new python langpack playground; ast aware settings.py code injection

.gitignore

+*.pyc

Readme.md

+virtualenv
+----------
+
+pip
+---
+
+Django settings.py
+------------------
+
+Sets up a db for every ENV ${NAME}_URL => postgres:// var:
+  DATABASES["DATABASE"]
+  DATABASES["SHARED_DATABASE"]
+  DATABASES["HEROKU_POSTGRESQL_ONYX"]
+
+Aliases DATABASE_URL to default database:
+  DATABASES["default"] = DATABASES["DATABASE"]
+
+Injected right after DATABASES = {...}
\ No newline at end of file

opt/dbs.py

+
+##########
+# BEGIN HEROKU PYTHON/DJANGO LANGUAGE PACK
+# Dynamically set DATABASES from ENV vars
+
+import os, urlparse
+urlparse.uses_netloc.append("postgres")
+key_re = re.compile(r"^(?P<name>[A-Z_]+)_URL$")
+
+for k,v in os.environ.items():
+    url = urlparse.urlparse(v)
+    matches = key_re.match(k)
+    if not matches or url.scheme != "postgres":
+        continue
+
+    DATABASES[matches.group("name")] = {
+        "ENGINE":   "django.db.backends.postgresql_psycopg2",
+        "NAME":     url.path[1:],
+        "USER":     url.username,
+        "PASSWORD": url.password,
+        "HOST":     url.hostname,
+        "PORT":     url.port,
+    }
+
+# alias "default" to DATABASE_URL
+if DATABASES["DATABASE"]:
+    DATABASES["default"] = DATABASES["DATABASE"]
+
+#
+# END HEROKU PYTHON/DJANGO LANGUAGE PACK
+##########

opt/inject_dbs.py

+#!/usr/bin/env python2.7
+import os
+import sys
+from lib2to3 import pygram, pytree
+from lib2to3.pgen2 import driver
+
+ROOTDIR = os.path.dirname(__file__)
+
+def find(node, leaf):
+    if node == leaf:
+        return node
+    for c in node.children:
+        if find(c, leaf):
+            return find(c, leaf)
+
+if __name__ == "__main__":
+    if len(sys.argv) != 2:
+        print "Usage: inject_dbs.py FILENAME"
+        sys.exit(1)
+
+    src     = sys.argv[1]
+    patch   = os.path.join(ROOTDIR, "dbs.py")
+    dest    = "_settings.py"
+
+    drv = driver.Driver(pygram.python_grammar, pytree.convert)
+    root = drv.parse_file(src)
+
+    node = find(root, pytree.Leaf(1, "DATABASES")) # Find first DATABASES
+    end  = node.parent.next_sibling
+
+    with open(src) as _src:
+        head = [_src.next() for x in xrange(end.lineno)]
+        tail = [l for x,l in enumerate(_src)]
+
+    with open(patch) as _patch:
+        body = [l for x,l in enumerate(_patch)]
+
+    with open(dest, "w") as _dest:
+        _dest.writelines(head)
+        _dest.writelines(body)
+        _dest.writelines(tail)

opt/settings.py

+# Django settings for myapp project.
+
+DEBUG = True
+TEMPLATE_DEBUG = DEBUG
+
+ADMINS = (
+    # ('Your Name', 'your_email@example.com'),
+)
+
+MANAGERS = ADMINS
+
+DATABASES = {
+    'default': {
+        'ENGINE': 'django.db.backends.', # Add 'postgresql_psycopg2', 'postgresql', 'mysql', 'sqlite3' or 'oracle'.
+        'NAME': '',                      # Or path to database file if using sqlite3.
+        'USER': '',                      # Not used with sqlite3.
+        'PASSWORD': '',                  # Not used with sqlite3.
+        'HOST': '',                      # Set to empty string for localhost. Not used with sqlite3.
+        'PORT': '',                      # Set to empty string for default. Not used with sqlite3.
+    }
+}
+
+# Local time zone for this installation. Choices can be found here:
+# http://en.wikipedia.org/wiki/List_of_tz_zones_by_name
+# although not all choices may be available on all operating systems.
+# On Unix systems, a value of None will cause Django to use the same
+# timezone as the operating system.
+# If running in a Windows environment this must be set to the same as your
+# system time zone.
+TIME_ZONE = 'America/Chicago'
+
+# Language code for this installation. All choices can be found here:
+# http://www.i18nguy.com/unicode/language-identifiers.html
+LANGUAGE_CODE = 'en-us'
+
+SITE_ID = 1
+
+# If you set this to False, Django will make some optimizations so as not
+# to load the internationalization machinery.
+USE_I18N = True
+
+# If you set this to False, Django will not format dates, numbers and
+# calendars according to the current locale
+USE_L10N = True
+
+# Absolute filesystem path to the directory that will hold user-uploaded files.
+# Example: "/home/media/media.lawrence.com/media/"
+MEDIA_ROOT = ''
+
+# URL that handles the media served from MEDIA_ROOT. Make sure to use a
+# trailing slash.
+# Examples: "http://media.lawrence.com/media/", "http://example.com/media/"
+MEDIA_URL = ''
+
+# Absolute path to the directory static files should be collected to.
+# Don't put anything in this directory yourself; store your static files
+# in apps' "static/" subdirectories and in STATICFILES_DIRS.
+# Example: "/home/media/media.lawrence.com/static/"
+STATIC_ROOT = ''
+
+# URL prefix for static files.
+# Example: "http://media.lawrence.com/static/"
+STATIC_URL = '/static/'
+
+# URL prefix for admin static files -- CSS, JavaScript and images.
+# Make sure to use a trailing slash.
+# Examples: "http://foo.com/static/admin/", "/static/admin/".
+ADMIN_MEDIA_PREFIX = '/static/admin/'
+
+# Additional locations of static files
+STATICFILES_DIRS = (
+    # Put strings here, like "/home/html/static" or "C:/www/django/static".
+    # Always use forward slashes, even on Windows.
+    # Don't forget to use absolute paths, not relative paths.
+)
+
+# List of finder classes that know how to find static files in
+# various locations.
+STATICFILES_FINDERS = (
+    'django.contrib.staticfiles.finders.FileSystemFinder',
+    'django.contrib.staticfiles.finders.AppDirectoriesFinder',
+#    'django.contrib.staticfiles.finders.DefaultStorageFinder',
+)
+
+# Make this unique, and don't share it with anybody.
+SECRET_KEY = 'urj6yp&_y^_%9*yf0=qtp+6=8%8eschux+m*a4)!s4xp5!$ldy'
+
+# List of callables that know how to import templates from various sources.
+TEMPLATE_LOADERS = (
+    'django.template.loaders.filesystem.Loader',
+    'django.template.loaders.app_directories.Loader',
+#     'django.template.loaders.eggs.Loader',
+)
+
+MIDDLEWARE_CLASSES = (
+    'django.middleware.common.CommonMiddleware',
+    'django.contrib.sessions.middleware.SessionMiddleware',
+    'django.middleware.csrf.CsrfViewMiddleware',
+    'django.contrib.auth.middleware.AuthenticationMiddleware',
+    'django.contrib.messages.middleware.MessageMiddleware',
+)
+
+ROOT_URLCONF = 'myapp.urls'
+
+TEMPLATE_DIRS = (
+    # Put strings here, like "/home/html/django_templates" or "C:/www/django/templates".
+    # Always use forward slashes, even on Windows.
+    # Don't forget to use absolute paths, not relative paths.
+)
+
+INSTALLED_APPS = (
+    'django.contrib.auth',
+    'django.contrib.contenttypes',
+    'django.contrib.sessions',
+    'django.contrib.sites',
+    'django.contrib.messages',
+    'django.contrib.staticfiles',
+    # Uncomment the next line to enable the admin:
+    # 'django.contrib.admin',
+    # Uncomment the next line to enable admin documentation:
+    # 'django.contrib.admindocs',
+)
+
+# A sample logging configuration. The only tangible logging
+# performed by this configuration is to send an email to
+# the site admins on every HTTP 500 error.
+# See http://docs.djangoproject.com/en/dev/topics/logging for
+# more details on how to customize your logging configuration.
+LOGGING = {
+    'version': 1,
+    'disable_existing_loggers': False,
+    'handlers': {
+        'mail_admins': {
+            'level': 'ERROR',
+            'class': 'django.utils.log.AdminEmailHandler'
+        }
+    },
+    'loggers': {
+        'django.request': {
+            'handlers': ['mail_admins'],
+            'level': 'ERROR',
+            'propagate': True,
+        },
+    }
+}

test/__main__.py

+import os
+import re
+import unittest
+
+DATABASES = {}
+ROOTDIR = os.path.dirname(__file__)
+
+class TestInjectDBs(unittest.TestCase):
+    def setUp(self):
+        DATABASES = {}
+        os.environ.update({
+            "DATABASE_URL":                 "postgres://victor:xray@localhost:5432/alfa",
+            "HEROKU_POSTGRESQL_ONYX_URL":   "postgres://victor:xray@localhost:5432/alfa",
+            "HEROKU_POSTGRESQL_RED_URL":    "postgres://juliet:zulu@localhost:5432/beta",
+            "SHARED_DATABASE_URL":          "postgres://quebec:kilo@localhost:5432/echo",
+            "THUNK":                        "postgres://localhost/db",
+            "FOO":                          "bar",
+        })
+
+    def testCode(self):
+        """
+        Test the code injected into settings.py to map ENV to settings.DATABASES hash
+        """
+        # read and exec code in this context
+        with open(os.path.join(ROOTDIR, "..", "opt/dbs.py")) as _src:
+            exec compile(_src.read(), "dbs.py", "exec")
+
+        self.assertEqual(5, len(DATABASES)) # default, DATABASE, ONYX, RED, SHARED_DATABASE
+
+        self.assertDictEqual({
+            "ENGINE":   "django.db.backends.postgresql_psycopg2",
+            "NAME":     "alfa",
+            "USER":     "victor",
+            "PASSWORD": "xray",
+            "HOST":     "localhost",
+            "PORT":     5432
+        }, DATABASES["HEROKU_POSTGRESQL_ONYX"])
+
+        self.assertDictEqual({
+            "ENGINE":   "django.db.backends.postgresql_psycopg2",
+            "NAME":     "beta",
+            "USER":     "juliet",
+            "PASSWORD": "zulu",
+            "HOST":     "localhost",
+            "PORT":     5432
+        }, DATABASES["HEROKU_POSTGRESQL_RED"])
+
+        self.assertDictEqual({
+            "ENGINE":   "django.db.backends.postgresql_psycopg2",
+            "NAME":     "echo",
+            "USER":     "quebec",
+            "PASSWORD": "kilo",
+            "HOST":     "localhost",
+            "PORT":     5432
+        }, DATABASES["SHARED_DATABASE"])
+
+        # aliases
+        self.assertDictEqual(DATABASES["HEROKU_POSTGRESQL_ONYX"], DATABASES["DATABASE"])
+        self.assertDictEqual(DATABASES["HEROKU_POSTGRESQL_ONYX"], DATABASES["default"])
+
+if __name__ == "__main__":
+    unittest.main()
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