fix #547: have username return the stringified UID in case UID cannot…

… be resolved by the system (as opposed to letting KeyError propagate)

HISTORY.rst

@@ -11,6 +11,7 @@ Bug tracker at https://github.com/giampaolo/psutil/issues
 **Bug fixes**
 
 - #496: [Solaris]: can't import psutil.
+- #547: [UNIX]: Process.username() may raise KeyError if UID can't be resolved.
 
 
 2.1.3 - 2014-09-26

README.rst

@@ -59,8 +59,8 @@ Example applications
 See also:
 
  * https://github.com/nicolargo/glances
+ * https://github.com/google/grr
  * https://github.com/Jahaja/psdash
- * https://code.google.com/p/grr/
 
 ==============
 Example usages
@@ -210,7 +210,7 @@ Process management
     >>>
     >>> p.memory_info()
     pmem(rss=7471104, vms=68513792)
-    >>> p.ext_memory_info()
+    >>> p.memory_info_ex()
     extmem(rss=9662464, vms=49192960, shared=3612672, text=2564096, lib=0, data=5754880, dirty=0)
     >>> p.memory_maps()
     [pmmap_grouped(path='/lib/x86_64-linux-gnu/libutil-2.15.so', rss=16384, anonymous=8192, swap=0),

psutil/__init__.py

@@ -563,7 +563,12 @@ def username(self):
                 # might happen if python was installed from sources
                 raise ImportError(
                     "requires pwd module shipped with standard python")
-            return pwd.getpwuid(self.uids().real).pw_name
+            real_uid = self.uids().real
+            try:
+                return pwd.getpwuid(real_uid).pw_name
+            except KeyError:
+                # the uid can't be resolved by the system
+                return str(real_uid)
         else:
             return self._proc.username()