fix: GET: /config return all configurations when running standalone (#2630)

* fix: config api return all configurations when running standalone

* chore: follow same style

* fix: avoid panic

src/frontend/src/error.rs

@@ -272,6 +272,12 @@ pub enum Error {
 
     #[snafu(display("Invalid auth config"))]
     IllegalAuthConfig { source: auth::error::Error },
+
+    #[snafu(display("Failed to serialize options to TOML"))]
+    TomlFormat {
+        #[snafu(source)]
+        error: toml::ser::Error,
+    },
 }
 
 pub type Result<T> = std::result::Result<T, Error>;
@@ -279,7 +285,8 @@ pub type Result<T> = std::result::Result<T, Error>;
 impl ErrorExt for Error {
     fn status_code(&self) -> StatusCode {
         match self {
-            Error::ParseAddr { .. }
+            Error::TomlFormat { .. }
+            | Error::ParseAddr { .. }
             | Error::InvalidSql { .. }
             | Error::InvalidInsertRequest { .. }
             | Error::InvalidDeleteRequest { .. }

src/frontend/src/frontend.rs

@@ -18,7 +18,9 @@ use serde::{Deserialize, Serialize};
 use servers::heartbeat_options::HeartbeatOptions;
 use servers::http::HttpOptions;
 use servers::Mode;
+use snafu::prelude::*;
 
+use crate::error::{Result, TomlFormatSnafu};
 use crate::service_config::{
     DatanodeOptions, GrpcOptions, InfluxdbOptions, MysqlOptions, OpentsdbOptions, OtlpOptions,
     PostgresOptions, PromStoreOptions,
@@ -76,6 +78,16 @@ impl FrontendOptions {
     }
 }
 
+pub trait TomlSerializable {
+    fn to_toml(&self) -> Result<String>;
+}
+
+impl TomlSerializable for FrontendOptions {
+    fn to_toml(&self) -> Result<String> {
+        toml::to_string(&self).context(TomlFormatSnafu)
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

src/frontend/src/instance.rs

@@ -88,7 +88,7 @@ use crate::error::{
     ParseSqlSnafu, PermissionSnafu, PlanStatementSnafu, Result, SqlExecInterceptedSnafu,
     TableOperationSnafu,
 };
-use crate::frontend::FrontendOptions;
+use crate::frontend::{FrontendOptions, TomlSerializable};
 use crate::heartbeat::handler::invalidate_table_cache::InvalidateTableCacheHandler;
 use crate::heartbeat::HeartbeatTask;
 use crate::metrics;
@@ -358,7 +358,10 @@ impl Instance {
         })
     }
 
-    pub async fn build_servers(&mut self, opts: &FrontendOptions) -> Result<()> {
+    pub async fn build_servers(
+        &mut self,
+        opts: impl Into<FrontendOptions> + TomlSerializable,
+    ) -> Result<()> {
         let servers = Services::build(opts, Arc::new(self.clone()), self.plugins.clone()).await?;
         self.servers = Arc::new(servers);
 

src/frontend/src/server.rs

@@ -33,7 +33,7 @@ use servers::server::Server;
 use snafu::ResultExt;
 
 use crate::error::{self, Result, StartServerSnafu};
-use crate::frontend::FrontendOptions;
+use crate::frontend::{FrontendOptions, TomlSerializable};
 use crate::instance::FrontendInstance;
 
 pub(crate) struct Services;
@@ -43,14 +43,17 @@ pub type ServerHandlers = HashMap<String, ServerHandler>;
 pub type ServerHandler = (Box<dyn Server>, SocketAddr);
 
 impl Services {
-    pub(crate) async fn build<T>(
-        opts: &FrontendOptions,
-        instance: Arc<T>,
+    pub(crate) async fn build<T, U>(
+        opts: T,
+        instance: Arc<U>,
         plugins: Plugins,
     ) -> Result<ServerHandlers>
     where
-        T: FrontendInstance,
+        T: Into<FrontendOptions> + TomlSerializable,
+        U: FrontendInstance,
     {
+        let toml = opts.to_toml()?;
+        let opts: FrontendOptions = opts.into();
         let mut result = Vec::<ServerHandler>::with_capacity(plugins.len());
         let user_provider = plugins.get::<UserProviderRef>();
 
@@ -120,7 +123,7 @@ impl Services {
                 .with_metrics_handler(MetricsHandler)
                 .with_script_handler(instance.clone())
                 .with_plugins(plugins)
-                .with_greptime_config_options(opts.to_toml_string())
+                .with_greptime_config_options(toml)
                 .build();
             result.push((Box::new(http_server), http_addr));
         }