When executing Snakemake workflows in containers, the container images may exist in a private registry that the Latch cloud cannot access. Downloading images from private registries at runtime requires two steps:
  1. Upload your private container registry’s password/access token to the Latch platform. See Storing and using Secrets.
  2. Add the docker_metadata field to your workflow’s SnakemakeMetadata object so the workflow engine knows where to pull your credentials. For example:
# latch_metadata.py
from latch.types.metadata import SnakemakeMetadata, SnakemakeFileParameter, DockerMetadata
from latch.types.directory import LatchDir
from latch.types.metadata import LatchAuthor, LatchMetadata, LatchParameter
from pathlib import Path

SnakemakeMetadata(
    display_name="snakemake_tutorial_workflow",
    author=LatchAuthor(
            name="latchbio",
    ),
    env_config=EnvironmentConfig(
      use_conda=False,
      use_container=True,
    ),
    docker_metadata=DockerMetadata(
      username="user0",
      secret_name="LATCH_SECRET_NAME",
    ),
    ...
)
Note: the secret_name field specifies the name of the Latch Secret uploaded in step #1, NOT the actual registry password.