Refactoring and fixes around ioformats.

bonobo/commands/run.py

@@ -6,6 +6,7 @@ DEFAULT_SERVICES_ATTR = 'get_services'
 DEFAULT_GRAPH_FILENAME = '__main__.py'
 DEFAULT_GRAPH_ATTR = 'get_graph'
 
+
 def get_default_services(filename, services=None):
     dirname = os.path.dirname(filename)
     services_filename = os.path.join(dirname, DEFAULT_SERVICES_FILENAME)

bonobo/examples/files/csv_handlers.py

@@ -2,7 +2,7 @@ import bonobo
 from bonobo.commands.run import get_default_services
 
 graph = bonobo.Graph(
-    bonobo.CsvReader('datasets/coffeeshops.txt', headers=('item',)),
+    bonobo.CsvReader('datasets/coffeeshops.txt', headers=('item', )),
     bonobo.PrettyPrinter(),
 )
 

bonobo/examples/files/pickle_handlers.py

@@ -52,12 +52,7 @@ graph = bonobo.Graph(
 
 
 def get_services():
-    return {
-        'fs':
-            TarFS(
-                bonobo.get_examples_path('datasets/spam.tgz')
-            )
-    }
+    return {'fs': TarFS(bonobo.get_examples_path('datasets/spam.tgz'))}
 
 
 if __name__ == '__main__':

bonobo/examples/tutorials/tut01e02.py

@@ -1,7 +1,11 @@
 import bonobo
 
 graph = bonobo.Graph(
-    ['foo', 'bar', 'baz', ],
+    [
+        'foo',
+        'bar',
+        'baz',
+    ],
     str.upper,
     print,
 )

bonobo/nodes/io/csv.py

@@ -59,7 +59,7 @@ class CsvReader(CsvHandler, FileReader):
 
         for row in reader:
             if len(row) != field_count:
-                raise ValueError('Got a line with %d fields, expecting %d.' % (len(row), field_count,))
+                raise ValueError('Got a line with %d fields, expecting %d.' % (len(row), field_count, ))
 
             yield self.get_output(dict(zip(_headers, row)))
 

bonobo/nodes/io/file.py

@@ -21,10 +21,8 @@ class FileHandler(Configurable):
     eol = Option(str, default='\n')  # type: str
     mode = Option(str)  # type: str
     encoding = Option(str, default='utf-8')  # type: str
-
     fs = Service('fs')  # type: str
-
-    ioformat = Option(settings.validate_io_format, default=settings.IOFORMAT)
+    ioformat = Option(default=settings.IOFORMAT.get)
 
     @ContextProcessor
     def file(self, context, fs):

bonobo/settings.py

@@ -1,6 +1,5 @@
-import os
-
 import logging
+import os
 
 from bonobo.errors import ValidationError
 
@@ -13,6 +12,36 @@ def to_bool(s):
     return False
 
 
+class Setting:
+    def __init__(self, name, default=None, validator=None):
+        self.name = name
+
+        if default:
+            self.default = default if callable(default) else lambda: default
+        else:
+            self.default = lambda: None
+
+        if validator:
+            self.validator = validator
+        else:
+            self.validator = None
+
+    def __repr__(self):
+        return '<Setting {}={!r}>'.format(self.name, self.value)
+
+    def set(self, value):
+        if self.validator and not self.validator(value):
+            raise ValidationError('Invalid value {!r} for setting {}.'.format(value, self.name))
+        self.value = value
+
+    def get(self):
+        try:
+            return self.value
+        except AttributeError:
+            self.value = self.default()
+            return self.value
+
+
 # Debug/verbose mode.
 DEBUG = to_bool(os.environ.get('DEBUG', 'f'))
 
@@ -34,21 +63,9 @@ IOFORMATS = {
     IOFORMAT_KWARGS,
 }
 
-IOFORMAT = os.environ.get('IOFORMAT', IOFORMAT_KWARGS)
-
-
-def validate_io_format(v):
-    if callable(v):
-        return v
-    if v in IOFORMATS:
-        return v
-    raise ValidationError('Unsupported format {!r}.'.format(v))
+IOFORMAT = Setting('IOFORMAT', default=IOFORMAT_KWARGS, validator=IOFORMATS.__contains__)
 
 
 def check():
     if DEBUG and QUIET:
         raise RuntimeError('I cannot be verbose and quiet at the same time.')
-
-    if IOFORMAT not in IOFORMATS:
-        raise RuntimeError('Invalid default input/output format.')
-

bonobo/util/iterators.py

@@ -21,7 +21,7 @@ def force_iterator(mixed):
 def ensure_tuple(tuple_or_mixed):
     if isinstance(tuple_or_mixed, tuple):
         return tuple_or_mixed
-    return (tuple_or_mixed,)
+    return (tuple_or_mixed, )
 
 
 def tuplize(generator):