Add Tracer.configure as the single way to configure the Tracer

ddtrace/reporter.py

@@ -16,8 +16,8 @@ class AgentReporter(object):
 
     SERVICES_FLUSH_INTERVAL = 120
 
-    def __init__(self):
-        self.transport = ThreadedHTTPTransport()
+    def __init__(self, hostname, port):
+        self.transport = ThreadedHTTPTransport(hostname, port)
         self.last_services_flush = 0
 
     def report(self, spans, services):

ddtrace/sampler.py

@@ -12,8 +12,8 @@
 log = logging.getLogger(__name__)
 
 
-class DefaultSampler(object):
-    """Default sampler, sampling all the traces"""
+class AllSampler(object):
+    """Sampler sampling all the traces"""
 
     def sample(self, span):
         span.sampled = True

ddtrace/tracer.py

@@ -3,7 +3,7 @@
 import threading
 
 from .buffer import ThreadLocalSpanBuffer
-from .sampler import DefaultSampler
+from .sampler import AllSampler
 from .span import Span
 from .writer import AgentWriter
 
@@ -12,9 +12,7 @@
 
 
 class Tracer(object):
-    """
-    Tracer is used to create, sample and submit spans that measure the
-    execution time of sections of code.
+    """Tracer is used to create, sample and submit spans that measure the execution time of sections of code.
 
     If you're running an application that will serve a single trace per thread,
     you can use the global traced instance:
@@ -23,37 +21,56 @@ class Tracer(object):
     >>> tracer.trace("foo").finish()
     """
 
-    def __init__(self, enabled=True, writer=None, span_buffer=None, sampler=None):
-        """
-        Create a new tracer.
+    DEFAULT_HOSTNAME = 'localhost'
+    DEFAULT_PORT = 7777
 
-        :param bool enabled: If true, finished traces will be submitted to the API. Otherwise they'll be dropped.
-        """
-        self.enabled = enabled
+    def __init__(self):
+        """Create a new tracer."""
 
-        self._writer = writer or AgentWriter()
-        self._span_buffer = span_buffer or ThreadLocalSpanBuffer()
-        self.sampler = sampler or DefaultSampler()
+        # Apply the default configuration
+        self.configure(enabled=True, hostname=self.DEFAULT_HOSTNAME, port=self.DEFAULT_PORT, sampler=AllSampler())
 
         # a list of buffered spans.
         self._spans_lock = threading.Lock()
         self._spans = []
 
+        # track the active span
+        self.span_buffer = ThreadLocalSpanBuffer()
+
         # a collection of registered services by name.
         self._services = {}
 
         # A hook for local debugging. shouldn't be needed or used
         # in production.
         self.debug_logging = False
 
-    def trace(self, name, service=None, resource=None, span_type=None):
+    def configure(self, enabled=None, hostname=None, port=None, sampler=None):
+        """Configure an existing Tracer the easy way.
+
+        Allow to configure or reconfigure a Tracer instance.
+
+        :param bool enabled: If True, finished traces will be submitted to the API. Otherwise they'll be dropped.
+        :param string hostname: Hostname running the Trace Agent
+        :param int port: Port of the Trace Agent
+        :param object sampler: A custom Sampler instance
         """
-        Return a span that will trace an operation called `name`.
+        if enabled is not None:
+            self.enabled = enabled
+
+        if hostname is not None or port is not None:
+            self.writer = AgentWriter(hostname or self.DEFAULT_HOSTNAME, port or self.DEFAULT_PORT)
+
+        if sampler is not None:
+            self.sampler = sampler
+
+    def trace(self, name, service=None, resource=None, span_type=None):
+        """Return a span that will trace an operation called `name`.
 
         :param str name: the name of the operation being traced
         :param str service: the name of the service being traced. If not set,
                             it will inherit the service from it's parent.
         :param str resource: an optional name of the resource being tracked.
+        :param str span_type: an optional operation type.
 
         You must call `finish` on all spans, either directly or with a context
         manager.
@@ -78,7 +95,7 @@ def trace(self, name, service=None, resource=None, span_type=None):
         >>> parent2.finish()
         """
         span = None
-        parent = self._span_buffer.get()
+        parent = self.span_buffer.get()
 
         if parent:
             # if we have a current span link the parent + child nodes.
@@ -104,26 +121,26 @@ def trace(self, name, service=None, resource=None, span_type=None):
             self.sampler.sample(span)
 
         # Note the current trace.
-        self._span_buffer.set(span)
+        self.span_buffer.set(span)
 
         return span
 
     def current_span(self):
-        """ Return the current active span or None. """
-        return self._span_buffer.get()
+        """Return the current active span or None."""
+        return self.span_buffer.get()
 
     def record(self, span):
-        """ Record the given finished span. """
+        """Record the given finished span."""
         spans = []
         with self._spans_lock:
             self._spans.append(span)
             parent = span._parent
-            self._span_buffer.set(parent)
+            self.span_buffer.set(parent)
             if not parent:
                 spans = self._spans
                 self._spans = []
 
-        if self._writer and span.sampled:
+        if self.writer and span.sampled:
             self.write(spans)
 
     def write(self, spans):
@@ -137,11 +154,10 @@ def write(self, spans):
 
         if self.enabled:
             # only submit the spans if we're actually enabled.
-            self._writer.write(spans, self._services)
+            self.writer.write(spans, self._services)
 
     def set_service_info(self, service, app, app_type):
-        """
-        Set the information about the given service.
+        """Set the information about the given service.
 
         :param str service: the internal name of the service (e.g. acme_search, datadog_web)
         :param str app: the off the shelf name of the application (e.g. rails, postgres, custom-app)
@@ -155,4 +171,3 @@ def set_service_info(self, service, app, app_type):
         if self.debug_logging:
             log.debug("set_service_info: service:%s app:%s type:%s",
                 service, app, app_type)
-

ddtrace/transport.py

@@ -21,6 +21,10 @@ class ThreadedHTTPTransport(object):
     # Async worker, to be defined at first run
     _worker = None
 
+    def __init__(self, hostname, port):
+        self.hostname = hostname
+        self.port = port
+
     def send(self, method, endpoint, data, headers):
         return self.async_send(
             method, endpoint, data, headers,
@@ -33,7 +37,7 @@ def async_send(self, method, endpoint, data, headers, success_cb, failure_cb):
 
     def send_sync(self, method, endpoint, data, headers, success_cb, failure_cb):
         try:
-            conn = httplib.HTTPConnection('localhost', 7777)
+            conn = httplib.HTTPConnection(self.hostname, self.port)
             conn.request(method, endpoint, data, headers)
         except Exception as e:
             failure_cb(e)

ddtrace/writer.py

@@ -3,8 +3,8 @@
 
 class AgentWriter(object):
 
-    def __init__(self):
-        self._reporter = AgentReporter()
+    def __init__(self, hostname='localhost', port=7777):
+        self._reporter = AgentReporter(hostname, port)
 
     def write(self, spans, services=None):
         self._reporter.report(spans, services)

tests/contrib/cassandra/test.py

@@ -41,7 +41,8 @@ def _assert_result_correct(self, result):
 
     def _traced_cluster(self):
         writer = DummyWriter()
-        tracer = Tracer(writer=writer)
+        tracer = Tracer()
+        tracer.writer = writer
         TracedCluster = get_traced_cassandra(tracer)
         return TracedCluster, writer
 
@@ -79,7 +80,8 @@ def test_trace_with_service(self):
         Tests tracing with a custom service
         """
         writer = DummyWriter()
-        tracer = Tracer(writer=writer)
+        tracer = Tracer()
+        tracer.writer = writer
         TracedCluster = get_traced_cassandra(tracer, service="custom")
         session = TracedCluster(port=9042).connect(self.TEST_KEYSPACE)
 

tests/contrib/django/tests.py

@@ -12,9 +12,9 @@
 
 def test_template():
     # trace and ensure it works
-    writer = DummyWriter()
-    tracer = Tracer(writer=writer)
-    assert not writer.pop()
+    tracer = Tracer()
+    tracer.writer = DummyWriter()
+    assert not tracer.writer.pop()
     patch_template(tracer)
 
     # setup a test template
@@ -36,7 +36,7 @@ def test_template():
     eq_(t.render(c), 'hello matt')
     end = time.time()
 
-    spans = writer.pop()
+    spans = tracer.writer.pop()
     assert spans, spans
     eq_(len(spans), 1)
 

tests/contrib/elasticsearch/test.py

@@ -41,7 +41,8 @@ def test_elasticsearch(self):
         All in this for now. Will split it later.
         """
         writer = DummyWriter()
-        tracer = Tracer(writer=writer)
+        tracer = Tracer()
+        tracer.writer = writer
         transport_class = get_traced_transport(datadog_tracer=tracer, datadog_service=self.TEST_SERVICE)
 
         es = elasticsearch.Elasticsearch(transport_class=transport_class)

tests/contrib/flask/test_flask.py

@@ -22,7 +22,8 @@
 
 # global writer tracer for the tests.
 writer = DummyWriter()
-tracer = Tracer(writer=writer)
+tracer = Tracer()
+tracer.writer =writer
 
 
 class TestError(Exception): pass

tests/contrib/psycopg/test_psycopg.py

@@ -18,7 +18,8 @@
 
 def test_wrap():
     writer = DummyWriter()
-    tracer = Tracer(writer=writer)
+    tracer = Tracer()
+    tracer.writer = writer
 
     params = {
         'host': 'localhost',

tests/contrib/pylons/test_pylons.py

@@ -29,7 +29,8 @@ def start_response(self, status, headers):
 
 def test_pylons():
     writer = DummyWriter()
-    tracer = Tracer(writer=writer)
+    tracer = Tracer()
+    tracer.writer = writer
     app = FakeWSGIApp()
     traced = PylonsTraceMiddleware(app, tracer, service="p")
 

tests/contrib/redis/test.py

@@ -31,7 +31,8 @@ def tearDown(self):
 
     def test_basic_class(self):
         writer = DummyWriter()
-        tracer = Tracer(writer=writer)
+        tracer = Tracer()
+        tracer.writer = writer
 
         TracedRedisCache = get_traced_redis(tracer, service=self.SERVICE)
         r = TracedRedisCache()
@@ -57,7 +58,8 @@ def test_basic_class(self):
 
     def test_meta_override(self):
         writer = DummyWriter()
-        tracer = Tracer(writer=writer)
+        tracer = Tracer()
+        tracer.writer = writer
 
         TracedRedisCache = get_traced_redis(tracer, service=self.SERVICE, meta={'cheese': 'camembert'})
         r = TracedRedisCache()
@@ -71,7 +73,8 @@ def test_meta_override(self):
 
     def test_basic_class_pipeline(self):
         writer = DummyWriter()
-        tracer = Tracer(writer=writer)
+        tracer = Tracer()
+        tracer.writer = writer
 
         TracedRedisCache = get_traced_redis(tracer, service=self.SERVICE)
         r = TracedRedisCache()
@@ -109,7 +112,8 @@ def execute_command(self, *args, **kwargs):
 
 
         writer = DummyWriter()
-        tracer = Tracer(writer=writer)
+        tracer = Tracer()
+        tracer.writer = writer
 
         TracedRedisCache = get_traced_redis_from(tracer, MyCustomRedis, service=self.SERVICE)
         r = TracedRedisCache()

tests/contrib/sqlite3/test_sqlite3.py

@@ -12,7 +12,8 @@
 
 def test_foo():
     writer = DummyWriter()
-    tracer = Tracer(writer=writer)
+    tracer = Tracer()
+    tracer.writer = writer
 
     # ensure we can trace multiple services without stomping
 

tests/test_sampler.py

@@ -15,8 +15,9 @@ class RateSamplerTest(unittest.TestCase):
 
     def test_random_sequence(self):
         writer = DummyWriter()
-        sampler = RateSampler(0.5)
-        tracer = Tracer(writer=writer, sampler=sampler)
+        tracer = Tracer()
+        tracer.writer = writer
+        tracer.sampler = RateSampler(0.5)
 
         # Set the seed so that the choice of sampled traces is deterministic, then write tests accordingly
         random.seed(4012)
@@ -52,7 +53,8 @@ class ThroughputSamplerTest(unittest.TestCase):
 
     def test_simple_limit(self):
         writer = DummyWriter()
-        tracer = Tracer(writer=writer)
+        tracer = Tracer()
+        tracer.writer = writer
 
         with patch_time() as fake_time:
             tps = 5
@@ -85,7 +87,8 @@ def test_simple_limit(self):
 
     def test_long_run(self):
         writer = DummyWriter()
-        tracer = Tracer(writer=writer)
+        tracer = Tracer()
+        tracer.writer = writer
 
         # Test a big matrix of combinaisons
         # Ensure to have total_time >> BUFFER_DURATION to reduce edge effects
@@ -118,7 +121,8 @@ def test_long_run(self):
     def test_concurrency(self):
         # Test that the sampler works well when used in different threads
         writer = DummyWriter()
-        tracer = Tracer(writer=writer)
+        tracer = Tracer()
+        tracer.writer = writer
 
         total_time = 10
         concurrency = 100