Metrics API with RFC 0003 (#87)

* Create functions

Comments for Meter

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Fix typos

* fix lint

* Fix lint

* fix typing

* Remove options, constructors, seperate labels

* Consistent naming for float and int

* Abstract time series

* Use ABC

* Fix typo

* Fix docs

* seperate measure classes

* Add examples

* fix lint

* Update to RFC 0003

* Add spancontext, measurebatch

* Fix docs

* Fix comments

* fix lint

* fix lint

* fix lint

* skip examples

* white space

* fix spacing

* fix imports

* fix imports

* LabelValues to str

* Black formatting

* fix isort

* Remove aggregation

* Fix names

* Remove aggregation from docs

* Fix lint

docs/index.rst

@@ -17,6 +17,7 @@ abstract types for OpenTelemetry implementations.
 
    opentelemetry.context
    opentelemetry.loader
+   opentelemetry.metrics
    opentelemetry.trace
 
 

docs/opentelemetry.metrics.rst

@@ -0,0 +1,14 @@
+opentelemetry.metrics package
+=============================
+
+Submodules
+----------
+
+.. toctree::
+
+   opentelemetry.metrics.time_series
+
+Module contents
+---------------
+
+.. automodule:: opentelemetry.metrics

docs/opentelemetry.metrics.time_series.rst

@@ -0,0 +1,5 @@
+opentelemetry.metrics.time\_series module
+==========================================
+
+.. automodule:: opentelemetry.metrics.time_series
+

opentelemetry-api/src/opentelemetry/metrics/__init__.py

@@ -11,3 +11,307 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+
+"""
+The OpenTelemetry metrics API describes the classes used to report raw
+measurements, as well as metrics with known aggregation and labels.
+
+The `Meter` class is used to construct `Metric` s to record raw statistics
+as well as metrics with predefined aggregation.
+
+See the `metrics api`_ spec for terminology and context clarification.
+
+.. _metrics api:
+    https://github.com/open-telemetry/opentelemetry-specification/blob/master/specification/api-metrics.md
+
+
+"""
+
+from abc import ABC, abstractmethod
+from typing import List
+
+from opentelemetry.metrics.time_series import (
+    CounterTimeSeries,
+    GaugeTimeSeries,
+    MeasureTimeSeries,
+)
+from opentelemetry.trace import SpanContext
+
+LabelKeys = List["LabelKey"]
+LabelValues = List[str]
+
+
+class Meter:
+    """An interface to allow the recording of metrics.
+
+    `Metric` s are used for recording pre-defined aggregation (gauge and
+    counter), or raw values (measure) in which the aggregation and labels
+    for the exported metric are deferred.
+    """
+
+    def create_float_counter(
+        self,
+        name: str,
+        description: str,
+        unit: str,
+        label_keys: LabelKeys,
+        span_context: SpanContext = None,
+    ) -> "FloatCounter":
+        """Creates a counter type metric that contains float values.
+
+        Args:
+            name: The name of the counter.
+            description: Human readable description of the metric.
+            unit: Unit of the metric values.
+            label_keys: list of keys for the labels with dynamic values.
+                Order of the list is important as the same order MUST be used
+                on recording when suppling values for these labels.
+            span_context: The `SpanContext` that identifies the `Span`
+                that the metric is associated with.
+
+        Returns: A new `FloatCounter`
+        """
+
+    def create_int_counter(
+        self,
+        name: str,
+        description: str,
+        unit: str,
+        label_keys: LabelKeys,
+        span_context: SpanContext = None,
+    ) -> "IntCounter":
+        """Creates a counter type metric that contains int values.
+
+        Args:
+            name: The name of the counter.
+            description: Human readable description of the metric.
+            unit: Unit of the metric values.
+            label_keys: list of keys for the labels with dynamic values.
+                Order of the list is important as the same order MUST be used
+                on recording when suppling values for these labels.
+            span_context: The `SpanContext` that identifies the `Span`
+                that the metric is associated with.
+
+        Returns:
+            A new `IntCounter`
+        """
+
+    def create_float_gauge(
+        self,
+        name: str,
+        description: str,
+        unit: str,
+        label_keys: LabelKeys,
+        span_context: SpanContext = None,
+    ) -> "FloatGauge":
+        """Creates a gauge type metric that contains float values.
+
+        Args:
+            name: The name of the counter.
+            description: Human readable description of the metric.
+            unit: Unit of the metric values.
+            label_keys: list of keys for the labels with dynamic values.
+                Order of the list is important as the same order MUST be used
+                on recording when suppling values for these labels.
+            span_context: The `SpanContext` that identifies the `Span`
+                that the metric is associated with.
+
+        Returns:
+            A new `FloatGauge`
+        """
+
+    def create_int_gauge(
+        self,
+        name: str,
+        description: str,
+        unit: str,
+        label_keys: LabelKeys,
+        span_context: SpanContext = None,
+    ) -> "IntGauge":
+        """Creates a gauge type metric that contains int values.
+
+        Args:
+            name: The name of the counter.
+            description: Human readable description of the metric.
+            unit: Unit of the metric values.
+            label_keys: list of keys for the labels with dynamic values.
+                Order of the list is important as the same order MUST be used
+                on recording when suppling values for these labels.
+            span_context: The `SpanContext` that identifies the `Span`
+                that the metric is associated with.
+
+        Returns:
+            A new `IntGauge`
+        """
+
+    def create_int_measure(
+        self,
+        name: str,
+        description: str,
+        unit: str,
+        label_keys: LabelKeys,
+        span_context: SpanContext = None,
+    ) -> "IntMeasure":
+        """Creates a measure used to record raw int values.
+
+        Args:
+            name: The name of the measure.
+            description: Human readable description of this measure.
+            unit: Unit of the measure values.
+            label_keys: list of keys for the labels with dynamic values.
+                Order of the list is important as the same order MUST be used
+                on recording when suppling values for these labels.
+            span_context: The `SpanContext` that identifies the `Span`
+                that the metric is associated with.
+
+        Returns:
+            A new `IntMeasure`
+        """
+
+    def create_float_measure(
+        self,
+        name: str,
+        description: str,
+        unit: str,
+        label_keys: LabelKeys,
+        span_context: SpanContext = None,
+    ) -> "FloatMeasure":
+        """Creates a Measure used to record raw float values.
+
+        Args:
+            name: the name of the measure
+            description: Human readable description of this measure.
+            unit: Unit of the measure values.
+            label_keys: list of keys for the labels with dynamic values.
+                Order of the list is important as the same order MUST be used
+                on recording when suppling values for these labels.
+            span_context: The `SpanContext` that identifies the `Span`
+                that the metric is associated with.
+
+        Returns:
+            A new `FloatMeasure`
+        """
+
+
+class Metric(ABC):
+    """Base class for various types of metrics.
+
+    Metric class that inherit from this class are specialized with the type of
+    time series that the metric holds. Metric is constructed from the meter.
+    """
+
+    @abstractmethod
+    def get_or_create_time_series(self, label_values: LabelValues) -> "object":
+        """Gets and returns a timeseries, a container for a cumulative value.
+
+        If the provided label values are not already associated with this
+        metric, a new timeseries is returned, otherwise it returns the existing
+        timeseries with the exact label values. The timeseries returned
+        contains logic and behaviour specific to the type of metric that
+        overrides this function.
+
+        Args:
+            label_values: A list of label values that will be associated
+                with the return timeseries.
+        """
+
+    def remove_time_series(self, label_values: LabelValues) -> None:
+        """Removes the timeseries from the Metric, if present.
+
+        The timeseries with matching label values will be removed.
+
+        args:
+            label_values: The list of label values to match against.
+        """
+
+    def clear(self) -> None:
+        """Removes all timeseries from the `Metric`."""
+
+
+class FloatCounter(Metric):
+    """A counter type metric that holds float values.
+
+    Cumulative values can go up or stay the same, but can never go down.
+    Cumulative values cannot be negative.
+    """
+
+    def get_or_create_time_series(
+        self, label_values: LabelValues
+    ) -> "CounterTimeSeries":
+        """Gets a `CounterTimeSeries` with a cumulative float value."""
+
+
+class IntCounter(Metric):
+    """A counter type metric that holds int values.
+
+    Cumulative values can go up or stay the same, but can never go down.
+    Cumulative values cannot be negative.
+    """
+
+    def get_or_create_time_series(
+        self, label_values: LabelValues
+    ) -> "CounterTimeSeries":
+        """Gets a `CounterTimeSeries` with a cumulative int value."""
+
+
+class FloatGauge(Metric):
+    """A gauge type metric that holds float values.
+
+    Cumulative value can go both up and down. Values can be negative.
+    """
+
+    def get_or_create_time_series(
+        self, label_values: LabelValues
+    ) -> "GaugeTimeSeries":
+        """Gets a `GaugeTimeSeries` with a cumulative float value."""
+
+
+class IntGauge(Metric):
+    """A gauge type metric that holds int values.
+
+    Cumulative value can go both up and down. Values can be negative.
+    """
+
+    def get_or_create_time_series(
+        self, label_values: LabelValues
+    ) -> "GaugeTimeSeries":
+        """Gets a `GaugeTimeSeries` with a cumulative int value."""
+
+
+class FloatMeasure(Metric):
+    """A measure type metric that holds float values.
+
+    Measure metrics represent raw statistics that are recorded.
+    """
+
+    def get_or_create_time_series(
+        self, label_values: LabelValues
+    ) -> "MeasureTimeSeries":
+        """Gets a `MeasureTimeSeries` with a cumulated float value."""
+
+
+class IntMeasure(Metric):
+    """A measure type metric that holds int values.
+
+    Measure metrics represent raw statistics that are recorded.
+    """
+
+    def get_or_create_time_series(
+        self, label_values: LabelValues
+    ) -> "MeasureTimeSeries":
+        """Gets a `MeasureTimeSeries` with a cumulated int value."""
+
+
+class LabelKey:
+    """The label keys associated with the metric.
+
+    :type key: str
+    :param key: the key for the label
+
+    :type description: str
+    :param description: description of the label
+    """
+
+    def __init__(self, key: str, description: str) -> None:
+        self.key = key
+        self.description = description

opentelemetry-api/src/opentelemetry/metrics/examples/pre_aggregated.py

@@ -0,0 +1,36 @@
+# Copyright 2019, OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# pylint: skip-file
+from opentelemetry.metrics import LabelKey, LabelValue, Meter
+
+METER = Meter()
+LABEL_KEYS = [
+    LabelKey("environment", "the environment the application is running in")
+]
+COUNTER = METER.create_int_counter(
+    "sum numbers",  # pragma: no cover
+    "sum numbers over time",
+    "number",
+    LABEL_KEYS,
+)
+LABEL_VALUE_TESTING = [LabelValue("Testing")]
+LABEL_VALUE_STAGING = [LabelValue("Staging")]
+
+# Metrics sent to some exporter
+METRIC_TESTING = COUNTER.get_or_create_time_series(LABEL_VALUE_TESTING)
+METRIC_STAGING = COUNTER.get_or_create_time_series(LABEL_VALUE_STAGING)
+
+for i in range(100):
+    METRIC_STAGING.add(i)