> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.nvidia.com/nemo/gym/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.nvidia.com/nemo/gym/_mcp/server.

# nemo_gym.orchestration.executors.script_templates

## Module Contents

### Functions

| Name                                                                                                                  | Description                                                                                  |
| --------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------- |
| [`bash_var`](#nemo_gym-orchestration-executors-script_templates-bash_var)                                             | -                                                                                            |
| [`escape_for_single_quoted_block`](#nemo_gym-orchestration-executors-script_templates-escape_for_single_quoted_block) | Make `body` safe to embed inside a single-quoted `bash -c '...'` block.                      |
| [`render_driver_entrypoint`](#nemo_gym-orchestration-executors-script_templates-render_driver_entrypoint)             | Render the srun entrypoint for the driver step.                                              |
| [`render_gym_cmd`](#nemo_gym-orchestration-executors-script_templates-render_gym_cmd)                                 | Render a bash array with each argument on its own line.                                      |
| [`render_health_check`](#nemo_gym-orchestration-executors-script_templates-render_health_check)                       | -                                                                                            |
| [`render_ray_prelude`](#nemo_gym-orchestration-executors-script_templates-render_ray_prelude)                         | -                                                                                            |
| [`render_repo_checkout`](#nemo_gym-orchestration-executors-script_templates-render_repo_checkout)                     | Render an &&-chained command that installs git if missing, then clones and checks out `ref`. |
| [`render_vllm_ray_symmetric_run`](#nemo_gym-orchestration-executors-script_templates-render_vllm_ray_symmetric_run)   | Render the Ray head/worker bootstrap that wraps a single vLLM instance's TP/PP command so    |
| [`render_write_file_from_base64`](#nemo_gym-orchestration-executors-script_templates-render_write_file_from_base64)   | Render a command that reconstructs `content` at `dest_path` via a base64 round-trip.         |

### Data

[`ENSURE_RAY_INSTALLED`](#nemo_gym-orchestration-executors-script_templates-ENSURE_RAY_INSTALLED)

[`RAY_SERVE_QUEUE_LENGTH_RESPONSE_DEADLINE_S`](#nemo_gym-orchestration-executors-script_templates-RAY_SERVE_QUEUE_LENGTH_RESPONSE_DEADLINE_S)

[`RAY_SYMMETRIC_RUN_CLUSTER_WAIT_TIMEOUT_S`](#nemo_gym-orchestration-executors-script_templates-RAY_SYMMETRIC_RUN_CLUSTER_WAIT_TIMEOUT_S)

[`_HEALTH_WAIT_MULTI`](#nemo_gym-orchestration-executors-script_templates-_HEALTH_WAIT_MULTI)

[`_RAY_PRELUDE`](#nemo_gym-orchestration-executors-script_templates-_RAY_PRELUDE)

[`_VLLM_RAY_SYMMETRIC_RUN`](#nemo_gym-orchestration-executors-script_templates-_VLLM_RAY_SYMMETRIC_RUN)

### API

```python
nemo_gym.orchestration.executors.script_templates.bash_var(
    name: str
) -> str
```

```python
nemo_gym.orchestration.executors.script_templates.escape_for_single_quoted_block(
    body: str
) -> str
```

Make `body` safe to embed inside a single-quoted `bash -c '...'` block.

POSIX shells do not nest single quotes: an inner quote ENDS the outer string
rather than nesting in it. Every value that had to be quoted -- a Hydra
override containing a space, or any of the JSON blobs vLLM flags take
(`--hf-overrides '{"architectures":[...]}'`) -- would otherwise break out of
the block and word-split. Both failure modes have been observed on real
submissions: Hydra rejecting `+multistage.stages=[{num_tasks:` on its own,
and `/usr/bin/env: Argument list too long` from a multi-node vLLM command
whose JSON flags reopened the quoting.

`'"'"'` is the standard end-quote / literal-quote / reopen-quote sequence.
It leaves `$VAR` and `$(( ))` untouched, which matters: the inner shell is
the one meant to expand them.

```python
nemo_gym.orchestration.executors.script_templates.render_driver_entrypoint(
    repo: str | None,
    ref: str | None,
    prepare_cmd: str | None
) -> str
```

Render the srun entrypoint for the driver step.

When either gym\_install or prepare is needed, wraps everything in a single
bash -c so prepare and run happen in the same srun step and container.

```python
nemo_gym.orchestration.executors.script_templates.render_gym_cmd(
    subcommand: str,
    var_name: str,
    args: list[str]
) -> str
```

Render a bash array with each argument on its own line.

```python
nemo_gym.orchestration.executors.script_templates.render_health_check(
    name: str,
    port: int,
    path: str,
    timeout: int
) -> str
```

```python
nemo_gym.orchestration.executors.script_templates.render_ray_prelude() -> str
```

```python
nemo_gym.orchestration.executors.script_templates.render_repo_checkout(
    repo: str,
    ref: str,
    dest: str | None = None
) -> str
```

Render an &&-chained command that installs git if missing, then clones and checks out `ref`.

`dest` is emitted verbatim so it may be a shell expression (the driver passes
`"$GYM_SRC/gym"` to clone outside the job directory); omit it to clone into a
directory named after the repo in the current one.

```python
nemo_gym.orchestration.executors.script_templates.render_vllm_ray_symmetric_run(
    inner_cmd: str,
    total_nodes: int,
    resource_flags: str
) -> str
```

Render the Ray head/worker bootstrap that wraps a single vLLM instance's TP/PP command so
it spans multiple Slurm nodes.

Uses `ray symmetric-run` when available (Ray >= 2.50), which starts/joins a Ray cluster across
every task and runs the entrypoint only on the elected head node. Containers with an older Ray
pin fall back to manually starting head/worker Ray processes, keyed on Slurm's per-node task
rank (\$SLURM\_NODEID).

```python
nemo_gym.orchestration.executors.script_templates.render_write_file_from_base64(
    content: str,
    dest_path: str
) -> str
```

Render a command that reconstructs `content` at `dest_path` via a base64 round-trip.

```python
nemo_gym.orchestration.executors.script_templates.ENSURE_RAY_INSTALLED = 'command -v ray >/dev/null 2>&1 || pip install -q "ray[default]"'
```

```python
nemo_gym.orchestration.executors.script_templates.RAY_SERVE_QUEUE_LENGTH_RESPONSE_DEADLINE_S = 1.0
```

```python
nemo_gym.orchestration.executors.script_templates.RAY_SYMMETRIC_RUN_CLUSTER_WAIT_TIMEOUT_S = 600
```

```python
nemo_gym.orchestration.executors.script_templates._HEALTH_WAIT_MULTI = '# Wait for {name} (try multiple health endpoints)\necho "Waiting for {name} at ...
```

```python
nemo_gym.orchestration.executors.script_templates._RAY_PRELUDE = '# Resolve the head node IP for multi-node vLLM services (spanning nodes via Ray...
```

```python
nemo_gym.orchestration.executors.script_templates._VLLM_RAY_SYMMETRIC_RUN = "bash -lc '\n    export RAY_SYMMETRIC_RUN_CLUSTER_WAIT_TIMEOUT=" + str(RAY_SYMME...
```