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/endpoints.rs | 14 +++++++-------
 rust/src/errors.rs    | 10 +++++++++-
 2 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/rust/src/endpoints.rs b/rust/src/endpoints.rs
index e04e7315..1a37ecfe 100644
--- a/rust/src/endpoints.rs
+++ b/rust/src/endpoints.rs
@@ -36,7 +36,7 @@ macro_rules! generic_auth_err_responses {
         match $val {
             NotFound(_, _) | DatabaseRowNotFound => $resp_type::NotFound($val.into()),
             InvalidCredentials(_) | InsufficientPrivileges(_) => $resp_type::Forbidden($val.into()),
-            DatabaseError(_) | InternalError(_) => {
+            DatabaseError(_) | InternalError(_) | DatabaseReadOnly => {
                 error!("{}", $val);
                 capture_fail(&$val);
                 $resp_type::GenericError($val.into())
@@ -51,7 +51,7 @@ macro_rules! generic_err_responses {
         //use crate::errors::FatcatError::*;
         match $val {
             NotFound(_, _) | DatabaseRowNotFound => $resp_type::NotFound($val.into()),
-            DatabaseError(_) | InternalError(_) => {
+            DatabaseError(_) | InternalError(_) | DatabaseReadOnly => {
                 error!("{}", $val);
                 capture_fail(&$val);
                 $resp_type::GenericError($val.into())
@@ -1100,7 +1100,7 @@ impl Api for Server {
                 NotFound(_, _) | DatabaseRowNotFound => {
                     CreateEditgroupResponse::NotFound(fe.into())
                 }
-                DatabaseError(_) | InternalError(_) => {
+                DatabaseError(_) | InternalError(_) | DatabaseReadOnly => {
                     error!("{}", fe);
                     capture_fail(&fe);
                     CreateEditgroupResponse::GenericError(fe.into())
@@ -1209,7 +1209,7 @@ impl Api for Server {
         {
             Ok(changelog) => GetChangelogResponse::Success(changelog),
             Err(fe) => match fe {
-                DatabaseError(_) | InternalError(_) => {
+                DatabaseError(_) | InternalError(_) | DatabaseReadOnly => {
                     error!("{}", fe);
                     capture_fail(&fe);
                     GetChangelogResponse::GenericError(fe.into())
@@ -1274,7 +1274,7 @@ impl Api for Server {
                 InvalidCredentials(_) | InsufficientPrivileges(_) => {
                     AuthOidcResponse::Forbidden(fe.into())
                 }
-                DatabaseError(_) | InternalError(_) => {
+                DatabaseError(_) | InternalError(_) | DatabaseReadOnly => {
                     error!("{}", fe);
                     capture_fail(&fe);
                     AuthOidcResponse::GenericError(fe.into())
@@ -1322,7 +1322,7 @@ impl Api for Server {
                 InvalidCredentials(_) | InsufficientPrivileges(_) => {
                     AuthCheckResponse::Forbidden(fe.into())
                 }
-                DatabaseError(_) | InternalError(_) => {
+                DatabaseError(_) | InternalError(_) | DatabaseReadOnly => {
                     error!("{}", fe);
                     capture_fail(&fe);
                     AuthCheckResponse::GenericError(fe.into())
@@ -1373,7 +1373,7 @@ impl Api for Server {
                 InvalidCredentials(_) | InsufficientPrivileges(_) => {
                     CreateAuthTokenResponse::Forbidden(fe.into())
                 }
-                DatabaseError(_) | InternalError(_) => {
+                DatabaseError(_) | InternalError(_) | DatabaseReadOnly => {
                     error!("{}", fe);
                     capture_fail(&fe);
                     CreateAuthTokenResponse::GenericError(fe.into())
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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