rust: implement ListScalars and ReadScalars

tensorboard/data/server/main.rs

@@ -13,15 +13,44 @@ See the License for the specific language governing permissions and
 limitations under the License.
 ==============================================================================*/
 
+use std::path::PathBuf;
+use std::time::{Duration, Instant};
 use tonic::transport::Server;
 
+use rustboard_core::commit::Commit;
+use rustboard_core::logdir::LogdirLoader;
 use rustboard_core::proto::tensorboard::data::tensor_board_data_provider_server::TensorBoardDataProviderServer;
 use rustboard_core::server::DataProviderHandler;
 
+const RELOAD_INTERVAL: Duration = Duration::from_secs(5);
+
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let addr = "[::0]:6806".parse::<std::net::SocketAddr>()?;
-    let handler = DataProviderHandler;
+    let logdir = match std::env::args_os().nth(1) {
+        Some(d) => PathBuf::from(d),
+        None => {
+            eprintln!("fatal: specify logdir as first command-line argument");
+            std::process::exit(1);
+        }
+    };
+
+    // Leak the commit object, since the Tonic server must have only 'static references. This only
+    // leaks the outer commit structure (of constant size), not the pointers to the actual data.
+    let commit: &'static Commit = Box::leak(Box::new(Commit::new()));
+    std::thread::spawn(move || {
+        let mut loader = LogdirLoader::new(commit, logdir);
+        loop {
+            eprintln!("beginning load cycle");
+            let start = Instant::now();
+            loader.reload();
+            let end = Instant::now();
+            eprintln!("finished load cycle ({:?})", end - start);
+            std::thread::sleep(RELOAD_INTERVAL);
+        }
+    });
+
+    let handler = DataProviderHandler { commit };
     Server::builder()
         .add_service(TensorBoardDataProviderServer::new(handler))
         .serve(addr)

tensorboard/data/server/run.rs

@@ -216,7 +216,8 @@ impl RunLoader {
     }
 
     fn commit_all(&mut self, run_data: &RwLock<commit::RunData>) {
-        let mut run = run_data.write().expect("acquiring run data lock");
+        let mut run = run_data.write().expect("acquiring tags lock");
+        run.start_time = self.start_time;
         for (tag, ts) in &mut self.time_series {
             ts.commit(tag, &mut *run);
         }