Added print and wait

bash/__init__.py

@@ -1,4 +1,4 @@
-import sys
+import sys, time
 from subprocess import PIPE, Popen
 SUBPROCESS_HAS_TIMEOUT = True
 if sys.version_info < (3, 0):
@@ -39,6 +39,7 @@ def sync(self, timeout=None):
         self.code = self.p.returncode
         return self
 
+
     def __repr__(self):
         return self.value()
 
@@ -58,3 +59,34 @@ def value(self):
         if self.stdout:
             return self.stdout.strip().decode(encoding='UTF-8')
         return ''
+
+    def print_and_wait(self):
+        """
+        Continuously prints stdout and stderr of the subprocess to stdout in realtime
+        Returns the exit code of the subprocess once the process finishes running.
+        Note that if you do the following you will not see the stdout and stderr from the 
+        subprocess until after the process completes,
+        process = bash('<bash commadn spawning a process>')
+        process.print_and_wait()
+        The process will finish synchronously when bash is called before print_and_wait gets called. 
+        To see the output in realtime do the following,
+        process = bash('<bash commadn spawning a process>', sync=False)
+        process.print_and_wait()
+        """
+        while True:
+            out_line = self.p.stdout.readline().decode()
+            err_line = self.p.stderr.readline().decode()
+            if len(out_line) > 0:
+                print(out_line)
+            elif len(err_line) > 0:
+                print(err_line)
+            elif self.p.poll() is None:
+                time.sleep(.05)
+            else:
+                break
+
+        exit_code = self.p.poll()
+        print(f'exit code {exit_code} from subprocess')
+        return exit_code
+
+

tests.py

@@ -1,5 +1,6 @@
 from datetime import datetime
 import unittest
+import io, sys
 
 try:
     from subprocess import TimeoutExpired
@@ -66,3 +67,18 @@ def test_sync_false_does_not_wait(self):
         self.assertTrue((t2-t1).total_seconds() < 0.5)
         b.sync()
         self.assertEqual(b.stdout, b'1\n')
+
+    def test_print_and_wait(self):
+        b = bash('echo hey', sync=False)
+        # with help from https://stackoverflow.com/a/35779140/3781537
+        old_stdout = sys.stdout
+        sys.stdout = io.StringIO()
+        b.print_and_wait()
+        what_was_printed = sys.stdout.getvalue()
+        self.assertTrue('hey' in what_was_printed)
+
+        sys.stdout = io.StringIO()
+        b = bash('./missing_command', sync=False)
+        b.print_and_wait()
+        self.assertTrue('No such file or directory' in sys.stdout.getvalue())
+        sys.stdout = old_stdout