[KVM-AUTOTEST PATCH 1/3] KVM test: kvm_subprocess.py: do not start tail thread by default

[Michael Goldish <mgoldish@redhat.com>]

Start the tail thread only if the user specifies a non-None output_func or
termination_func.

Signed-off-by: Michael Goldish <mgoldish@redhat.com>
---
 client/tests/kvm/kvm_subprocess.py |   14 ++++++++++++--
 1 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/client/tests/kvm/kvm_subprocess.py b/client/tests/kvm/kvm_subprocess.py
index 2ac062a..ede8081 100755
--- a/client/tests/kvm/kvm_subprocess.py
+++ b/client/tests/kvm/kvm_subprocess.py
@@ -596,9 +596,10 @@ class kvm_tail(kvm_spawn):
         self.output_prefix = output_prefix
 
         # Start the thread in the background
+        self.tail_thread = None
         self.__thread_kill_requested = False
-        self.tail_thread = threading.Thread(None, self._tail)
-        self.tail_thread.start()
+        if termination_func or output_func:
+            self._start_thread()
 
 
     def __getinitargs__(self):
@@ -617,6 +618,8 @@ class kvm_tail(kvm_spawn):
                 Must take a single parameter -- the exit status.
         """
         self.termination_func = termination_func
+        if termination_func and not self.tail_thread:
+            self._start_thread()
 
 
     def set_termination_params(self, termination_params):
@@ -637,6 +640,8 @@ class kvm_tail(kvm_spawn):
                 output from the process.  Must take a single string parameter.
         """
         self.output_func = output_func
+        if output_func and not self.tail_thread:
+            self._start_thread()
 
 
     def set_output_params(self, output_params):
@@ -726,6 +731,11 @@ class kvm_tail(kvm_spawn):
             pass
 
 
+    def _start_thread(self):
+        self.tail_thread = threading.Thread(None, self._tail)
+        self.tail_thread.start()
+
+
     def _join_thread(self):
         # Wait for the tail thread to exit
         if self.tail_thread:
-- 
1.5.4.1