[TAAS-23] Added a single-source processor and front-end.

setup.py

@@ -7,7 +7,7 @@
     py_modules=['taas'],
     entry_points={
         'console_scripts': [
-            "fetch = taas:process_all_sources",
+            "gss2json = taas.cmdline:gss2json"
         ]
     },
 

taas/__init__.py

@@ -225,34 +225,34 @@ def google_sheet_to_json(name, version, key, gid, mapping, directory=None):
 def process_source(source_name, source):
     """
         Processes a source, generating JSON and potentially other supporting
-        files. Right now this is only able to flip sheets to JSON, but we may
-        support other services in the future.
+        files.
 
-        Expects a dictionary of vesions, with service descriptions underneath.
+        Expects a `source_name`, with which we label our output, and a dictionary
+        of vesions, with service descriptions underneath.
     """
 
     # TODO: We should have a service class definition, rather than trusting our
     #       config file is in the right format.
 
     for version in source:
-
         options = source[version]
 
         google_sheet_to_json(
             source_name, version, options['key'], options['gid'], options['mapping']
         )
 
 
-def process_all_sources(config=None):
-    """
-        Processes all sources in a given config, generating JSON output. Uses
-        the default config if none supplied.
+def process_sources(config, sources=None):
     """
+        Uses the config provided to process the sources given.
 
-    if config is None:
-        config = read_config()
+        Process all sources if none are provided.
+    """
+    if sources is None:
+        sources = config['sources']
 
-    sources = config['sources']
+    for source in sources:
+        if source not in config['sources']:
+            raise KeyError("Asked to process source '{}', but not found in config.".format(source))
 
-    for source_name in sources:
-        process_source(source_name, sources[source_name])
+        process_source(source, config['sources'][source])

taas/cmdline.py

@@ -0,0 +1,38 @@
+import argparse
+import taas
+
+"""Command-line interfaces to TAAS functions."""
+
+
+def gss2json():
+    """Console script for processing google spreadsheet(s) to JSON."""
+
+    parser = argparse.ArgumentParser(
+        description='''
+            Processes Google spreadsheet(s) to JSON.
+
+            If no arguments are given, all sheets will be processed.
+        '''
+    )
+
+    parser.add_argument('--config', metavar="FILE", help="Config file to use.")
+
+    parser.add_argument(
+        'sheets',
+        metavar='sheet',
+        nargs="*",
+        help="A sheet to process, as named in the config file",
+    )
+
+    args = parser.parse_args()
+
+    # This reads the default file if none is specified.
+    config = taas.read_config(args.config)
+
+    # Sheets always comes back as a list. We flip it explicitly to
+    # a None value if it's empty.
+    sheets = args.sheets
+    if not sheets:
+        sheets = None
+
+    taas.process_sources(config, sheets)