[cli] adds ability to override reader/writer options from cli convert.

bonobo/commands/convert.py

@@ -1,7 +1,10 @@
 import mimetypes
 import os
 
+import re
+
 import bonobo
+from bonobo.commands.util.arguments import parse_variable_argument
 
 SHORTCUTS = {
     'csv': 'text/csv',
@@ -23,7 +26,7 @@ READER = 'reader'
 WRITER = 'writer'
 
 
-def resolve_factory(name, filename, factory_type):
+def resolve_factory(name, filename, factory_type, options=None):
     """
     Try to resolve which transformation factory to use for this filename. User eventually provided a name, which has
     priority, otherwise we try to detect it using the mimetype detection on filename.
@@ -42,6 +45,12 @@ def resolve_factory(name, filename, factory_type):
         if _ext in SHORTCUTS:
             name = SHORTCUTS[_ext]
 
+    if options:
+        options = dict(map(parse_variable_argument, options))
+
+    else:
+        options = dict()
+
     if not name in REGISTRY:
         raise RuntimeError(
             'Could not resolve {factory_type} factory for {filename} ({name}). Try providing it explicitely using -{opt} <format>.'.
@@ -49,19 +58,22 @@ def resolve_factory(name, filename, factory_type):
         )
 
     if factory_type == READER:
-        return REGISTRY[name][0]
+        return REGISTRY[name][0], options
     elif factory_type == WRITER:
-        return REGISTRY[name][1]
+        return REGISTRY[name][1], options
     else:
         raise ValueError('Invalid factory type.')
 
 
 def execute(input, output, reader=None, reader_options=None, writer=None, writer_options=None, options=None):
-    reader = resolve_factory(reader, input, READER)(input)
-    writer = resolve_factory(writer, output, WRITER)(output)
+    reader_factory, reader_options = resolve_factory(reader, input, READER, (options or []) + (reader_options or []))
+    writer_factory, writer_options = resolve_factory(writer, output, WRITER, (options or []) + (writer_options or []))
 
     graph = bonobo.Graph()
-    graph.add_chain(reader, writer)
+    graph.add_chain(
+        reader_factory(input, **reader_options),
+        writer_factory(output, **writer_options),
+    )
 
     return bonobo.run(
         graph, services={
@@ -71,11 +83,37 @@ def execute(input, output, reader=None, reader_options=None, writer=None, writer
 
 
 def register(parser):
-    parser.add_argument('input')
-    parser.add_argument('output')
-    parser.add_argument('--' + READER, '-r')
-    parser.add_argument('--' + WRITER, '-w')
-    # parser.add_argument('--reader-option', '-ro', dest='reader_options')
-    # parser.add_argument('--writer-option', '-wo', dest='writer_options')
-    # parser.add_argument('--option', '-o', dest='options')
+    parser.add_argument('input', help='Input filename.')
+    parser.add_argument('output', help='Output filename.')
+    parser.add_argument(
+        '--' + READER,
+        '-r',
+        help='Choose the reader factory if it cannot be detected from extension, or if detection is wrong.'
+    )
+    parser.add_argument(
+        '--' + WRITER,
+        '-w',
+        help='Choose the writer factory if it cannot be detected from extension, or if detection is wrong.'
+    )
+    parser.add_argument(
+        '--option',
+        '-O',
+        dest='options',
+        action='append',
+        help='Add a named option to both reader and writer factories (i.e. foo="bar").'
+    )
+    parser.add_argument(
+        '--' + READER + '-option',
+        '-' + READER[0].upper(),
+        dest=READER + '_options',
+        action='append',
+        help='Add a named option to the reader factory.'
+    )
+    parser.add_argument(
+        '--' + WRITER + '-option',
+        '-' + WRITER[0].upper(),
+        dest=WRITER + '_options',
+        action='append',
+        help='Add a named option to the writer factory.'
+    )
     return execute

bonobo/commands/util/arguments.py

@@ -0,0 +1,26 @@
+import json
+
+
+def parse_variable_argument(arg):
+    try:
+        key, val = arg.split('=', 1)
+    except ValueError:
+        return arg, True
+
+    try:
+        val = json.loads(val)
+    except json.JSONDecodeError:
+        pass
+
+    return key, val
+
+
+def test_parse_variable_argument():
+    assert parse_variable_argument('foo=bar') == ('foo', 'bar')
+    assert parse_variable_argument('foo="bar"') == ('foo', 'bar')
+    assert parse_variable_argument('sep=";"') == ('sep', ';')
+    assert parse_variable_argument('foo') == ('foo', True)
+
+
+if __name__ == '__main__':
+    test_parse_var()