api: a log line per HTTP request

Requests weren't logged at all, short of what a handler logs itself. Now a middleware,
outermost on the API (and on a relay-only node's), logs a line per request as web
servers do: method and path (with the query), status, the milliseconds until the answer
began (a stream goes on after), where it came from (the address, or `unix`), and the
user (`-` where none was authenticated). The user comes back on the response:
`basic_auth` puts it there, for a token as for a password or a trusted proxy's header.

At debug, under the target `http` (`RUST_LOG=info,http=debug`, or `PUT /admin/log`):
an open dashboard alone would fill the log at info. With the target off, the request
passes untouched.

1 files changed, 14 insertions, 5 deletions

diff --git a/src/api/auth.rs b/src/api/auth.rs
index ac70b82..f4806ca 100644
--- a/src/api/auth.rs
+++ b/src/api/auth.rs
@@ -211,7 +211,8 @@ fn parse_basic(headers: &HeaderMap) -> Option<(String, String)> {
 }
 
 /// The user a request authenticated as (a request extension, set by [`basic_auth`], or
-/// by `login::bearer` for a token).
+/// by `login::bearer` for a token; on the response too, for the request log,
+/// `request_log`).
 #[derive(Clone, Debug)]
 pub(crate) struct AuthenticatedUser(pub(crate) String);
 
@@ -293,8 +294,8 @@ pub(crate) async fn basic_auth(
     next: axum::middleware::Next,
 ) -> Response {
     // A token, taken already (`login::bearer`).
-    if request.extensions().get::<AuthenticatedUser>().is_some() {
-        return next.run(request).await;
+    if let Some(user) = request.extensions().get::<AuthenticatedUser>().cloned() {
+        return with_user(next.run(request).await, user);
     }
     let from = request
         .extensions()
@@ -343,9 +344,17 @@ pub(crate) async fn basic_auth(
         };
     };
 
-    request.extensions_mut().insert(AuthenticatedUser(user));
+    request
+        .extensions_mut()
+        .insert(AuthenticatedUser(user.clone()));
     request.extensions_mut().insert(via);
-    next.run(request).await
+    with_user(next.run(request).await, AuthenticatedUser(user))
+}
+
+/// `response`, naming the user it answered (`request_log`).
+fn with_user(mut response: Response, user: AuthenticatedUser) -> Response {
+    response.extensions_mut().insert(user);
+    response
 }
 
 #[cfg(test)]