feat: add route admin api in metasrv (#1734)

* feat: add route admin api in metasrv

* fix: add license

src/meta-srv/src/service/admin.rs

@@ -16,6 +16,7 @@ mod health;
 mod heartbeat;
 mod leader;
 mod meta;
+mod route;
 
 use std::collections::HashMap;
 use std::convert::Infallible;
@@ -73,6 +74,13 @@ pub fn make_admin_service(meta_srv: MetaSrv) -> Admin {
         },
     );
 
+    let router = router.route(
+        "/route",
+        route::RouteHandler {
+            kv_store: meta_srv.kv_store(),
+        },
+    );
+
     let router = Router::nest("/admin", router);
 
     Admin::new(router)

src/meta-srv/src/service/admin/route.rs

@@ -0,0 +1,86 @@
+// Copyright 2023 Greptime Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use std::collections::HashMap;
+
+use api::v1::meta::{RangeRequest, RangeResponse, TableRouteValue};
+use common_meta::key::TABLE_ROUTE_PREFIX;
+use prost::Message;
+use snafu::{OptionExt, ResultExt};
+use tonic::codegen::http;
+
+use super::HttpHandler;
+use crate::error::Result;
+use crate::service::store::kv::KvStoreRef;
+use crate::{error, util};
+
+pub struct RouteHandler {
+    pub kv_store: KvStoreRef,
+}
+
+#[async_trait::async_trait]
+impl HttpHandler for RouteHandler {
+    async fn handle(
+        &self,
+        _path: &str,
+        params: &HashMap<String, String>,
+    ) -> Result<http::Response<String>> {
+        let full_table_name = params
+            .get("full_table_name")
+            .map(|full_table_name| full_table_name.replace('.', "-"))
+            .context(error::MissingRequiredParameterSnafu {
+                param: "full_table_name",
+            })?;
+
+        let route_key = format!("{}-{}", TABLE_ROUTE_PREFIX, full_table_name).into_bytes();
+
+        let range_end = util::get_prefix_end_key(&route_key);
+
+        let req = RangeRequest {
+            key: route_key,
+            range_end,
+            keys_only: false,
+            ..Default::default()
+        };
+
+        let resp = self.kv_store.range(req).await?;
+
+        let show = pretty_fmt(resp)?;
+
+        http::Response::builder()
+            .status(http::StatusCode::OK)
+            .body(show)
+            .context(error::InvalidHttpBodySnafu)
+    }
+}
+
+fn pretty_fmt(response: RangeResponse) -> Result<String> {
+    let mut show = "".to_string();
+
+    for kv in response.kvs.into_iter() {
+        let route_key = String::from_utf8(kv.key).unwrap();
+        let route_val =
+            TableRouteValue::decode(&kv.value[..]).context(error::DecodeTableRouteSnafu)?;
+
+        show.push_str("route_key:\n");
+        show.push_str(&route_key);
+        show.push('\n');
+
+        show.push_str("route_value:\n");
+        show.push_str(&format!("{:#?}", route_val));
+        show.push('\n');
+    }
+
+    Ok(show)
+}