Add auto-formatter to CI

.gitignore

@@ -3,6 +3,9 @@ __pycache__/
 *.py[cod]
 *$py.class
 
+# Static typed files
+.pytype
+
 # C extensions
 *.so
 
@@ -76,4 +79,4 @@ venv.bak/
 .docker-tox/
 tests/sample-data/cds*.grib
 tests/sample-data/cds*.nc
-*.idx
+*.idx

.travis.yml

@@ -5,8 +5,8 @@ sudo: false # use container based build
 matrix:
   fast_finish: true
   include:
-  - env: ENV=py36
-  - env: ENV=py37
+    - env: ENV=py36
+    - env: ENV=py37
 
 before_install:
   - wget http://repo.continuum.io/miniconda/Miniconda3-3.16.0-Linux-x86_64.sh -O miniconda.sh;
@@ -24,15 +24,16 @@ install:
   - pip install --no-deps -e .
 
 script:
+  - black --check .
   - which python
   - python --version
   - python -c "import eccodes"
   - if [[ "$ENV" == "docs" ]]; then
-      sphinx-build -W -b html docs build/sphinx/html;
+    sphinx-build -W -b html docs build/sphinx/html;
     elif [[ "$ENV" == *"-qc" ]]; then
-      pytest -v --flakes --doctest-glob="*.rst" --cov=eccodes --cov=gribapi --cov-report term-missing --pep8 --mccabe $EXTRA_FLAGS;
+    pytest -v --flakes --doctest-glob="*.rst" --cov=eccodes --cov=gribapi --cov-report term-missing --pep8 --mccabe $EXTRA_FLAGS;
     else
-      pytest -v --cov=eccodes --cov=gribapi --cov-report term-missing $EXTRA_FLAGS;
+    pytest -v --cov=eccodes --cov=gribapi --cov-report term-missing $EXTRA_FLAGS;
     fi
 
 after_success:

CONTRIBUTING.rst

@@ -8,7 +8,7 @@ Contributing
 Contributions are welcome, and they are greatly appreciated! Every
 little bit helps, and credit will always be given.
 
-Please note, that we have hooked a CLA assiatant to this GitHub Repo. Please accept the contributors license agreement to allow us to keep a legal track of contributions and keep this package open source for the future.  
+Please note, that we have hooked a CLA assiatant to this GitHub Repo. Please accept the contributors license agreement to allow us to keep a legal track of contributions and keep this package open source for the future.
 
 You can contribute in many ways:
 
@@ -82,13 +82,17 @@ you already have `virtualenv` and `Git` installed and ready to go.
 
 8. If your contribution is a bug fix or new feature, you should add a test to the existing test suite.
 
-9. Commit your changes and push your branch to GitHub::
+9. Format your Python code with the Black auto-formatter, to ensure the code is uses the library's style. We use the default Black configuration (88 lines per character and `"` instead of `'` for string encapsulation)::
+
+    $ black .
+
+10. Commit your changes and push your branch to GitHub::
 
     $ git add .
     $ git commit -m "Your detailed description of your changes."
     $ git push origin name-of-your-bugfix-or-feature
 
-10. Submit a pull request through the GitHub website.
+11. Submit a pull request through the GitHub website.
 
 Pull Request Guidelines
 -----------------------

builder.py

@@ -5,14 +5,9 @@
 
 ffibuilder = cffi.FFI()
 ffibuilder.set_source(
-    "gribapi._bindings",
-    '#include <eccodes.h>',
-    libraries=["eccodes"],
-)
-ffibuilder.cdef(
-    open("gribapi/grib_api.h").read() +
-    open("gribapi/eccodes.h").read()
+    "gribapi._bindings", "#include <eccodes.h>", libraries=["eccodes"],
 )
+ffibuilder.cdef(open("gribapi/grib_api.h").read() + open("gribapi/eccodes.h").read())
 
 if __name__ == "__main__":
     try:

ci/requirements-dev.txt

@@ -11,3 +11,4 @@ tox
 tox-pyenv
 wheel
 zest.releaser
+black

ci/requirements-py36-qc.yml

@@ -15,3 +15,4 @@ dependencies:
   - pytest-pep8
   - python=3.6
   - typing
+  - black

ci/requirements-py36.yml

@@ -12,3 +12,4 @@ dependencies:
   - pytest-cov
   - python=3.6
   - typing
+  - black

ci/requirements-py37.yml

@@ -13,3 +13,4 @@ dependencies:
   - pytest-flakes
   - python=3.7
   - typing
+  - black

docs/conf.py

@@ -17,22 +17,22 @@
 
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
-extensions = ['sphinx.ext.autodoc', 'sphinx.ext.viewcode']
+extensions = ["sphinx.ext.autodoc", "sphinx.ext.viewcode"]
 
 # Add any paths that contain templates here, relative to this directory.
-templates_path = ['_templates']
+templates_path = ["_templates"]
 
 # The suffix of source filenames.
-source_suffix = '.rst'
+source_suffix = ".rst"
 
 # The encoding of source files.
 # source_encoding = 'utf-8-sig'
 
 # The master toctree document.
-master_doc = 'index'
+master_doc = "index"
 
 # General information about the project.
-project = u'eccodes-python'
+project = u"eccodes-python"
 copyright = u"2017-2019, European Centre for Medium-Range Weather Forecasts (ECMWF)."
 
 # The version info for the project you're documenting, acts as replacement
@@ -42,7 +42,7 @@
 # The full version, including alpha/beta/rc tags.
 release = pkg_resources.get_distribution("eccodes-python").version
 # The short X.Y version.
-version = '.'.join(release.split('.')[:2])
+version = ".".join(release.split(".")[:2])
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
@@ -56,7 +56,7 @@
 
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
-exclude_patterns = ['_build']
+exclude_patterns = ["_build"]
 
 # The reST default role (used for this markup: `text`) to use for all
 # documents.
@@ -74,7 +74,7 @@
 # show_authors = False
 
 # The name of the Pygments (syntax highlighting) style to use.
-pygments_style = 'sphinx'
+pygments_style = "sphinx"
 
 # A list of ignored prefixes for module index sorting.
 # modindex_common_prefix = []
@@ -88,7 +88,7 @@
 
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
-html_theme = 'default'
+html_theme = "default"
 
 # Theme options are theme-specific and customize the look and feel of a
 # theme further.  For a list of options available for each theme, see the
@@ -119,7 +119,7 @@
 # here, relative to this directory. They are copied after the builtin
 # static files, so a file named "default.css" will overwrite the builtin
 # "default.css".
-html_static_path = ['_static']
+html_static_path = ["_static"]
 
 # If not '', a 'Last updated on:' timestamp is inserted at every page
 # bottom, using the given strftime format.
@@ -165,4 +165,4 @@
 # html_file_suffix = None
 
 # Output file base name for HTML help builder.
-htmlhelp_basename = 'cfgribdoc'
+htmlhelp_basename = "cfgribdoc"

eccodes/__main__.py

@@ -29,13 +29,15 @@ def selfcheck():
 
 def main(argv=None):
     parser = argparse.ArgumentParser()
-    parser.add_argument('command')
+    parser.add_argument("command")
     args = parser.parse_args(args=argv)
-    if args.command == 'selfcheck':
+    if args.command == "selfcheck":
         selfcheck()
     else:
-        raise RuntimeError("Command not recognised %r. See usage with --help." % args.command)
+        raise RuntimeError(
+            "Command not recognised %r. See usage with --help." % args.command
+        )
 
 
-if __name__ == '__main__':  # pragma: no cover
+if __name__ == "__main__":  # pragma: no cover
     main()

eccodes/high_level/bufr.py

@@ -16,33 +16,31 @@
 class BufrMessage(CodesMessage):
 
     __doc__ = "\n".join(CodesMessage.__doc__.splitlines()[4:]).format(
-        prod_type="BUFR", classname="BufrMessage", parent="BufrFile",
-        alias="bufr")
+        prod_type="BUFR", classname="BufrMessage", parent="BufrFile", alias="bufr"
+    )
 
     product_kind = eccodes.CODES_PRODUCT_BUFR
 
     # Arguments included explicitly to support introspection
     # TODO: Can we get this to work with an index?
-    def __init__(self, codes_file=None, clone=None, sample=None,
-                 headers_only=False):
+    def __init__(self, codes_file=None, clone=None, sample=None, headers_only=False):
         """
         Open a message and inform the GRIB file that it's been incremented.
 
         The message is taken from ``codes_file``, cloned from ``clone`` or
         ``sample``, or taken from ``index``, in that order of precedence.
         """
-        super(self.__class__, self).__init__(codes_file, clone, sample,
-                                             headers_only)
-        #self._unpacked = False
+        super(self.__class__, self).__init__(codes_file, clone, sample, headers_only)
+        # self._unpacked = False
 
-    #def get(self, key, ktype=None):
+    # def get(self, key, ktype=None):
     #    """Return requested value, unpacking data values if necessary."""
     #    # TODO: Only do this if accessing arrays that need unpacking
     #    if not self._unpacked:
     #        self.unpacked = True
     #    return super(self.__class__, self).get(key, ktype)
 
-    #def missing(self, key):
+    # def missing(self, key):
     #    """
     #    Report if key is missing.#
     #
@@ -52,15 +50,15 @@ def __init__(self, codes_file=None, clone=None, sample=None,
 
     def unpack(self):
         """Decode data section"""
-        eccodes.codes_set(self.codes_id, 'unpack', 1)
+        eccodes.codes_set(self.codes_id, "unpack", 1)
 
     def pack(self):
         """Encode data section"""
-        eccodes.codes_set(self.codes_id, 'pack', 1)
+        eccodes.codes_set(self.codes_id, "pack", 1)
 
     def keys(self, namespace=None):
-        #self.unpack()
-        #return super(self.__class__, self).keys(namespace)
+        # self.unpack()
+        # return super(self.__class__, self).keys(namespace)
         iterator = eccodes.codes_bufr_keys_iterator_new(self.codes_id)
         keys = []
         while eccodes.codes_bufr_keys_iterator_next(iterator):
@@ -69,16 +67,16 @@ def keys(self, namespace=None):
         eccodes.codes_bufr_keys_iterator_delete(iterator)
         return keys
 
-    #@property
-    #def unpacked(self):
+    # @property
+    # def unpacked(self):
     #    return self._unpacked
 
-    #@unpacked.setter
-    #def unpacked(self, val):
+    # @unpacked.setter
+    # def unpacked(self, val):
     #    eccodes.codes_set(self.codes_id, "unpack", val)
     #    self._unpacked = val
 
-    #def __setitem__(self, key, value):
+    # def __setitem__(self, key, value):
     #    """Set item and pack BUFR."""
     #    if not self._unpacked:
     #        self.unpacked = True
@@ -89,9 +87,11 @@ def copy_data(self, destMsg):
         """Copy data values from this message to another message"""
         return eccodes.codes_bufr_copy_data(self.codes_id, destMsg.codes_id)
 
+
 class BufrFile(CodesFile):
 
     __doc__ = "\n".join(CodesFile.__doc__.splitlines()[4:]).format(
-        prod_type="BUFR", classname="BufrFile", alias="bufr")
+        prod_type="BUFR", classname="BufrFile", alias="bufr"
+    )
 
     MessageClass = BufrMessage

eccodes/high_level/codesfile.py

@@ -8,6 +8,7 @@
 from .. import eccodes
 import io
 
+
 class CodesFile(io.FileIO):
 
     """
@@ -50,7 +51,7 @@ def __exit__(self, exception_type, exception_value, traceback):
         while self.open_messages:
             self.open_messages.pop().close()
         eccodes.codes_close_file(self.file_handle)
-        #self.file_handle.close()
+        # self.file_handle.close()
 
     def __len__(self):
         """Return total number of messages in file."""

eccodes/high_level/codesmessage.py

@@ -62,8 +62,14 @@ class CodesMessage(object):
     #: ecCodes enum-like PRODUCT constant
     product_kind = None
 
-    def __init__(self, codes_file=None, clone=None, sample=None,
-                 headers_only=False, other_args_found=False):
+    def __init__(
+        self,
+        codes_file=None,
+        clone=None,
+        sample=None,
+        headers_only=False,
+        other_args_found=False,
+    ):
         """
         Open a message and inform the host file that it's been incremented.
 
@@ -75,16 +81,21 @@ def __init__(self, codes_file=None, clone=None, sample=None,
         :param clone: A valid ``CodesMessage``
         :param sample: A valid sample path to create ``CodesMessage`` from
         """
-        if not other_args_found and codes_file is None and clone is None and sample is None:
-            raise RuntimeError("CodesMessage initialization parameters not "
-                               "present.")
+        if (
+            not other_args_found
+            and codes_file is None
+            and clone is None
+            and sample is None
+        ):
+            raise RuntimeError("CodesMessage initialization parameters not " "present.")
         #: Unique ID, for ecCodes interface
         self.codes_id = None
         #: File containing message
         self.codes_file = None
         if codes_file is not None:
             self.codes_id = eccodes.codes_new_from_file(
-                codes_file.file_handle, self.product_kind, headers_only)
+                codes_file.file_handle, self.product_kind, headers_only
+            )
             if self.codes_id is None:
                 raise IOError("CodesFile %s is exhausted" % codes_file.name)
             self.codes_file = codes_file
@@ -93,8 +104,7 @@ def __init__(self, codes_file=None, clone=None, sample=None,
         elif clone is not None:
             self.codes_id = eccodes.codes_clone(clone.codes_id)
         elif sample is not None:
-            self.codes_id = eccodes.codes_new_from_samples(
-                sample, self.product_kind)
+            self.codes_id = eccodes.codes_new_from_samples(sample, self.product_kind)
 
     def write(self, outfile=None):
         """Write message to file."""
@@ -116,14 +126,15 @@ def __setitem__(self, key, value):
                 eccodes.codes_set(self.codes_id, key, value)
         else:
             if len(key) != len(value):
-                raise ValueError('Key array must have same size as value array')
-            eccodes.codes_set_key_vals(self.codes_id,",".join([str(key[i])+"="+str(value[i]) for i in range(len(key))]))
-
+                raise ValueError("Key array must have same size as value array")
+            eccodes.codes_set_key_vals(
+                self.codes_id,
+                ",".join([str(key[i]) + "=" + str(value[i]) for i in range(len(key))]),
+            )
 
     def keys(self, namespace=None):
         """Get available keys in message."""
-        iterator = eccodes.codes_keys_iterator_new(self.codes_id,
-                                                   namespace=namespace)
+        iterator = eccodes.codes_keys_iterator_new(self.codes_id, namespace=namespace)
         keys = []
         while eccodes.codes_keys_iterator_next(iterator):
             key = eccodes.codes_keys_iterator_get_name(iterator)