hgweb: make refresh interval configurable

hgwebdir refreshes the set of known repositories periodically. This
is necessary because refreshing on every request could add significant
request latency.

More than once I've found myself wanting to tweak this interval at
Mozilla. I've also wanted the ability to always refresh (often when
writing tests for our replication setup).

This patch makes the refresh interval configurable. Negative values
indicate to always refresh. The default is left unchanged.

mercurial/help/config.txt

@@ -1752,6 +1752,14 b' The full set of options is:'
     Whether to require that inbound pushes be transported over SSL to
     prevent password sniffing. Default is True.
 
+``refreshinterval``
+    How frequently directory listings re-scan the filesystem for new
+    repositories, in seconds. This is relevant when wildcards are used
+    to define paths. Depending on how much filesystem traversal is
+    required, refreshing may negatively impact performance.
+
+    Default is 20. Values less than or equal to 0 always refresh.
+
 ``staticurl``
     Base URL to use for static files. If unset, static files (e.g. the
     hgicon.png favicon) will be served by the CGI script itself. Use

mercurial/hgweb/hgwebdir_mod.py

@@ -79,17 +79,23 b' def geturlcgivars(baseurl, port):'
     return name, str(port), path
 
 class hgwebdir(object):
-    refreshinterval = 20
-
     def __init__(self, conf, baseui=None):
         self.conf = conf
         self.baseui = baseui
+        self.ui = None
         self.lastrefresh = 0
         self.motd = None
         self.refresh()
 
     def refresh(self):
-        if self.lastrefresh + self.refreshinterval > time.time():
+        refreshinterval = 20
+        if self.ui:
+            refreshinterval = self.ui.configint('web', 'refreshinterval',
+                                                refreshinterval)
+
+        # refreshinterval <= 0 means to always refresh.
+        if (refreshinterval > 0 and
+            self.lastrefresh + refreshinterval > time.time()):
             return
 
         if self.baseui:

tests/test-hgwebdir.t

@@ -1245,6 +1245,67 b' rss-log with basedir /foo/'
   $ get-with-headers.py localhost:$HGPORT2 'a/rss-log' | grep '<guid'
       <guid isPermaLink="true">http://hg.example.com:8080/foo/a/rev/8580ff50825a</guid>
 
+Path refreshing works as expected
+
+  $ killdaemons.py
+  $ mkdir $root/refreshtest
+  $ hg init $root/refreshtest/a
+  $ cat > paths.conf << EOF
+  > [paths]
+  > / = $root/refreshtest/*
+  > EOF
+  $ hg serve -p $HGPORT1 -d --pid-file hg.pid --webdir-conf paths.conf
+  $ cat hg.pid >> $DAEMON_PIDS
+
+  $ get-with-headers.py localhost:$HGPORT1 '?style=raw'
+  200 Script output follows
+  
+  
+  /a/
+  
+
+By default refreshing occurs every 20s and a new repo won't be listed
+immediately.
+
+  $ hg init $root/refreshtest/b
+  $ get-with-headers.py localhost:$HGPORT1 '?style=raw'
+  200 Script output follows
+  
+  
+  /a/
+  
+
+Restart the server with no refresh interval. New repo should appear
+immediately.
+
+  $ killdaemons.py
+  $ cat > paths.conf << EOF
+  > [web]
+  > refreshinterval = -1
+  > [paths]
+  > / = $root/refreshtest/*
+  > EOF
+  $ hg serve -p $HGPORT1 -d --pid-file hg.pid --webdir-conf paths.conf
+  $ cat hg.pid >> $DAEMON_PIDS
+
+  $ get-with-headers.py localhost:$HGPORT1 '?style=raw'
+  200 Script output follows
+  
+  
+  /a/
+  /b/
+  
+
+  $ hg init $root/refreshtest/c
+  $ get-with-headers.py localhost:$HGPORT1 '?style=raw'
+  200 Script output follows
+  
+  
+  /a/
+  /b/
+  /c/
+  
+
 paths errors 1
 
   $ cat error-paths-1.log