From fd20bbc6cbed7158e8756fd850d2750bd99b6647 Mon Sep 17 00:00:00 2001
From: Conrad Ludgate <conrad@neon.tech>
Date: Fri, 29 Sep 2023 09:40:27 +0100
Subject: [PATCH] proxy: log params when no endpoint (#5418)

## Problem

Our SNI error dashboard features IP addresses but it's not immediately
clear who that is still (#5369)

## Summary of changes

Log some startup params with this error
---
 proxy/src/auth/backend.rs | 13 +++++++++++++
 proxy/src/proxy.rs        |  9 ++++++++-
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/proxy/src/auth/backend.rs b/proxy/src/auth/backend.rs
index ff73f2b625..03c9029862 100644
--- a/proxy/src/auth/backend.rs
+++ b/proxy/src/auth/backend.rs
@@ -160,6 +160,19 @@ impl BackendType<'_, ClientCredentials<'_>> {
             Test(_) => Some("test".to_owned()),
         }
     }
+
+    /// Get username from the credentials.
+    pub fn get_user(&self) -> &str {
+        use BackendType::*;
+
+        match self {
+            Console(_, creds) => creds.user,
+            Postgres(_, creds) => creds.user,
+            Link(_) => "link",
+            Test(_) => "test",
+        }
+    }
+
     /// Authenticate the client via the requested backend, possibly using credentials.
     #[tracing::instrument(fields(allow_cleartext = allow_cleartext), skip_all)]
     pub async fn authenticate(
diff --git a/proxy/src/proxy.rs b/proxy/src/proxy.rs
index c8f534b2b7..71e00ed58f 100644
--- a/proxy/src/proxy.rs
+++ b/proxy/src/proxy.rs
@@ -697,7 +697,14 @@ impl<S: AsyncRead + AsyncWrite + Unpin> Client<'_, S> {
             .await
         {
             Ok(auth_result) => auth_result,
-            Err(e) => return stream.throw_error(e).await,
+            Err(e) => {
+                let user = creds.get_user();
+                let db = params.get("database");
+                let app = params.get("application_name");
+                let params_span = tracing::info_span!("", ?user, ?db, ?app);
+
+                return stream.throw_error(e).instrument(params_span).await;
+            }
         };
 
         let AuthSuccess {