config: Fix titan blob-run-mode setting (#15988) (#16013)

close #15978, close #15987

Fix titan config blob-run-mode's from<ConfigValue> implementation.

Signed-off-by: tonyxuqqi <tonyxuqi@outlook.com>

Co-authored-by: tonyxuqqi <tonyxuqi@outlook.com>

components/engine_rocks/src/config.rs

@@ -340,9 +340,9 @@ pub enum BlobRunMode {
 impl From<BlobRunMode> for ConfigValue {
     fn from(mode: BlobRunMode) -> ConfigValue {
         let str_value = match mode {
-            BlobRunMode::Normal => "normal",
-            BlobRunMode::ReadOnly => "read-only",
-            BlobRunMode::Fallback => "fallback",
+            BlobRunMode::Normal => "kNormal",
+            BlobRunMode::ReadOnly => "kReadOnly",
+            BlobRunMode::Fallback => "kFallback",
         };
         ConfigValue::String(str_value.into())
     }
@@ -366,8 +366,11 @@ impl FromStr for BlobRunMode {
             "normal" => Ok(BlobRunMode::Normal),
             "read-only" => Ok(BlobRunMode::ReadOnly),
             "fallback" => Ok(BlobRunMode::Fallback),
+            "kNormal" => Ok(BlobRunMode::Normal),
+            "kReadOnly" => Ok(BlobRunMode::ReadOnly),
+            "kFallback" => Ok(BlobRunMode::Fallback),
             m => Err(format!(
-                "expect: normal, read-only or fallback, got: {:?}",
+                "expect: normal, kNormal, read-only, kReadOnly, kFallback or fallback, got: {:?}",
                 m
             )),
         }

src/config/mod.rs

@@ -4251,15 +4251,20 @@ impl ConfigController {
 
     pub fn update(&self, change: HashMap<String, String>) -> CfgResult<()> {
         let diff = to_config_change(change.clone())?;
-        self.update_impl(diff, Some(change))
+        self.update_impl(diff, Some(change), true)
+    }
+
+    pub fn update_without_persist(&self, change: HashMap<String, String>) -> CfgResult<()> {
+        let diff = to_config_change(change.clone())?;
+        self.update_impl(diff, Some(change), false)
     }
 
     pub fn update_from_toml_file(&self) -> CfgResult<()> {
         let current = self.get_current();
         match TikvConfig::from_file(Path::new(&current.cfg_path), None) {
             Ok(incoming) => {
                 let diff = current.diff(&incoming);
-                self.update_impl(diff, None)
+                self.update_impl(diff, None, true)
             }
             Err(e) => Err(e),
         }
@@ -4269,6 +4274,7 @@ impl ConfigController {
         &self,
         mut diff: HashMap<String, ConfigValue>,
         change: Option<HashMap<String, String>>,
+        persist: bool,
     ) -> CfgResult<()> {
         diff = {
             let incoming = self.get_current();
@@ -4301,6 +4307,11 @@ impl ConfigController {
             }
         }
         debug!("all config change had been dispatched"; "change" => ?to_update);
+
+        if !persist {
+            return Ok(());
+        }
+
         // we already verified the correctness at the beginning of this function.
         inner.current.update(to_update).unwrap();
         // Write change to the config file
@@ -5107,7 +5118,28 @@ mod tests {
         let diff = config_value_to_string(diff.into_iter().collect());
         assert_eq!(diff.len(), 1);
         assert_eq!(diff[0].0.as_str(), "blob_run_mode");
-        assert_eq!(diff[0].1.as_str(), "fallback");
+        assert_eq!(diff[0].1.as_str(), "kFallback");
+    }
+
+    #[test]
+    fn test_update_titan_blob_run_mode_config() {
+        let mut cfg = TikvConfig::default();
+        cfg.rocksdb.titan.enabled = true;
+        let (_, cfg_controller, ..) = new_engines::<ApiV1>(cfg);
+        for run_mode in [
+            "kFallback",
+            "kNormal",
+            "kReadOnly",
+            "fallback",
+            "normal",
+            "read-only",
+        ] {
+            let change = HashMap::from([(
+                "rocksdb.defaultcf.titan.blob-run-mode".to_string(),
+                run_mode.to_string(),
+            )]);
+            cfg_controller.update_without_persist(change).unwrap();
+        }
     }
 
     #[test]