feat: sglang-omni model picker on manual server launch

4 files changed, 75 insertions, 5 deletions

diff --git a/app/backends/servers.py b/app/backends/servers.py
index 7815f30..d352717 100644
--- a/app/backends/servers.py
+++ b/app/backends/servers.py
@@ -54,6 +54,14 @@ _BOOT_HINTS = (
     ("fp8e4nv not supported",
      "the server crashed compiling an FP8 MoE kernel: FP8 needs compute "
      "capability 8.9+ (RTX 4090/5090, Hopper) and cannot run on this GPU"),
+    # A model companion package missing from the backend venv (e.g. the
+    # sglang-omni Qwen3-TTS models need qwen-tts; a shared-cache weight
+    # install or a failed pip run leaves it absent).
+    ("ModuleNotFoundError",
+     "the backend venv is missing a Python module this model needs — "
+     "re-install the model via Configure Backends (checking the model "
+     "installs its companion packages), or pip-install it into the "
+     "backend's venv manually"),
 )
 
 # Progress callback: called with an event dict. KIND is one of:
diff --git a/app/backends/sglomni/__init__.py b/app/backends/sglomni/__init__.py
index 688e488..be94a0e 100644
--- a/app/backends/sglomni/__init__.py
+++ b/app/backends/sglomni/__init__.py
@@ -38,6 +38,7 @@ from .catalog import (
     entries_by_keys,
     entry_by_key,
     entry_by_repo,
+    extra_import_name,
     install_tree_families,
 )
 from .pythonenv import (
@@ -47,9 +48,11 @@ from .pythonenv import (
 )
 from .models import (
     delete_model_weights,
+    install_companions,
     install_model,
     installed_entries,
     installed_keys,
+    missing_companions,
     model_installed,
     preset_voices,
     repo_dir,
@@ -82,12 +85,14 @@ __all__ = [
     # catalog
     "CAPABILITY_CLONE", "CAPABILITY_DESIGN", "CAPABILITY_SPEAKER",
     "ENTRIES", "ModelEntry", "config_path", "entries_by_keys",
-    "entry_by_key", "entry_by_repo", "install_tree_families",
+    "entry_by_key", "entry_by_repo", "extra_import_name",
+    "install_tree_families",
     # pythonenv
     "env_compatible", "env_version", "prepare_env",
     # models
-    "delete_model_weights", "install_model", "installed_entries",
-    "installed_keys", "model_installed", "preset_voices", "repo_dir",
+    "delete_model_weights", "install_companions", "install_model",
+    "installed_entries", "installed_keys", "missing_companions",
+    "model_installed", "preset_voices", "repo_dir",
     "resolve_model", "uninstall_model",
     # status
     "build_spec", "detect", "gpu_fallback_note", "launch_config_path",
diff --git a/app/backends/sglomni/catalog.py b/app/backends/sglomni/catalog.py
index 5ff0c81..61cb11c 100644
--- a/app/backends/sglomni/catalog.py
+++ b/app/backends/sglomni/catalog.py
@@ -96,6 +96,26 @@ _DAC_EXTRAS: Tuple[Extra, ...] = (
     ("descript-audiotools==0.7.2", False),
     ("descript-audio-codec==1.0.0", False))
 
+# Companion distributions whose top-level import name differs from the pip
+# name's plain dash-to-underscore normalization (verified against their
+# top_level.txt). Anything absent here normalizes: qwen-tts -> qwen_tts.
+_EXTRA_IMPORT_OVERRIDES = {
+    "descript-audiotools": "audiotools",
+    "descript-audio-codec": "dac",
+}
+
+
+def extra_import_name(spec: str) -> str:
+    """The Python module an extras requirement SPEC provides.
+
+    Takes the distribution name portion of the pip requirement (so
+    ``qwen-tts==0.1.1`` -> ``qwen_tts``) — the name a venv probe must
+    import to prove the companion is installed."""
+    base = spec.split("=")[0].split("<")[0].split(">")[0].strip()
+    if base in _EXTRA_IMPORT_OVERRIDES:
+        return _EXTRA_IMPORT_OVERRIDES[base]
+    return base.replace("-", "_")
+
 ENTRIES: Tuple[ModelEntry, ...] = (
     ModelEntry(
         key="qwen3_tts_0_6b_customvoice",
diff --git a/app/backends/sglomni/models.py b/app/backends/sglomni/models.py
index a5211f6..607e36a 100644
--- a/app/backends/sglomni/models.py
+++ b/app/backends/sglomni/models.py
@@ -22,7 +22,8 @@ from pathlib import Path
 from typing import List, Optional
 
 from backends import common, envs
-from backends.sglomni.catalog import ModelEntry, entry_by_key, entry_by_repo
+from backends.sglomni.catalog import ModelEntry, entry_by_key, \
+    entry_by_repo, extra_import_name
 from backends.sglomni.constants import SERVER_NAME, SGLOMNI_PIP_PKG
 from backends.sglomni.pythonenv import SGLOMNI_ENV, prepare_env
 
@@ -129,6 +130,42 @@ def system_dep_missing(entry: ModelEntry) -> Optional[str]:
     return None
 
 
+def missing_companions(entry: ModelEntry) -> List[Extra]:
+    """ENTRY's companion packages absent from the sglang-omni venv.
+
+    One import probe per extra (its top-level module, see
+    ``extra_import_name``) against the venv's interpreter, so a model whose
+    weights landed in the shared HF cache by another route — or whose
+    companions failed to pip-install during setup, which install_model only
+    warns about — is detected before the server dies on the import. A venv
+    that does not exist at all yields no verdict: the start flow fails on
+    the missing ``sgl-omni`` executable anyway."""
+    if not entry.extras or not envs.env_exists(SGLOMNI_ENV):
+        return []
+    return [extra for extra in entry.extras
+            if not envs.module_available(extra_import_name(extra[0]),
+                                         SGLOMNI_ENV)]
+
+
+def install_companions(entry: ModelEntry, *, emit=None, cancel=None) -> int:
+    """pip-install ENTRY's missing companion packages into the venv.
+
+    The same recipe ``install_model`` runs (the catalog's ``--no-deps``
+    flags preserved — the Qwen3-TTS companions must not replace the pinned
+    Transformers 5 stack), limited to what the import probe found absent,
+    so a start-time heal touches as little of the pinned environment as
+    possible. Returns the first failing exit code, 0 when all present."""
+    for spec, no_deps in missing_companions(entry):
+        args = ["--no-deps"] if no_deps else None
+        rc = common.pip_install([spec], emit=emit, cancel=cancel,
+                                env_dir=SGLOMNI_ENV, extra_args=args)
+        if rc != 0:
+            print(f"[ERROR] pip install {spec} failed (exit {rc}); "
+                  f"install it into {SGLOMNI_ENV} manually")
+            return rc
+    return 0
+
+
 def install_model(key: str, *, emit=None, cancel=None) -> int:
     """Install a catalog model: companion packages, then its weights.
 
@@ -157,7 +194,7 @@ def install_model(key: str, *, emit=None, cancel=None) -> int:
     note = sg_status.gpu_fallback_note(entry)
     if note:
         print(f"[WARNING] {note}")
-    for spec, no_deps in entry.extras:
+    for spec, no_deps in missing_companions(entry):
         args = ["--no-deps"] if no_deps else None
         rc = common.pip_install([spec], emit=emit, cancel=cancel,
                                 env_dir=SGLOMNI_ENV, extra_args=args)