Add SHOW CONFIG FILE to admin db

pgdog/src/admin/error.rs

@@ -36,6 +36,9 @@ pub enum Error {
 
     #[error("address is not valid")]
     InvalidAddress,
+
+    #[error("{0}")]
+    Toml(#[from] toml::ser::Error),
 }
 
 impl From<crate::backend::Error> for Error {

pgdog/src/admin/mod.rs

@@ -22,6 +22,7 @@ pub mod setup_schema;
 pub mod show_client_memory;
 pub mod show_clients;
 pub mod show_config;
+pub mod show_config_file;
 pub mod show_instance_id;
 pub mod show_lists;
 pub mod show_mirrors;

pgdog/src/admin/parser.rs

@@ -5,12 +5,12 @@ use super::{
     prelude::Message, probe::Probe, reconnect::Reconnect, reload::Reload,
     reset_query_cache::ResetQueryCache, set::Set, setup_schema::SetupSchema,
     show_client_memory::ShowClientMemory, show_clients::ShowClients, show_config::ShowConfig,
-    show_instance_id::ShowInstanceId, show_lists::ShowLists, show_mirrors::ShowMirrors,
-    show_peers::ShowPeers, show_pools::ShowPools, show_prepared_statements::ShowPreparedStatements,
-    show_query_cache::ShowQueryCache, show_replication::ShowReplication,
-    show_server_memory::ShowServerMemory, show_servers::ShowServers, show_stats::ShowStats,
-    show_transactions::ShowTransactions, show_version::ShowVersion, shutdown::Shutdown, Command,
-    Error,
+    show_config_file::ShowConfigFile, show_instance_id::ShowInstanceId, show_lists::ShowLists,
+    show_mirrors::ShowMirrors, show_peers::ShowPeers, show_pools::ShowPools,
+    show_prepared_statements::ShowPreparedStatements, show_query_cache::ShowQueryCache,
+    show_replication::ShowReplication, show_server_memory::ShowServerMemory,
+    show_servers::ShowServers, show_stats::ShowStats, show_transactions::ShowTransactions,
+    show_version::ShowVersion, shutdown::Shutdown, Command, Error,
 };
 
 use tracing::debug;
@@ -23,6 +23,7 @@ pub enum ParseResult {
     Reload(Reload),
     ShowPools(ShowPools),
     ShowConfig(ShowConfig),
+    ShowConfigFile(ShowConfigFile),
     ShowServers(ShowServers),
     ShowPeers(ShowPeers),
     ShowQueryCache(ShowQueryCache),
@@ -58,6 +59,7 @@ impl ParseResult {
             Reload(reload) => reload.execute().await,
             ShowPools(show_pools) => show_pools.execute().await,
             ShowConfig(show_config) => show_config.execute().await,
+            ShowConfigFile(show_config_file) => show_config_file.execute().await,
             ShowServers(show_servers) => show_servers.execute().await,
             ShowPeers(show_peers) => show_peers.execute().await,
             ShowQueryCache(show_query_cache) => show_query_cache.execute().await,
@@ -93,6 +95,7 @@ impl ParseResult {
             Reload(reload) => reload.name(),
             ShowPools(show_pools) => show_pools.name(),
             ShowConfig(show_config) => show_config.name(),
+            ShowConfigFile(show_config_file) => show_config_file.name(),
             ShowServers(show_servers) => show_servers.name(),
             ShowPeers(show_peers) => show_peers.name(),
             ShowQueryCache(show_query_cache) => show_query_cache.name(),
@@ -137,7 +140,22 @@ impl Parser {
             "show" => match iter.next().ok_or(Error::Syntax)?.trim() {
                 "clients" => ParseResult::ShowClients(ShowClients::parse(&sql)?),
                 "pools" => ParseResult::ShowPools(ShowPools::parse(&sql)?),
-                "config" => ParseResult::ShowConfig(ShowConfig::parse(&sql)?),
+                "config" => {
+                    let next_keyword = iter.clone().find_map(|token| {
+                        let trimmed = token.trim();
+                        if trimmed.is_empty() {
+                            None
+                        } else {
+                            Some(trimmed)
+                        }
+                    });
+
+                    if next_keyword == Some("file") {
+                        ParseResult::ShowConfigFile(ShowConfigFile::parse(&sql)?)
+                    } else {
+                        ParseResult::ShowConfig(ShowConfig::parse(&sql)?)
+                    }
+                }
                 "servers" => ParseResult::ShowServers(ShowServers::parse(&sql)?),
                 "server" => match iter.next().ok_or(Error::Syntax)?.trim() {
                     "memory" => ParseResult::ShowServerMemory(ShowServerMemory::parse(&sql)?),
@@ -229,4 +247,10 @@ mod tests {
         let result = Parser::parse("SHOW CLIENT MEMORY;");
         assert!(matches!(result, Ok(ParseResult::ShowClientMemory(_))));
     }
+
+    #[test]
+    fn parses_show_config_file_command() {
+        let result = Parser::parse("SHOW CONFIG FILE;");
+        assert!(matches!(result, Ok(ParseResult::ShowConfigFile(_))));
+    }
 }

pgdog/src/admin/show_config_file.rs

@@ -0,0 +1,55 @@
+//! SHOW CONFIG FILE command.
+
+use crate::config::config;
+
+use super::prelude::*;
+
+pub struct ShowConfigFile;
+
+#[async_trait]
+impl Command for ShowConfigFile {
+    fn name(&self) -> String {
+        "SHOW".into()
+    }
+
+    fn parse(_sql: &str) -> Result<Self, Error> {
+        Ok(Self {})
+    }
+
+    async fn execute(&self) -> Result<Vec<Message>, Error> {
+        let config = config();
+        let snapshot = sanitize_for_toml(config.config.clone());
+        let toml = toml::to_string_pretty(&snapshot)?;
+
+        let mut messages = vec![RowDescription::new(&[Field::text("pgdog.toml")]).message()?];
+
+        let mut row = DataRow::new();
+        row.add(&toml);
+        messages.push(row.message()?);
+
+        Ok(messages)
+    }
+}
+
+fn sanitize_for_toml(mut config: crate::config::Config) -> crate::config::Config {
+    let max_i64 = i64::MAX as u64;
+    let max_i64_usize = i64::MAX as usize;
+
+    if config.general.client_idle_timeout > max_i64 {
+        config.general.client_idle_timeout = max_i64;
+    }
+
+    if config.general.query_timeout > max_i64 {
+        config.general.query_timeout = max_i64;
+    }
+
+    if config.general.lsn_check_delay > max_i64 {
+        config.general.lsn_check_delay = max_i64;
+    }
+
+    if config.general.prepared_statements_limit > max_i64_usize {
+        config.general.prepared_statements_limit = max_i64_usize;
+    }
+
+    config
+}

pgdog/src/admin/tests/mod.rs

@@ -6,6 +6,7 @@ use crate::net::messages::{DataRow, DataType, FromBytes, Protocol, RowDescriptio
 
 use super::show_client_memory::ShowClientMemory;
 use super::show_config::ShowConfig;
+use super::show_config_file::ShowConfigFile;
 use super::show_lists::ShowLists;
 use super::show_mirrors::ShowMirrors;
 use super::show_pools::ShowPools;
@@ -197,6 +198,91 @@ async fn show_config_pretty_prints_general_settings() {
     assert_eq!(connect_timeout, "2s");
 }
 
+#[tokio::test(flavor = "current_thread")]
+async fn show_config_file_dumps_live_state_as_toml() {
+    let context = TestAdminContext::new();
+
+    let mut config = ConfigAndUsers::default();
+    config.config.general.default_pool_size = 11;
+    config.config.general.connect_timeout = 7_000;
+    config.config.general.log_connections = true;
+    config.config.general.tls_client_required = true;
+    config.config.databases.push(Database {
+        name: "app".into(),
+        host: "127.0.0.1".into(),
+        database_name: Some("postgres".into()),
+        user: Some("postgres".into()),
+        password: Some("hunter2".into()),
+        shard: 0,
+        ..Default::default()
+    });
+
+    context.set_config(config);
+
+    let command = ShowConfigFile;
+    let messages = command
+        .execute()
+        .await
+        .expect("show config file execution failed");
+
+    assert_eq!(messages.len(), 2, "expected row description plus data row");
+
+    let row_description = RowDescription::from_bytes(messages[0].payload())
+        .expect("row description message should parse");
+    let columns: Vec<&str> = row_description
+        .fields
+        .iter()
+        .map(|field| field.name.as_str())
+        .collect();
+    assert_eq!(columns, vec!["pgdog.toml"]);
+    assert_eq!(row_description.fields[0].data_type(), DataType::Text);
+
+    let row = DataRow::from_bytes(messages[1].payload()).expect("data row should parse");
+    let payload = row.get_text(0).expect("toml payload should be text");
+
+    let actual_value: toml::Value = payload
+        .parse()
+        .expect("payload should parse back into toml value");
+
+    let general = actual_value
+        .get("general")
+        .and_then(|value| value.as_table())
+        .expect("general section should exist and be a table");
+    assert_eq!(
+        general
+            .get("default_pool_size")
+            .and_then(|v| v.as_integer()),
+        Some(11)
+    );
+    assert_eq!(
+        general.get("connect_timeout").and_then(|v| v.as_integer()),
+        Some(7_000)
+    );
+    assert_eq!(
+        general.get("log_connections").and_then(|v| v.as_bool()),
+        Some(true)
+    );
+    assert_eq!(
+        general.get("tls_client_required").and_then(|v| v.as_bool()),
+        Some(true)
+    );
+
+    let databases = actual_value
+        .get("databases")
+        .and_then(|value| value.as_array())
+        .expect("databases array should be present");
+    assert_eq!(databases.len(), 1);
+
+    let database = databases[0]
+        .as_table()
+        .expect("database entry should be a table");
+    assert_eq!(database.get("name").and_then(|v| v.as_str()), Some("app"));
+    assert_eq!(
+        database.get("password").and_then(|v| v.as_str()),
+        Some("hunter2")
+    );
+}
+
 #[tokio::test(flavor = "current_thread")]
 async fn show_mirrors_reports_counts() {
     let context = TestAdminContext::new();