From c8b2d48106f92215ca2fbd761f8ac4cf254135e6 Mon Sep 17 00:00:00 2001
From: Bryan Newbold <bnewbold@robocracy.org>
Date: Fri, 21 Jan 2022 16:42:58 -0800
Subject: rust: handle database read-only mode (as 5xx errors, not 4xx)

---
 rust/src/errors.rs | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

(limited to 'rust/src/errors.rs')

diff --git a/rust/src/errors.rs b/rust/src/errors.rs
index e18e660f..ea0f9646 100644
--- a/rust/src/errors.rs
+++ b/rust/src/errors.rs
@@ -81,10 +81,13 @@ pub enum FatcatError {
     // Utf8Decode, StringDecode, Uuid
     BadRequest(String),
 
-    #[fail(display = "unexpected database error: {}", _0)]
+    #[fail(display = "database error: {}", _0)]
     // Diesel constraint that we think is a user error
     ConstraintViolation(String),
 
+    #[fail(display = "database in read-only mode (usually replica or maintenance)")]
+    DatabaseReadOnly,
+
     #[fail(display = "generic database 'not-found'")]
     // This should generally get caught and handled
     DatabaseRowNotFound,
@@ -117,6 +120,11 @@ impl From<diesel::result::Error> for FatcatError {
     fn from(inner: diesel::result::Error) -> FatcatError {
         match inner {
             diesel::result::Error::NotFound => FatcatError::DatabaseRowNotFound,
+            diesel::result::Error::DatabaseError(_, info)
+                if info.message().contains("in a read-only transaction") =>
+            {
+                FatcatError::DatabaseReadOnly
+            }
             diesel::result::Error::DatabaseError(_, _) => {
                 FatcatError::ConstraintViolation(inner.to_string())
             }
-- 
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