Merge pull request #8 from instana/flask

Flask Instrumentation through WSGI middleware.

Author: pglombardo

README.md

@@ -18,12 +18,29 @@ Any and all feedback is welcome.  Happy Python visibility.
 
 ## Installation
 
-There are two steps required to install the the Instana package for your applications:
+For this BETA, we currently support tracing of Django and Flask applications or optionally just runtime monitoring of your Python applications.
 
-1. `pip install instana` into the virtual-env or container ([hosted on pypi](https://pypi.python.org/pypi/instana))
+`pip install instana` into the virtual-env or container ([hosted on pypi](https://pypi.python.org/pypi/instana))
 
-2. Enable instrumentation for the frameworks in use by setting an environment variable:
-  `AUTOWRAPT_BOOTSTRAP=instana.django`
+## Django
+
+To enable the Django instrumentation, set the following environment variable in your _application boot environment_ and then restart your application:
+
+  `export AUTOWRAPT_BOOTSTRAP=django`
+
+## Flask
+
+To enable the Flask instrumentation, set the following environment variable in your _application boot environment_ and then restart your application:
+
+  `export AUTOWRAPT_BOOTSTRAP=flask`
+
+## Runtime Monitoring Only
+
+_Note: When the Django or Flask instrumentation is used, runtime monitoring is automatically included.  Use this section if you only want to see runtime metrics._
+
+To enable runtime monitoring (without request tracing), set the following environment variable in your _application boot environment_ and then restart your application:
+
+  `export AUTOWRAPT_BOOTSTRAP=runtime`
 
 ## Usage
 

instana/agent.py

@@ -80,7 +80,6 @@ def full_request_response(self, url, method, o, body, header):
                 request = urllib2.Request(url, self.to_json(o))
                 request.add_header("Content-Type", "application/json")
 
-            l.debug("request: ", method, self.to_json(o))
             response = urllib2.urlopen(request, timeout=2)
 
             if not response:

instana/flaskana.py

@@ -0,0 +1,15 @@
+from instana import wsgi
+from flask.cli import ScriptInfo
+
+
+def wrap_load_app(func):
+    def wrapper(self, *args):
+        app = func(self, *args)
+        app.wsgi_app = wsgi.iWSGIMiddleware(app.wsgi_app)
+        return app
+    return wrapper
+
+
+def hook(module):
+    """ Hook method to install the Instana middleware into Flask """
+    ScriptInfo.load_app = wrap_load_app(ScriptInfo.load_app)

instana/meter.py

@@ -148,7 +148,12 @@ def process(self):
 
     def collect_snapshot(self):
         try:
-            s = Snapshot(name=self.sensor.service_name,
+            if "FLASK_APP" in os.environ:
+                appname = os.environ["FLASK_APP"]
+            else:
+                appname = os.path.basename(sys.executable)
+
+            s = Snapshot(name=appname,
                          version=sys.version,
                          rlimit_core=resource.getrlimit(resource.RLIMIT_CORE),
                          rlimit_cpu=resource.getrlimit(resource.RLIMIT_CPU),

instana/propagator.py

@@ -1,6 +1,7 @@
 from __future__ import absolute_import
 import opentracing as ot
-from instana import util
+from basictracer.context import SpanContext
+from instana import util, log
 
 prefix_tracer_state = 'HTTP_X_INSTANA_'
 field_name_trace_id = prefix_tracer_state + 'T'
@@ -12,27 +13,40 @@ class HTTPPropagator():
     """A Propagator for Format.HTTP_HEADERS. """
 
     def inject(self, span_context, carrier):
-        carrier[field_name_trace_id] = util.id_to_header(span_context.trace_id)
-        carrier[field_name_span_id] = util.id_to_header(span_context.span_id)
+        try:
+            trace_id = util.id_to_header(span_context.trace_id)
+            span_id = util.id_to_header(span_context.span_id)
+            if type(carrier) is dict:
+                carrier[field_name_trace_id] = trace_id
+                carrier[field_name_span_id] = span_id
+            elif type(carrier) is list:
+                trace_header = (field_name_trace_id, trace_id)
+                carrier.append(trace_header)
+                span_header = (field_name_span_id, span_id)
+                carrier.append(span_header)
+            else:
+                raise Exception("Unsupported carrier type", type(carrier))
+
+        except Exception as e:
+            log.debug("inject error: ", str(e))
 
     def extract(self, carrier):  # noqa
-        count = 0
-        span_id, trace_id = (0, 0)
-        for k in carrier:
-            v = carrier[k]
-            k = k.lower()
-            if k == field_name_span_id:
-                span_id = util.header_to_id(v)
-                count += 1
-            elif k == field_name_trace_id:
-                trace_id = util.header_to_id(v)
-                count += 1
-
-        if count != field_count:
-            raise ot.SpanContextCorruptedException()
-
-        return ot.SpanContext(
-            span_id=span_id,
-            trace_id=trace_id,
-            baggage={},
-            sampled=True)
+        try:
+            if type(carrier) is dict:
+                dc = carrier
+            elif type(carrier) is list:
+                dc = dict(carrier)
+            else:
+                raise ot.SpanContextCorruptedException()
+
+            if field_name_trace_id in dc and field_name_span_id in dc:
+                trace_id = util.header_to_id(dc[field_name_trace_id])
+                span_id = util.header_to_id(dc[field_name_span_id])
+
+            return SpanContext(span_id=span_id,
+                               trace_id=trace_id,
+                               baggage={},
+                               sampled=True)
+
+        except Exception as e:
+            log.debug("extract error: ", str(e))

instana/recorder.py

@@ -16,7 +16,7 @@
 
 class InstanaRecorder(SpanRecorder):
     sensor = None
-    registered_spans = ("django", "memcache", "rpc-client", "rpc-server")
+    registered_spans = ("django", "memcache", "rpc-client", "rpc-server", "wsgi")
     entry_kind = ["entry", "server", "consumer"]
     exit_kind = ["exit", "client", "producer"]
     queue = queue.Queue()

instana/runtime.py

@@ -0,0 +1,15 @@
+import opentracing as ot
+from instana import tracer, options
+import logging
+import os
+
+
+def hook(module):
+    """ Hook method to install the Instana middleware into Flask """
+    if os.environ["AUTOWRAPT_BOOTSTRAP"] == "runtime":
+        if "INSTANA_DEV" in os.environ:
+            level = logging.DEBUG
+        else:
+            level = logging.WARN
+        opts = options.Options(log_level=level)
+        ot.global_tracer = tracer.InstanaTracer(opts)

instana/span.py

@@ -16,6 +16,7 @@ class InstanaSpan(object):
     def __init__(self, **kwds):
         self.__dict__.update(kwds)
 
+
 class Data(object):
     service = None
     http = None
@@ -26,6 +27,7 @@ class Data(object):
     def __init__(self, **kwds):
         self.__dict__.update(kwds)
 
+
 class HttpData(object):
     host = None
     url = None
@@ -35,13 +37,15 @@ class HttpData(object):
     def __init__(self, **kwds):
         self.__dict__.update(kwds)
 
+
 class CustomData(object):
     tags = None
     logs = None
 
     def __init__(self, **kwds):
         self.__dict__.update(kwds)
 
+
 class SDKData(object):
     name = None
     Type = None

instana/wsgi.py

@@ -0,0 +1,45 @@
+from __future__ import print_function
+import opentracing as ot
+from instana import tracer, options
+import opentracing.ext.tags as ext
+import logging
+
+
+class iWSGIMiddleware(object):
+    """ Instana WSGI middleware """
+
+    def __init__(self, app):
+        self.app = app
+        opts = options.Options(log_level=logging.DEBUG)
+        ot.global_tracer = tracer.InstanaTracer(opts)
+        self
+
+    def __call__(self, environ, start_response):
+        env = environ
+
+        def new_start_response(status, headers, exc_info=None):
+            """Modified start response with additional headers."""
+            ot.global_tracer.inject(span.context, ot.Format.HTTP_HEADERS, headers)
+            res = start_response(status, headers, exc_info)
+            span.set_tag(ext.HTTP_STATUS_CODE, status.split(' ')[0])
+            span.finish()
+            return res
+
+        if 'HTTP_X_INSTANA_T' in env and 'HTTP_X_INSTANA_S' in env:
+            ctx = ot.global_tracer.extract(ot.Format.HTTP_HEADERS, env)
+            span = ot.global_tracer.start_span("wsgi", child_of=ctx)
+        else:
+            span = ot.global_tracer.start_span("wsgi")
+
+        span.set_tag(ext.HTTP_URL, env['PATH_INFO'])
+        span.set_tag("http.params", env['QUERY_STRING'])
+        span.set_tag(ext.HTTP_METHOD, env['REQUEST_METHOD'])
+        span.set_tag("http.host", env['HTTP_HOST'])
+
+        return self.app(environ, new_start_response)
+
+
+def make_middleware(app=None, *args, **kw):
+    """ Given an app, return that app wrapped in iWSGIMiddleware """
+    app = iWSGIMiddleware(app, *args, **kw)
+    return app

setup.py

@@ -17,7 +17,9 @@
                         'opentracing>=1.2.1,<1.3',
                         'basictracer>=2.2.0',
                         'psutil>=5.1.3'],
-      entry_points={'instana.django': ['django.core.handlers.base = instana.django:hook']},
+      entry_points={'django': ['django.core.handlers.base = instana.django:hook'],
+                    'flask': ['flask.cli = instana.flaskana:hook'],
+                    'runtime': ['string = instana.runtime:hook']},
       test_suite='nose.collector',
       keywords=['performance', 'opentracing', 'metrics', 'monitoring'],
       classifiers=[