tap-grib

tap-grib is a Singer tap for Grib files extractions. It has been tested on ERA5 datasets so far but could be extended to more use cases.

Built with the Meltano Tap SDK for Singer Taps.

Installation

Install from PyPI:

uv tool install tap-grib

Install from GitHub:

uv tool install git+https://github.com/ORG_NAME/tap-grib.git@main

Capabilities

• catalog
• discover

Supported Python Versions

• 3.10
• 3.11
• 3.12
• 3.13
• 3.14

Configuration

Note: Use a tool like ECCODES to view the grib structure and associate proper configurations. E.g.

grib_ls ./data/test.grib  | less

Accepted Config Options

Settings

Setting	Required	Default	Description
paths	True	None	List of GRIB file path definitions (supports globs).
stream_maps	False	None	Config object for stream maps capability. For more information check out Stream Maps.
stream_maps.else	False	None	Currently, only setting this to __NULL__ is supported. This will remove all other streams.
stream_map_config	False	None	User-defined config values to be used within map expressions.
faker_config	False	None	Config for the Faker instance variable fake used within map expressions. Only applicable if the plugin specifies faker as an additional dependency (through the singer-sdk faker extra or directly).
faker_config.seed	False	None	Value to seed the Faker generator for deterministic output: https://faker.readthedocs.io/en/master/#seeding-the-generator
faker_config.locale	False	None	One or more LCID locale strings to produce localized output for: https://faker.readthedocs.io/en/master/#localization
flattening_enabled	False	None	'True' to enable schema flattening and automatically expand nested properties.
flattening_max_depth	False	None	The max depth to flatten schemas.

A full list of supported settings and capabilities for this tap is available by running:

tap-grib --about --format=markdown

Examples

config:
  paths:
    # all values in a table
    - path: ./data/test.grib
      # optional bboxes filter, skip records outside the bbox
      # format for bbox is [north_lat, west_lon, south_lat, east_lon]
      bboxes: 
       - [7.0, 45.0, 12.0, 48.0]  # Western Europe
      # optional table name, defaults to file name
      table_name: my_table
      # skip the listed columns
      ignore_fields:
        - ensemble
        - grid_type
        - centre
        - edition
      # drop messages from the past
      skip_past: True
      # drop messages before this reference date, defaults to now
      # skip_past_reference: 2025-01-01

    # test with local docker compose (eg. docker compose up)
    - path: s3://local-data/test.grib
      table_name: s3_test
      ignore_fields:
        - ensemble
        - grid_type
        - centre
        - edition

To use an S3-based storage ensure to provide those envirnoment variables:

• S3_ACCESS_KEY_ID, S3_SECRET_ACCESS_KEY access key/secret pair
• S3_ENDPOINT_URL Custom S3 endpoint such as minio or compatible interface

Example:

S3_ACCESS_KEY_ID=minioadmin S3_SECRET_ACCESS_KEY=minioadmin S3_ENDPOINT_URL=http://localhost:19000 meltano run tap-grib target-jsonl

Configure using environment variables

This Singer tap will automatically import any environment variables within the working directory's .env if the --config=ENV is provided, such that config values will be considered if a matching environment variable is set either in the terminal context or in the .env file.

Usage

You can easily run tap-grib by itself or in a pipeline using Meltano.

Executing the Tap Directly

tap-grib --version
tap-grib --help
tap-grib --config CONFIG --discover > ./catalog.json

Developer Resources

Follow these instructions to contribute to this project.

Initialize your Development Environment

Prerequisites:

• Python 3.10+
• uv

uv sync

Create and Run Tests

Create tests within the tests subfolder and then run:

uv run pytest

You can also test the tap-grib CLI interface directly using uv run:

uv run tap-grib --help

Testing with Meltano

Note: This tap will work in any Singer environment and does not require Meltano. Examples here are for convenience and to streamline end-to-end orchestration scenarios.

Next, install Meltano (if you haven't already) and any needed plugins:

# Install meltano
uv tool install meltano
# Initialize meltano within this directory
cd tap-grib
meltano install

Now you can test and orchestrate using Meltano:

# Test invocation:
meltano invoke tap-grib --version

# OR run a test ELT pipeline:
meltano run tap-grib target-jsonl

SDK Dev Guide

See the dev guide for more instructions on how to use the SDK to develop your own taps and targets.