Implemented PGBouncer like database Proxy functionality using Auth_Query

pgcat.proxy.toml

@@ -0,0 +1,33 @@
+# This is an example of the most basic config
+# that will mimic what PgBouncer does in transaction mode with one server.
+
+[general]
+
+log_level = "DEBUG"
+
+host = "0.0.0.0"
+port = 6433
+admin_username = "pgcat"
+admin_password = "pgcat"
+
+[pools.pgml]
+auth_query="SELECT usename, passwd FROM pg_shadow WHERE usename='$1'"
+
+# Be sure to grant this user LOGIN on Postgres
+auth_query_user = "postgres"
+auth_query_password = "postgres"
+
+proxy = true
+
+[pools.pgml.users.0]
+username = "postgres"
+#password = "postgres"
+pool_size = 10
+min_pool_size = 1
+pool_mode = "session"
+
+[pools.pgml.shards.0]
+servers = [
+  ["localhost", 5432, "primary"]
+]
+database = "postgres"

src/client.rs

@@ -20,7 +20,7 @@ use crate::config::{
 use crate::constants::*;
 use crate::messages::*;
 use crate::plugins::PluginOutput;
-use crate::pool::{get_pool, ClientServerMap, ConnectionPool};
+use crate::pool::{get_or_create_pool, get_pool, ClientServerMap, ConnectionPool};
 use crate::query_router::{Command, QueryRouter};
 use crate::server::{Server, ServerParameters};
 use crate::stats::{ClientStats, ServerStats};
@@ -557,7 +557,7 @@ where
         }
         // Authenticate normal user.
         else {
-            let pool = match get_pool(pool_name, username) {
+            let pool = match get_or_create_pool(pool_name, username).await {
                 Some(pool) => pool,
                 None => {
                     error_response(

src/config.rs

@@ -589,6 +589,9 @@ pub struct Pool {
     #[serde(default = "Pool::default_prepared_statements_cache_size")]
     pub prepared_statements_cache_size: usize,
 
+    #[serde(default = "Pool::default_proxy")]
+    pub proxy: bool,
+
     pub plugins: Option<Plugins>,
     pub shards: BTreeMap<String, Shard>,
     pub users: BTreeMap<String, User>,
@@ -642,6 +645,10 @@ impl Pool {
         0
     }
 
+    pub fn default_proxy() -> bool {
+        false
+    }
+
     pub fn validate(&mut self) -> Result<(), Error> {
         match self.default_role.as_ref() {
             "any" => (),
@@ -753,6 +760,7 @@ impl Default for Pool {
             cleanup_server_connections: true,
             log_client_parameter_status_changes: false,
             prepared_statements_cache_size: Self::default_prepared_statements_cache_size(),
+            proxy: Self::default_proxy(),
             plugins: None,
             shards: BTreeMap::from([(String::from("1"), Shard::default())]),
             users: BTreeMap::default(),
@@ -1228,6 +1236,11 @@ impl Config {
                 pool_name,
                 pool_config.pool_mode.to_string()
             );
+            info!(
+                "[pool: {}] Proxy mode: {}",
+                pool_name,
+                pool_config.proxy.to_string()
+            );
             info!(
                 "[pool: {}] Load Balancing mode: {:?}",
                 pool_name, pool_config.load_balancing_mode