Better context management & support of deeply nested spans (#63)

* Rename InstanaSpan to JsonSpan

* Rename span to a more appropriate name

* Update import to follow rename

* Introduce InstanaSpan so that we can override interesting points.

* Better context management & support of deeply nested spans

* Use InstanaSpan.finish to track span closures
* Tests: add validations to assure span relationships
* Tests: add tests to validate urllib3 redirects
* In case of ID errors, return 0xBADDCAFE (indicating where I was when I wrote the code)

Author: pglombardo

instana/json_span.py

@@ -0,0 +1,56 @@
+class JsonSpan(object):
+    t = 0
+    p = None
+    s = 0
+    ts = 0
+    ta = "py"
+    d = 0
+    n = None
+    f = None
+    ec = 0
+    error = None
+    data = None
+
+    def __init__(self, **kwds):
+        for key in kwds:
+            self.__dict__[key] = kwds[key]
+
+
+class Data(object):
+    service = None
+    http = None
+    baggage = None
+    custom = None
+    sdk = None
+
+    def __init__(self, **kwds):
+        self.__dict__.update(kwds)
+
+
+class HttpData(object):
+    host = None
+    url = None
+    status = 0
+    method = None
+
+    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
+    arguments = None
+    Return = None
+    custom = None
+
+    def __init__(self, **kwds):
+        self.__dict__.update(kwds)

instana/recorder.py

@@ -6,7 +6,7 @@
 
 import opentracing.ext.tags as ext
 from basictracer import Sampler, SpanRecorder
-from .span import CustomData, Data, HttpData, InstanaSpan, SDKData
+from .json_span import CustomData, Data, HttpData, JsonSpan, SDKData
 from .agent_const import AGENT_TRACES_URL
 
 import sys
@@ -65,21 +65,21 @@ def clear_spans(self):
 
     def record_span(self, span):
         """
-        Convert the passed BasicSpan into an InstanaSpan and
+        Convert the passed BasicSpan into an JsonSpan and
         add it to the span queue
         """
         if self.sensor.agent.can_send() or "INSTANA_TEST" in os.environ:
-            instana_span = None
+            json_span = None
 
             if span.operation_name in self.registered_spans:
-                instana_span = self.build_registered_span(span)
+                json_span = self.build_registered_span(span)
             else:
-                instana_span = self.build_sdk_span(span)
+                json_span = self.build_sdk_span(span)
 
-            self.queue.put(instana_span)
+            self.queue.put(json_span)
 
     def build_registered_span(self, span):
-        """ Takes a BasicSpan and converts it into a registered InstanaSpan """
+        """ Takes a BasicSpan and converts it into a registered JsonSpan """
         data = Data(http=HttpData(host=self.get_host_name(span),
                                   url=self.get_string_tag(span, ext.HTTP_URL),
                                   method=self.get_string_tag(span, ext.HTTP_METHOD),
@@ -90,7 +90,7 @@ def build_registered_span(self, span):
         entityFrom = {'e': self.sensor.agent.from_.pid,
                       'h': self.sensor.agent.from_.agentUuid}
 
-        return InstanaSpan(
+        return JsonSpan(
                     n=span.operation_name,
                     t=span.context.trace_id,
                     p=span.parent_id,
@@ -103,7 +103,7 @@ def build_registered_span(self, span):
                     data=data)
 
     def build_sdk_span(self, span):
-        """ Takes a BasicSpan and converts into an SDK type InstanaSpan """
+        """ Takes a BasicSpan and converts into an SDK type JsonSpan """
 
         custom_data = CustomData(tags=span.tags,
                                  logs=self.collect_logs(span))
@@ -116,7 +116,7 @@ def build_sdk_span(self, span):
         entityFrom = {'e': self.sensor.agent.from_.pid,
                       'h': self.sensor.agent.from_.agentUuid}
 
-        return InstanaSpan(
+        return JsonSpan(
                     t=span.context.trace_id,
                     p=span.parent_id,
                     s=span.context.span_id,

instana/span.py

@@ -1,56 +1,16 @@
-class InstanaSpan(object):
-    t = 0
-    p = None
-    s = 0
-    ts = 0
-    ta = "py"
-    d = 0
-    n = None
-    f = None
-    ec = 0
-    error = None
-    data = None
-
-    def __init__(self, **kwds):
-        for key in kwds:
-            self.__dict__[key] = kwds[key]
-
-
-class Data(object):
-    service = None
-    http = None
-    baggage = None
-    custom = None
-    sdk = None
-
-    def __init__(self, **kwds):
-        self.__dict__.update(kwds)
-
-
-class HttpData(object):
-    host = None
-    url = None
-    status = 0
-    method = None
-
-    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
-    arguments = None
-    Return = None
-    custom = None
-
-    def __init__(self, **kwds):
-        self.__dict__.update(kwds)
+from basictracer.span import BasicSpan
+from basictracer.context import SpanContext
+
+
+class InstanaSpan(BasicSpan):
+    def finish(self, finish_time=None):
+        if self.parent_id is None:
+            self.tracer.cur_ctx = None
+        else:
+            # Set tracer context to the parent span
+            pctx = SpanContext(span_id=self.parent_id,
+                               trace_id=self.context.trace_id,
+                               baggage={},
+                               sampled=True)
+            self.tracer.cur_ctx = pctx
+        super(InstanaSpan, self).finish(finish_time)

instana/tracer.py

@@ -5,16 +5,16 @@
 import instana
 import instana.options as o
 
+from instana.util import generate_id
+from instana.span import InstanaSpan
 from basictracer.context import SpanContext
-from basictracer.span import BasicSpan
 from instana.http_propagator import HTTPPropagator
 from instana.text_propagator import TextPropagator
-from instana.util import generate_id
 
 
 class InstanaTracer(BasicTracer):
     sensor = None
-    current_span = None
+    cur_ctx = None
 
     def __init__(self, options=o.Options()):
         self.sensor = instana.global_sensor
@@ -58,20 +58,21 @@ def start_span(
             ctx.sampled = self.sampler.sampled(ctx.trace_id)
 
         # Tie it all together
-        self.current_span = BasicSpan(
+        span = InstanaSpan(
             self,
             operation_name=operation_name,
             context=ctx,
             parent_id=(None if parent_ctx is None else parent_ctx.span_id),
             tags=tags,
             start_time=start_time)
 
-        return self.current_span
+        self.cur_ctx = span.context
+        return span
 
     def current_context(self):
         context = None
-        if self.current_span:
-            context = self.current_span.context
+        if self.cur_ctx is not None:
+            context = self.cur_ctx
         return context
 
     def inject(self, span_context, format, carrier):

instana/util.py

@@ -1,5 +1,6 @@
 import random
 import os
+import json
 import time
 import struct
 import binascii
@@ -14,8 +15,9 @@
 _rnd = random.Random()
 _current_pid = 0
 
-BAD_ID_LONG = 3135097598   # Bad Cafe in base 10
-BAD_ID_HEADER = "BADDCAFE" # Bad Cafe
+BAD_ID_LONG = 3135097598  # Bad Cafe in base 10
+BAD_ID_HEADER = "BADDCAFE"  # Bad Cafe
+
 
 def generate_id():
     """ Generate a 64bit signed integer for use as a Span or Trace ID """
@@ -58,3 +60,11 @@ def header_to_id(header):
         return struct.unpack('>q', r)[0]
     except ValueError:
         return BAD_ID_LONG
+
+
+def to_json(obj):
+    try:
+        return json.dumps(obj, default=lambda obj: {k.lower(): v for k, v in obj.__dict__.items()},
+                          sort_keys=False, separators=(',', ':')).encode()
+    except Exception as e:
+        log.info("to_json: ", e, obj)

tests/apps/flaskalino.py

@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
-from flask import Flask
+from flask import Flask, redirect
 app = Flask(__name__)
 app.debug = False
 app.use_reloader = False
@@ -11,24 +11,34 @@ def hello():
     return "<center><h1>🐍 Hello Stan! 🦄</h1></center>"
 
 
+@app.route("/301")
+def threehundredone():
+    return redirect('/', code=301)
+
+
+@app.route("/302")
+def threehundredtwo():
+    return redirect('/', code=302)
+
+
 @app.route("/400")
 def fourhundred():
-    return "Bad Request", 400
+    return "Simulated Bad Request", 400
 
 
 @app.route("/405")
 def fourhundredfive():
-    return "Method not allowed", 405
+    return "Simulated Method not allowed", 405
 
 
 @app.route("/500")
 def fivehundred():
-    return "Internal Server Error", 500
+    return "Simulated Internal Server Error", 500
 
 
 @app.route("/504")
 def fivehundredfour():
-    return "Gateway Timeout", 504
+    return "Simulated Gateway Timeout", 504
 
 
 @app.route("/exception")

tests/test_helpers.py

@@ -19,6 +19,7 @@ def test_vanilla_eum_snippet():
     assert eum_string.find(trace_id) != -1
     assert eum_string.find(eum_api_key) != -1
 
+
 def test_eum_snippet_with_meta():
     meta_kvs = {}
     meta_kvs['meta1'] = meta1
@@ -34,6 +35,7 @@ def test_eum_snippet_with_meta():
     assert eum_string.find(meta2) != -1
     assert eum_string.find(meta3) != -1
 
+
 def test_eum_snippet_error():
     meta_kvs = {}
     meta_kvs['meta1'] = meta1
@@ -44,6 +46,7 @@ def test_eum_snippet_error():
     eum_string = eum_snippet(eum_api_key=eum_api_key, meta=meta_kvs)
     assert_equals('', eum_string)
 
+
 def test_vanilla_eum_test_snippet():
     eum_string = eum_test_snippet(trace_id=trace_id, eum_api_key=eum_api_key)
     assert type(eum_string) is str
@@ -53,6 +56,7 @@ def test_vanilla_eum_test_snippet():
     assert eum_string.find('reportingUrl') != -1
     assert eum_string.find('//eum-test-fullstack-0-us-west-2.instana.io') != -1
 
+
 def test_eum_test_snippet_with_meta():
     meta_kvs = {}
     meta_kvs['meta1'] = meta1
@@ -70,6 +74,7 @@ def test_eum_test_snippet_with_meta():
     assert eum_string.find(meta2) != -1
     assert eum_string.find(meta3) != -1
 
+
 def test_eum_test_snippet_error():
     meta_kvs = {}
     meta_kvs['meta1'] = meta1