segrails.utils¶

Utility helpers for the Segrails library.

Builds blob paths and APIM URLs from a SegrailsConfig instance, and provides device resolution with safe CPU fallback.

Example

>>> from altametris.segrails.config import SegrailsConfig
>>> from altametris.segrails.utils import get_weight_blob_path, get_apim_weight_url
>>> config = SegrailsConfig()
>>> get_weight_blob_path(config, "model.pt")
'segrails/model.pt'

Functions¶

`get_weight_blob_path`(→ str)	Build the blob path for a weight file.
`get_apim_weight_url`(→ str)	Build the full APIM URL to download a weight file.
`resolve_device`(→ torch.device)	Resolve a device string to a `torch.device`, with silent CPU fallback.

Module Contents¶

segrails.utils.get_weight_blob_path(config: altametris.segrails.config.SegrailsConfig, filename: str) → str¶

Build the blob path for a weight file.

Prepends weights_prefix to the filename when a prefix is configured.

Parameters:

config – Segrails configuration instance.
filename – Weight file name (e.g. “model.pt”).

Returns:

Full path in the container (e.g. “segrails/model.pt”), or just the filename when no prefix is set.

Example

>>> config = SegrailsConfig(weights_prefix="segrails")
>>> get_weight_blob_path(config, "model.pt")
'segrails/model.pt'

>>> config = SegrailsConfig(weights_prefix="")
>>> get_weight_blob_path(config, "model.pt")
'model.pt'

segrails.utils.get_apim_weight_url(config: altametris.segrails.config.SegrailsConfig, filename: str) → str¶

Build the full APIM URL to download a weight file.

Parameters:

config – Segrails configuration instance.
filename – Weight file name (e.g. “model.pt”).

Returns:

//apim.example.com/weights/segrails/model.pt”).

Return type:

Full APIM URL (e.g. “https

Raises:

ValueError – If api_base_url is not configured.

Example

>>> config = SegrailsConfig(
...     api_base_url="https://am-ds-apim-dev.azure-api.net",
...     weights_prefix="segrails",
... )
>>> get_apim_weight_url(config, "model.pt")
'https://am-ds-apim-dev.azure-api.net/weights/segrails/model.pt'

segrails.utils.resolve_device(device: str) → torch.device¶

Resolve a device string to a torch.device, with silent CPU fallback.

Normalises "gpu" to "cuda". If CUDA is requested but unavailable, falls back to "cpu" and logs a warning instead of raising.

Parameters:: device – Device string — "cpu", "cuda", "gpu", or any value accepted by torch.device (e.g. "cuda:0").
Returns:: Resolved torch.device.

Example

>>> resolve_device("cpu")
device(type='cpu')
>>> # resolve_device("gpu") returns device(type='cuda') when CUDA is
>>> # available, or device(type='cpu') with a warning otherwise.