# HG changeset patch
# User Yuya Nishihara <yuya@tcha.org>
# Date 2018-11-10 09:19:34
# Node ID 368ecbf734af109b936f309e7feec788d5597290
# Parent  6a75363f834a299b85ad88dd2e96ca61804fc232

commandserver: enable logging when server process started

This allows us to keep track of server events before client connects to
the server.

Tests will be added later. Currently there's no log() call to check if
things are working well.

diff --git a/mercurial/commandserver.py b/mercurial/commandserver.py
--- a/mercurial/commandserver.py
+++ b/mercurial/commandserver.py
@@ -208,15 +208,10 @@ class server(object):
     def __init__(self, ui, repo, fin, fout):
         self.cwd = encoding.getcwd()
 
-        # developer config: cmdserver.log
-        logpath = ui.config("cmdserver", "log")
-        if logpath:
+        if ui.config("cmdserver", "log") == '-':
             global logfile
-            if logpath == '-':
-                # write log on a special 'd' (debug) channel
-                logfile = channeledoutput(fout, 'd')
-            else:
-                logfile = open(logpath, 'a')
+            # switch log stream to the 'd' (debug) channel
+            logfile = channeledoutput(fout, 'd')
 
         if repo:
             # the ui here is really the repo ui so take its baseui so we don't
@@ -361,6 +356,24 @@ class server(object):
 
         return 0
 
+def setuplogging(ui):
+    """Set up server logging facility
+
+    If cmdserver.log is '-', log messages will be sent to the 'd' channel
+    while a client is connected. Otherwise, messages will be written to
+    the stderr of the server process.
+    """
+    # developer config: cmdserver.log
+    logpath = ui.config(b'cmdserver', b'log')
+    if not logpath:
+        return
+
+    global logfile
+    if logpath == b'-':
+        logfile = ui.ferr
+    else:
+        logfile = open(logpath, 'ab')
+
 class pipeservice(object):
     def __init__(self, ui, repo, opts):
         self.ui = ui
diff --git a/mercurial/server.py b/mercurial/server.py
--- a/mercurial/server.py
+++ b/mercurial/server.py
@@ -155,9 +155,11 @@ def runservice(opts, parentfn=None, init
 def _createcmdservice(ui, repo, opts):
     mode = opts['cmdserver']
     try:
-        return _cmdservicemap[mode](ui, repo, opts)
+        servicefn = _cmdservicemap[mode]
     except KeyError:
         raise error.Abort(_('unknown mode %s') % mode)
+    commandserver.setuplogging(ui)
+    return servicefn(ui, repo, opts)
 
 def _createhgwebservice(ui, repo, opts):
     # this way we can check if something was given in the command-line