add application_name_add_host setting

.schema/pgdog.schema.json

@@ -25,6 +25,7 @@
       "description": "General settings are relevant to the operations of the pooler itself, or apply to all database pools.\n\n<https://docs.pgdog.dev/configuration/pgdog.toml/general/>",
       "$ref": "#/$defs/General",
       "default": {
+        "application_name_add_host": false,
         "auth_type": "scram",
         "ban_replica_lag": 9223372036854775807,
         "ban_replica_lag_bytes": 9223372036854775807,
@@ -653,6 +654,11 @@
       "description": "General settings are relevant to the operations of the pooler itself, or apply to all database pools.\n\n<https://docs.pgdog.dev/configuration/pgdog.toml/general/>",
       "type": "object",
       "properties": {
+        "application_name_add_host": {
+          "description": "Add the client host address and port to `application_name` at connection start\nand whenever the client later changes it with `SET` / `set_config`.\n\nThe result is `{application_name} - {ip}:{port}`. If the client sent no name,\nthe prefix is empty (` - 10.0.0.5:1234`). A later `SET application_name` replaces\nthe name and the host is appended again.\n\n_Default:_ `false`\n\n<https://docs.pgdog.dev/configuration/pgdog.toml/general/#application_name_add_host>",
+          "type": "boolean",
+          "default": false
+        },
         "auth_type": {
           "description": "What kind of authentication mechanism to use for client connections.\n\n_Default:_ `scram`\n\n<https://docs.pgdog.dev/configuration/pgdog.toml/general/#auth_type>",
           "$ref": "#/$defs/AuthType",

pgdog-config/src/general.rs

@@ -606,6 +606,19 @@ pub struct General {
     #[serde(default = "General::log_disconnections")]
     pub log_disconnections: bool,
 
+    /// Add the client host address and port to `application_name` at connection start
+    /// and whenever the client later changes it with `SET` / `set_config`.
+    ///
+    /// The result is `{application_name} - {ip}:{port}`. If the client sent no name,
+    /// the prefix is empty (` - 10.0.0.5:1234`). A later `SET application_name` replaces
+    /// the name and the host is appended again.
+    ///
+    /// _Default:_ `false`
+    ///
+    /// <https://docs.pgdog.dev/configuration/pgdog.toml/general/#application_name_add_host>
+    #[serde(default = "General::application_name_add_host")]
+    pub application_name_add_host: bool,
+
     /// Window, in milliseconds, over which to deduplicate identical log messages. Set to `0` to disable throttling.
     ///
     /// **Note:** When enabled, identical messages (same level, target, and body) that exceed `log_dedup_threshold` within this window are suppressed and replaced with a single summary line at the end of the window.
@@ -955,6 +968,7 @@ impl Default for General {
             log_level: Self::log_level(),
             log_connections: Self::log_connections(),
             log_disconnections: Self::log_disconnections(),
+            application_name_add_host: Self::application_name_add_host(),
             log_dedup_window: 0,
             log_dedup_threshold: 0,
             two_phase_commit: bool::default(),
@@ -1488,6 +1502,10 @@ impl General {
         Self::env_bool_or_default("PGDOG_LOG_DISCONNECTIONS", true)
     }
 
+    pub fn application_name_add_host() -> bool {
+        Self::env_bool_or_default("PGDOG_APPLICATION_NAME_ADD_HOST", false)
+    }
+
     pub fn expanded_explain() -> bool {
         Self::env_bool_or_default("PGDOG_EXPANDED_EXPLAIN", false)
     }
@@ -2052,21 +2070,25 @@ mod tests {
         let _guard = set_env_var("PGDOG_CROSS_SHARD_DISABLED", "yes");
         let _guard = set_env_var("PGDOG_LOG_CONNECTIONS", "false");
         let _guard = set_env_var("PGDOG_LOG_DISCONNECTIONS", "0");
+        let _guard = set_env_var("PGDOG_APPLICATION_NAME_ADD_HOST", "true");
 
         assert!(General::dry_run());
         assert!(General::cross_shard_disabled());
         assert!(!General::log_connections());
         assert!(!General::log_disconnections());
+        assert!(General::application_name_add_host());
 
         let _guard = remove_env_var("PGDOG_DRY_RUN");
         let _guard = remove_env_var("PGDOG_CROSS_SHARD_DISABLED");
         let _guard = remove_env_var("PGDOG_LOG_CONNECTIONS");
         let _guard = remove_env_var("PGDOG_LOG_DISCONNECTIONS");
+        let _guard = remove_env_var("PGDOG_APPLICATION_NAME_ADD_HOST");
 
         assert!(!General::dry_run());
         assert!(!General::cross_shard_disabled());
         assert!(General::log_connections());
         assert!(General::log_disconnections());
+        assert!(!General::application_name_add_host());
     }
 
     #[test]

pgdog/src/frontend/client/mod.rs

@@ -8,7 +8,6 @@ use std::sync::Arc;
 use std::time::{Duration, Instant};
 
 use pgdog_config::users::PasswordKind;
-use timeouts::Timeouts;
 use tokio::{select, spawn};
 use tracing::{Level as LogLevel, debug, enabled, error, info, trace, warn};
 
@@ -29,16 +28,21 @@ use crate::net::messages::{
     Authentication, BackendKeyData, ErrorResponse, FromBytes, FrontendPid, Message, Password,
     Protocol, ProtocolVersion, ReadyForQuery, ToBytes,
 };
-use crate::net::{MessageBuffer, ProtocolMessage, Stream, parameter::Parameters};
+use crate::net::{
+    MessageBuffer, ProtocolMessage, Stream,
+    parameter::{Parameters, application_name_with_host},
+};
 use crate::state::State;
 use crate::stats::memory::MemoryUsage;
 use crate::util::{safe_timeout, user_database_from_params};
 
 pub mod query_engine;
+pub(crate) mod request_settings;
 pub mod sticky;
 pub mod timeouts;
 pub mod transaction_type;
 
+pub(crate) use request_settings::ClientRequestSettings;
 pub(crate) use sticky::Sticky;
 pub use transaction_type::TransactionType;
 
@@ -73,10 +77,8 @@ pub struct Client {
     prepared_statements: PreparedStatements,
     // Client transaction state.
     transaction: Option<TransactionType>,
-    // Current timeouts to use for client/server communication.
-    // These change based on client state, e.g. if client is running query,
-    // the `query_timeout` is active, and if the client is idle, the `client_idle_timeout` is.
-    timeouts: Timeouts,
+    // Per-request settings snapshot, refreshed in [`Self::buffer`].
+    request_settings: ClientRequestSettings,
     // Stateful buffer containing the current whole client request.
     // This can be a query or just a `Parse` and `Flush`, but in either case, the client
     // will expect a response immediately and we need to handle it.
@@ -89,10 +91,6 @@ pub struct Client {
     sticky: Sticky,
     /// Client database.
     database: String,
-    /// Log queries to stdout.
-    query_log_stdout: bool,
-    /// Maximum query message size before a warning is logged.
-    query_size_limit: Option<usize>,
 }
 
 /// Inputs to the per-user client certificate check.
@@ -242,7 +240,7 @@ impl Client {
     /// Create new frontend client from the given TCP stream.
     async fn login(
         mut stream: Stream,
-        params: Parameters,
+        mut params: Parameters,
         addr: SocketAddr,
         config: Arc<ConfigAndUsers>,
         protocol_version: ProtocolVersion,
@@ -253,6 +251,11 @@ impl Client {
             return Ok(None);
         }
 
+        Self::maybe_add_application_name_host(
+            &mut params,
+            addr,
+            config.config.general.application_name_add_host,
+        );
         let (user, database) = user_database_from_params(&params);
         let admin = database == config.config.admin.name && config.config.admin.user == user;
         let admin_password = &config.config.admin.password;
@@ -420,19 +423,29 @@ impl Client {
             params: params.clone(),
             prepared_statements: PreparedStatements::new(),
             transaction: None,
-            timeouts: Timeouts::from_config(&config.config.general),
+            request_settings: ClientRequestSettings::from_general(&config.config.general),
             client_request: ClientRequest::default(),
             stream_buffer: MessageBuffer::new(
                 config.config.memory.message_buffer,
                 config.config.general.frontend_query_size_limit_block(),
             ),
             sticky: Sticky::from_params(&params),
             database: database.to_string(),
-            query_log_stdout: false,
-            query_size_limit: None,
         }))
     }
 
+    fn maybe_add_application_name_host(params: &mut Parameters, addr: SocketAddr, enabled: bool) {
+        if !enabled {
+            return;
+        }
+
+        let current = params.get_default("application_name", "");
+        params.insert(
+            "application_name",
+            application_name_with_host(current, &addr.to_string()),
+        );
+    }
+
     #[cfg(test)]
     pub fn new_test(stream: Stream, params: Parameters) -> Self {
         use crate::config::config;
@@ -442,21 +455,28 @@ impl Client {
         connect_params.insert("database", "pgdog");
         connect_params.merge(params);
 
+        let addr = SocketAddr::from(([127, 0, 0, 1], 1234));
+        Self::maybe_add_application_name_host(
+            &mut connect_params,
+            addr,
+            config().config.general.application_name_add_host,
+        );
+
         let id = FrontendPid::new();
         let key = BackendKeyData::new_frontend(ProtocolVersion::V3_0, id);
         let mut prepared_statements = PreparedStatements::new();
         prepared_statements.level = config().config.general.prepared_statements;
 
         Self {
             stream,
-            addr: SocketAddr::from(([127, 0, 0, 1], 1234)),
+            addr,
             key,
             comms: ClientComms::new(id),
             streaming: false,
             prepared_statements,
             admin: false,
             transaction: None,
-            timeouts: Timeouts::from_config(&config().config.general),
+            request_settings: ClientRequestSettings::from_general(&config().config.general),
             client_request: ClientRequest::default(),
             stream_buffer: MessageBuffer::new(
                 4096,
@@ -465,8 +485,6 @@ impl Client {
             sticky: Sticky::from_params(&connect_params),
             params: connect_params,
             database: "pgdog".to_string(),
-            query_log_stdout: false,
-            query_size_limit: None,
         }
     }
 
@@ -633,14 +651,13 @@ impl Client {
         let config = config::config();
         // Configure prepared statements cache.
         self.prepared_statements.level = config.prepared_statements();
-        self.timeouts = Timeouts::from_config(&config.config.general);
-        self.query_log_stdout = config.config.general.query_log_stdout;
-        self.query_size_limit = config.config.general.query_size_limit;
+        self.request_settings = ClientRequestSettings::from_general(&config.config.general);
         self.stream_buffer
-            .set_size_limit_block(config.config.general.frontend_query_size_limit_block());
+            .set_size_limit_block(self.request_settings.frontend_query_size_limit_block);
 
         while !self.client_request.is_complete() {
             let idle_timeout = self
+                .request_settings
                 .timeouts
                 .client_idle_timeout(&state, &self.client_request);
 
@@ -736,7 +753,7 @@ impl MemoryUsage for Client {
             + std::mem::size_of::<ClientComms>()
             + std::mem::size_of::<bool>() * 5
             + self.prepared_statements.memory_used()
-            + std::mem::size_of::<Timeouts>()
+            + std::mem::size_of::<ClientRequestSettings>()
             + self.stream_buffer.capacity()
             + self.client_request.memory_usage()
     }

pgdog/src/frontend/client/query_engine/connect.rs

@@ -42,7 +42,10 @@ impl QueryEngine {
                 self.stats.connected();
                 self.debug_connected(context, false);
 
-                let query_timeout = context.timeouts.query_timeout(&self.stats.state);
+                let query_timeout = context
+                    .request_settings
+                    .timeouts
+                    .query_timeout(&self.stats.state);
                 let begin_stmt = self.begin_stmt.take();
 
                 // We may need to sync params with the server and that reads from the socket.

pgdog/src/frontend/client/query_engine/context.rs

@@ -2,11 +2,12 @@ use crate::{
     backend::pool::{connection::mirror::Mirror, stats::MemoryStats},
     frontend::{
         Client, ClientRequest, PreparedStatements,
-        client::{Sticky, TransactionType, timeouts::Timeouts},
+        client::{ClientRequestSettings, Sticky, TransactionType},
         router::parser::rewrite::statement::plan::RewriteResult,
     },
     net::{FrontendPid, Parameters, Stream},
 };
+use std::net::SocketAddr;
 
 /// Context passed to the query engine to execute a query.
 pub struct QueryEngineContext<'a> {
@@ -24,8 +25,8 @@ pub struct QueryEngineContext<'a> {
     pub(super) stream: &'a mut Stream,
     /// Client in transaction?
     pub(super) transaction: Option<TransactionType>,
-    /// Timeouts
-    pub(super) timeouts: Timeouts,
+    /// Per-request settings snapshot.
+    pub(super) request_settings: ClientRequestSettings,
     /// Cross shard  queries are disabled.
     pub(super) cross_shard_disabled: Option<bool>,
     /// Client memory usage.
@@ -38,10 +39,8 @@ pub struct QueryEngineContext<'a> {
     pub(super) sticky: Sticky,
     /// Rewrite result.
     pub(super) rewrite_result: Option<RewriteResult>,
-    /// Log queries to stdout.
-    pub(super) query_log_stdout: bool,
-    /// Maximum query message size before a warning is logged.
-    pub(super) query_size_limit: Option<usize>,
+    /// Client TCP address, used for `application_name_add_host`.
+    pub(super) client_addr: SocketAddr,
 }
 
 impl<'a> QueryEngineContext<'a> {
@@ -55,16 +54,15 @@ impl<'a> QueryEngineContext<'a> {
             client_request: &mut client.client_request,
             stream: &mut client.stream,
             transaction: client.transaction,
-            timeouts: client.timeouts,
+            request_settings: client.request_settings,
             cross_shard_disabled: None,
             memory_stats,
             admin: client.admin,
             requests_left: 0,
             rollback: false,
             sticky: client.sticky,
             rewrite_result: None,
-            query_log_stdout: client.query_log_stdout,
-            query_size_limit: client.query_size_limit,
+            client_addr: client.addr,
         }
     }
 
@@ -83,16 +81,18 @@ impl<'a> QueryEngineContext<'a> {
             client_request: buffer,
             stream: &mut mirror.stream,
             transaction: mirror.transaction,
-            timeouts: mirror.timeouts,
+            request_settings: ClientRequestSettings {
+                timeouts: mirror.timeouts,
+                ..ClientRequestSettings::default()
+            },
             cross_shard_disabled: None,
             memory_stats: MemoryStats::default(),
             admin: false,
             requests_left: 0,
             rollback: false,
             sticky: Sticky::new(),
             rewrite_result: None,
-            query_log_stdout: false,
-            query_size_limit: None,
+            client_addr: SocketAddr::from(([0, 0, 0, 0], 0)),
         }
     }
 

pgdog/src/frontend/client/query_engine/mod.rs

@@ -1,6 +1,5 @@
 use crate::{
     backend::pool::{Connection, Request},
-    config::config,
     frontend::{
         BufferedQuery, Client, ClientComms, Command, Error, Router, RouterContext, Stats,
         client::query_engine::{hooks::QueryEngineHooks, route_query::ClusterCheck},
@@ -171,7 +170,7 @@ impl QueryEngine {
             .route // Admin commands don't have a route.
             .as_mut()
             .and_then(|route| route.take_explain())
-            && config().config.general.expanded_explain
+            && context.request_settings.expanded_explain
         {
             self.pending_explain = Some(ExplainResponseState::new(trace));
         }