[PATCH] Use tail process to ensure line buffered output to screen and log file at the same moment... (#506664)

[Martin Sivak <msivak@xxxxxxxxxx>]

---
 iutil.py |   84 ++++++++++++++++++++++++++++++++++++++++++++++++++------------
 1 files changed, 68 insertions(+), 16 deletions(-)

diff --git a/iutil.py b/iutil.py
index ba1d0b4..0a4adfa 100644
--- a/iutil.py
+++ b/iutil.py
@@ -33,6 +33,7 @@ from flags import flags
 from constants import *
 from rhpl.translate import _
 import re
+import select
 
 import logging
 log = logging.getLogger("anaconda")
@@ -81,37 +82,88 @@ def execWithRedirect(command, argv, stdin = None, stdout = None,
 
     runningLog = open("/tmp/program.log", "a")
     runningLog.write("Running... %s\n" % ([command] + argv,))
+   
+    #prepare os pipes for feeding tee proceses
+    pstdout, pstdin = os.pipe()
+    perrout, perrin = os.pipe()
 
     env = os.environ.copy()
     env.update({"LC_ALL": "C"})
 
+    #prepare "empty" tee proceses so we can properly detect errors
+    proc_std = None
+    proc_err = None
+
     try:
-        proc = subprocess.Popen([command] + argv, stdin=stdin,
-                                stdout=subprocess.PIPE,
+        #create output pipes with logging (it needs to be different process to avoid deadlock and EOF detection..)
+        proc_std = subprocess.Popen(["tee", "-a", "/tmp/program.log"], stdin=pstdout,
+                                stdout=stdout,
                                 stderr=subprocess.PIPE,
+                                cwd=root,
+                                env=env, bufsize = 1)
+        
+        proc_err = subprocess.Popen(["tee", "-a", "/tmp/program.log"], stdin=perrout,
+                                stdout=stderr,
+                                stderr=subprocess.PIPE,
+                                cwd=root,
+                                env=env, bufsize = 1)
+
+        #run the command
+        proc = subprocess.Popen([command] + argv, stdin=stdin,
+                                stdout=pstdin,
+                                stderr=perrin,
                                 preexec_fn=chroot, cwd=root,
-                                env=env)
+                                env=env, bufsize = 1)
+        
+        proc.wait()
+
+        #close the output pipes
+        if proc_std:
+            proc_std.terminate()
+            proc_std.wait()
+            proc_std = None
+
+        if proc_err:
+            proc_err.terminate()
+            proc_err.wait()
+            proc_err = None
+
+        ret = proc.returncode
 
-        while True:
-            (outStr, errStr) = proc.communicate()
-            if outStr:
-                os.write(stdout, outStr)
-                runningLog.write(outStr)
-            if errStr:
-                os.write(stderr, errStr)
-                runningLog.write(errStr)
 
-            if proc.returncode is not None:
-                ret = proc.returncode
-                break
     except OSError as e:
         errstr = "Error running %s: %s" % (command, e.strerror)
         log.error(errstr)
+
+        #free descriptors
+        os.close(pstdout)
+        os.close(perrout)
+        os.close(pstdin)
+        os.close(perrin)
+        
+        #close the output pipes
+        if proc_std:
+            proc_std.terminate()
+            proc_std.wait()
+            proc_std = None
+
+        if proc_err:
+            proc_err.terminate()
+            proc_err.wait()
+            proc_err = None
+
         runningLog.write(errstr)
         runningLog.close()
         raise RuntimeError, errstr
 
     runningLog.close()
+
+    #free descriptors
+    os.close(pstdout)
+    os.close(perrout)
+    os.close(pstdin)
+    os.close(perrin)
+
     return ret
 
 ## Run an external program and capture standard out.
-- 
1.5.4.3

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