diff --git a/server/djrandom/frontend/frontend.py b/server/djrandom/frontend/frontend.py
index 8608c80468e3870d8ef647bcd2397b350fee6787..8129be6152caf1988b177754f9188d248a802f54 100644
--- a/server/djrandom/frontend/frontend.py
+++ b/server/djrandom/frontend/frontend.py
@@ -39,6 +39,13 @@ def run_frontend(opts):
# Start the WSGI profiling middleware, if requested.
if opts.profile:
+ from djrandom.frontend.latency import LatencyProfilerMiddleware
+ app.wsgi_app = LatencyProfilerMiddleware(
+ app.wsgi_app,
+ ['/json/album', '/json/song', '/album_image',
+ '/json/playlist/get', '/json/playlist/by_title',
+ '/json/playlist/list', '/user/activate'])
+
from repoze.profile.profiler import AccumulatingProfileMiddleware
app.wsgi_app = AccumulatingProfileMiddleware(
app.wsgi_app,
diff --git a/server/djrandom/frontend/latency.py b/server/djrandom/frontend/latency.py
new file mode 100644
index 0000000000000000000000000000000000000000..b8f3a7ea6a6302647b46023695c512603d1b183f
--- /dev/null
+++ b/server/djrandom/frontend/latency.py
@@ -0,0 +1,81 @@
+import collections
+import time
+import pygooglechart
+
+
+LATENCY_BUCKETS = [
+ 1, 2, 5,
+ 10, 20, 50,
+ 100, 200, 500,
+ ]
+
+N_BUCKETS = len(LATENCY_BUCKETS) + 1
+
+
+def _build_buckets():
+ return [0] * N_BUCKETS
+
+def _percent(counts):
+ tot = float(sum(counts))
+ return [(x, 100 * x / tot) for x in counts]
+
+
+class LatencyProfilerMiddleware(object):
+
+ def __init__(self, app, urls=[]):
+ self._app = app
+ self._urls = sorted(urls, key=lambda x: len(x), reverse=True)
+ self._buckets = collections.defaultdict(_build_buckets)
+
+ def __call__(self, environ, start_response):
+ start = time.time()
+ url = environ['PATH_INFO']
+ if url.endswith('/__latency__'):
+ return self.handler(environ, start_response)
+
+ try:
+ return self._app(environ, start_response)
+ finally:
+ elapsed_ms = 1000 * (time.time() - start)
+ for url_prefix in self._urls:
+ if url.startswith(url_prefix):
+ url = url_prefix
+ break
+ for bkt, threshold in enumerate(LATENCY_BUCKETS):
+ if elapsed_ms < threshold:
+ break
+ else:
+ bkt = len(LATENCY_BUCKETS)
+ self._buckets[url][bkt] += 1
+
+ def handler(self, environ, start_response):
+ headers = [('Content-type', 'text/html')]
+ start_response('200 OK', headers)
+
+ result = [
+ '<!doctype html>\n'
+ '<html><head><title>Latency Breakdown</title>\n'
+ '<style type="text/css">\n'
+ 'body { background: white; font-family: sans-serif; }\n'
+ '</style></head><body>\n'
+ '<h3>Latency report by URL</h3>\n'
+ '<table><thead><tr>'
+ '<th rowspan="2">URL</th>',
+ '<th colspan="%d">Latencies (ms)</th>' % N_BUCKETS,
+ '</tr><tr>'
+ ]
+
+ for ms in enumerate(LATENCY_BUCKETS):
+ result.append('<th><%d</th>' % ms)
+ result.append('<th>>%d</th>' % ms)
+ result.append('</tr></thead><tbody>')
+
+ for url in sorted(self._buckets.keys()):
+ result.append('<tr><td class="url">%s</td>' % url)
+ for count, pct in _percent(self._buckets[url]):
+ result.append('<td>%d (%.3g%%)</td>' % (count, pct))
+ result.append('</tr>')
+
+ result.append('</tbody></table>')
+ result.append('</body></html>\n')
+ return result