feat: add support for environment variables

The observer's position and timezone can now be set using the following
environment variables:

- `KOSMORRO_LATITUDE`: the observer's latitude
- `KOSMORRO_LONGITUDE`: the observer's longitude
- `KOSMORRO_TIMEZONE`: the observer's timezone

.editorconfig

@@ -8,3 +8,6 @@ indent_style = space
 insert_final_newline = true
 max_line_length = 120
 trim_trailing_whitespace = true
+
+[*.md]
+trim_trailing_whitespace = false

.scripts/tests-e2e.sh

@@ -87,6 +87,11 @@ assertSuccess "kosmorro --latitude=50.5876 --longitude=3.0624 -d 2020-01-27 --ti
 assertSuccess "kosmorro --latitude=50.5876 --longitude=3.0624 -d 2020-01-27 --timezone=-1"
 assertSuccess "kosmorro --latitude=50.5876 --longitude=3.0624 -d 2020-01-27 --format=json"
 assertFailure "kosmorro --latitude=50.5876 --longitude=3.0624 -d 2020-01-27 --format=pdf"
+
+# Environment variables
+assertSuccess "LATITUDE=50.5876 LONGITUDE=3.0624 TIMEZONE=1 kosmorro -d 2020-01-27"
+assertSuccess "LATITUDE=50.5876 LONGITUDE=3.0624 TIMEZONE=-1 kosmorro -d 2020-01-27"
+
 # Missing dependencies, should fail
 assertFailure "kosmorro --latitude=50.5876 --longitude=3.0624 -d 2020-01-27 --format=pdf -o /tmp/document.pdf"
 

kosmorrolib/core.py

@@ -16,6 +16,8 @@
 #    You should have received a copy of the GNU Affero General Public License
 #    along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
+import os
+import re
 from shutil import rmtree
 from pathlib import Path
 
@@ -25,6 +27,33 @@ from skyfield.nutationlib import iau2000b
 
 CACHE_FOLDER = str(Path.home()) + '/.kosmorro-cache'
 
+class Environment:
+    def __init__(self):
+        self._vars = {}
+
+    def __set__(self, key, value):
+        self._vars[key] = value
+
+    def __getattr__(self, key):
+        return self._vars[key] if key in self._vars else None
+
+    def __str__(self):
+        return self._vars.__str__()
+
+    def __len__(self):
+        return len(self._vars)
+
+def get_env() -> Environment:
+    environment = Environment()
+
+    for var in os.environ:
+        if not re.search('^KOSMORRO_', var):
+            continue
+
+        [_, env] = var.split('_', 1)
+        environment.__set__(env.lower(), os.getenv(var))
+
+    return environment
 
 def get_loader():
     return Loader(CACHE_FOLDER)

kosmorrolib/locales/messages.pot

@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: kosmorro 0.6.2\n"
 "Report-Msgid-Bugs-To: EMAIL@ADDRESS\n"
-"POT-Creation-Date: 2020-03-19 20:13+0100\n"
+"POT-Creation-Date: 2020-03-24 13:44+0100\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -185,95 +185,101 @@ msgid ""
 "information."
 msgstr ""
 
-#: kosmorrolib/main.py:55
+#: kosmorrolib/main.py:58
 msgid ""
 "Save the planet and paper!\n"
 "Consider printing you PDF document only if really necessary, and use the "
 "other side of the sheet."
 msgstr ""
 
-#: kosmorrolib/main.py:59
+#: kosmorrolib/main.py:62
 msgid ""
 "PDF output will not contain the ephemerides, because you didn't provide "
 "the observation coordinate."
 msgstr ""
 
-#: kosmorrolib/main.py:81
+#: kosmorrolib/main.py:91
 msgid "Could not save the output in \"{path}\": {error}"
 msgstr ""
 
-#: kosmorrolib/main.py:86
+#: kosmorrolib/main.py:96
 msgid "Selected output format needs an output file (--output)."
 msgstr ""
 
-#: kosmorrolib/main.py:94
+#: kosmorrolib/main.py:104
 msgid "The date {date} does not match the required YYYY-MM-DD format."
 msgstr ""
 
-#: kosmorrolib/main.py:99
+#: kosmorrolib/main.py:109
 msgid "The date {date} is not valid: {error}"
 msgstr ""
 
-#: kosmorrolib/main.py:113
+#: kosmorrolib/main.py:123
 msgid "Running on Python {python_version}"
 msgstr ""
 
-#: kosmorrolib/main.py:119
+#: kosmorrolib/main.py:129
 msgid "Do you really want to clear Kosmorro's cache? [yN] "
 msgstr ""
 
-#: kosmorrolib/main.py:126
+#: kosmorrolib/main.py:136
 msgid "Answer did not match expected options, cache not cleared."
 msgstr ""
 
-#: kosmorrolib/main.py:135
+#: kosmorrolib/main.py:145
 msgid ""
 "Compute the ephemerides and the events for a given date, at a given "
 "position on Earth."
 msgstr ""
 
-#: kosmorrolib/main.py:137
+#: kosmorrolib/main.py:147
 msgid ""
 "By default, only the events will be computed for today ({date}).\n"
 "To compute also the ephemerides, latitude and longitude arguments are "
 "needed."
 msgstr ""
 
-#: kosmorrolib/main.py:142
+#: kosmorrolib/main.py:152
 msgid "Show the program version"
 msgstr ""
 
-#: kosmorrolib/main.py:144
+#: kosmorrolib/main.py:154
 msgid "Delete all the files Kosmorro stored in the cache."
 msgstr ""
 
-#: kosmorrolib/main.py:146
+#: kosmorrolib/main.py:156
 msgid "The format under which the information have to be output"
 msgstr ""
 
-#: kosmorrolib/main.py:148
-msgid "The observer's latitude on Earth"
+#: kosmorrolib/main.py:158
+msgid ""
+"The observer's latitude on Earth. Can also be set in the "
+"KOSMORRO_LATITUDE environment variable."
 msgstr ""
 
-#: kosmorrolib/main.py:150
-msgid "The observer's longitude on Earth"
+#: kosmorrolib/main.py:161
+msgid ""
+"The observer's longitude on Earth. Can also be set in the "
+"KOSMORRO_LONGITUDE environment variable."
 msgstr ""
 
-#: kosmorrolib/main.py:152
+#: kosmorrolib/main.py:164
 msgid ""
 "The date for which the ephemerides must be computed (in the YYYY-MM-DD "
 "format). Defaults to the current date ({default_date})"
 msgstr ""
 
-#: kosmorrolib/main.py:156
-msgid "The timezone to display the hours in (e.g. 2 for UTC+2 or -3 for UTC-3)."
+#: kosmorrolib/main.py:168
+msgid ""
+"The timezone to display the hours in (e.g. 2 for UTC+2 or -3 for UTC-3). "
+"Can also be set in the KOSMORRO_TIMEZONE environment variable."
 msgstr ""
 
-#: kosmorrolib/main.py:158
+#: kosmorrolib/main.py:171
 msgid "Disable the colors in the console."
 msgstr ""
 
-#: kosmorrolib/main.py:160
+#: kosmorrolib/main.py:173
 msgid ""
 "A file to export the output to. If not given, the standard output is "
 "used. This argument is needed for PDF format."

kosmorrolib/main.py

@@ -34,6 +34,7 @@ from .exceptions import UnavailableFeatureError
 
 
 def main():
+    environment = core.get_env()
     output_formats = get_dumpers()
     args = get_args(list(output_formats.keys()))
 
@@ -46,10 +47,12 @@ def main():
         print(colored(error.args[0], color='red', attrs=['bold']))
         return -1
 
-    if args.latitude is None or args.longitude is None:
-        position = None
-    else:
+    position = None
+
+    if args.latitude is not None or args.longitude is not None:
         position = Position(args.latitude, args.longitude)
+    elif environment.latitude is not None and environment.longitude is not None:
+        position = Position(float(environment.latitude), float(environment.longitude))
 
     if args.format == 'pdf':
         print(_('Save the planet and paper!\n'
@@ -65,8 +68,15 @@ def main():
 
         events_list = events.search_events(compute_date)
 
+        timezone = args.timezone
+
+        if timezone is None and environment.timezone is not None:
+            timezone = int(environment.timezone)
+        elif timezone is None:
+            timezone = 0
+
         selected_dumper = output_formats[args.format](ephemerides, events_list,
-                                                      date=compute_date, timezone=args.timezone,
+                                                      date=compute_date, timezone=timezone,
                                                       with_colors=args.colors)
         output = selected_dumper.to_string()
     except UnavailableFeatureError as error:
@@ -145,15 +155,18 @@ def get_args(output_formats: [str]):
     parser.add_argument('--format', '-f', type=str, default=output_formats[0], choices=output_formats,
                         help=_('The format under which the information have to be output'))
     parser.add_argument('--latitude', '-lat', type=float, default=None,
-                        help=_("The observer's latitude on Earth"))
+                        help=_("The observer's latitude on Earth. Can also be set in the KOSMORRO_LATITUDE environment "
+                               "variable."))
     parser.add_argument('--longitude', '-lon', type=float, default=None,
-                        help=_("The observer's longitude on Earth"))
+                        help=_("The observer's longitude on Earth. Can also be set in the KOSMORRO_LONGITUDE "
+                               "environment variable."))
     parser.add_argument('--date', '-d', type=str, default=today.strftime('%Y-%m-%d'),
                         help=_('The date for which the ephemerides must be computed (in the YYYY-MM-DD format). '
                                'Defaults to the current date ({default_date})').format(
                                    default_date=today.strftime('%Y-%m-%d')))
-    parser.add_argument('--timezone', '-t', type=int, default=0,
-                        help=_('The timezone to display the hours in (e.g. 2 for UTC+2 or -3 for UTC-3).'))
+    parser.add_argument('--timezone', '-t', type=int, default=None,
+                        help=_('The timezone to display the hours in (e.g. 2 for UTC+2 or -3 for UTC-3). '
+                               'Can also be set in the KOSMORRO_TIMEZONE environment variable.'))
     parser.add_argument('--no-colors', dest='colors', action='store_false',
                         help=_('Disable the colors in the console.'))
     parser.add_argument('--output', '-o', type=str, default=None,

manpage/kosmorro.1.md

@@ -31,12 +31,29 @@
 `--no-colors`  
     disable the colors in the console
 
-`--output=`_OUTPUT_, `-o` _OUTPUT_
+`--output=`_OUTPUT_, `-o` _OUTPUT_  
     a file to export the output to; if not given, the standard output is used
 
 `--format=`_FORMAT_, `-f` _FORMAT_  
     the format under which the information have to be output; one of the following: text, json, pdf
 
+## ENVIRONMENT VARIABLES
+
+The environment variable listed below may be used instead of the options.
+The options have a higher priority than the environment variable.
+As a consequence, any option that would be given to `kosmorro` will override its corresponding environment variable.
+
+Available environment variables are:
+
+`KOSMORRO_LATITUDE`  
+    the observer's latitude on Earth (alternative to `--latitude`)
+    
+`KOSMORRO_LONGITUDE`  
+    the observer's longitude on Earth (alternative to `--longitude`)
+    
+`KOSMORRO_TIMEZONE`  
+    the observer's timezone (alternative to `--timezone`)
+
 ## EXAMPLES
 
 Compute the events only for the current date:

test/core.py

@@ -1,5 +1,6 @@
 import unittest
 
+import os
 import kosmorrolib.core as core
 
 
@@ -7,6 +8,25 @@ class CoreTestCase(unittest.TestCase):
     def test_flatten_list(self):
         self.assertEqual([0, 1, 2, 3, 4, 5, 6, 7, 8, 9], core.flatten_list([0, 1, 2, [3, 4, [5, 6], 7], 8, [9]]))
 
+    def test_get_env(self):
+        self.assertEqual(0, len(core.get_env()))
+
+        os.environ['SOME_RANDOM_VAR'] = 'an awesome value'
+        self.assertEqual(0, len(core.get_env()))
+
+        os.environ['KOSMORRO_GREAT_VARIABLE'] = 'value'
+        env = core.get_env()
+        self.assertEqual(1, len(env))
+        self.assertEqual('value', env.great_variable)
+
+        os.environ['KOSMORRO_ANOTHER_VARIABLE'] = 'another value'
+        env = core.get_env()
+        self.assertEqual(2, len(env))
+        self.assertEqual('value', env.great_variable)
+        self.assertEqual('another value', env.another_variable)
+
+        self.assertEqual("{'great_variable': 'value', 'another_variable': 'another value'}", str(env))
+
 
 if __name__ == '__main__':
     unittest.main()