simplified write!; generic new functions

src/admin.rs

@@ -800,7 +800,7 @@ async fn pause<T>(stream: &mut T, query: &str) -> Result<(), Error>
 where
     T: tokio::io::AsyncWrite + std::marker::Unpin,
 {
-    let parts: Vec<&str> = query.split(",").map(|part| part.trim()).collect();
+    let parts: Vec<&str> = query.split(',').map(|part| part.trim()).collect();
 
     if parts.len() != 2 {
         error_response(
@@ -847,7 +847,7 @@ async fn resume<T>(stream: &mut T, query: &str) -> Result<(), Error>
 where
     T: tokio::io::AsyncWrite + std::marker::Unpin,
 {
-    let parts: Vec<&str> = query.split(",").map(|part| part.trim()).collect();
+    let parts: Vec<&str> = query.split(',').map(|part| part.trim()).collect();
 
     if parts.len() != 2 {
         error_response(

src/auth_passthrough.rs

@@ -12,7 +12,7 @@ pub struct AuthPassthrough {
 
 impl AuthPassthrough {
     /// Initializes an AuthPassthrough.
-    pub fn new(query: &str, user: &str, password: &str) -> Self {
+    pub fn new<S: ToString>(query: S, user: S, password: S) -> Self {
         AuthPassthrough {
             password: password.to_string(),
             query: query.to_string(),

src/client.rs

@@ -123,7 +123,7 @@ pub async fn client_entrypoint(
         // Client requested a TLS connection.
         Ok((ClientConnectionType::Tls, _)) => {
             // TLS settings are configured, will setup TLS now.
-            if tls_certificate != None {
+            if tls_certificate.is_some() {
                 debug!("Accepting TLS request");
 
                 let mut yes = BytesMut::new();
@@ -431,7 +431,7 @@ where
             None => "pgcat",
         };
 
-        let client_identifier = ClientIdentifier::new(&application_name, &username, &pool_name);
+        let client_identifier = ClientIdentifier::new(application_name, username, pool_name);
 
         let admin = ["pgcat", "pgbouncer"]
             .iter()
@@ -930,16 +930,12 @@ where
             }
 
             // Check on plugin results.
-            match plugin_output {
+            if let Some(PluginOutput::Deny(error)) = plugin_output {
-                Some(PluginOutput::Deny(error)) => {
+                self.buffer.clear();
-                    self.buffer.clear();
+                error_response(&mut self.write, &error).await?;
-                    error_response(&mut self.write, &error).await?;
+                plugin_output = None;
-                    plugin_output = None;
+                continue;
-                    continue;
+            }
-                }
-
-                _ => (),
-            };
 
             // Get a pool instance referenced by the most up-to-date
             // pointer. This ensures we always read the latest config
@@ -1213,7 +1209,7 @@ where
 
                 // Safe to unwrap because we know this message has a certain length and has the code
                 // This reads the first byte without advancing the internal pointer and mutating the bytes
-                let code = *message.get(0).unwrap() as char;
+                let code = *message.first().unwrap() as char;
 
                 trace!("Message: {}", code);
 
@@ -1331,14 +1327,11 @@ where
                             let close: Close = (&message).try_into()?;
 
                             if close.is_prepared_statement() && !close.anonymous() {
-                                match self.prepared_statements.get(&close.name) {
+                                if let Some(parse) = self.prepared_statements.get(&close.name) {
-                                    Some(parse) => {
+                                    server.will_close(&parse.generated_name);
-                                        server.will_close(&parse.generated_name);
+                                } else {
-                                    }
-
                                     // A prepared statement slipped through? Not impossible, since we don't support PREPARE yet.
-                                    None => (),
+                                }
-                                };
                             }
                         }
 
@@ -1376,7 +1369,7 @@ where
 
                         self.buffer.put(&message[..]);
 
-                        let first_message_code = (*self.buffer.get(0).unwrap_or(&0)) as char;
+                        let first_message_code = (*self.buffer.first().unwrap_or(&0)) as char;
 
                         // Almost certainly true
                         if first_message_code == 'P' && !prepared_statements_enabled {

src/cmd_args.rs

@@ -25,7 +25,7 @@ pub struct Args {
 }
 
 pub fn parse() -> Args {
-    return Args::parse();
+    Args::parse()
 }
 
 #[derive(ValueEnum, Clone, Debug)]

src/config.rs

@@ -217,19 +217,15 @@ impl Default for User {
 
 impl User {
     fn validate(&self) -> Result<(), Error> {
-        match self.min_pool_size {
+        if let Some(min_pool_size) = self.min_pool_size {
-            Some(min_pool_size) => {
+            if min_pool_size > self.pool_size {
-                if min_pool_size > self.pool_size {
+                error!(
-                    error!(
+                    "min_pool_size of {} cannot be larger than pool_size of {}",
-                        "min_pool_size of {} cannot be larger than pool_size of {}",
+                    min_pool_size, self.pool_size
-                        min_pool_size, self.pool_size
+                );
-                    );
+                return Err(Error::BadConfig);
-                    return Err(Error::BadConfig);
-                }
             }
-
+        }
-            None => (),
-        };
 
         Ok(())
     }
@@ -631,9 +627,9 @@ impl Pool {
             Some(key) => {
                 // No quotes in the key so we don't have to compare quoted
                 // to unquoted idents.
-                let key = key.replace("\"", "");
+                let key = key.replace('\"', "");
 
-                if key.split(".").count() != 2 {
+                if key.split('.').count() != 2 {
                     error!(
                         "automatic_sharding_key '{}' must be fully qualified, e.g. t.{}`",
                         key, key
@@ -646,7 +642,7 @@ impl Pool {
             None => None,
         };
 
-        for (_, user) in &self.users {
+        for user in self.users.values() {
             user.validate()?;
         }
 
@@ -818,8 +814,8 @@ pub struct Query {
 impl Query {
     pub fn substitute(&mut self, db: &str, user: &str) {
         for col in self.result.iter_mut() {
-            for i in 0..col.len() {
+            for c in col {
-                col[i] = col[i].replace("${USER}", user).replace("${DATABASE}", db);
+                *c = c.replace("${USER}", user).replace("${DATABASE}", db);
             }
         }
     }
@@ -929,8 +925,8 @@ impl From<&Config> for std::collections::HashMap<String, String> {
                     (
                         format!("pools.{:?}.users", pool_name),
                         pool.users
-                            .iter()
+                            .values()
-                            .map(|(_username, user)| &user.username)
+                            .map(|user| &user.username)
                             .cloned()
                             .collect::<Vec<String>>()
                             .join(", "),
@@ -1015,13 +1011,9 @@ impl Config {
             Some(tls_certificate) => {
                 info!("TLS certificate: {}", tls_certificate);
 
-                match self.general.tls_private_key.clone() {
+                if let Some(tls_private_key) = self.general.tls_private_key.clone() {
-                    Some(tls_private_key) => {
+                    info!("TLS private key: {}", tls_private_key);
-                        info!("TLS private key: {}", tls_private_key);
+                    info!("TLS support is enabled");
-                        info!("TLS support is enabled");
-                    }
-
-                    None => (),
                 }
             }
 
@@ -1056,8 +1048,8 @@ impl Config {
                 pool_name,
                 pool_config
                     .users
-                    .iter()
+                    .values()
-                    .map(|(_, user_cfg)| user_cfg.pool_size)
+                    .map(|user_cfg| user_cfg.pool_size)
                     .sum::<u32>()
                     .to_string()
             );
@@ -1214,35 +1206,32 @@ impl Config {
         }
 
         // Validate TLS!
-        match self.general.tls_certificate.clone() {
+        if let Some(tls_certificate) = self.general.tls_certificate.clone() {
-            Some(tls_certificate) => {
+            match load_certs(Path::new(&tls_certificate)) {
-                match load_certs(Path::new(&tls_certificate)) {
+                Ok(_) => {
-                    Ok(_) => {
+                    // Cert is okay, but what about the private key?
-                        // Cert is okay, but what about the private key?
+                    match self.general.tls_private_key.clone() {
-                        match self.general.tls_private_key.clone() {
+                        Some(tls_private_key) => match load_keys(Path::new(&tls_private_key)) {
-                            Some(tls_private_key) => match load_keys(Path::new(&tls_private_key)) {
+                            Ok(_) => (),
-                                Ok(_) => (),
+                            Err(err) => {
-                                Err(err) => {
+                                error!("tls_private_key is incorrectly configured: {:?}", err);
-                                    error!("tls_private_key is incorrectly configured: {:?}", err);
-                                    return Err(Error::BadConfig);
-                                }
-                            },
-
-                            None => {
-                                error!("tls_certificate is set, but the tls_private_key is not");
                                 return Err(Error::BadConfig);
                             }
-                        };
+                        },
-                    }
 
-                    Err(err) => {
+                        None => {
-                        error!("tls_certificate is incorrectly configured: {:?}", err);
+                            error!("tls_certificate is set, but the tls_private_key is not");
-                        return Err(Error::BadConfig);
+                            return Err(Error::BadConfig);
-                    }
+                        }
+                    };
+                }
+
+                Err(err) => {
+                    error!("tls_certificate is incorrectly configured: {:?}", err);
+                    return Err(Error::BadConfig);
                 }
             }
-            None => (),
+        }
-        };
 
         for pool in self.pools.values_mut() {
             pool.validate()?;

src/errors.rs

@@ -37,11 +37,11 @@ pub struct ClientIdentifier {
 }
 
 impl ClientIdentifier {
-    pub fn new(application_name: &str, username: &str, pool_name: &str) -> ClientIdentifier {
+    pub fn new<S: ToString>(application_name: S, username: S, pool_name: S) -> ClientIdentifier {
         ClientIdentifier {
-            application_name: application_name.into(),
+            application_name: application_name.to_string(),
-            username: username.into(),
+            username: username.to_string(),
-            pool_name: pool_name.into(),
+            pool_name: pool_name.to_string(),
         }
     }
 }
@@ -63,10 +63,10 @@ pub struct ServerIdentifier {
 }
 
 impl ServerIdentifier {
-    pub fn new(username: &str, database: &str) -> ServerIdentifier {
+    pub fn new<S: ToString>(username: S, database: S) -> ServerIdentifier {
         ServerIdentifier {
-            username: username.into(),
+            username: username.to_string(),
-            database: database.into(),
+            database: database.to_string(),
         }
     }
 }
@@ -84,41 +84,36 @@ impl std::fmt::Display for ServerIdentifier {
 impl std::fmt::Display for Error {
     fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
         match &self {
-            &Error::ClientSocketError(error, client_identifier) => write!(
+            Error::ClientSocketError(error, client_identifier) => {
-                f,
+                write!(f, "Error reading {error} from client {client_identifier}",)
-                "Error reading {} from client {}",
-                error, client_identifier
-            ),
-            &Error::ClientGeneralError(error, client_identifier) => {
-                write!(f, "{} {}", error, client_identifier)
             }
-            &Error::ClientAuthImpossible(username) => write!(
+            Error::ClientGeneralError(error, client_identifier) => {
+                write!(f, "{error} {client_identifier}")
+            }
+            Error::ClientAuthImpossible(username) => write!(
                 f,
                 "Client auth not possible, \
-                no cleartext password set for username: {} \
+                no cleartext password set for username: {username} \
                 in config and auth passthrough (query_auth) \
-                is not set up.",
+                is not set up."
-                username
             ),
-            &Error::ClientAuthPassthroughError(error, client_identifier) => write!(
+            Error::ClientAuthPassthroughError(error, client_identifier) => write!(
                 f,
                 "No cleartext password set, \
                     and no auth passthrough could not \
-                    obtain the hash from server for {}, \
+                    obtain the hash from server for {client_identifier}, \
-                    the error was: {}",
+                    the error was: {error}",
-                client_identifier, error
             ),
-            &Error::ServerStartupError(error, server_identifier) => write!(
+            Error::ServerStartupError(error, server_identifier) => write!(
                 f,
-                "Error reading {} on server startup {}",
+                "Error reading {error} on server startup {server_identifier}",
-                error, server_identifier,
             ),
-            &Error::ServerAuthError(error, server_identifier) => {
+            Error::ServerAuthError(error, server_identifier) => {
-                write!(f, "{} for {}", error, server_identifier,)
+                write!(f, "{error} for {server_identifier}")
             }
 
             // The rest can use Debug.
-            err => write!(f, "{:?}", err),
+            err => write!(f, "{err:?}"),
         }
     }
 }

src/lib.rs

@@ -25,18 +25,11 @@ pub mod tls;
 ///
 /// * `duration` - A duration of time
 pub fn format_duration(duration: &chrono::Duration) -> String {
-    let milliseconds = format!("{:0>3}", duration.num_milliseconds() % 1000);
+    let milliseconds = duration.num_milliseconds() % 1000;
+    let seconds = duration.num_seconds() % 60;
+    let minutes = duration.num_minutes() % 60;
+    let hours = duration.num_hours() % 24;
+    let days = duration.num_days();
 
-    let seconds = format!("{:0>2}", duration.num_seconds() % 60);
+    format!("{days}d {hours:0>2}:{minutes:0>2}:{seconds:0>2}.{milliseconds:0>3}")
-
-    let minutes = format!("{:0>2}", duration.num_minutes() % 60);
-
-    let hours = format!("{:0>2}", duration.num_hours() % 24);
-
-    let days = duration.num_days().to_string();
-
-    format!(
-        "{}d {}:{}:{}.{}",
-        days, hours, minutes, seconds, milliseconds
-    )
 }

src/main.rs

@@ -160,10 +160,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
             }
         };
 
-        tokio::task::spawn(async move {
+        Collector::collect();
-            let mut stats_collector = Collector::default();
-            stats_collector.collect().await;
-        });
 
         info!("Config autoreloader: {}", match config.general.autoreload {
             Some(interval) => format!("{} ms", interval),

src/messages.rs

@@ -156,12 +156,10 @@ where
 
     match stream.write_all(&startup).await {
         Ok(_) => Ok(()),
-        Err(err) => {
+        Err(err) => Err(Error::SocketError(format!(
-            return Err(Error::SocketError(format!(
+            "Error writing startup to server socket - Error: {:?}",
-                "Error writing startup to server socket - Error: {:?}",
+            err
-                err
+        ))),
-            )))
-        }
     }
 }
 
@@ -237,8 +235,8 @@ pub fn md5_hash_password(user: &str, password: &str, salt: &[u8]) -> Vec<u8> {
     let mut md5 = Md5::new();
 
     // First pass
-    md5.update(&password.as_bytes());
+    md5.update(password.as_bytes());
-    md5.update(&user.as_bytes());
+    md5.update(user.as_bytes());
 
     let output = md5.finalize_reset();
 
@@ -274,7 +272,7 @@ where
 {
     let password = md5_hash_password(user, password, salt);
 
-    let mut message = BytesMut::with_capacity(password.len() as usize + 5);
+    let mut message = BytesMut::with_capacity(password.len() + 5);
 
     message.put_u8(b'p');
     message.put_i32(password.len() as i32 + 4);
@@ -288,7 +286,7 @@ where
     S: tokio::io::AsyncWrite + std::marker::Unpin,
 {
     let password = md5_hash_second_pass(hash, salt);
-    let mut message = BytesMut::with_capacity(password.len() as usize + 5);
+    let mut message = BytesMut::with_capacity(password.len() + 5);
 
     message.put_u8(b'p');
     message.put_i32(password.len() as i32 + 4);
@@ -509,7 +507,7 @@ pub fn data_row_nullable(row: &Vec<Option<String>>) -> BytesMut {
             data_row.put_i32(column.len() as i32);
             data_row.put_slice(column);
         } else {
-            data_row.put_i32(-1 as i32);
+            data_row.put_i32(-1_i32);
         }
     }
 
@@ -564,12 +562,10 @@ where
 {
     match stream.write_all(&buf).await {
         Ok(_) => Ok(()),
-        Err(err) => {
+        Err(err) => Err(Error::SocketError(format!(
-            return Err(Error::SocketError(format!(
+            "Error writing to socket - Error: {:?}",
-                "Error writing to socket - Error: {:?}",
+            err
-                err
+        ))),
-            )))
-        }
     }
 }
 
@@ -580,12 +576,10 @@ where
 {
     match stream.write_all(buf).await {
         Ok(_) => Ok(()),
-        Err(err) => {
+        Err(err) => Err(Error::SocketError(format!(
-            return Err(Error::SocketError(format!(
+            "Error writing to socket - Error: {:?}",
-                "Error writing to socket - Error: {:?}",
+            err
-                err
+        ))),
-            )))
-        }
     }
 }
 
@@ -596,19 +590,15 @@ where
     match stream.write_all(buf).await {
         Ok(_) => match stream.flush().await {
             Ok(_) => Ok(()),
-            Err(err) => {
+            Err(err) => Err(Error::SocketError(format!(
-                return Err(Error::SocketError(format!(
+                "Error flushing socket - Error: {:?}",
-                    "Error flushing socket - Error: {:?}",
-                    err
-                )))
-            }
-        },
-        Err(err) => {
-            return Err(Error::SocketError(format!(
-                "Error writing to socket - Error: {:?}",
                 err
-            )))
+            ))),
-        }
+        },
+        Err(err) => Err(Error::SocketError(format!(
+            "Error writing to socket - Error: {:?}",
+            err
+        ))),
     }
 }
 
@@ -723,7 +713,7 @@ impl BytesMutReader for Cursor<&BytesMut> {
         let mut buf = vec![];
         match self.read_until(b'\0', &mut buf) {
             Ok(_) => Ok(String::from_utf8_lossy(&buf[..buf.len() - 1]).to_string()),
-            Err(err) => return Err(Error::ParseBytesError(err.to_string())),
+            Err(err) => Err(Error::ParseBytesError(err.to_string())),
         }
     }
 }

src/mirrors.rs

@@ -142,12 +142,12 @@ impl MirroringManager {
         });
 
         Self {
-            byte_senders: byte_senders,
+            byte_senders,
             disconnect_senders: exit_senders,
         }
     }
 
-    pub fn send(self: &mut Self, bytes: &BytesMut) {
+    pub fn send(&mut self, bytes: &BytesMut) {
         // We want to avoid performing an allocation if we won't be able to send the message
         // There is a possibility of a race here where we check the capacity and then the channel is
         // closed or the capacity is reduced to 0, but mirroring is best effort anyway
@@ -169,7 +169,7 @@ impl MirroringManager {
         });
     }
 
-    pub fn disconnect(self: &mut Self) {
+    pub fn disconnect(&mut self) {
         self.disconnect_senders
             .iter_mut()
             .for_each(|sender| match sender.try_send(()) {

src/plugins/intercept.rs

@@ -92,7 +92,7 @@ impl<'a> Plugin for Intercept<'a> {
                             .map(|s| {
                                 let s = s.as_str().to_string();
 
-                                if s == "" {
+                                if s.is_empty() {
                                     None
                                 } else {
                                     Some(s)

src/plugins/mod.rs

@@ -30,6 +30,7 @@ pub enum PluginOutput {
     Intercept(BytesMut),
 }
 
+#[allow(clippy::ptr_arg)]
 #[async_trait]
 pub trait Plugin {
     // Run before the query is sent to the server.

src/plugins/prewarmer.rs

@@ -20,7 +20,7 @@ impl<'a> Prewarmer<'a> {
                 self.server.address(),
                 query
             );
-            self.server.query(&query).await?;
+            self.server.query(query).await?;
         }
 
         Ok(())

src/plugins/query_logger.rs

@@ -31,7 +31,7 @@ impl<'a> Plugin for QueryLogger<'a> {
             .map(|q| q.to_string())
             .collect::<Vec<String>>()
             .join("; ");
-        info!("[pool: {}][user: {}] {}", self.user, self.db, query);
+        info!("[pool: {}][user: {}] {}", self.db, self.user, query);
 
         Ok(PluginOutput::Allow)
     }

src/plugins/table_access.rs

@@ -30,27 +30,22 @@ impl<'a> Plugin for TableAccess<'a> {
             return Ok(PluginOutput::Allow);
         }
 
-        let mut found = None;
+        let control_flow = visit_relations(ast, |relation| {
-
-        visit_relations(ast, |relation| {
             let relation = relation.to_string();
-            let parts = relation.split(".").collect::<Vec<&str>>();
+            let table_name = relation.split('.').last().unwrap().to_string();
-            let table_name = parts.last().unwrap();
 
-            if self.tables.contains(&table_name.to_string()) {
+            if self.tables.contains(&table_name) {
-                found = Some(table_name.to_string());
+                ControlFlow::Break(table_name)
-                ControlFlow::<()>::Break(())
             } else {
-                ControlFlow::<()>::Continue(())
+                ControlFlow::Continue(())
             }
         });
 
-        if let Some(found) = found {
+        if let ControlFlow::Break(found) = control_flow {
-            debug!("Blocking access to table \"{}\"", found);
+            debug!("Blocking access to table \"{found}\"");
 
             Ok(PluginOutput::Deny(format!(
-                "permission for table \"{}\" denied",
+                "permission for table \"{found}\" denied",
-                found
             )))
         } else {
             Ok(PluginOutput::Allow)

src/pool.rs

@@ -229,20 +229,17 @@ impl ConnectionPool {
                 let old_pool_ref = get_pool(pool_name, &user.username);
                 let identifier = PoolIdentifier::new(pool_name, &user.username);
 
-                match old_pool_ref {
+                if let Some(pool) = old_pool_ref {
-                    Some(pool) => {
+                    // If the pool hasn't changed, get existing reference and insert it into the new_pools.
-                        // If the pool hasn't changed, get existing reference and insert it into the new_pools.
+                    // We replace all pools at the end, but if the reference is kept, the pool won't get re-created (bb8).
-                        // We replace all pools at the end, but if the reference is kept, the pool won't get re-created (bb8).
+                    if pool.config_hash == new_pool_hash_value {
-                        if pool.config_hash == new_pool_hash_value {
+                        info!(
-                            info!(
+                            "[pool: {}][user: {}] has not changed",
-                                "[pool: {}][user: {}] has not changed",
+                            pool_name, user.username
-                                pool_name, user.username
+                        );
-                            );
+                        new_pools.insert(identifier.clone(), pool.clone());
-                            new_pools.insert(identifier.clone(), pool.clone());
+                        continue;
-                            continue;
-                        }
                     }
-                    None => (),
                 }
 
                 info!(
@@ -628,7 +625,7 @@ impl ConnectionPool {
             let mut force_healthcheck = false;
 
             if self.is_banned(address) {
-                if self.try_unban(&address).await {
+                if self.try_unban(address).await {
                     force_healthcheck = true;
                 } else {
                     debug!("Address {:?} is banned", address);
@@ -748,8 +745,8 @@ impl ConnectionPool {
         // Don't leave a bad connection in the pool.
         server.mark_bad();
 
-        self.ban(&address, BanReason::FailedHealthCheck, Some(client_info));
+        self.ban(address, BanReason::FailedHealthCheck, Some(client_info));
-        return false;
+        false
     }
 
     /// Ban an address (i.e. replica). It no longer will serve
@@ -861,10 +858,10 @@ impl ConnectionPool {
         let guard = self.banlist.read();
         for banlist in guard.iter() {
             for (address, (reason, timestamp)) in banlist.iter() {
-                bans.push((address.clone(), (reason.clone(), timestamp.clone())));
+                bans.push((address.clone(), (reason.clone(), *timestamp)));
             }
         }
-        return bans;
+        bans
     }
 
     /// Get the address from the host url
@@ -921,7 +918,7 @@ impl ConnectionPool {
         }
         let busy = provisioned - idle;
         debug!("{:?} has {:?} busy connections", address, busy);
-        return busy;
+        busy
     }
 }
 

src/query_router.rs

@@ -67,6 +67,7 @@ static CUSTOM_SQL_REGEX_SET: OnceCell<RegexSet> = OnceCell::new();
 static CUSTOM_SQL_REGEX_LIST: OnceCell<Vec<Regex>> = OnceCell::new();
 
 /// The query router.
+#[derive(Default)]
 pub struct QueryRouter {
     /// Which shard we should be talking to right now.
     active_shard: Option<usize>,
@@ -91,7 +92,7 @@ impl QueryRouter {
     /// One-time initialization of regexes
     /// that parse our custom SQL protocol.
     pub fn setup() -> bool {
-        let set = match RegexSet::new(&CUSTOM_SQL_REGEXES) {
+        let set = match RegexSet::new(CUSTOM_SQL_REGEXES) {
             Ok(rgx) => rgx,
             Err(err) => {
                 error!("QueryRouter::setup Could not compile regex set: {:?}", err);
@@ -116,15 +117,8 @@ impl QueryRouter {
 
     /// Create a new instance of the query router.
     /// Each client gets its own.
-    pub fn new() -> QueryRouter {
+    pub fn new() -> Self {
-        QueryRouter {
+        Self::default()
-            active_shard: None,
-            active_role: None,
-            query_parser_enabled: None,
-            primary_reads_enabled: None,
-            pool_settings: PoolSettings::default(),
-            placeholders: Vec::new(),
-        }
     }
 
     /// Pool settings can change because of a config reload.
@@ -132,7 +126,7 @@ impl QueryRouter {
         self.pool_settings = pool_settings;
     }
 
-    pub fn pool_settings<'a>(&'a self) -> &'a PoolSettings {
+    pub fn pool_settings(&self) -> &PoolSettings {
         &self.pool_settings
     }
 
@@ -143,7 +137,7 @@ impl QueryRouter {
         let code = message_cursor.get_u8() as char;
 
         // Check for any sharding regex matches in any queries
-        match code as char {
+        match code {
             // For Parse and Query messages peek to see if they specify a shard_id as a comment early in the statement
             'P' | 'Q' => {
                 if self.pool_settings.shard_id_regex.is_some()
@@ -397,14 +391,10 @@ impl QueryRouter {
                             // or discard shard selection. If they point to the same shard though,
                             // we can let them through as-is.
                             // This is basically building a database now :)
-                            match self.infer_shard(query) {
+                            if let Some(shard) = self.infer_shard(query) {
-                                Some(shard) => {
+                                self.active_shard = Some(shard);
-                                    self.active_shard = Some(shard);
+                                debug!("Automatically using shard: {:?}", self.active_shard);
-                                    debug!("Automatically using shard: {:?}", self.active_shard);
+                            }
-                                }
-
-                                None => (),
-                            };
                         }
 
                         None => (),
@@ -576,8 +566,8 @@ impl QueryRouter {
             .automatic_sharding_key
             .as_ref()
             .unwrap()
-            .split(".")
+            .split('.')
-            .map(|ident| Ident::new(ident))
+            .map(Ident::new)
             .collect::<Vec<Ident>>();
 
         // Sharding key must be always fully qualified
@@ -593,7 +583,7 @@ impl QueryRouter {
                 Expr::Identifier(ident) => {
                     // Only if we're dealing with only one table
                     // and there is no ambiguity
-                    if &ident.value == &sharding_key[1].value {
+                    if ident.value == sharding_key[1].value {
                         // Sharding key is unique enough, don't worry about
                         // table names.
                         if &sharding_key[0].value == "*" {
@@ -606,13 +596,13 @@ impl QueryRouter {
                                 //      SELECT * FROM t WHERE sharding_key = 5
                                 // Make sure the table name from the sharding key matches
                                 // the table name from the query.
-                                found = &sharding_key[0].value == &table[0].value;
+                                found = sharding_key[0].value == table[0].value;
                             } else if table.len() == 2 {
                                 // Table name is fully qualified with the schema: e.g.
                                 //      SELECT * FROM public.t WHERE sharding_key = 5
                                 // Ignore the schema (TODO: at some point, we want schema support)
                                 // and use the table name only.
-                                found = &sharding_key[0].value == &table[1].value;
+                                found = sharding_key[0].value == table[1].value;
                             } else {
                                 debug!("Got table name with more than two idents, which is not possible");
                             }
@@ -624,8 +614,8 @@ impl QueryRouter {
                     // The key is fully qualified in the query,
                     // it will exist or Postgres will throw an error.
                     if idents.len() == 2 {
-                        found = &sharding_key[0].value == &idents[0].value
+                        found = sharding_key[0].value == idents[0].value
-                            && &sharding_key[1].value == &idents[1].value;
+                            && sharding_key[1].value == idents[1].value;
                     }
                     // TODO: key can have schema as well, e.g. public.data.id (len == 3)
                 }
@@ -657,7 +647,7 @@ impl QueryRouter {
                 }
 
                 Expr::Value(Value::Placeholder(placeholder)) => {
-                    match placeholder.replace("$", "").parse::<i16>() {
+                    match placeholder.replace('$', "").parse::<i16>() {
                         Ok(placeholder) => result.push(ShardingKey::Placeholder(placeholder)),
                         Err(_) => {
                             debug!(
@@ -683,12 +673,9 @@ impl QueryRouter {
 
         match &*query.body {
             SetExpr::Query(query) => {
-                match self.infer_shard(&*query) {
+                if let Some(shard) = self.infer_shard(query) {
-                    Some(shard) => {
+                    shards.insert(shard);
-                        shards.insert(shard);
+                }
-                    }
-                    None => (),
-                };
             }
 
             // SELECT * FROM ...
@@ -698,38 +685,22 @@ impl QueryRouter {
                 let mut table_names = Vec::new();
 
                 for table in select.from.iter() {
-                    match &table.relation {
+                    if let TableFactor::Table { name, .. } = &table.relation {
-                        TableFactor::Table { name, .. } => {
+                        table_names.push(name.0.clone());
-                            table_names.push(name.0.clone());
+                    }
-                        }
-
-                        _ => (),
-                    };
 
                     // Get table names from all the joins.
                     for join in table.joins.iter() {
-                        match &join.relation {
+                        if let TableFactor::Table { name, .. } = &join.relation {
-                            TableFactor::Table { name, .. } => {
+                            table_names.push(name.0.clone());
-                                table_names.push(name.0.clone());
+                        }
-                            }
-
-                            _ => (),
-                        };
 
                         // We can filter results based on join conditions, e.g.
                         // SELECT * FROM t INNER JOIN B ON B.sharding_key = 5;
-                        match &join.join_operator {
+                        if let JoinOperator::Inner(JoinConstraint::On(expr)) = &join.join_operator {
-                            JoinOperator::Inner(inner_join) => match &inner_join {
+                            // Parse the selection criteria later.
-                                JoinConstraint::On(expr) => {
+                            exprs.push(expr.clone());
-                                    // Parse the selection criteria later.
+                        }
-                                    exprs.push(expr.clone());
-                                }
-
-                                _ => (),
-                            },
-
-                            _ => (),
-                        };
                     }
                 }
 
@@ -803,16 +774,16 @@ impl QueryRouter {
                 db: &self.pool_settings.db,
             };
 
-            let _ = query_logger.run(&self, ast).await;
+            let _ = query_logger.run(self, ast).await;
         }
 
         if let Some(ref intercept) = plugins.intercept {
             let mut intercept = Intercept {
                 enabled: intercept.enabled,
-                config: &intercept,
+                config: intercept,
             };
 
-            let result = intercept.run(&self, ast).await;
+            let result = intercept.run(self, ast).await;
 
             if let Ok(PluginOutput::Intercept(output)) = result {
                 return Ok(PluginOutput::Intercept(output));
@@ -825,7 +796,7 @@ impl QueryRouter {
                 tables: &table_access.tables,
             };
 
-            let result = table_access.run(&self, ast).await;
+            let result = table_access.run(self, ast).await;
 
             if let Ok(PluginOutput::Deny(error)) = result {
                 return Ok(PluginOutput::Deny(error));
@@ -861,7 +832,7 @@ impl QueryRouter {
 
     /// Should we attempt to parse queries?
     pub fn query_parser_enabled(&self) -> bool {
-        let enabled = match self.query_parser_enabled {
+        match self.query_parser_enabled {
             None => {
                 debug!(
                     "Using pool settings, query_parser_enabled: {}",
@@ -877,9 +848,7 @@ impl QueryRouter {
                 );
                 value
             }
-        };
+        }
-
-        enabled
     }
 
     pub fn primary_reads_enabled(&self) -> bool {
@@ -910,10 +879,14 @@ mod test {
     fn test_infer_replica() {
         QueryRouter::setup();
         let mut qr = QueryRouter::new();
-        assert!(qr.try_execute_command(&simple_query("SET SERVER ROLE TO 'auto'")) != None);
+        assert!(qr
+            .try_execute_command(&simple_query("SET SERVER ROLE TO 'auto'"))
+            .is_some());
         assert!(qr.query_parser_enabled());
 
-        assert!(qr.try_execute_command(&simple_query("SET PRIMARY READS TO off")) != None);
+        assert!(qr
+            .try_execute_command(&simple_query("SET PRIMARY READS TO off"))
+            .is_some());
 
         let queries = vec![
             simple_query("SELECT * FROM items WHERE id = 5"),
@@ -954,7 +927,9 @@ mod test {
         QueryRouter::setup();
         let mut qr = QueryRouter::new();
         let query = simple_query("SELECT * FROM items WHERE id = 5");
-        assert!(qr.try_execute_command(&simple_query("SET PRIMARY READS TO on")) != None);
+        assert!(qr
+            .try_execute_command(&simple_query("SET PRIMARY READS TO on"))
+            .is_some());
 
         assert!(qr.infer(&QueryRouter::parse(&query).unwrap()).is_ok());
         assert_eq!(qr.role(), None);
@@ -965,7 +940,9 @@ mod test {
         QueryRouter::setup();
         let mut qr = QueryRouter::new();
         qr.try_execute_command(&simple_query("SET SERVER ROLE TO 'auto'"));
-        assert!(qr.try_execute_command(&simple_query("SET PRIMARY READS TO off")) != None);
+        assert!(qr
+            .try_execute_command(&simple_query("SET PRIMARY READS TO off"))
+            .is_some());
 
         let prepared_stmt = BytesMut::from(
             &b"WITH t AS (SELECT * FROM items WHERE name = $1) SELECT * FROM t WHERE id = $2\0"[..],
@@ -1133,9 +1110,11 @@ mod test {
         QueryRouter::setup();
         let mut qr = QueryRouter::new();
         let query = simple_query("SET SERVER ROLE TO 'auto'");
-        assert!(qr.try_execute_command(&simple_query("SET PRIMARY READS TO off")) != None);
+        assert!(qr
+            .try_execute_command(&simple_query("SET PRIMARY READS TO off"))
+            .is_some());
 
-        assert!(qr.try_execute_command(&query) != None);
+        assert!(qr.try_execute_command(&query).is_some());
         assert!(qr.query_parser_enabled());
         assert_eq!(qr.role(), None);
 
@@ -1149,7 +1128,7 @@ mod test {
 
         assert!(qr.query_parser_enabled());
         let query = simple_query("SET SERVER ROLE TO 'default'");
-        assert!(qr.try_execute_command(&query) != None);
+        assert!(qr.try_execute_command(&query).is_some());
         assert!(!qr.query_parser_enabled());
     }
 
@@ -1194,11 +1173,11 @@ mod test {
         assert!(!qr.primary_reads_enabled());
 
         let q1 = simple_query("SET SERVER ROLE TO 'primary'");
-        assert!(qr.try_execute_command(&q1) != None);
+        assert!(qr.try_execute_command(&q1).is_some());
         assert_eq!(qr.active_role.unwrap(), Role::Primary);
 
         let q2 = simple_query("SET SERVER ROLE TO 'default'");
-        assert!(qr.try_execute_command(&q2) != None);
+        assert!(qr.try_execute_command(&q2).is_some());
         assert_eq!(qr.active_role.unwrap(), pool_settings.default_role);
     }
 
@@ -1263,17 +1242,17 @@ mod test {
 
         // Make sure setting it works
         let q1 = simple_query("/* shard_id: 1 */ select 1 from foo;");
-        assert!(qr.try_execute_command(&q1) == None);
+        assert!(qr.try_execute_command(&q1).is_none());
         assert_eq!(qr.active_shard, Some(1));
 
         // And make sure changing it works
         let q2 = simple_query("/* shard_id: 0 */ select 1 from foo;");
-        assert!(qr.try_execute_command(&q2) == None);
+        assert!(qr.try_execute_command(&q2).is_none());
         assert_eq!(qr.active_shard, Some(0));
 
         // Validate setting by shard with expected shard copied from sharding.rs tests
         let q2 = simple_query("/* sharding_key: 6 */ select 1 from foo;");
-        assert!(qr.try_execute_command(&q2) == None);
+        assert!(qr.try_execute_command(&q2).is_none());
         assert_eq!(qr.active_shard, Some(2));
     }
 
@@ -1411,9 +1390,11 @@ mod test {
         };
 
         QueryRouter::setup();
-        let mut pool_settings = PoolSettings::default();
+        let pool_settings = PoolSettings {
-        pool_settings.query_parser_enabled = true;
+            query_parser_enabled: true,
-        pool_settings.plugins = Some(plugins);
+            plugins: Some(plugins),
+            ..Default::default()
+        };
 
         let mut qr = QueryRouter::new();
         qr.update_pool_settings(pool_settings);

src/scram.rs

@@ -79,12 +79,12 @@ impl ScramSha256 {
         let server_message = Message::parse(message)?;
 
         if !server_message.nonce.starts_with(&self.nonce) {
-            return Err(Error::ProtocolSyncError(format!("SCRAM")));
+            return Err(Error::ProtocolSyncError("SCRAM".to_string()));
         }
 
         let salt = match general_purpose::STANDARD.decode(&server_message.salt) {
             Ok(salt) => salt,
-            Err(_) => return Err(Error::ProtocolSyncError(format!("SCRAM"))),
+            Err(_) => return Err(Error::ProtocolSyncError("SCRAM".to_string())),
         };
 
         let salted_password = Self::hi(
@@ -166,9 +166,9 @@ impl ScramSha256 {
     pub fn finish(&mut self, message: &BytesMut) -> Result<(), Error> {
         let final_message = FinalMessage::parse(message)?;
 
-        let verifier = match general_purpose::STANDARD.decode(&final_message.value) {
+        let verifier = match general_purpose::STANDARD.decode(final_message.value) {
             Ok(verifier) => verifier,
-            Err(_) => return Err(Error::ProtocolSyncError(format!("SCRAM"))),
+            Err(_) => return Err(Error::ProtocolSyncError("SCRAM".to_string())),
         };
 
         let mut hmac = match Hmac::<Sha256>::new_from_slice(&self.salted_password) {
@@ -230,14 +230,14 @@ impl Message {
             .collect::<Vec<String>>();
 
         if parts.len() != 3 {
-            return Err(Error::ProtocolSyncError(format!("SCRAM")));
+            return Err(Error::ProtocolSyncError("SCRAM".to_string()));
         }
 
         let nonce = str::replace(&parts[0], "r=", "");
         let salt = str::replace(&parts[1], "s=", "");
         let iterations = match str::replace(&parts[2], "i=", "").parse::<u32>() {
             Ok(iterations) => iterations,
-            Err(_) => return Err(Error::ProtocolSyncError(format!("SCRAM"))),
+            Err(_) => return Err(Error::ProtocolSyncError("SCRAM".to_string())),
         };
 
         Ok(Message {
@@ -257,7 +257,7 @@ impl FinalMessage {
     /// Parse the server final validation message.
     pub fn parse(message: &BytesMut) -> Result<FinalMessage, Error> {
         if !message.starts_with(b"v=") || message.len() < 4 {
-            return Err(Error::ProtocolSyncError(format!("SCRAM")));
+            return Err(Error::ProtocolSyncError("SCRAM".to_string()));
         }
 
         Ok(FinalMessage {

src/server.rs

@@ -316,10 +316,7 @@ impl Server {
 
                 // Something else?
                 m => {
-                    return Err(Error::SocketError(format!(
+                    return Err(Error::SocketError(format!("Unknown message: {}", { m })));
-                        "Unknown message: {}",
-                        m as char
-                    )));
                 }
             }
         } else {
@@ -337,27 +334,18 @@ impl Server {
             None => &user.username,
         };
 
-        let password = match user.server_password {
+        let password = user.server_password.as_ref();
-            Some(ref server_password) => Some(server_password),
-            None => match user.password {
-                Some(ref password) => Some(password),
-                None => None,
-            },
-        };
 
         startup(&mut stream, username, database).await?;
 
         let mut server_info = BytesMut::new();
         let mut process_id: i32 = 0;
         let mut secret_key: i32 = 0;
-        let server_identifier = ServerIdentifier::new(username, &database);
+        let server_identifier = ServerIdentifier::new(username, database);
 
         // We'll be handling multiple packets, but they will all be structured the same.
         // We'll loop here until this exchange is complete.
-        let mut scram: Option<ScramSha256> = match password {
+        let mut scram: Option<ScramSha256> = password.map(|password| ScramSha256::new(password));
-            Some(password) => Some(ScramSha256::new(password)),
-            None => None,
-        };
 
         loop {
             let code = match stream.read_u8().await {
@@ -753,7 +741,7 @@ impl Server {
         self.mirror_send(messages);
         self.stats().data_sent(messages.len());
 
-        match write_all_flush(&mut self.stream, &messages).await {
+        match write_all_flush(&mut self.stream, messages).await {
             Ok(_) => {
                 // Successfully sent to server
                 self.last_activity = SystemTime::now();
@@ -1199,16 +1187,14 @@ impl Server {
     }
 
     pub fn mirror_send(&mut self, bytes: &BytesMut) {
-        match self.mirror_manager.as_mut() {
+        if let Some(manager) = self.mirror_manager.as_mut() {
-            Some(manager) => manager.send(bytes),
+            manager.send(bytes);
-            None => (),
         }
     }
 
     pub fn mirror_disconnect(&mut self) {
-        match self.mirror_manager.as_mut() {
+        if let Some(manager) = self.mirror_manager.as_mut() {
-            Some(manager) => manager.disconnect(),
+            manager.disconnect();
-            None => (),
         }
     }
 
@@ -1236,7 +1222,7 @@ impl Server {
         server.send(&simple_query(query)).await?;
         let mut message = server.recv().await?;
 
-        Ok(parse_query_message(&mut message).await?)
+        parse_query_message(&mut message).await
     }
 }
 

src/sharding.rs

@@ -64,7 +64,7 @@ impl Sharder {
     fn sha1(&self, key: i64) -> usize {
         let mut hasher = Sha1::new();
 
-        hasher.update(&key.to_string().as_bytes());
+        hasher.update(key.to_string().as_bytes());
 
         let result = hasher.finalize();
 

src/stats.rs

@@ -77,13 +77,12 @@ impl Reporter {
 /// The statistics collector which used for calculating averages
 /// There is only one collector (kind of like a singleton)
 /// it updates averages every 15 seconds.
-#[derive(Default)]
+pub struct Collector;
-pub struct Collector {}
 
 impl Collector {
     /// The statistics collection handler. It will collect statistics
     /// for `address_id`s starting at 0 up to `addresses`.
-    pub async fn collect(&mut self) {
+    pub fn collect() {
         info!("Events reporter started");
 
         tokio::task::spawn(async move {

src/stats/pool.rs

@@ -86,11 +86,11 @@ impl PoolStats {
             }
         }
 
-        return map;
+        map
     }
 
     pub fn generate_header() -> Vec<(&'static str, DataType)> {
-        return vec![
+        vec![
             ("database", DataType::Text),
             ("user", DataType::Text),
             ("pool_mode", DataType::Text),
@@ -105,11 +105,11 @@ impl PoolStats {
             ("sv_login", DataType::Numeric),
             ("maxwait", DataType::Numeric),
             ("maxwait_us", DataType::Numeric),
-        ];
+        ]
     }
 
     pub fn generate_row(&self) -> Vec<String> {
-        return vec![
+        vec![
             self.identifier.db.clone(),
             self.identifier.user.clone(),
             self.mode.to_string(),
@@ -124,7 +124,7 @@ impl PoolStats {
             self.sv_login.to_string(),
             (self.maxwait / 1_000_000).to_string(),
             (self.maxwait % 1_000_000).to_string(),
-        ];
+        ]
     }
 }
 

src/tls.rs

@@ -44,25 +44,17 @@ impl Tls {
     pub fn new() -> Result<Self, Error> {
         let config = get_config();
 
-        let certs = match load_certs(Path::new(&config.general.tls_certificate.unwrap())) {
+        let certs = load_certs(Path::new(&config.general.tls_certificate.unwrap()))
-            Ok(certs) => certs,
+            .map_err(|_| Error::TlsError)?;
-            Err(_) => return Err(Error::TlsError),
+        let key_der = load_keys(Path::new(&config.general.tls_private_key.unwrap()))
-        };
+            .map_err(|_| Error::TlsError)?
+            .remove(0);
 
-        let mut keys = match load_keys(Path::new(&config.general.tls_private_key.unwrap())) {
+        let config = rustls::ServerConfig::builder()
-            Ok(keys) => keys,
-            Err(_) => return Err(Error::TlsError),
-        };
-
-        let config = match rustls::ServerConfig::builder()
             .with_safe_defaults()
             .with_no_client_auth()
-            .with_single_cert(certs, keys.remove(0))
+            .with_single_cert(certs, key_der)
-            .map_err(|err| std::io::Error::new(std::io::ErrorKind::InvalidInput, err))
+            .map_err(|_| Error::TlsError)?;
-        {
-            Ok(c) => c,
-            Err(_) => return Err(Error::TlsError),
-        };
 
         Ok(Tls {
             acceptor: TlsAcceptor::from(Arc::new(config)),