.. image:: https://img.shields.io/pypi/v/eccodes.svg
   :target: https://pypi.python.org/pypi/eccodes/

Python 3 interface to decode and encode GRIB and BUFR files via the
`ECMWF ecCodes library <https://confluence.ecmwf.int/display/ECC/>`_.

Features:

- reads and writes GRIB 1 and 2 files,
- reads and writes BUFR 3 and 4 files,
- supports all modern versions of Python and PyPy3,
- works on most *Linux* distributions and *MacOS*, the *ecCodes* C-library
  is the only system dependency,
- PyPI package can be installed without compiling,
  at the cost of being twice as slow as the original *ecCodes* module,
- an optional compile step makes the code as fast as the original module
  but it needs the recommended (the most up-to-date) version of *ecCodes*.

Limitations:

- Microsoft Windows support is untested.


Installation
============

**From version 2.37.0, the ecCodes Python bindings additionally provide the ecCodes binary library, and will
follow the version numbering of the ecCodes binary library. See below for details.**


The package can be installed from PyPI with::

    $ pip install eccodes

This installation will, by default, include the ecCodes binary library (as of version 2.37.0), meaning that no
external ecCodes binary library is required. If you have an external ecCodes binary library that you wish to use,
set the following environment variable before you import eccodes::

    $ export ECCODES_PYTHON_USE_FINDLIBS=1

If this is set, the ecCodes' Python bindings will use the `findlibs <https://github.com/ecmwf/findlibs>`_ package
to locate the binary library (findlibs was the only mechanism used before version 2.37.0).

In order to gain insights into the search for the binary library, set the following environment variable before
importing eccodes::

    $ export ECCODES_PYTHON_TRACE_LIB_SEARCH=1
 
You may also install a version of ecCodes' Python interface that does not include a binary library at all,
in which case the findlibs mechanism will be used as before::

    $ pip install eccodes --no-binary eccodes


System dependencies
-------------------

The Python module depends on the ECMWF *ecCodes* library. From version 2.37.0, this is supplied with
the Python module. If you wish to install and use a separate binary library (see above), it
must be installed on the system and accessible as a shared library.

On a MacOS with HomeBrew use::

    $ brew install eccodes

Or if you manage binary packages with *Conda* use::

    $ conda install -c conda-forge eccodes

As an alternative you may install the official source distribution
by following the instructions at
https://confluence.ecmwf.int/display/ECC/ecCodes+installation

You may run a simple selfcheck command to ensure that your system is set up correctly::

    $ python -m eccodes selfcheck
    Found: ecCodes v2.37.0.
    Your system is ready.


Usage
-----

Refer to the *ecCodes* `documentation pages <https://confluence.ecmwf.int/display/ECC/Documentation>`_
for usage.


Experimental features
=====================

Fast bindings
-------------

To test the much faster *CFFI* API level, out-of-line mode you need the
*ecCodes* header files.
Then you need to clone the repo in the same folder as your *ecCodes*
source tree, make a ``pip`` development install and custom compile
the binary bindings::

    $ git clone https://github.com/ecmwf/eccodes-python
    $ cd eccodes-python
    $ pip install -e .
    $ python builder.py

To revert back to ABI level, in-line mode just remove the compiled bindings::

    $ rm gribapi/_bindings.*


Project resources
=================

============= =========================================================
Development   https://github.com/ecmwf/eccodes-python
Download      https://pypi.org/project/eccodes
============= =========================================================


Contributing
============

The main repository is hosted on GitHub,
testing, bug reports and contributions are highly welcomed and appreciated:

https://github.com/ecmwf/eccodes-python

Please see the CONTRIBUTING.rst document for the best way to help.

Maintainer:

- `Shahram Najm <https://github.com/shahramn>`_ - `ECMWF <https://ecmwf.int>`_

Contributors:

- `Alessandro Amici <https://github.com/alexamici>`_ - `B-Open <https://bopen.eu>`_

See also the list of `contributors <https://github.com/ecmwf/eccodes-python/contributors>`_
who participated in this project.

.. |copy|   unicode:: U+000A9 .. COPYRIGHT SIGN

License
=======

|copy| Copyright 2017- ECMWF.

This software is licensed under the terms of the Apache Licence Version 2.0
which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.

In applying this licence, ECMWF does not waive the privileges and immunities
granted to it by virtue of its status as an intergovernmental organisation nor
does it submit to any jurisdiction.
