Merge in latest from datadog/dd-trace-py (#1)

ddtrace/contrib/pylons/renderer.py

@@ -0,0 +1,36 @@
+import pylons
+
+from pylons import config
+
+from ddtrace.vendor.wrapt import wrap_function_wrapper as _w
+
+from .compat import legacy_pylons
+from .constants import CONFIG_MIDDLEWARE
+
+
+def trace_rendering():
+    """Patch all Pylons renderers. It supports multiple versions
+    of Pylons and multiple renderers.
+    """
+    # patch only once
+    if getattr(pylons.templating, '__datadog_patch', False):
+        return
+    setattr(pylons.templating, '__datadog_patch', True)
+
+    if legacy_pylons:
+        # Pylons <= 0.9.7
+        _w('pylons.templating', 'render', _traced_renderer)
+    else:
+        # Pylons > 0.9.7
+        _w('pylons.templating', 'render_mako', _traced_renderer)
+        _w('pylons.templating', 'render_mako_def', _traced_renderer)
+        _w('pylons.templating', 'render_genshi', _traced_renderer)
+        _w('pylons.templating', 'render_jinja2', _traced_renderer)
+
+
+def _traced_renderer(wrapped, instance, args, kwargs):
+    """Traced renderer"""
+    tracer = config[CONFIG_MIDDLEWARE]._tracer
+    with tracer.trace('pylons.render') as span:
+        span.set_tag('template.name', args[0])
+        return wrapped(*args, **kwargs)