add command to stop (not kill) the server

Author: jkrumbiegel

src/execute/julia.ts

@@ -858,11 +858,19 @@ function populateJuliaEngineCommand(command: Command) {
       "Prints the julia server log file if it exists which can be used to diagnose problems.",
     )
     .action(printJuliaServerLog)
-    .command("close", "Close the worker for a given notebook")
+    .command(
+      "close",
+      "Close the worker for a given notebook. If it is currently running, it will not be interrupted.",
+    )
     .arguments("<file:string>")
     .action(async (_, file) => {
       await closeWorker(file);
-    });
+    })
+    .command("stop", "Stop the server")
+    .description(
+      "Sends a message to the server that it should stop all notebooks and itself. Running notebooks will not be interrupted.",
+    )
+    .action(stopServer);
   return;
 }
 
@@ -961,3 +969,11 @@ async function closeWorker(file: string) {
   });
   info("Worker closed successfully.");
 }
+
+async function stopServer() {
+  const result = await connectAndWriteJuliaCommandToRunningServer({
+    type: "stop",
+    content: {},
+  });
+  info(result.message);
+}

tests/smoke/call/engine/julia/julia.test.ts

@@ -2,6 +2,7 @@ import { assert, assertStringIncludes } from "testing/asserts";
 import { docs, quartoDevCmd } from "../../../../utils.ts";
 import { existsSync } from "fs/exists";
 import { juliaServerLogFile, juliaTransportFile } from "../../../../../src/execute/julia.ts";
+import { sleep } from "../../../../../src/core/wait.ts";
 
 const sleepQmd = docs("call/engine/julia/sleep.qmd");
 assert(existsSync(sleepQmd));
@@ -104,4 +105,22 @@ Deno.test("log exists", () => {
   ).outputSync();
   assertSuccess(log_output);
   assertStdoutIncludes(log_output, "Log started at");
-});
+});
+
+Deno.test("stop the idling server", async () => {
+  const stop_output = new Deno.Command(
+    quartoDevCmd(),
+    {args: ["call", "engine", "julia", "stop"]}
+  ).outputSync();
+  assertSuccess(stop_output);
+  assertStderrIncludes(stop_output, "Server stopped");
+
+  await sleep(2000); // allow a little bit of time for the server to stop and the log message to be written
+
+  const log_output = new Deno.Command(
+    quartoDevCmd(),
+    {args: ["call", "engine", "julia", "log"]}
+  ).outputSync();
+  assertSuccess(log_output);
+  assertStdoutIncludes(log_output, "Server stopped");
+});