add multi chained and make work pipe stdin between process

README.rst

@@ -34,12 +34,11 @@ Advanced Usage::
 
     >>> ls = procs.Process('ls /usr/bin')
     >>> grep = procs.Process('grep python')
-    >>> chain = ls | grep
+    >>> wc = procs.Process('wc -l')
+    >>> chain = ls | grep | wc
     >>> chain.run()
     >>> print(chain.stdout)
-    python
-    python3
-    python3.4
+    19
 
     >>> from procs import ProcessHandler
 

procs/chain.py

@@ -1,5 +1,4 @@
 from __future__ import print_function
-import os
 
 
 class Chain(object):
@@ -7,26 +6,23 @@ class Chain(object):
     def __init__(self, processes):
         self.processes = processes
 
-
     def run(self):
-        for proc, next_proc in zip(self.processes, self.processes[1:]):
-            read, write = os.pipe()
-            proc.set_stdout(write)
-            next_proc.set_stdin(read)
-        for proc in self.processes:
+        for i, proc in enumerate(self.processes, start=1):
+            if i > 1:
+                proc.set_stdin(self.processes[i-2].subprocess.stdout)
             proc.start()
-        for proc in self.processes:
-            proc.wait()
-            if proc._stdout is not None:
-                os.close(proc._stdout)
-
+            if i != len(self.processes):
+                proc.wait(unread=True)
+            else:
+                proc.wait()
 
     @property
     def returncode(self):
         return self.processes[-1].returncode
 
-
     @property
     def stdout(self):
         return self.processes[-1].stdout
 
+    def __or__(self, other):
+        return Chain(self.processes + [other])

procs/process.py

@@ -47,12 +47,12 @@ class Process(object):
             args=self.command,
             shell=True,
             stdin=self._stdin if self._stdin else subprocess.PIPE,
-            stdout=self._stdout if self._stdout else subprocess.PIPE,
+            stdout=subprocess.PIPE,
         )
 
-    def wait(self):
+    def wait(self, unread=False):
         self._returncode = self._subprocess.wait()
-        if self._subprocess.stdout is not None:
+        if self._subprocess.stdout is not None and not unread:
             self._stdout_text = self._subprocess.stdout.read().decode()
 
 

tests/test_chain.py

@@ -16,3 +16,12 @@ def test_chained_procs():
     assert chain.returncode == 0
     assert chain.stdout.strip() == 'file2'
 
+def test_multi_chained_procs():
+    ls = Process('ls {test_dir}'.format(test_dir=TEST_DIR))
+    grep = Process('grep 2')
+    wc = Process('wc -c')
+    chain = ls | grep | wc
+    chain.run()
+    assert chain.returncode == 0
+    assert chain.stdout.strip() == '6'
+