Storage

Upload and download steps enable transferring files and folders to/from H2O Drive during workflow execution.

Overview

Steps can upload and download files using H2O Drive:

• Upload to H2O Drive: Transfer local files/folders to H2O Drive.
• Download from H2O Drive: Transfer files/folders from H2O Drive to local filesystem.

These are explicit step types, distinct from shell command execution. Currently, only H2O Drive is supported as a storage backend.

Schema

See Schema Reference for the complete #UploadH2ODrive and #DownloadH2ODrive definitions.

Upload

Upload local files or folders to H2O Drive storage.

Fields

path (required)

Local filesystem path or glob pattern to upload.

Supports:

• Single files: model.pkl.
• Folders: models/ (uploads recursively).
• Glob patterns: *.log, models/**/*.pkl.

Examples:

path: model.pkl              # Single trained model
path: models/                # Entire models folder
path: "*.json"               # All metric files in current dir
path: "checkpoints/**"       # All checkpoints recursively

destination (required)

Destination in H2O Drive.

Format: drive://bucket-name/path/to/destination

Examples:

destination: drive://bucket/models/trained_model.pkl
destination: drive://bucket/experiments/exp-123/models/

Path Behavior

Single File:

upload:
  path: training.log
  destination: drive://bucket/logs/training.log
# Local: training.log → Drive: drive://bucket/logs/training.log

Folder (Recursive):

upload:
  path: models/
  destination: drive://bucket/trained-models/models/
# Local: models/model.pkl → Drive: drive://bucket/trained-models/models/model.pkl
# Local: models/checkpoints/epoch_10.h5 → Drive: drive://bucket/trained-models/models/checkpoints/epoch_10.h5
# Structure under models/ is preserved

Standard Drive Behavior:

• The base path (models/) is stripped.
• Structure under it is preserved at destination.
• Trailing / on destination indicates a directory/prefix.

Glob Pattern:

upload:
  path: "*.log"
  destination: drive://bucket/logs/
# Local: training.log → Drive: drive://bucket/logs/training.log
# Local: evaluation.log → Drive: drive://bucket/logs/evaluation.log

upload:
  path: "models/**/*.pkl"
  destination: drive://bucket/model-artifacts/
# Local: models/classifier.pkl → Drive: drive://bucket/model-artifacts/classifier.pkl
# Local: models/ensemble/voting.pkl → Drive: drive://bucket/model-artifacts/ensemble/voting.pkl
# Base (models/) is stripped, structure under it preserved

Download

Download files or folders from H2O Drive storage to local filesystem.

Fields

source (required)

Drive URL source in H2O Drive.

Format: drive://bucket-name/path/to/source

Examples:

source: drive://bucket/models/trained_model.pkl
source: drive://bucket/datasets/processed-data/

path (required)

Local filesystem destination path.

Examples:

path: ./model.pkl           # Download to specific file
path: ./data/               # Download to folder

Path Behavior

Single File:

download:
  source: drive://bucket/models/trained_model.pkl
  path: ./model.pkl
# Drive: drive://bucket/models/trained_model.pkl → Local: ./model.pkl

Folder (Recursive):

download:
  source: drive://bucket/training-artifacts/models/
  path: ./models/
# Drive: drive://bucket/training-artifacts/models/model.pkl → Local: ./models/model.pkl
# Drive: drive://bucket/training-artifacts/models/features/engineered.parquet → Local: ./models/features/engineered.parquet
# Structure is preserved

Download to Different Path:

download:
  source: drive://bucket/datasets/training-data/
  path: ./data/
# Drive: drive://bucket/datasets/training-data/features.csv → Local: ./data/features.csv

Drive URL Format

H2O Drive URLs follow the standard format:

drive://bucket-name/path/to/object

Components:

• drive:// — Protocol prefix (required).
• bucket-name — The H2O Drive workspace ID, not a free-form bucket name. This first path segment is mapped internally to workspaces/<bucket-name>, so it must be a valid workspace identifier.
• /path/to/object — Object key/path within the workspace (required).

An object path is required. A URL with no object path is rejected — both drive://bucket-name and drive://bucket-name/ (trailing slash, empty object path) fail validation. Always include a path segment after the workspace ID, for example drive://bucket-name/models/model.pkl or, for a prefix, drive://bucket-name/models/.

Common Patterns

Share Artifacts Between Jobs

jobs:
  train:
    steps:
      - name: Upload model
        upload:
          path: models/
          destination: drive://ml-artifacts/models/

  evaluate:
    depends_on: [train]
    steps:
      - name: Download model
        download:
          source: drive://ml-artifacts/models/
          path: ./models/

Download Dataset and Upload Results

steps:
  - name: Download training data
    download:
      source: drive://datasets/features.parquet
      path: ./data/features.parquet
  - name: Train and upload metrics
    run: python train.py
  - name: Upload results
    upload:
      path: "*.json"
      destination: drive://results/

Glob Patterns

Supported glob patterns:

Pattern	Description	Example
*	Match any characters (except /)	*.json matches metrics.json, config.json
**	Match any characters (including /)	models/**/*.pkl matches all .pkl files recursively
?	Match single character	model?.pkl matches model1.pkl, modelA.pkl
[abc]	Match character set	checkpoint[123].pkl matches checkpoint1.pkl, checkpoint2.pkl

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