pexrc support

.gitignore

@@ -1,6 +1,7 @@
 *~
 *.pyc
 *.egg-info
+/venv
 /build/*
 /dist/*
 /docs/_build

docs/buildingpex.rst

@@ -322,7 +322,8 @@ Tailoring PEX execution at build time
 
 There are a few options that can tailor how PEX environments are invoked.  These can be found
 by running ``pex --help``.  Every flag mentioned here has a corresponding environment variable
-that can be used to override the runtime behavior.
+that can be used to override the runtime behavior which can be set directly in your environment,
+or sourced from a ``.pexrc`` file (checking for ``~/.pexrc`` first, then for a relative ``.pexrc``).
 
 
 ``--zip-safe``/``--not-zip-safe``

pex/variables.py

@@ -5,6 +5,7 @@
 # checkstyle: noqa
 
 import os
+import sys
 from contextlib import contextmanager
 
 from .common import die
@@ -32,9 +33,13 @@ def iter_help(cls):
       variable_type, variable_text = cls.process_pydoc(getattr(value, '__doc__'))
       yield variable_name, variable_type, variable_text
 
-  def __init__(self, environ=None, use_defaults=True):
-    self._environ = environ.copy() if environ is not None else os.environ
+  def __init__(self, environ=None, rc='~/.pexrc', use_defaults=True):
     self._use_defaults = use_defaults
+    self._environ = environ.copy() if environ else os.environ
+    if not self.PEX_IGNORE_RCFILES:
+      rc_values = self._from_rc(rc).copy()
+      rc_values.update(self._environ)
+      self._environ = rc_values
 
   def copy(self):
     return self._environ.copy()
@@ -45,6 +50,22 @@ def delete(self, variable):
   def set(self, variable, value):
     self._environ[variable] = str(value)
 
+  def _from_rc(self, rc):
+    ret_vars = {}
+    for filename in [rc, os.path.join(os.path.dirname(sys.argv[0]), '.pexrc')]:
+      try:
+        with open(os.path.expanduser(filename)) as fh:
+          rc_items = map(self._get_kv, fh)
+          ret_vars.update(dict(filter(None, rc_items)))
+      except IOError:
+        continue
+    return ret_vars
+
+  def _get_kv(self, variable):
+    kv = variable.strip().split('=')
+    if len(list(filter(None, kv))) == 2:
+      return kv
+
   def _defaulted(self, default):
     return default if self._use_defaults else None
 
@@ -271,6 +292,14 @@ def PEX_HTTP_RETRIES(self):
     """
     return self._get_int('PEX_HTTP_RETRIES', default=5)
 
+  @property
+  def PEX_IGNORE_RCFILES(self):
+    """Boolean
+
+    Explicitly disable the reading/parsing of pexrc files (~/.pexrc). Default: false.
+    """
+    return self._get_bool('PEX_IGNORE_RCFILES', default=False)
+
 
 # Global singleton environment
 ENV = Variables()

tests/test_variables.py

@@ -1,6 +1,8 @@
 # Copyright 2015 Pants project contributors (see CONTRIBUTORS.md).
 # Licensed under the Apache License, Version 2.0 (see LICENSE).
 
+import tempfile
+
 import pytest
 
 from pex.variables import Variables
@@ -74,6 +76,38 @@ def test_pex_vars_set():
   assert v._get_int('HELLO') is None
 
 
+def test_pex_get_kv():
+  v = Variables(environ={})
+  assert v._get_kv('HELLO') is None
+  assert v._get_kv('=42') is None
+  assert v._get_kv('TOO=MANY=COOKS') is None
+  assert v._get_kv('THIS=WORKS') == ['THIS', 'WORKS']
+
+
+def test_pex_from_rc():
+  with tempfile.NamedTemporaryFile(mode='w') as pexrc:
+    pexrc.write('HELLO=42')
+    pexrc.flush()
+    v = Variables(rc=pexrc.name)
+    assert v._get_int('HELLO') == 42
+
+
+def test_pexrc_precedence():
+  with tempfile.NamedTemporaryFile(mode='w') as pexrc:
+    pexrc.write('HELLO=FORTYTWO')
+    pexrc.flush()
+    v = Variables(environ={'HELLO': 42}, rc=pexrc.name)
+    assert v._get_int('HELLO') == 42
+
+
+def test_rc_ignore():
+  with tempfile.NamedTemporaryFile(mode='w') as pexrc:
+    pexrc.write('HELLO=FORTYTWO')
+    pexrc.flush()
+    v = Variables(environ={'PEX_IGNORE_RC_FILES': True, 'HELLO': 42}, rc=pexrc.name)
+    assert v._get_int('HELLO') == 42
+
+
 def test_pex_vars_defaults_stripped():
   v = Variables(environ={})
   stripped = v.strip_defaults()