feat(playground): focus the terminal on ready, bash completion for heph

website/src/components/playground/Playground.tsx

@@ -110,6 +110,12 @@ export function Playground() {
 
   useEffect(() => teardown, [teardown]);
 
+  // The terminal stays hidden until the VM is ready, and a hidden element
+  // can't take focus: focus it once the render that reveals it is done.
+  useEffect(() => {
+    if (status.kind === 'ready') termRef.current?.xterm.focus();
+  }, [status.kind]);
+
   const release = releases?.find((r) => r.tag === tag)
     ?? (picked?.tag === tag ? picked : undefined);
 
@@ -151,7 +157,6 @@ export function Playground() {
         },
       });
       await enterShell(vm);
-      termRef.current.xterm.focus();
       setStatus({ kind: 'ready', vcpus, restored });
     } catch (e) {
       if (!ac.signal.aborted) setStatus({ kind: 'error', message: errorMessage(e) });

website/src/components/playground/vm.ts

@@ -41,6 +41,8 @@ int fcntl64(int fd, int cmd, long arg) { return fcntl(fd, cmd, arg); }
 `;
 const HEPH_BIN = '/opt/heph/bin/heph';
 const COMPAT_LIB = '/opt/heph/lib/libhephcompat.so';
+// heph's bash completion, generated by the installed release.
+const COMPLETION = '/etc/heph-completion.bash';
 
 type SetupStep =
   | { run: string }
@@ -69,7 +71,12 @@ const BASE_SETUP: SetupStep[] = [
   },
   {
     write: '/etc/profile.d/heph.sh',
-    content: ['export PS1="\\w \\$ "', 'cat /etc/heph-welcome', ''].join('\n'),
+    content: [
+      'export PS1="\\w \\$ "',
+      `[ -n "$BASH_VERSION" ] && [ -r ${COMPLETION} ] && . ${COMPLETION}`,
+      'cat /etc/heph-welcome',
+      '',
+    ].join('\n'),
   },
 ];
 
@@ -82,7 +89,9 @@ const PLUGIN_OPTIONS: Record<string, string> = {
   'heph-go-plugin': '    options:\n      gotool: host\n',
 };
 
-async function run(vm: Vm, command: string, timeoutMs = 300_000): Promise<string> {
+/** Run `commands` in one exec, stopping at the first that fails. */
+async function run(vm: Vm, commands: string | string[], timeoutMs = 300_000): Promise<string> {
+  const command = [commands].flat().join(' && ');
   const { output, exitCode } = await vm.exec(command, { timeoutMs });
   if (exitCode !== 0) {
     throw new Error(`\`${command}\` exited ${exitCode}:\n${output.slice(-2000)}`);
@@ -272,15 +281,19 @@ export async function bootPlayground(
     const script = files.map(([path, content]) => (
       `mkdir -p '${path.replace(/\/[^/]+$/, '')}'\ncat > '${path}' <<'HEPH_PLAYGROUND_EOF'\n${content}${content.endsWith('\n') ? '' : '\n'}HEPH_PLAYGROUND_EOF\n`
     )).join('');
-    // Mounts the image lacks: pseudo-terminals for `heph run --shell`, and,
-    // for the examples, a filesystem with extended attributes, which
-    // `codegen = "copy"` needs (the root filesystem has none).
-    const mounts = [
+    await vm.writeFile('/tmp/heph-install.sh', script);
+    await run(vm, [
+      // Mounts the image lacks: pseudo-terminals for `heph run --shell`, and,
+      // for the examples, a filesystem with extended attributes, which
+      // `codegen = "copy"` needs (the root filesystem has none).
       'mountpoint -q /dev/pts || { mkdir -p /dev/pts && mount -t devpts devpts /dev/pts; }',
       'mkdir -p /root/examples && { mountpoint -q /root/examples || mount -t tmpfs tmpfs /root/examples; }',
-    ].join(' && ');
-    await vm.writeFile('/tmp/heph-install.sh', script);
-    await run(vm, `${mounts} && sh /tmp/heph-install.sh && rm /tmp/heph-install.sh && heph version`);
+      'sh /tmp/heph-install.sh',
+      'rm /tmp/heph-install.sh',
+      // Releases without `heph tool completions` just go without completion.
+      `{ heph tool completions bash > ${COMPLETION} 2>/dev/null || rm -f ${COMPLETION}; }`,
+      'heph version',
+    ]);
   } catch (e) {
     vm.dispose();
     throw e;