From a1690a76c54005121f7f34221b7da86debab5d4a Mon Sep 17 00:00:00 2001
From: Vita Tauer <v.tauer@tricentis.com>
Date: Wed, 6 Nov 2024 16:40:24 +0100
Subject: [PATCH 1/2] Add 'Fail' mode when no shard selected

---
 pgcat.toml    | 1 +
 src/config.rs | 3 +++
 src/errors.rs | 1 +
 src/pool.rs   | 3 ++-
 4 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/pgcat.toml b/pgcat.toml
index 87f2700c..888a920b 100644
--- a/pgcat.toml
+++ b/pgcat.toml
@@ -179,6 +179,7 @@ primary_reads_enabled = true
 # `random`: picks a shard at random
 # `random_healthy`: picks a shard at random favoring shards with the least number of recent errors
 # `shard_<number>`: e.g. shard_0, shard_4, etc. picks a specific shard, everytime
+# `fail`: fails to pick up shard. (require explicit shard setup)
 # default_shard = "shard_0"
 
 # So what if you wanted to implement a different hashing function,
diff --git a/src/config.rs b/src/config.rs
index b0d98fb5..0fca24d6 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -773,6 +773,7 @@ pub enum DefaultShard {
     Shard(usize),
     Random,
     RandomHealthy,
+    Fail
 }
 impl Default for DefaultShard {
     fn default() -> Self {
@@ -787,6 +788,7 @@ impl serde::Serialize for DefaultShard {
             }
             DefaultShard::Random => serializer.serialize_str("random"),
             DefaultShard::RandomHealthy => serializer.serialize_str("random_healthy"),
+            DefaultShard::Fail => serializer.serialize_str("fail"),
         }
     }
 }
@@ -804,6 +806,7 @@ impl<'de> serde::Deserialize<'de> for DefaultShard {
         match s.as_str() {
             "random" => Ok(DefaultShard::Random),
             "random_healthy" => Ok(DefaultShard::RandomHealthy),
+            "fail" => Ok(DefaultShard::Fail),
             _ => Err(serde::de::Error::custom(
                 "invalid value for no_shard_specified_behavior",
             )),
diff --git a/src/errors.rs b/src/errors.rs
index 13047b4b..8dc93ab3 100644
--- a/src/errors.rs
+++ b/src/errors.rs
@@ -30,6 +30,7 @@ pub enum Error {
     QueryRouterError(String),
     InvalidShardId(usize),
     PreparedStatementError,
+    NoShardSelected
 }
 
 #[derive(Clone, PartialEq, Debug)]
diff --git a/src/pool.rs b/src/pool.rs
index 7915a0a4..76e70a77 100644
--- a/src/pool.rs
+++ b/src/pool.rs
@@ -719,7 +719,8 @@ impl ConnectionPool {
                             .partial_cmp(&a.error_count.load(Ordering::Relaxed))
                             .unwrap()
                     });
-                }
+                },
+                DefaultShard::Fail => return Err(Error::NoShardSelected)
             },
         };
 

From c0ae53484f1cc7a60d96da794d7c1a81580ee152 Mon Sep 17 00:00:00 2001
From: Vita Tauer <v.tauer@tricentis.com>
Date: Mon, 11 Nov 2024 12:09:19 +0100
Subject: [PATCH 2/2] Fixed linter errors

---
 src/config.rs | 2 +-
 src/errors.rs | 2 +-
 src/pool.rs   | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/config.rs b/src/config.rs
index 0fca24d6..b9dc3ee1 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -773,7 +773,7 @@ pub enum DefaultShard {
     Shard(usize),
     Random,
     RandomHealthy,
-    Fail
+    Fail,
 }
 impl Default for DefaultShard {
     fn default() -> Self {
diff --git a/src/errors.rs b/src/errors.rs
index 8dc93ab3..66a5b521 100644
--- a/src/errors.rs
+++ b/src/errors.rs
@@ -30,7 +30,7 @@ pub enum Error {
     QueryRouterError(String),
     InvalidShardId(usize),
     PreparedStatementError,
-    NoShardSelected
+    NoShardSelected,
 }
 
 #[derive(Clone, PartialEq, Debug)]
diff --git a/src/pool.rs b/src/pool.rs
index 76e70a77..5f044d80 100644
--- a/src/pool.rs
+++ b/src/pool.rs
@@ -719,8 +719,8 @@ impl ConnectionPool {
                             .partial_cmp(&a.error_count.load(Ordering::Relaxed))
                             .unwrap()
                     });
-                },
-                DefaultShard::Fail => return Err(Error::NoShardSelected)
+                }
+                DefaultShard::Fail => return Err(Error::NoShardSelected),
             },
         };