create_env.py

import os
import subprocess
import sys

def setup_dependencies():
    """Install NeMo and pin transformers in the right order to satisfy
    gradio 6.20's huggingface-hub>=1.2 requirement while still ending up
    on transformers 5.3.0 (which the Gepard checkpoint needs).

    Why not put nemo-toolkit in requirements.txt? NeMo's
    ``nemo-toolkit[tts]==2.4.0`` pulls in ``transformers<=4.52`` (which
    resolves to 4.51.x), and that requires ``huggingface-hub<1.0`` —
    conflicting with gradio 6.20's ``huggingface-hub>=1.2`` at build time
    so pip refuses to resolve. We install nemo-toolkit itself at runtime
    with ``--no-deps`` instead.

    All of NeMo's OTHER [tts] dependencies (librosa, soundfile, omegaconf,
    matplotlib, seaborn, einops, kornia, lhotse, lightning, peft,
    torchmetrics, datasets, …) are pre-installed at build time from
    requirements.txt — the complete list minus the conflicting
    transformers pin (source: pypi.org/pypi/nemo-toolkit/2.4.0/json).
    So installing nemo with --no-deps doesn't miss anything import-time.

    Order is load-bearing:
      1. transformers==5.3.0 with --no-deps — forces the runtime onto the
         Qwen3.5 backbone version the Gepard checkpoint was trained on.
         Combined with the pre-installed hub>=1.2, satisfies gradio 6.20.
      2. nemo-toolkit[tts]==2.4.0 with --no-deps — installed on top of
         transformers 5.3.0 without re-resolving its declared (conflicting)
         transformers<=4.52 constraint.
      3. numpy<2.0 — keep the NeMo/codec stack on numpy 1.x.

    Idempotent: writes a sentinel file so the install only runs once per
    container.
    """
    os.environ["OMP_NUM_THREADS"] = "4"

    sentinel = "/tmp/deps_installed"
    if os.path.exists(sentinel):
        return

    pip = [sys.executable, "-m", "pip", "install", "--no-cache-dir"]
    try:
        # 1. Pin the transformers + hub versions gradio 6.20 needs, before
        #    NeMo gets a chance to downgrade them. --no-deps because we
        #    already have these libraries installed at compatible versions.
        print("Pinning transformers==5.3.0 + hub>=1.2 (no-deps) ...")
        subprocess.check_call(pip + [
            "--no-deps", "transformers==5.3.0", "huggingface-hub>=1.2,<2.0",
        ])

        # 2. Install NeMo on top without re-resolving dependencies. Its
        #    declared transformers<=4.52 / hub<1.0 would conflict; with
        #    --no-deps the resolver doesn't see those constraints.
        print("Installing nemo-toolkit[tts]==2.4.0 (no-deps) ...")
        subprocess.check_call(pip + ["--no-deps", "nemo-toolkit[tts]==2.4.0"])

        # 3. Cap numpy so a transitive bump doesn't break the NeMo/codec
        #    stack, which is built against numpy 1.x.
        print("Capping numpy<2.0 ...")
        subprocess.check_call(pip + ["numpy<2.0"])

        with open(sentinel, "w") as f:
            f.write("done")

    except Exception as e:
        print(f"Dependencies setup error: {e}")
        raise