get env support with a helper function, deferr to it

1 files changed, 23 insertions, 0 deletions

diff --git a/pecan/configuration.py b/pecan/configuration.py
index 94dd579..897bf52 100644
--- a/pecan/configuration.py
+++ b/pecan/configuration.py
@@ -147,6 +147,8 @@ def conf_from_file(filepath):
 
     abspath = os.path.abspath(os.path.expanduser(filepath))
     conf_dict = {}
+    if not os.path.isfile(abspath):
+        raise RuntimeError('`%s` is not a file.' % abspath)
 
     execfile(abspath, globals(), conf_dict)
     conf_dict['__file__'] = abspath
@@ -154,6 +156,25 @@ def conf_from_file(filepath):
     return conf_from_dict(conf_dict)
 
 
+def conf_from_env():
+    '''
+    If the ``PECAN_CONFIG`` environment variable exists and it points to
+    a valid path it will return that, otherwise it will raise
+    a ``RuntimeError``.
+    '''
+    config_path = os.environ.get('PECAN_CONFIG')
+    error = None
+    if not config_path:
+        error = "PECAN_CONFIG is not set and " \
+                "no config file was passed as an argument."
+    elif not os.path.isfile(config_path):
+        error = "PECAN_CONFIG was set to an invalid path: %s" % config_path
+
+    if error:
+        raise RuntimeError(error)
+    return config_path
+
+
 def conf_from_dict(conf_dict):
     '''
     Creates a configuration dictionary from a dictionary.
@@ -191,6 +212,8 @@ def set_config(config, overwrite=False):
     if overwrite is True:
         _runtime_conf.empty()
 
+    config = config or conf_from_env()
+
     if isinstance(config, basestring):
         config = conf_from_file(config)
         _runtime_conf.update(config)