owned());
+    for (number, line) in reader.lines().enumerate() {
+        let line = line.with_context(|| format!("Reading the htpasswd file {path}"))?;
+        let line = line.trim();
+        if line.is_empty() || line.starts_with('#') {
+            continue;
         }
+        let Some((user, hash)) = line.split_once(':') else {
+            anyhow::bail!("{path}, line {}: not `user:hash`", number + 1);
+        };
+        users.insert(user.to_owned(), hash.to_owned());
+    }
+    if users.is_empty() {
+        anyhow::bail!("The htpasswd file {path} has no users");
     }
 
     Ok(users)
@@ -49,15 +60,15 @@ pub struct AuthState {
 }
 
 impl AuthState {
-    pub fn new(path: &str) -> Self {
-        let users = load_users(path).unwrap_or_default();
+    pub fn new(path: &str) -> anyhow::Result<Self> {
+        let users = load_users(path)?;
 
-        Self {
+        Ok(Self {
             idle_timeout: Duration::from_secs(300),
             cache: Arc::new(DashMap::new()),
             users: Arc::new(users),
             verify_slots: Arc::new(Semaphore::new(2)),
-        }
+        })
     }
 }