report number of fds in stats, added /debug endpoint to retrieve memo…

…ry stats

splash/resources.py

@@ -4,7 +4,7 @@
 from twisted.internet import reactor, defer
 from twisted.python import log
 from splash.qtrender import HtmlRender, PngRender, RenderError
-from splash.utils import getarg, BadRequest
+from splash.utils import getarg, BadRequest, get_num_fds, get_leaks
 from splash import sentry
 
 
@@ -48,8 +48,9 @@ def _writeOutput(self, html, request):
             "path": request.path,
             "args": request.args,
             "rendertime": time.time() - request.starttime,
-            "rss": resource.getrusage(resource.RUSAGE_SELF).ru_maxrss,
+            "maxrss": resource.getrusage(resource.RUSAGE_SELF).ru_maxrss,
             "load": os.getloadavg(),
+            "fds": get_num_fds(),
         }
         log.msg(json.dumps(stats), system="stats")
         request.setHeader("content-type", self.content_type)
@@ -90,12 +91,23 @@ def _getRender(self, request):
         return PngRender(url, baseurl, width, height, vwidth, vheight)
 
 
+class Debug(Resource):
+
+    isLeaf = True
+
+    def render_GET(self, request):
+        return json.dumps({
+            "leaks": get_leaks(),
+        })
+
+
 class Root(Resource):
 
     def __init__(self):
         Resource.__init__(self)
         self.putChild("render.html", RenderHtml())
         self.putChild("render.png", RenderPng())
+        self.putChild("debug", Debug())
 
     def getChild(self, name, request):
         if name == "":

splash/utils.py

@@ -1,3 +1,5 @@
+import os, gc, inspect
+from collections import defaultdict
 
 _REQUIRED = object()
 
@@ -15,3 +17,18 @@ def getarg(request, name, default=_REQUIRED, type=str, range=None):
     else:
         return default
 
+PID = os.getpid()
+def get_num_fds():
+    return len(os.listdir("/proc/%s/fd" % PID))
+
+def get_leaks():
+    relevant_types = frozenset(('CustomQWebPage', 'CustomQNetworkAccessManager',
+        'QWebView', 'HtmlRender', 'PngRender', 'QNetworkRequest'))
+    leaks = defaultdict(int)
+    gc.collect()
+    for o in gc.get_objects():
+        if not inspect.isclass(o):
+            cname = type(o).__name__
+            if cname in relevant_types:
+                leaks[cname] += 1
+    return leaks