Prometheus Remote Write Exporter (6/6) (#227)

* adding README

adding sample app

adding examples readme

fixing lint errors

linting examples

updating readme tls_config example

excluding examples

adding examples to exclude in all linters

adding isort.cfg skip

changing isort to path

ignoring yml only

adding it to excluded directories in pylintrc

only adding exclude to directory

removing readme.rst and adding explicit file names to ignore

adding the rest of the files

adding readme.rst back

adding to ignore glob instead

reverting back to ignore list

converting README.md to README.rst

* addressing readme comments

* adding link to spec for details on aggregators

* updating readme

* adding python-snappy to setup.cfg

Author: Azfaar Qureshi

.pylintrc

@@ -7,7 +7,7 @@ extension-pkg-whitelist=
 
 # Add list of files or directories to be excluded. They should be base names, not
 # paths.
-ignore=CVS,gen
+ignore=CVS,gen,Dockerfile,docker-compose.yml,README.md,requirements.txt,cortex-config.yml
 
 # Add files or directories matching the regex patterns to be excluded. The
 # regex matches against base names, not paths.

CHANGELOG.md

@@ -29,14 +29,16 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#216](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/216))
 - `opentelemetry-instrumentation-grpc` Add tests for grpc span attributes, grpc `abort()` conditions
   ([#236](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/236))
+- Add README and example app for Prometheus Remote Write Exporter
+  ([#227](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/227]))
 
 ### Changed
 - `opentelemetry-instrumentation-asgi`, `opentelemetry-instrumentation-wsgi` Return `None` for `CarrierGetter` if key not found
   ([#1374](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/233))
 - `opentelemetry-instrumentation-grpc` Comply with updated spec, rework tests
   ([#236](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/236))
 - `opentelemetry-instrumentation-asgi`, `opentelemetry-instrumentation-falcon`, `opentelemetry-instrumentation-flask`, `opentelemetry-instrumentation-pyramid`, `opentelemetry-instrumentation-wsgi` Renamed `host.port` attribute to `net.host.port`
-  ([#242](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/242))  
+  ([#242](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/242))
 - `opentelemetry-instrumentation-flask` Do not emit a warning message for request contexts created with `app.test_request_context`
   ([#253](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/253))
 - `opentelemetry-instrumentation-requests`, `opentelemetry-instrumentation-urllib` Fix span name callback parameters

exporter/opentelemetry-exporter-prometheus-remote-write/README.rst

@@ -1,27 +1,322 @@
 OpenTelemetry Prometheus Remote Write Exporter
-==============================================
+=========================================================
 
-This library allows exporting metric data to `Prometheus Remote Write Integrated Backends
-<https://prometheus.io/docs/operating/integrations/>`_. Latest `types.proto
-<https://github.com/prometheus/prometheus/blob/master/prompb/types.proto>` and `remote.proto
-<https://github.com/prometheus/prometheus/blob/master/prompb/remote.proto>` Protocol Buffers 
-used to create WriteRequest objects were taken from Prometheus repository. Development is 
-currently in progress.
+This package contains an exporter to send `OTLP`_ metrics from the
+`OpenTelemetry Python SDK`_ directly to a `Prometheus Remote Write integrated backend`_
+(such as Cortex or Thanos) without having to run an instance of the
+Prometheus server. The latest `types.proto`_ and `remote.proto`_
+protocol buffers are used to create the WriteRequest. The image below shows the
+two Prometheus exporters in the OpenTelemetry Python SDK.
+
+Pipeline 1 illustrates the setup required for a `Prometheus "pull" exporter`_.
+
+Pipeline 2 illustrates the setup required for the Prometheus Remote
+Write exporter.
+
+|Prometheus SDK pipelines|
+
+The Prometheus Remote Write Exporter is a "push" based exporter and only
+works with the OpenTelemetry `push controller`_. The controller
+periodically collects data and passes it to the exporter. This exporter
+then converts the data into `timeseries`_ and sends it to the Remote
+Write integrated backend through HTTP POST requests. The metrics
+collection datapath is shown below:
+
+
+See the ``examples`` folder for a demo usage of this exporter
+
+Table of Contents
+=================
+
+-  `Summary`_
+-  `Table of Contents`_
+
+   -  `Installation`_
+   -  `Quickstart`_
+   -  `Examples`_
+   -  `Configuring the Exporter`_
+   -  `Securing the Exporter`_
+
+      -  `Authentication`_
+      -  `TLS`_
+
+   -  `Supported Aggregators`_
+   -  `Error Handling`_
+   -  `Contributing`_
+
+      -  `Design Doc`_
 
 Installation
 ------------
+Prerequisites
+~~~~~~~~~~~~~
+1. Install the snappy c-library
+    **DEB**: ``sudo apt-get install libsnappy-dev``
 
-::
+    **RPM**: ``sudo yum install libsnappy-devel``
 
-    pip install opentelemetry-exporter-prometheus-remote-write
+    **OSX/Brew**: ``brew install snappy``
 
+    **Windows**: ``pip install python_snappy-0.5-cp36-cp36m-win_amd64.whl``
 
-.. _Prometheus: https://prometheus.io/
-.. _OpenTelemetry: https://github.com/open-telemetry/opentelemetry-python/
+Exporter
+~~~~~~~~
 
+-  To install from the latest PyPi release, run
+   ``pip install opentelemetry-exporter-prometheus-remote-write``
 
-References
+
+Quickstart
 ----------
 
-* `Prometheus <https://prometheus.io/>`_
-* `OpenTelemetry Project <https://opentelemetry.io/>`_
+.. code:: python
+
+   from opentelemetry import metrics
+   from opentelemetry.sdk.metrics import MeterProvider
+   from opentelemetry.exporter.prometheus_remote_write import (
+       PrometheusRemoteWriteMetricsExporter
+   )
+
+   # Sets the global MeterProvider instance
+   metrics.set_meter_provider(MeterProvider())
+
+   # 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 = PrometheusRemoteWriteMetricsExporter(endpoint="endpoint_here") # add other params as needed
+
+   metrics.get_meter_provider().start_pipeline(meter, exporter, 5)
+
+
+Examples
+--------
+
+This example uses `Docker Compose`_ to set up:
+
+1. A Python program that creates 5 instruments with 5 unique aggregators
+   and a randomized load generator
+2. An instance of `Cortex`_ to recieve the metrics data
+3. An instance of `Grafana`_ to visualizse the exported data
+
+Requirements
+~~~~~~~~~~~~
+
+-  Have Docker Compose `installed`_
+
+*Users do not need to install Python as the app will be run in the
+Docker Container*
+
+Instructions
+~~~~~~~~~~~~
+
+1. Run ``docker-compose up -d`` in the the ``examples/`` directory
+
+The ``-d`` flag causes all services to run in detached mode and frees up
+your terminal session. This also causes no logs to show up. Users can
+attach themselves to the service’s logs manually using
+``docker logs ${CONTAINER_ID} --follow``
+
+2. Log into the Grafana instance at http://localhost:3000
+
+   -  login credentials are ``username: admin`` and ``password: admin``
+   -  There may be an additional screen on setting a new password. This
+      can be skipped and is optional
+
+3. Navigate to the ``Data Sources`` page
+
+   -  Look for a gear icon on the left sidebar and select
+      ``Data Sources``
+
+4. Add a new Prometheus Data Source
+
+   -  Use ``http://cortex:9009/api/prom`` as the URL
+   -  Set the scrape interval to ``2s`` to make updates
+      appear quickly **(Optional)**
+   -  click ``Save & Test``
+
+5. Go to ``Metrics Explore`` to query metrics
+
+   -  Look for a compass icon on the left sidebar
+   -  click ``Metrics`` for a dropdown list of all the available metrics
+   -  Adjust time range by clicking the ``Last 6 hours``
+      button on the upper right side of the graph **(Optional)**
+   -  Set up auto-refresh by selecting an option under the
+      dropdown next to the refresh button on the upper right side of the
+      graph **(Optional)**
+   -  Click the refresh button and data should show up on hte graph
+
+6. Shutdown the services when finished
+
+   -  Run ``docker-compose down`` in the examples directory
+
+Configuring the Exporter
+------------------------
+
+The exporter can be configured through parameters passed to the
+constructor. Here are all the options:
+
+-  ``endpoint``: url where data will be sent **(Required)**
+-  ``basic_auth``: username and password for authentication
+   **(Optional)**
+-  ``headers``: additional headers for remote write request as
+   determined by the remote write backend's API **(Optional)**
+-  ``timeout``: timeout for requests to the remote write endpoint in
+   seconds **(Optional)**
+-  ``proxies``: dict mapping request proxy protocols to proxy urls
+   **(Optional)**
+-  ``tls_config``: configuration for remote write TLS settings
+   **(Optional)**
+
+Example with all the configuration options:
+
+.. code:: python
+
+   exporter = PrometheusRemoteWriteMetricsExporter(
+       endpoint="http://localhost:9009/api/prom/push",
+       timeout=30,
+       basic_auth={
+           "username": "user",
+           "password": "pass123",
+       },
+       headers={
+           "X-Scope-Org-ID": "5",
+           "Authorization": "Bearer mytoken123",
+       },
+       proxies={
+           "http": "http://10.10.1.10:3000",
+           "https": "http://10.10.1.10:1080",
+       },
+       tls_config={
+           "cert_file": "path/to/file",
+           "key_file": "path/to/file",
+           "ca_file": "path_to_file",
+           "insecure_skip_verify": true, # for developing purposes
+       }
+   )
+
+Securing the Exporter
+---------------------
+
+Authentication
+~~~~~~~~~~~~~~
+
+The exporter provides two forms of authentication which are shown below.
+Users can add their own custom authentication by setting the appropriate
+values in the ``headers`` dictionary
+
+1. Basic Authentication Basic authentication sets a HTTP Authorization
+   header containing a base64 encoded username/password pair. See `RFC
+   7617`_ for more information. This
+
+.. code:: python
+
+   exporter = PrometheusRemoteWriteMetricsExporter(
+       basic_auth={"username": "base64user",  "password": "base64pass"}
+   )
+
+2. Bearer Token Authentication This custom configuration can be achieved
+   by passing in a custom ``header`` to the constructor. See `RFC 6750`_
+   for more information.
+
+.. code:: python
+
+   header = {
+       "Authorization": "Bearer mytoken123"
+   }
+
+TLS
+~~~
+
+Users can add TLS to the exporter's HTTP Client by providing certificate
+and key files in the ``tls_config`` parameter.
+
+Supported Aggregators
+---------------------
+Behaviour of these aggregators is outlined in the `OpenTelemetry Specification <https://github.com/open-telemetry/opentelemetry-specification/blob/master/specification/metrics/api.md#aggregations>`_.
+All aggregators are converted into the `timeseries`_ data format. However, method in
+which they are converted `differs <https://github.com/open-telemetry/opentelemetry-python-contrib/blob/master/exporter/opentelemetry-exporter-prometheus-remote-write/src/opentelemetry/exporter/prometheus_remote_write/__init__.py#L196>`_ from aggregator to aggregator. A
+map of the conversion methods can be found `here <https://github.com/open-telemetry/opentelemetry-python-contrib/blob/master/exporter/opentelemetry-exporter-prometheus-remote-write/src/opentelemetry/exporter/prometheus_remote_write/__init__.py#L75>`_.
+
++------------------------------+-------------------------------------+------------------------------------------------------------------------------------------------------------+
+| **OpenTelemetry Aggregator** | **Equivalent Prometheus Data Type** | **Behaviour**                                                                                              |
++------------------------------+-------------------------------------+------------------------------------------------------------------------------------------------------------+
+| Sum                          | Counter                             | Metric value can only go up or be reset to 0                                                               |
++------------------------------+-------------------------------------+------------------------------------------------------------------------------------------------------------+
+| MinMaxSumCount               | Gauge                               | Metric value can arbitrarily increment or decrement                                                        |
++------------------------------+-------------------------------------+------------------------------------------------------------------------------------------------------------+
+| Histogram                    | Histogram                           | Unlike the Prometheus histogram, the OpenTelemetry Histogram does not provide a sum of all observed values |
++------------------------------+-------------------------------------+------------------------------------------------------------------------------------------------------------+
+| LastValue                    | N/A                                 | Metric only contains the most recently observed value                                                      |
++------------------------------+-------------------------------------+------------------------------------------------------------------------------------------------------------+
+| ValueObserver                | N/A                                 | Similar to MinMaxSumCount but also contains LastValue                                                      |
++------------------------------+-------------------------------------+------------------------------------------------------------------------------------------------------------+
+
+
+Error Handling
+--------------
+
+In general, errors are raised by the calling function. The exception is
+for failed requests where any error status code is logged as a warning
+instead.
+
+This is because the exporter does not implement any retry logic as data that
+failed to export will be dropped.
+
+For example, consider a situation where a user increments a Counter
+instrument 5 times and an export happens between each increment. If the
+exports happen like so:
+
+::
+
+   SUCCESS FAIL FAIL SUCCESS SUCCESS
+   1       2    3    4       5
+
+Then the received data will be:
+
+::
+
+   1 4 5
+
+Contributing
+------------
+
+If you would like to learn more about the exporter's structure and
+design decisions please view the design document below
+
+Design Doc
+~~~~~~~~~~
+
+`Design Document`_
+
+This document is stored elsewhere as it contains large images which will
+significantly increase the size of this repo.
+
+.. _Summary: #opentelemetry-python-sdk-prometheus-remote-write-exporter
+.. _Table of Contents: #table-of-contents
+.. _Installation: #installation
+.. _Quickstart: #quickstart
+.. _Examples: #examples
+.. _Configuring the Exporter: #configuring-the-exporter
+.. _Securing the Exporter: #securing-the-exporter
+.. _Authentication: #authentication
+.. _TLS: #tls
+.. _Supported Aggregators: #supported-aggregators
+.. _Error Handling: #error-handling
+.. _Contributing: #contributing
+.. _Design Doc: #design-doc
+.. |Prometheus SDK pipelines| image:: https://user-images.githubusercontent.com/20804975/100285430-e320fd80-2f3e-11eb-8217-a562c559153c.png
+.. _RFC 7617: https://tools.ietf.org/html/rfc7617
+.. _RFC 6750: https://tools.ietf.org/html/rfc6750
+.. _Design Document: https://github.com/open-o11y/docs/blob/master/python-prometheus-remote-write/design-doc.md
+.. _OTLP: https://github.com/open-telemetry/opentelemetry-specification/blob/master/specification/protocol/otlp.md
+.. _OpenTelemetry Python SDK: https://github.com/open-telemetry/opentelemetry-python
+.. _Prometheus "pull" exporter: https://github.com/open-telemetry/opentelemetry-python/tree/master/exporter/opentelemetry-exporter-prometheus
+.. _Prometheus Remote Write integrated backend: https://prometheus.io/docs/operating/integrations/
+.. _types.proto: https://github.com/prometheus/prometheus/blob/master/prompb/types.proto
+.. _remote.proto: https://github.com/prometheus/prometheus/blob/master/prompb/remote.proto
+.. _push controller: https://github.com/open-telemetry/opentelemetry-python/blob/master/opentelemetry-sdk/src/opentelemetry/sdk/metrics/export/controller.py#L22
+.. _timeseries: https://prometheus.io/docs/concepts/data_model/
+.. _Docker Compose: https://docs.docker.com/compose/
+.. _Cortex: https://cortexmetrics.io/
+.. _Grafana: https://grafana.com/
+.. _installed: https://docs.docker.com/compose/install/

exporter/opentelemetry-exporter-prometheus-remote-write/examples/Dockerfile

@@ -0,0 +1,8 @@
+FROM python:3.7
+WORKDIR /code
+
+COPY . .
+RUN apt-get update -y && apt-get install libsnappy-dev -y
+RUN pip install -e .
+RUN pip install -r ./examples/requirements.txt
+CMD ["python", "./examples/sampleapp.py"]