From 0ea0301a3ff244dc1b8b4403811188fe31e96808 Mon Sep 17 00:00:00 2001
From: Leighton <lechen@microsoft.com>
Date: Mon, 8 Jun 2020 22:08:50 -0700
Subject: [PATCH 01/10] init

---
 docs/examples/basic_meter/basic_metrics.py    | 20 +++++++------
 .../basic_meter/calling_conventions.py        | 11 ++++---
 docs/examples/basic_meter/observer.py         | 10 +++++--
 .../src/opentelemetry/sdk/metrics/__init__.py | 30 +++++++++++++++----
 .../sdk/metrics/export/controller.py          | 25 +++++++++++-----
 5 files changed, 66 insertions(+), 30 deletions(-)

diff --git a/docs/examples/basic_meter/basic_metrics.py b/docs/examples/basic_meter/basic_metrics.py
index b9ff8d87417..07b72e299ad 100644
--- a/docs/examples/basic_meter/basic_metrics.py
+++ b/docs/examples/basic_meter/basic_metrics.py
@@ -28,8 +28,6 @@
 from opentelemetry.sdk.metrics.export import ConsoleMetricsExporter
 from opentelemetry.sdk.metrics.export.controller import PushController
 
-stateful = True
-
 print(
     "Starting example, values will be printed to the console every 5 seconds."
 )
@@ -37,17 +35,21 @@
 # Stateful determines whether how metrics are collected: if true, metrics
 # accumulate over the process lifetime. If false, metrics are reset at the
 # beginning of each collection interval.
-metrics.set_meter_provider(MeterProvider(stateful))
-# The Meter is responsible for creating and recording metrics. Each meter has a
-# unique name, which we set as the module's name here.
-meter = metrics.get_meter(__name__)
+stateful = True
 
 # Exporter to export metrics to the console
 exporter = ConsoleMetricsExporter()
 
-# A PushController collects metrics created from meter and exports it via the
-# exporter every interval
-controller = PushController(meter=meter, exporter=exporter, interval=5)
+metrics.set_meter_provider(
+    MeterProvider(
+        exporter=exporter,
+        interval=5,
+        stateful=stateful
+    )
+)
+# The Meter is responsible for creating and recording metrics. Each meter has a
+# unique name, which we set as the module's name here.
+meter = metrics.get_meter(__name__)
 
 # Metric instruments allow to capture measurements
 requests_counter = meter.create_metric(
diff --git a/docs/examples/basic_meter/calling_conventions.py b/docs/examples/basic_meter/calling_conventions.py
index f8cc3dddbb1..b1b88bae991 100644
--- a/docs/examples/basic_meter/calling_conventions.py
+++ b/docs/examples/basic_meter/calling_conventions.py
@@ -24,10 +24,13 @@
 from opentelemetry.sdk.metrics.export.controller import PushController
 
 # Use the meter type provided by the SDK package
-metrics.set_meter_provider(MeterProvider())
+metrics.set_meter_provider(
+    MeterProvider(
+        exporter=ConsoleMetricsExporter(),
+        interval=5
+    )
+)
 meter = metrics.get_meter(__name__)
-exporter = ConsoleMetricsExporter()
-controller = PushController(meter=meter, exporter=exporter, interval=5)
 
 requests_counter = meter.create_metric(
     name="requests",
@@ -62,7 +65,7 @@
 # You can record metrics directly using the metric instrument. You pass in
 # labels that you would like to record for.
 requests_counter.add(25, labels)
-time.sleep(5)
+time.sleep(10)
 
 print("Updating using a bound instrument...")
 # You can record metrics with bound metric instruments. Bound metric
diff --git a/docs/examples/basic_meter/observer.py b/docs/examples/basic_meter/observer.py
index b61b9e4db80..54380647ee9 100644
--- a/docs/examples/basic_meter/observer.py
+++ b/docs/examples/basic_meter/observer.py
@@ -24,10 +24,13 @@
 from opentelemetry.sdk.metrics.export.batcher import UngroupedBatcher
 from opentelemetry.sdk.metrics.export.controller import PushController
 
-metrics.set_meter_provider(MeterProvider())
+metrics.set_meter_provider(
+    MeterProvider(
+        exporter=ConsoleMetricsExporter(),
+        interval=5,
+    )
+)
 meter = metrics.get_meter(__name__)
-exporter = ConsoleMetricsExporter()
-controller = PushController(meter=meter, exporter=exporter, interval=2)
 
 
 # Callback to gather cpu usage
@@ -60,6 +63,7 @@ def get_ram_usage_callback(observer):
     description="RAM memory usage",
     unit="1",
     value_type=float,
+    observer_type=ValueObserver,
     label_keys=(),
 )
 
diff --git a/opentelemetry-sdk/src/opentelemetry/sdk/metrics/__init__.py b/opentelemetry-sdk/src/opentelemetry/sdk/metrics/__init__.py
index 507e00d8ead..6a9644b6ed0 100644
--- a/opentelemetry-sdk/src/opentelemetry/sdk/metrics/__init__.py
+++ b/opentelemetry-sdk/src/opentelemetry/sdk/metrics/__init__.py
@@ -17,8 +17,10 @@
 from typing import Dict, Sequence, Tuple, Type
 
 from opentelemetry import metrics as metrics_api
+from opentelemetry.sdk.metrics.export import ConsoleMetricsExporter
 from opentelemetry.sdk.metrics.export.aggregate import Aggregator
 from opentelemetry.sdk.metrics.export.batcher import UngroupedBatcher
+from opentelemetry.sdk.metrics.export.controller import PushController
 from opentelemetry.sdk.resources import Resource
 from opentelemetry.sdk.util.instrumentation import InstrumentationInfo
 
@@ -406,10 +408,23 @@ class MeterProvider(metrics_api.MeterProvider):
     """
 
     def __init__(
-        self, stateful=True, resource: Resource = Resource.create_empty(),
+        self,
+        exporter=None,
+        interval=15.0,
+        stateful=True,
+        resource: Resource = Resource.create_empty(),
     ):
+        if not exporter:
+            self.exporter = ConsoleMetricsExporter()
         self.stateful = stateful
         self.resource = resource
+        # InstrumentationInfo to Meter
+        self.meter_registry = {}
+        self.controller = PushController(
+            self.meter_registry,
+            exporter,
+            interval
+        )
 
     def get_meter(
         self,
@@ -418,9 +433,12 @@ def get_meter(
     ) -> "metrics_api.Meter":
         if not instrumenting_module_name:  # Reject empty strings too.
             raise ValueError("get_meter called with missing module name.")
-        return Meter(
-            self,
-            InstrumentationInfo(
-                instrumenting_module_name, instrumenting_library_version
-            ),
+        info = InstrumentationInfo(
+            instrumenting_module_name,
+            instrumenting_library_version,
         )
+        meter = self.meter_registry.get(info)
+        if not meter:
+            meter = Meter(self, info)
+            self.meter_registry[info] = meter
+        return meter
diff --git a/opentelemetry-sdk/src/opentelemetry/sdk/metrics/export/controller.py b/opentelemetry-sdk/src/opentelemetry/sdk/metrics/export/controller.py
index 88abed410a1..bddd01eaa99 100644
--- a/opentelemetry-sdk/src/opentelemetry/sdk/metrics/export/controller.py
+++ b/opentelemetry-sdk/src/opentelemetry/sdk/metrics/export/controller.py
@@ -27,9 +27,15 @@ class PushController(threading.Thread):
 
     daemon = True
 
-    def __init__(self, meter, exporter, interval, shutdown_on_exit=True):
+    def __init__(
+        self,
+        meter_registry,
+        exporter,
+        interval,
+        shutdown_on_exit=True,
+    ):
         super().__init__()
-        self.meter = meter
+        self.meter_registry = meter_registry
         self.exporter = exporter
         self.interval = interval
         self.finished = threading.Event()
@@ -40,7 +46,9 @@ def __init__(self, meter, exporter, interval, shutdown_on_exit=True):
 
     def run(self):
         while not self.finished.wait(self.interval):
-            self.tick()
+            # Only run if meters exist
+            if self.meter_registry:
+                self.tick()
 
     def shutdown(self):
         self.finished.set()
@@ -53,10 +61,11 @@ def shutdown(self):
 
     def tick(self):
         # Collect all of the meter's metrics to be exported
-        self.meter.collect()
         token = attach(set_value("suppress_instrumentation", True))
-        # Export the given metrics in the batcher
-        self.exporter.export(self.meter.batcher.checkpoint_set())
+        for meter in self.meter_registry.values():
+            meter.collect()
+            # Export the collected metrics
+            self.exporter.export(meter.batcher.checkpoint_set())
+            # Perform post-exporting logic
+            meter.batcher.finished_collection()
         detach(token)
-        # Perform post-exporting logic based on batcher configuration
-        self.meter.batcher.finished_collection()

From 8e8893514e56ef3f81d9ee4641c205f70daa1794 Mon Sep 17 00:00:00 2001
From: Leighton <lechen@microsoft.com>
Date: Mon, 8 Jun 2020 22:30:38 -0700
Subject: [PATCH 02/10] changelog

---
 opentelemetry-api/CHANGELOG.md | 2 ++
 opentelemetry-sdk/CHANGELOG.md | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/opentelemetry-api/CHANGELOG.md b/opentelemetry-api/CHANGELOG.md
index 4503489fa85..071e7603d3e 100644
--- a/opentelemetry-api/CHANGELOG.md
+++ b/opentelemetry-api/CHANGELOG.md
@@ -8,6 +8,8 @@
   ([#761](https://github.com/open-telemetry/opentelemetry-python/pull/761))
 - Rename Observer to ValueObserver
   ([#764](https://github.com/open-telemetry/opentelemetry-python/pull/764))
+- Move exporter and controller as part of MeterProvider
+  ([#764](https://github.com/open-telemetry/opentelemetry-python/pull/764))
 
 ## 0.8b0
 
diff --git a/opentelemetry-sdk/CHANGELOG.md b/opentelemetry-sdk/CHANGELOG.md
index d8eb23ab525..2c319372db8 100644
--- a/opentelemetry-sdk/CHANGELOG.md
+++ b/opentelemetry-sdk/CHANGELOG.md
@@ -10,6 +10,8 @@
   ([#775](https://github.com/open-telemetry/opentelemetry-python/pull/775))
 - Rename Observer to ValueObserver
   ([#764](https://github.com/open-telemetry/opentelemetry-python/pull/764))
+- Move exporter and controller as part of MeterProvider
+  ([#764](https://github.com/open-telemetry/opentelemetry-python/pull/764))
 
 ## 0.8b0
 

From 207a658cc96b597e33b996aef3b98cfc2311981d Mon Sep 17 00:00:00 2001
From: Leighton <lechen@microsoft.com>
Date: Mon, 8 Jun 2020 23:54:02 -0700
Subject: [PATCH 03/10] pipeline

---
 docs/examples/basic_meter/basic_metrics.py    | 19 ++---
 .../basic_meter/calling_conventions.py        |  9 +--
 docs/examples/basic_meter/observer.py         | 11 +--
 opentelemetry-api/CHANGELOG.md                |  2 -
 opentelemetry-sdk/CHANGELOG.md                |  2 +-
 .../src/opentelemetry/sdk/metrics/__init__.py | 74 +++++++++++++------
 .../sdk/metrics/export/controller.py          | 35 +++------
 7 files changed, 75 insertions(+), 77 deletions(-)

diff --git a/docs/examples/basic_meter/basic_metrics.py b/docs/examples/basic_meter/basic_metrics.py
index 07b72e299ad..1f1165b6277 100644
--- a/docs/examples/basic_meter/basic_metrics.py
+++ b/docs/examples/basic_meter/basic_metrics.py
@@ -26,7 +26,6 @@
 from opentelemetry import metrics
 from opentelemetry.sdk.metrics import Counter, MeterProvider, ValueRecorder
 from opentelemetry.sdk.metrics.export import ConsoleMetricsExporter
-from opentelemetry.sdk.metrics.export.controller import PushController
 
 print(
     "Starting example, values will be printed to the console every 5 seconds."
@@ -37,20 +36,18 @@
 # beginning of each collection interval.
 stateful = True
 
-# Exporter to export metrics to the console
-exporter = ConsoleMetricsExporter()
+# Sets the global MeterProvider instance
+metrics.set_meter_provider(MeterProvider())
 
-metrics.set_meter_provider(
-    MeterProvider(
-        exporter=exporter,
-        interval=5,
-        stateful=stateful
-    )
-)
 # The Meter is responsible for creating and recording metrics. Each meter has a
 # unique name, which we set as the module's name here.
 meter = metrics.get_meter(__name__)
 
+# Exporter to export metrics to the console
+exporter = ConsoleMetricsExporter()
+
+metrics.get_meter_provider().start_pipeline(meter, exporter, 5)
+
 # Metric instruments allow to capture measurements
 requests_counter = meter.create_metric(
     name="requests",
@@ -79,7 +76,7 @@
 # Update the metric instruments using the direct calling convention
 requests_counter.add(25, staging_labels)
 requests_size.record(100, staging_labels)
-time.sleep(5)
+time.sleep(10)
 
 requests_counter.add(50, staging_labels)
 requests_size.record(5000, staging_labels)
diff --git a/docs/examples/basic_meter/calling_conventions.py b/docs/examples/basic_meter/calling_conventions.py
index b1b88bae991..3615f60d7d4 100644
--- a/docs/examples/basic_meter/calling_conventions.py
+++ b/docs/examples/basic_meter/calling_conventions.py
@@ -21,16 +21,11 @@
 from opentelemetry import metrics
 from opentelemetry.sdk.metrics import Counter, MeterProvider, ValueRecorder
 from opentelemetry.sdk.metrics.export import ConsoleMetricsExporter
-from opentelemetry.sdk.metrics.export.controller import PushController
 
 # Use the meter type provided by the SDK package
-metrics.set_meter_provider(
-    MeterProvider(
-        exporter=ConsoleMetricsExporter(),
-        interval=5
-    )
-)
+metrics.set_meter_provider(MeterProvider())
 meter = metrics.get_meter(__name__)
+metrics.get_meter_provider().start_pipeline(meter, ConsoleMetricsExporter(), 5)
 
 requests_counter = meter.create_metric(
     name="requests",
diff --git a/docs/examples/basic_meter/observer.py b/docs/examples/basic_meter/observer.py
index 54380647ee9..56ebfd9ed68 100644
--- a/docs/examples/basic_meter/observer.py
+++ b/docs/examples/basic_meter/observer.py
@@ -21,17 +21,10 @@
 from opentelemetry import metrics
 from opentelemetry.sdk.metrics import MeterProvider, ValueObserver
 from opentelemetry.sdk.metrics.export import ConsoleMetricsExporter
-from opentelemetry.sdk.metrics.export.batcher import UngroupedBatcher
-from opentelemetry.sdk.metrics.export.controller import PushController
 
-metrics.set_meter_provider(
-    MeterProvider(
-        exporter=ConsoleMetricsExporter(),
-        interval=5,
-    )
-)
+metrics.set_meter_provider(MeterProvider())
 meter = metrics.get_meter(__name__)
-
+metrics.get_meter_provider().start_pipeline(meter, ConsoleMetricsExporter(), 5)
 
 # Callback to gather cpu usage
 def get_cpu_usage_callback(observer):
diff --git a/opentelemetry-api/CHANGELOG.md b/opentelemetry-api/CHANGELOG.md
index 071e7603d3e..4503489fa85 100644
--- a/opentelemetry-api/CHANGELOG.md
+++ b/opentelemetry-api/CHANGELOG.md
@@ -8,8 +8,6 @@
   ([#761](https://github.com/open-telemetry/opentelemetry-python/pull/761))
 - Rename Observer to ValueObserver
   ([#764](https://github.com/open-telemetry/opentelemetry-python/pull/764))
-- Move exporter and controller as part of MeterProvider
-  ([#764](https://github.com/open-telemetry/opentelemetry-python/pull/764))
 
 ## 0.8b0
 
diff --git a/opentelemetry-sdk/CHANGELOG.md b/opentelemetry-sdk/CHANGELOG.md
index 2c319372db8..cb2ad8bf670 100644
--- a/opentelemetry-sdk/CHANGELOG.md
+++ b/opentelemetry-sdk/CHANGELOG.md
@@ -10,7 +10,7 @@
   ([#775](https://github.com/open-telemetry/opentelemetry-python/pull/775))
 - Rename Observer to ValueObserver
   ([#764](https://github.com/open-telemetry/opentelemetry-python/pull/764))
-- Move exporter and controller as part of MeterProvider
+- Add start_pipeline to MeterProvider
   ([#764](https://github.com/open-telemetry/opentelemetry-python/pull/764))
 
 ## 0.8b0
diff --git a/opentelemetry-sdk/src/opentelemetry/sdk/metrics/__init__.py b/opentelemetry-sdk/src/opentelemetry/sdk/metrics/__init__.py
index 6a9644b6ed0..23719a13880 100644
--- a/opentelemetry-sdk/src/opentelemetry/sdk/metrics/__init__.py
+++ b/opentelemetry-sdk/src/opentelemetry/sdk/metrics/__init__.py
@@ -12,12 +12,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import atexit
 import logging
 import threading
 from typing import Dict, Sequence, Tuple, Type
 
 from opentelemetry import metrics as metrics_api
-from opentelemetry.sdk.metrics.export import ConsoleMetricsExporter
+from opentelemetry.sdk.metrics.export import (
+    ConsoleMetricsExporter,
+    MetricsExporter,
+)
 from opentelemetry.sdk.metrics.export.aggregate import Aggregator
 from opentelemetry.sdk.metrics.export.batcher import UngroupedBatcher
 from opentelemetry.sdk.metrics.export.controller import PushController
@@ -405,40 +409,68 @@ class MeterProvider(metrics_api.MeterProvider):
     Args:
         stateful: Indicates whether meters created are going to be stateful
         resource: Resource for this MeterProvider
+        shutdown_on_exit: Register an atexit hook to shut down when the
+            application exists
     """
 
     def __init__(
         self,
-        exporter=None,
-        interval=15.0,
         stateful=True,
         resource: Resource = Resource.create_empty(),
+        shutdown_on_exit: bool = True,
     ):
-        if not exporter:
-            self.exporter = ConsoleMetricsExporter()
         self.stateful = stateful
         self.resource = resource
-        # InstrumentationInfo to Meter
-        self.meter_registry = {}
-        self.controller = PushController(
-            self.meter_registry,
-            exporter,
-            interval
-        )
+        self._controllers = []
+        self._exporters = set()
+        self._atexit_handler = None
+        if shutdown_on_exit:
+            self._atexit_handler = atexit.register(self.shutdown)
 
     def get_meter(
         self,
         instrumenting_module_name: str,
         instrumenting_library_version: str = "",
     ) -> "metrics_api.Meter":
+        """See `opentelemetry.metrics.MeterProvider`.get_meter."""
         if not instrumenting_module_name:  # Reject empty strings too.
-            raise ValueError("get_meter called with missing module name.")
-        info = InstrumentationInfo(
-            instrumenting_module_name,
-            instrumenting_library_version,
+            instrumenting_module_name = "ERROR:MISSING MODULE NAME"
+            logger.error("get_meter called with missing module name.")
+        return Meter(
+            self,
+            InstrumentationInfo(
+                instrumenting_module_name,
+                instrumenting_library_version,
+            )
+        )
+
+    def start_pipeline(
+        self,
+        meter: metrics_api.Meter,
+        exporter: MetricsExporter = None,
+        interval: float = 15.0
+    ) -> None:
+        """Method to begin the collect/export pipeline.
+        
+        Args:
+            meter: The meter to collect metrics from.
+            exporter: The exporter to export metrics to.
+            interval: The collect/export interval in seconds.
+        """
+        if not exporter:
+            exporter = ConsoleMetricsExporter()
+        self._exporters.add(exporter)
+        # TODO: Controller type configurable?
+        self._controllers.append(
+            PushController(
+                meter,
+                exporter,
+                interval
+            )
         )
-        meter = self.meter_registry.get(info)
-        if not meter:
-            meter = Meter(self, info)
-            self.meter_registry[info] = meter
-        return meter
+
+    def shutdown(self) -> None:
+        for controller in self._controllers:
+            controller.shutdown()
+        for exporter in self._exporters:
+            exporter.shutdown()
diff --git a/opentelemetry-sdk/src/opentelemetry/sdk/metrics/export/controller.py b/opentelemetry-sdk/src/opentelemetry/sdk/metrics/export/controller.py
index bddd01eaa99..4a5eb1b40c8 100644
--- a/opentelemetry-sdk/src/opentelemetry/sdk/metrics/export/controller.py
+++ b/opentelemetry-sdk/src/opentelemetry/sdk/metrics/export/controller.py
@@ -12,14 +12,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import atexit
 import threading
 
 from opentelemetry.context import attach, detach, set_value
 
 
 class PushController(threading.Thread):
-    """A push based controller, used for exporting.
+    """A push based controller, used for collecting and exporting.
 
     Uses a worker thread that periodically collects metrics for exporting,
     exports them and performs some post-processing.
@@ -27,45 +26,29 @@ class PushController(threading.Thread):
 
     daemon = True
 
-    def __init__(
-        self,
-        meter_registry,
-        exporter,
-        interval,
-        shutdown_on_exit=True,
-    ):
+    def __init__(self, meter, exporter, interval):
         super().__init__()
-        self.meter_registry = meter_registry
+        self.meter = meter
         self.exporter = exporter
         self.interval = interval
         self.finished = threading.Event()
-        self._atexit_handler = None
-        if shutdown_on_exit:
-            self._atexit_handler = atexit.register(self.shutdown)
         self.start()
 
     def run(self):
         while not self.finished.wait(self.interval):
-            # Only run if meters exist
-            if self.meter_registry:
-                self.tick()
+            self.tick()
 
     def shutdown(self):
         self.finished.set()
         # Run one more collection pass to flush metrics batched in the meter
         self.tick()
-        self.exporter.shutdown()
-        if self._atexit_handler is not None:
-            atexit.unregister(self._atexit_handler)
-            self._atexit_handler = None
 
     def tick(self):
         # Collect all of the meter's metrics to be exported
+        self.meter.collect()
+        # Export the collected metrics
         token = attach(set_value("suppress_instrumentation", True))
-        for meter in self.meter_registry.values():
-            meter.collect()
-            # Export the collected metrics
-            self.exporter.export(meter.batcher.checkpoint_set())
-            # Perform post-exporting logic
-            meter.batcher.finished_collection()
+        self.exporter.export(self.meter.batcher.checkpoint_set())
         detach(token)
+        # Perform post-exporting logic
+        self.meter.batcher.finished_collection()

From 5a68ecf8fb840510cb1e757bbae695592ec65ac5 Mon Sep 17 00:00:00 2001
From: Leighton <lechen@microsoft.com>
Date: Tue, 9 Jun 2020 00:39:12 -0700
Subject: [PATCH 04/10] add tests

---
 docs/examples/basic_meter/basic_metrics.py    |  2 ++
 .../tests/metrics/export/test_export.py       |  1 -
 .../tests/metrics/test_implementation.py      |  1 -
 .../tests/metrics/test_metrics.py             | 20 +++++++++++++++++++
 4 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/docs/examples/basic_meter/basic_metrics.py b/docs/examples/basic_meter/basic_metrics.py
index 1f1165b6277..e65aa788b83 100644
--- a/docs/examples/basic_meter/basic_metrics.py
+++ b/docs/examples/basic_meter/basic_metrics.py
@@ -46,6 +46,8 @@
 # Exporter to export metrics to the console
 exporter = ConsoleMetricsExporter()
 
+# start_pipeline will notify the MeterProvider to begin collecting/exporting
+# metrics with the given meter, exporter and interval in seconds
 metrics.get_meter_provider().start_pipeline(meter, exporter, 5)
 
 # Metric instruments allow to capture measurements
diff --git a/opentelemetry-sdk/tests/metrics/export/test_export.py b/opentelemetry-sdk/tests/metrics/export/test_export.py
index 178e41b2134..901d5a94046 100644
--- a/opentelemetry-sdk/tests/metrics/export/test_export.py
+++ b/opentelemetry-sdk/tests/metrics/export/test_export.py
@@ -614,7 +614,6 @@ def test_push_controller(self):
 
         controller.shutdown()
         self.assertTrue(controller.finished.isSet())
-        exporter.shutdown.assert_any_call()
 
         # shutdown should flush the meter
         self.assertEqual(meter.collect.call_count, 1)
diff --git a/opentelemetry-sdk/tests/metrics/test_implementation.py b/opentelemetry-sdk/tests/metrics/test_implementation.py
index 1679f618341..d57e6d39783 100644
--- a/opentelemetry-sdk/tests/metrics/test_implementation.py
+++ b/opentelemetry-sdk/tests/metrics/test_implementation.py
@@ -25,7 +25,6 @@ class TestMeterImplementation(unittest.TestCase):
     to the API with different expected results. See issue for more details:
     https://github.com/open-telemetry/opentelemetry-python/issues/142
     """
-
     def test_meter(self):
         meter = metrics.MeterProvider().get_meter(__name__)
         metric = meter.create_metric("", "", "", float, metrics.Counter)
diff --git a/opentelemetry-sdk/tests/metrics/test_metrics.py b/opentelemetry-sdk/tests/metrics/test_metrics.py
index 4c2d691549d..f360bd887d6 100644
--- a/opentelemetry-sdk/tests/metrics/test_metrics.py
+++ b/opentelemetry-sdk/tests/metrics/test_metrics.py
@@ -38,6 +38,26 @@ def test_resource_empty(self):
         # pylint: disable=protected-access
         self.assertIs(meter.resource, resources._EMPTY_RESOURCE)
 
+    def test_start_pipeline(self):
+        exporter = mock.Mock()
+        meter_provider = metrics.MeterProvider()
+        meter = meter_provider.get_meter(__name__)
+        # pylint: disable=protected-access
+        meter_provider.start_pipeline(meter, exporter, 6)
+        self.assertEqual(len(meter_provider._exporters), 1)
+        self.assertEqual(len(meter_provider._controllers), 1)
+
+    def test_shutdown(self):
+        controller = mock.Mock()
+        exporter = mock.Mock()
+        meter_provider = metrics.MeterProvider()
+        # pylint: disable=protected-access
+        meter_provider._controllers = [controller]
+        meter_provider._exporters = [exporter]
+        meter_provider.shutdown()
+        self.assertEqual(controller.shutdown.call_count, 1)
+        self.assertEqual(exporter.shutdown.call_count, 1)
+
 
 class TestMeter(unittest.TestCase):
     def test_extends_api(self):

From ec22325ad6ffa3c3470a8db95eb20d13267a613a Mon Sep 17 00:00:00 2001
From: Leighton <lechen@microsoft.com>
Date: Tue, 9 Jun 2020 09:37:48 -0700
Subject: [PATCH 05/10] lint

---
 .../src/opentelemetry/sdk/metrics/__init__.py     | 15 ++++-----------
 .../tests/metrics/test_implementation.py          |  1 +
 2 files changed, 5 insertions(+), 11 deletions(-)

diff --git a/opentelemetry-sdk/src/opentelemetry/sdk/metrics/__init__.py b/opentelemetry-sdk/src/opentelemetry/sdk/metrics/__init__.py
index 23719a13880..0ebb9d397ba 100644
--- a/opentelemetry-sdk/src/opentelemetry/sdk/metrics/__init__.py
+++ b/opentelemetry-sdk/src/opentelemetry/sdk/metrics/__init__.py
@@ -439,16 +439,15 @@ def get_meter(
         return Meter(
             self,
             InstrumentationInfo(
-                instrumenting_module_name,
-                instrumenting_library_version,
-            )
+                instrumenting_module_name, instrumenting_library_version,
+            ),
         )
 
     def start_pipeline(
         self,
         meter: metrics_api.Meter,
         exporter: MetricsExporter = None,
-        interval: float = 15.0
+        interval: float = 15.0,
     ) -> None:
         """Method to begin the collect/export pipeline.
         
@@ -461,13 +460,7 @@ def start_pipeline(
             exporter = ConsoleMetricsExporter()
         self._exporters.add(exporter)
         # TODO: Controller type configurable?
-        self._controllers.append(
-            PushController(
-                meter,
-                exporter,
-                interval
-            )
-        )
+        self._controllers.append(PushController(meter, exporter, interval))
 
     def shutdown(self) -> None:
         for controller in self._controllers:
diff --git a/opentelemetry-sdk/tests/metrics/test_implementation.py b/opentelemetry-sdk/tests/metrics/test_implementation.py
index d57e6d39783..1679f618341 100644
--- a/opentelemetry-sdk/tests/metrics/test_implementation.py
+++ b/opentelemetry-sdk/tests/metrics/test_implementation.py
@@ -25,6 +25,7 @@ class TestMeterImplementation(unittest.TestCase):
     to the API with different expected results. See issue for more details:
     https://github.com/open-telemetry/opentelemetry-python/issues/142
     """
+
     def test_meter(self):
         meter = metrics.MeterProvider().get_meter(__name__)
         metric = meter.create_metric("", "", "", float, metrics.Counter)

From 4592653885449323013e92688e287e4b05969452 Mon Sep 17 00:00:00 2001
From: Leighton <lechen@microsoft.com>
Date: Tue, 9 Jun 2020 14:31:34 -0700
Subject: [PATCH 06/10] address comments

---
 docs/examples/basic_meter/observer.py              |  1 +
 docs/examples/cloud_monitoring/basic_metrics.py    | 10 +++-------
 .../opencensus-exporter-metrics/collector.py       |  3 +--
 .../src/opentelemetry/ext/prometheus/__init__.py   |  8 +++-----
 .../opentelemetry/ext/system_metrics/__init__.py   |  7 +++----
 .../src/opentelemetry/sdk/metrics/__init__.py      |  5 ++++-
 .../opentelemetry/sdk/metrics/export/controller.py | 14 +++++++++++++-
 opentelemetry-sdk/tests/metrics/test_metrics.py    |  2 ++
 8 files changed, 30 insertions(+), 20 deletions(-)

diff --git a/docs/examples/basic_meter/observer.py b/docs/examples/basic_meter/observer.py
index 56ebfd9ed68..076c416c0ab 100644
--- a/docs/examples/basic_meter/observer.py
+++ b/docs/examples/basic_meter/observer.py
@@ -26,6 +26,7 @@
 meter = metrics.get_meter(__name__)
 metrics.get_meter_provider().start_pipeline(meter, ConsoleMetricsExporter(), 5)
 
+
 # Callback to gather cpu usage
 def get_cpu_usage_callback(observer):
     for (number, percent) in enumerate(psutil.cpu_percent(percpu=True)):
diff --git a/docs/examples/cloud_monitoring/basic_metrics.py b/docs/examples/cloud_monitoring/basic_metrics.py
index e0ceb420b62..1a8e8eb0151 100644
--- a/docs/examples/cloud_monitoring/basic_metrics.py
+++ b/docs/examples/cloud_monitoring/basic_metrics.py
@@ -20,14 +20,10 @@
     CloudMonitoringMetricsExporter,
 )
 from opentelemetry.sdk.metrics import Counter, MeterProvider
-from opentelemetry.sdk.metrics.export.controller import PushController
 
-meter = metrics.get_meter(__name__, True)
-
-# Gather and export metrics every 5 seconds
-controller = PushController(
-    meter=meter, exporter=CloudMonitoringMetricsExporter(), interval=5
-)
+metrics.set_meter_provider(MeterProvider())
+meter = metrics.get_meter(__name__)
+metrics.get_meter_provider().start_pipeline(meter, CloudMonitoringMetricsExporter(), 5)
 
 requests_counter = meter.create_metric(
     name="request_counter",
diff --git a/docs/examples/opencensus-exporter-metrics/collector.py b/docs/examples/opencensus-exporter-metrics/collector.py
index 89dabd12eab..725f07b77ab 100644
--- a/docs/examples/opencensus-exporter-metrics/collector.py
+++ b/docs/examples/opencensus-exporter-metrics/collector.py
@@ -21,7 +21,6 @@
     OpenCensusMetricsExporter,
 )
 from opentelemetry.sdk.metrics import Counter, MeterProvider
-from opentelemetry.sdk.metrics.export.controller import PushController
 
 exporter = OpenCensusMetricsExporter(
     service_name="basic-service", endpoint="localhost:55678"
@@ -29,7 +28,7 @@
 
 metrics.set_meter_provider(MeterProvider())
 meter = metrics.get_meter(__name__)
-controller = PushController(meter, exporter, 5)
+metrics.get_meter_provider().start_pipeline(meter, exporter, 5)
 
 requests_counter = meter.create_metric(
     name="requests",
diff --git a/ext/opentelemetry-ext-prometheus/src/opentelemetry/ext/prometheus/__init__.py b/ext/opentelemetry-ext-prometheus/src/opentelemetry/ext/prometheus/__init__.py
index 59ef3f1708a..da22042dcc5 100644
--- a/ext/opentelemetry-ext-prometheus/src/opentelemetry/ext/prometheus/__init__.py
+++ b/ext/opentelemetry-ext-prometheus/src/opentelemetry/ext/prometheus/__init__.py
@@ -29,7 +29,6 @@
     from opentelemetry import metrics
     from opentelemetry.ext.prometheus import PrometheusMetricsExporter
     from opentelemetry.sdk.metrics import Counter, Meter
-    from opentelemetry.sdk.metrics.export.controller import PushController
     from prometheus_client import start_http_server
 
     # Start Prometheus client
@@ -37,13 +36,12 @@
 
     # Meter is responsible for creating and recording metrics
     metrics.set_meter_provider(MeterProvider())
-    meter = metrics.meter()
+    meter = metrics.get_meter(__name__)
     # exporter to export metrics to Prometheus
     prefix = "MyAppPrefix"
     exporter = PrometheusMetricsExporter(prefix)
-    # controller collects metrics created from meter and exports it via the
-    # exporter every interval
-    controller = PushController(meter, exporter, 5)
+    # Starts the collect/export pipeline for metrics
+    metrics.get_meter_provider().start_pipeline(meter, exporter, 5)
 
     counter = meter.create_metric(
         "requests",
diff --git a/ext/opentelemetry-ext-system-metrics/src/opentelemetry/ext/system_metrics/__init__.py b/ext/opentelemetry-ext-system-metrics/src/opentelemetry/ext/system_metrics/__init__.py
index 09c633f14b4..cd9ccd8bdcb 100644
--- a/ext/opentelemetry-ext-system-metrics/src/opentelemetry/ext/system_metrics/__init__.py
+++ b/ext/opentelemetry-ext-system-metrics/src/opentelemetry/ext/system_metrics/__init__.py
@@ -28,9 +28,11 @@
 
 .. code:: python
 
+    from opentelemetry import metrics
     from opentelemetry.ext.system_metrics import SystemMetrics
     from opentelemetry.sdk.metrics.export import ConsoleMetricsExporter
 
+    metrics.set_meter_provider(MeterProvider())
     exporter = ConsoleMetricsExporter()
     SystemMetrics(exporter)
 
@@ -60,7 +62,6 @@
 from opentelemetry import metrics
 from opentelemetry.sdk.metrics import ValueObserver
 from opentelemetry.sdk.metrics.export import MetricsExporter
-from opentelemetry.sdk.metrics.export.controller import PushController
 
 
 class SystemMetrics:
@@ -73,9 +74,7 @@ def __init__(
     ):
         self._labels = {} if labels is None else labels
         self.meter = metrics.get_meter(__name__)
-        self.controller = PushController(
-            meter=self.meter, exporter=exporter, interval=interval
-        )
+        metrics.get_meter_provider().start_pipeline(meter, exporter, interval)
         if config is None:
             self._config = {
                 "system_memory": ["total", "available", "used", "free"],
diff --git a/opentelemetry-sdk/src/opentelemetry/sdk/metrics/__init__.py b/opentelemetry-sdk/src/opentelemetry/sdk/metrics/__init__.py
index 0ebb9d397ba..f126ca47cce 100644
--- a/opentelemetry-sdk/src/opentelemetry/sdk/metrics/__init__.py
+++ b/opentelemetry-sdk/src/opentelemetry/sdk/metrics/__init__.py
@@ -450,7 +450,7 @@ def start_pipeline(
         interval: float = 15.0,
     ) -> None:
         """Method to begin the collect/export pipeline.
-        
+
         Args:
             meter: The meter to collect metrics from.
             exporter: The exporter to export metrics to.
@@ -467,3 +467,6 @@ def shutdown(self) -> None:
             controller.shutdown()
         for exporter in self._exporters:
             exporter.shutdown()
+        if self._atexit_handler is not None:
+            atexit.unregister(self._atexit_handler)
+            self._atexit_handler = None
diff --git a/opentelemetry-sdk/src/opentelemetry/sdk/metrics/export/controller.py b/opentelemetry-sdk/src/opentelemetry/sdk/metrics/export/controller.py
index 4a5eb1b40c8..88a7e950730 100644
--- a/opentelemetry-sdk/src/opentelemetry/sdk/metrics/export/controller.py
+++ b/opentelemetry-sdk/src/opentelemetry/sdk/metrics/export/controller.py
@@ -15,6 +15,8 @@
 import threading
 
 from opentelemetry.context import attach, detach, set_value
+from opentelemetry.metrics import Meter
+from opentelemetry.sdk.metrics.export import MetricsExporter
 
 
 class PushController(threading.Thread):
@@ -22,11 +24,21 @@ class PushController(threading.Thread):
 
     Uses a worker thread that periodically collects metrics for exporting,
     exports them and performs some post-processing.
+
+    Args:
+        meter: The meter used to collect metrics.
+        exporter: The exporter used to export metrics.
+        interval: The collect/export interval in seconds.
     """
 
     daemon = True
 
-    def __init__(self, meter, exporter, interval):
+    def __init__(
+        self,
+        meter: Meter,
+        exporter: MetricsExporter,
+        interval: float
+    ):
         super().__init__()
         self.meter = meter
         self.exporter = exporter
diff --git a/opentelemetry-sdk/tests/metrics/test_metrics.py b/opentelemetry-sdk/tests/metrics/test_metrics.py
index f360bd887d6..a6d59ffc28c 100644
--- a/opentelemetry-sdk/tests/metrics/test_metrics.py
+++ b/opentelemetry-sdk/tests/metrics/test_metrics.py
@@ -46,6 +46,7 @@ def test_start_pipeline(self):
         meter_provider.start_pipeline(meter, exporter, 6)
         self.assertEqual(len(meter_provider._exporters), 1)
         self.assertEqual(len(meter_provider._controllers), 1)
+        meter_provider.shutdown()
 
     def test_shutdown(self):
         controller = mock.Mock()
@@ -57,6 +58,7 @@ def test_shutdown(self):
         meter_provider.shutdown()
         self.assertEqual(controller.shutdown.call_count, 1)
         self.assertEqual(exporter.shutdown.call_count, 1)
+        self.assertIsNone(meter_provider._atexit_handler)
 
 
 class TestMeter(unittest.TestCase):

From 1203111824e3b926fe5a4ae102573fe1ee5b3740 Mon Sep 17 00:00:00 2001
From: Leighton <lechen@microsoft.com>
Date: Tue, 9 Jun 2020 15:00:21 -0700
Subject: [PATCH 07/10] address comment

---
 .../src/opentelemetry/ext/system_metrics/__init__.py      | 2 +-
 opentelemetry-sdk/tests/metrics/test_metrics.py           | 8 +++++---
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/ext/opentelemetry-ext-system-metrics/src/opentelemetry/ext/system_metrics/__init__.py b/ext/opentelemetry-ext-system-metrics/src/opentelemetry/ext/system_metrics/__init__.py
index cd9ccd8bdcb..2bb57ad6a3f 100644
--- a/ext/opentelemetry-ext-system-metrics/src/opentelemetry/ext/system_metrics/__init__.py
+++ b/ext/opentelemetry-ext-system-metrics/src/opentelemetry/ext/system_metrics/__init__.py
@@ -74,7 +74,7 @@ def __init__(
     ):
         self._labels = {} if labels is None else labels
         self.meter = metrics.get_meter(__name__)
-        metrics.get_meter_provider().start_pipeline(meter, exporter, interval)
+        metrics.get_meter_provider().start_pipeline(self.meter, exporter, interval)
         if config is None:
             self._config = {
                 "system_memory": ["total", "available", "used", "free"],
diff --git a/opentelemetry-sdk/tests/metrics/test_metrics.py b/opentelemetry-sdk/tests/metrics/test_metrics.py
index a6d59ffc28c..4eb8a0d9fc1 100644
--- a/opentelemetry-sdk/tests/metrics/test_metrics.py
+++ b/opentelemetry-sdk/tests/metrics/test_metrics.py
@@ -44,9 +44,11 @@ def test_start_pipeline(self):
         meter = meter_provider.get_meter(__name__)
         # pylint: disable=protected-access
         meter_provider.start_pipeline(meter, exporter, 6)
-        self.assertEqual(len(meter_provider._exporters), 1)
-        self.assertEqual(len(meter_provider._controllers), 1)
-        meter_provider.shutdown()
+        try:
+            self.assertEqual(len(meter_provider._exporters), 1)
+            self.assertEqual(len(meter_provider._controllers), 1)
+        finally:
+            meter_provider.shutdown()
 
     def test_shutdown(self):
         controller = mock.Mock()

From 449e8a9b9d3782845973e78e291fe5f76aba0439 Mon Sep 17 00:00:00 2001
From: Leighton <lechen@microsoft.com>
Date: Tue, 9 Jun 2020 15:27:26 -0700
Subject: [PATCH 08/10] fix tests

---
 .../src/opentelemetry/ext/system_metrics/__init__.py        | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/ext/opentelemetry-ext-system-metrics/src/opentelemetry/ext/system_metrics/__init__.py b/ext/opentelemetry-ext-system-metrics/src/opentelemetry/ext/system_metrics/__init__.py
index 2bb57ad6a3f..10b09795571 100644
--- a/ext/opentelemetry-ext-system-metrics/src/opentelemetry/ext/system_metrics/__init__.py
+++ b/ext/opentelemetry-ext-system-metrics/src/opentelemetry/ext/system_metrics/__init__.py
@@ -30,6 +30,7 @@
 
     from opentelemetry import metrics
     from opentelemetry.ext.system_metrics import SystemMetrics
+    from opentelemetry.sdk.metrics import MeterProvider,
     from opentelemetry.sdk.metrics.export import ConsoleMetricsExporter
 
     metrics.set_meter_provider(MeterProvider())
@@ -62,6 +63,7 @@
 from opentelemetry import metrics
 from opentelemetry.sdk.metrics import ValueObserver
 from opentelemetry.sdk.metrics.export import MetricsExporter
+from opentelemetry.sdk.metrics.export.controller import PushController
 
 
 class SystemMetrics:
@@ -74,7 +76,9 @@ def __init__(
     ):
         self._labels = {} if labels is None else labels
         self.meter = metrics.get_meter(__name__)
-        metrics.get_meter_provider().start_pipeline(self.meter, exporter, interval)
+        self.controller = PushController(
+            meter=self.meter, exporter=exporter, interval=interval
+        )
         if config is None:
             self._config = {
                 "system_memory": ["total", "available", "used", "free"],

From 5a45c836a0217dd139a966633442ef9fbc46abbd Mon Sep 17 00:00:00 2001
From: Leighton <lechen@microsoft.com>
Date: Tue, 9 Jun 2020 15:28:24 -0700
Subject: [PATCH 09/10] lint

---
 .../src/opentelemetry/sdk/metrics/export/controller.py       | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/opentelemetry-sdk/src/opentelemetry/sdk/metrics/export/controller.py b/opentelemetry-sdk/src/opentelemetry/sdk/metrics/export/controller.py
index 88a7e950730..7448f353c45 100644
--- a/opentelemetry-sdk/src/opentelemetry/sdk/metrics/export/controller.py
+++ b/opentelemetry-sdk/src/opentelemetry/sdk/metrics/export/controller.py
@@ -34,10 +34,7 @@ class PushController(threading.Thread):
     daemon = True
 
     def __init__(
-        self,
-        meter: Meter,
-        exporter: MetricsExporter,
-        interval: float
+        self, meter: Meter, exporter: MetricsExporter, interval: float
     ):
         super().__init__()
         self.meter = meter

From 0c5a051ad7a95d70ddaaa092fd216b12d470a93b Mon Sep 17 00:00:00 2001
From: Leighton <lechen@microsoft.com>
Date: Tue, 9 Jun 2020 15:55:59 -0700
Subject: [PATCH 10/10] lint

---
 docs/examples/cloud_monitoring/basic_metrics.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/docs/examples/cloud_monitoring/basic_metrics.py b/docs/examples/cloud_monitoring/basic_metrics.py
index 1a8e8eb0151..fa00fc068b6 100644
--- a/docs/examples/cloud_monitoring/basic_metrics.py
+++ b/docs/examples/cloud_monitoring/basic_metrics.py
@@ -23,7 +23,9 @@
 
 metrics.set_meter_provider(MeterProvider())
 meter = metrics.get_meter(__name__)
-metrics.get_meter_provider().start_pipeline(meter, CloudMonitoringMetricsExporter(), 5)
+metrics.get_meter_provider().start_pipeline(
+    meter, CloudMonitoringMetricsExporter(), 5
+)
 
 requests_counter = meter.create_metric(
     name="request_counter",