launchpad-reviewers team mailing list archive

[Colin Watson <mp+431818@xxxxxxxxxxxxxxxxxx>]

Colin Watson has proposed merging ~cjwatson/launchpad:print-flush into launchpad:master.

Commit message:
Use print(flush=True) where appropriate

Requested reviews:
  Launchpad code reviewers (launchpad-reviewers)

For more details, see:
https://code.launchpad.net/~cjwatson/launchpad/+git/launchpad/+merge/431818

This was added in Python 3.3, and lets us make a few things a bit more concise and (IMO) clearer.
-- 
Your team Launchpad code reviewers is requested to review the proposed merge of ~cjwatson/launchpad:print-flush into launchpad:master.

diff --git a/database/replication/helpers.py b/database/replication/helpers.py
index f1f8349..5ab5b50 100644
--- a/database/replication/helpers.py
+++ b/database/replication/helpers.py
@@ -227,8 +227,7 @@ def execute_slonik(script, sync=None, exit_on_fail=True, auto_preamble=True):
     # to slonik via stdin. This way it can be examined if slonik appears
     # to hang.
     script_on_disk = NamedTemporaryFile(prefix="slonik", suffix=".sk")
-    print(script, file=script_on_disk)
-    script_on_disk.flush()
+    print(script, file=script_on_disk, flush=True)
 
     # Run slonik
     log.debug("Executing slonik script %s" % script_on_disk.name)
diff --git a/lib/lp/app/doc/menus.rst b/lib/lp/app/doc/menus.rst
index 916f4ab..10f0bba 100644
--- a/lib/lp/app/doc/menus.rst
+++ b/lib/lp/app/doc/menus.rst
@@ -1173,8 +1173,7 @@ NavigationMenus used in the previous TALES section.
     ...    </ul>
     ...  </div>"""
     >>> template_file = tempfile.NamedTemporaryFile(mode="w")
-    >>> _ = template_file.write(menu_fragment)
-    >>> template_file.flush()
+    >>> print(menu_fragment, file=template_file, flush=True)
 
     >>> class FacetMenuView(LaunchpadView):
     ...     template = ViewPageTemplateFile(template_file.name)
diff --git a/lib/lp/archivepublisher/tests/test_publish_ftpmaster.py b/lib/lp/archivepublisher/tests/test_publish_ftpmaster.py
index 9c00c43..a5a1d0f 100644
--- a/lib/lp/archivepublisher/tests/test_publish_ftpmaster.py
+++ b/lib/lp/archivepublisher/tests/test_publish_ftpmaster.py
@@ -88,8 +88,7 @@ def write_marker_file(path, contents, mode=None):
     :param mode: If given, explicitly set the file to this permission mode.
     """
     with open(os.path.join(*path), "w") as marker:
-        marker.write(contents)
-        marker.flush()
+        print(contents, end="", file=marker, flush=True)
         if mode is not None:
             os.fchmod(marker.fileno(), mode)
 
diff --git a/lib/lp/codehosting/tests/test_rewrite.py b/lib/lp/codehosting/tests/test_rewrite.py
index ff82882..0424f32 100644
--- a/lib/lp/codehosting/tests/test_rewrite.py
+++ b/lib/lp/codehosting/tests/test_rewrite.py
@@ -321,8 +321,7 @@ class TestBranchRewriterScript(TestCaseWithFactory):
         # For each complete line of input, the script should, without
         # buffering, write a complete line of output.
         for input_line in input_lines:
-            proc.stdin.write(input_line + "\n")
-            proc.stdin.flush()
+            print(input_line, file=proc.stdin, flush=True)
             output_lines.append(
                 nonblocking_readline(proc.stdout, 60).rstrip("\n")
             )
@@ -339,8 +338,7 @@ class TestBranchRewriterScript(TestCaseWithFactory):
             "file:///var/tmp/bazaar.launchpad.test/mirrors/%s/.bzr/README"
             % branch_id_to_path(new_branch.id)
         )
-        proc.stdin.write(new_branch_input + "\n")
-        proc.stdin.flush()
+        print(new_branch_input, file=proc.stdin, flush=True)
         output_lines.append(nonblocking_readline(proc.stdout, 60).rstrip("\n"))
 
         edited_branch_input = "/%s/.bzr/README" % edited_branch.unique_name
@@ -348,8 +346,7 @@ class TestBranchRewriterScript(TestCaseWithFactory):
             "file:///var/tmp/bazaar.launchpad.test/mirrors/%s/.bzr/README"
             % branch_id_to_path(edited_branch.id)
         )
-        proc.stdin.write(edited_branch_input + "\n")
-        proc.stdin.flush()
+        print(edited_branch_input, file=proc.stdin, flush=True)
         output_lines.append(nonblocking_readline(proc.stdout, 60).rstrip("\n"))
 
         os.kill(proc.pid, signal.SIGINT)
@@ -379,8 +376,7 @@ class TestBranchRewriterScriptHandlesDisconnects(TestCase):
         self.addCleanup(self.rewriter_proc.terminate)
 
     def request(self, query):
-        self.rewriter_proc.stdin.write(query + "\n")
-        self.rewriter_proc.stdin.flush()
+        print(query, file=self.rewriter_proc.stdin, flush=True)
 
         # 60 second timeout as we might need to wait for the script to
         # finish starting up.
diff --git a/lib/lp/services/pidfile.py b/lib/lp/services/pidfile.py
index 3c9cdd2..6981f90 100644
--- a/lib/lp/services/pidfile.py
+++ b/lib/lp/services/pidfile.py
@@ -45,8 +45,7 @@ def make_pidfile(service_name):
 
     fd, tempname = tempfile.mkstemp(dir=os.path.dirname(pidfile))
     outf = os.fdopen(fd, "w")
-    outf.write(str(os.getpid()) + "\n")
-    outf.flush()
+    print(os.getpid(), file=outf, flush=True)
     outf.close()
     os.rename(tempname, pidfile)
 
diff --git a/lib/lp/services/profile/mem.py b/lib/lp/services/profile/mem.py
index 4bbbb75..128f9b8 100644
--- a/lib/lp/services/profile/mem.py
+++ b/lib/lp/services/profile/mem.py
@@ -214,8 +214,7 @@ def logInThread(n=30):
 def _logRefsEverySecond(log, n):
     while True:
         printCounts(mostRefs(n=n), file=log)
-        log.write("\n")
-        log.flush()
+        print(file=log, flush=True)
         time.sleep(1)
 
 
diff --git a/lib/lp/services/scripts/tests/test_cronscript_enabled.py b/lib/lp/services/scripts/tests/test_cronscript_enabled.py
index 9eb5f36..e958e92 100644
--- a/lib/lp/services/scripts/tests/test_cronscript_enabled.py
+++ b/lib/lp/services/scripts/tests/test_cronscript_enabled.py
@@ -20,9 +20,8 @@ class TestCronscriptEnabled(TestCase):
         self.log = BufferLogger()
 
     def makeConfig(self, body):
-        tempfile = NamedTemporaryFile(suffix=".ini")
-        tempfile.write(body.encode("UTF-8"))
-        tempfile.flush()
+        tempfile = NamedTemporaryFile(mode="w+", suffix=".ini")
+        print(body, end="", file=tempfile, flush=True)
         # Ensure a reference is kept until the test is over.
         # tempfile will then clean itself up.
         self.addCleanup(lambda x: None, tempfile)
diff --git a/lib/lp/services/tests/test_command_spawner.py b/lib/lp/services/tests/test_command_spawner.py
index be79b57..87d2904 100644
--- a/lib/lp/services/tests/test_command_spawner.py
+++ b/lib/lp/services/tests/test_command_spawner.py
@@ -25,12 +25,6 @@ def make_pipe():
     return fdopen(r, "r"), fdopen(w, "w")
 
 
-def write_and_flush(pipe, text):
-    """Write `text` into `pipe`, and flush."""
-    pipe.write(text)
-    pipe.flush()
-
-
 class FakeProcess:
     """Fake `subprocess.Popen` result."""
 
@@ -124,7 +118,7 @@ class TestCommandSpawner(TestCase):
         spawner, process = self._makeSpawnerAndProcess()
         stdout_handler = FakeMethod()
         spawner.start("ls", stdout_handler=stdout_handler)
-        write_and_flush(process.stdout_sink, "readme.txt\n")
+        print("readme.txt", file=process.stdout_sink, flush=True)
         spawner.communicate()
         self.assertEqual([("readme.txt\n",)], stdout_handler.extract_args())
 
@@ -132,7 +126,7 @@ class TestCommandSpawner(TestCase):
         spawner, process = self._makeSpawnerAndProcess()
         stderr_handler = FakeMethod()
         spawner.start("ls", stderr_handler=stderr_handler)
-        write_and_flush(process.stderr_sink, "File not found.\n")
+        print("File not found.", file=process.stderr_sink, flush=True)
         spawner.communicate()
         self.assertEqual(
             [("File not found.\n",)], stderr_handler.extract_args()
@@ -180,7 +174,7 @@ class TestCommandSpawner(TestCase):
         spawner.start(
             "hello", stdout_handler=handler, completion_handler=handler
         )
-        write_and_flush(process.stdout_sink, "Hello\n")
+        print("Hello", file=process.stdout_sink, flush=True)
         spawner.complete()
         self.assertEqual([("Hello\n",), (0,)], handler.extract_args())
 
diff --git a/scripts/branch-rewrite.py b/scripts/branch-rewrite.py
index c752744..51753c9 100755
--- a/scripts/branch-rewrite.py
+++ b/scripts/branch-rewrite.py
@@ -54,8 +54,7 @@ class BranchRewriteScript(LaunchpadScript):
                 transaction.abort()
                 # Mod-rewrite always gives us a newline terminated string.
                 if line:
-                    print(rewriter.rewriteLine(line.strip()))
-                    sys.stdout.flush()
+                    print(rewriter.rewriteLine(line.strip()), flush=True)
                 else:
                     # Standard input has been closed, so die.
                     return
@@ -63,8 +62,7 @@ class BranchRewriteScript(LaunchpadScript):
                 sys.exit()
             except Exception:
                 self.logger.exception("Exception occurred:")
-                print("NULL")
-                sys.stdout.flush()
+                print("NULL", flush=True)
                 # The exception might have been a DisconnectionError or
                 # similar. Cleanup such as database reconnection will
                 # not happen until the transaction is rolled back.