Add a configuration manager (#466)

Fixes #123

This basically removes loader.py (uses entry points instead) and all the calls
for set_preferred_implementation* in order to cleanly separate user code from
configuration. It introduces a configuration manager that can have
configuration set by a configuration file or environment variables that
override the former configuration method.

Co-authored-by: Mauricio Vásquez <[email protected]>
Co-authored-by: Chris Kleinknecht <[email protected]>

Author: 3 people

docs/api/api.rst

@@ -9,4 +9,3 @@ OpenTelemetry Python API
     context
     metrics
     trace
-    util.loader

docs/api/util.loader.rst

@@ -45,19 +45,16 @@
     print("Using ConsoleSpanExporter")
     exporter = ConsoleSpanExporter()
 
-# The preferred tracer implementation must be set, as the opentelemetry-api
-# defines the interface with a no-op implementation.
-trace.set_preferred_tracer_provider_implementation(lambda T: TracerProvider())
-
+trace.set_tracer_provider(TracerProvider())
 # We tell OpenTelemetry who it is that is creating spans. In this case, we have
 # no real name (no setup.py), so we make one up. If we had a version, we would
 # also specify it here.
 tracer = trace.get_tracer(__name__)
 
 # SpanExporter receives the spans and send them to the target location.
 span_processor = BatchExportSpanProcessor(exporter)
+trace.get_tracer_provider().add_span_processor(span_processor)
 
-trace.tracer_provider().add_span_processor(span_processor)
 with tracer.start_as_current_span("foo"):
     with tracer.start_as_current_span("bar"):
         with tracer.start_as_current_span("baz"):

docs/examples/basic_tracer/tracer.py

@@ -39,19 +39,17 @@
 else:
     exporter = ConsoleSpanExporter()
 
-# The preferred tracer implementation must be set, as the opentelemetry-api
-# defines the interface with a no-op implementation.
-trace.set_preferred_tracer_provider_implementation(lambda T: TracerProvider())
 tracer = trace.get_tracer(__name__)
 
 # SpanExporter receives the spans and send them to the target location.
 span_processor = BatchExportSpanProcessor(exporter)
-trace.tracer_provider().add_span_processor(span_processor)
+trace.set_tracer_provider(TracerProvider())
+trace.get_tracer_provider().add_span_processor(span_processor)
 
 # Integrations are the glue that binds the OpenTelemetry API and the
 # frameworks and libraries that are used together, automatically creating
 # Spans and propagating context as appropriate.
-http_requests.enable(trace.tracer_provider())
+http_requests.enable(trace.get_tracer_provider())
 app = flask.Flask(__name__)
 app.wsgi_app = OpenTelemetryMiddleware(app.wsgi_app)
 

docs/examples/http/server.py

@@ -37,10 +37,8 @@
 else:
     exporter = ConsoleSpanExporter()
 
-# The preferred tracer implementation must be set, as the opentelemetry-api
-# defines the interface with a no-op implementation.
-trace.set_preferred_tracer_provider_implementation(lambda T: TracerProvider())
-tracer_provider = trace.tracer_provider()
+trace.set_tracer_provider(TracerProvider())
+tracer_provider = trace.get_tracer_provider()
 
 # SpanExporter receives the spans and send them to the target location.
 span_processor = BatchExportSpanProcessor(exporter)

docs/examples/http/tracer_client.py

@@ -19,15 +19,14 @@
 import psutil
 
 from opentelemetry import metrics
-from opentelemetry.sdk.metrics import LabelSet, MeterProvider
+from opentelemetry.sdk.metrics import LabelSet
 from opentelemetry.sdk.metrics.export import ConsoleMetricsExporter
 from opentelemetry.sdk.metrics.export.batcher import UngroupedBatcher
 from opentelemetry.sdk.metrics.export.controller import PushController
 
 # Configure a stateful batcher
 batcher = UngroupedBatcher(stateful=True)
 
-metrics.set_preferred_meter_provider_implementation(lambda _: MeterProvider())
 meter = metrics.get_meter(__name__)
 
 # Exporter to export metrics to the console

docs/examples/metrics/observer_example.py

@@ -21,14 +21,13 @@
 
 from opentelemetry import metrics
 from opentelemetry.ext.prometheus import PrometheusMetricsExporter
-from opentelemetry.sdk.metrics import Counter, MeterProvider
+from opentelemetry.sdk.metrics import Counter
 from opentelemetry.sdk.metrics.export.controller import PushController
 
 # Start Prometheus client
 start_http_server(port=8000, addr="localhost")
 
 # Meter is responsible for creating and recording metrics
-metrics.set_preferred_meter_provider_implementation(lambda _: MeterProvider())
 meter = metrics.get_meter(__name__)
 # exporter to export metrics to Prometheus
 prefix = "MyAppPrefix"

docs/examples/metrics/prometheus.py

@@ -19,13 +19,10 @@
 import time
 
 from opentelemetry import metrics
-from opentelemetry.sdk.metrics import Counter, MeterProvider
+from opentelemetry.sdk.metrics import Counter
 from opentelemetry.sdk.metrics.export import ConsoleMetricsExporter
 from opentelemetry.sdk.metrics.export.controller import PushController
 
-# The preferred tracer implementation must be set, as the opentelemetry-api
-# defines the interface with a no-op implementation.
-metrics.set_preferred_meter_provider_implementation(lambda _: MeterProvider())
 # Meter is responsible for creating and recording metrics
 meter = metrics.get_meter(__name__)
 # exporter to export metrics to the console

docs/examples/metrics/record.py

@@ -23,7 +23,7 @@
 import time
 
 from opentelemetry import metrics
-from opentelemetry.sdk.metrics import Counter, Measure, MeterProvider
+from opentelemetry.sdk.metrics import Counter, Measure
 from opentelemetry.sdk.metrics.export import ConsoleMetricsExporter
 from opentelemetry.sdk.metrics.export.controller import PushController
 
@@ -44,7 +44,6 @@ def usage(argv):
         sys.exit(1)
 
 # Meter is responsible for creating and recording metrics
-metrics.set_preferred_meter_provider_implementation(lambda _: MeterProvider())
 
 # Meter's namespace corresponds to the string passed as the first argument Pass
 # in True/False to indicate whether the batcher is stateful. True indicates the

docs/examples/metrics/simple_example.py

@@ -23,7 +23,6 @@
 import opentelemetry.ext.http_requests
 from opentelemetry import trace
 from opentelemetry.ext.flask import instrument_app
-from opentelemetry.sdk.trace import TracerProvider
 
 
 def configure_opentelemetry(flask_app: flask.Flask):
@@ -42,20 +41,14 @@ def configure_opentelemetry(flask_app: flask.Flask):
     """
     # Start by configuring all objects required to ensure
     # a complete end to end workflow.
-    # The preferred implementation of these objects must be set,
-    # as the opentelemetry-api defines the interface with a no-op
-    # implementation.
-    trace.set_preferred_tracer_provider_implementation(
-        lambda _: TracerProvider()
-    )
 
     # Next, we need to configure how the values that are used by
     # traces and metrics are propagated (such as what specific headers
     # carry this value).
     # Integrations are the glue that binds the OpenTelemetry API
     # and the frameworks and libraries that are used together, automatically
     # creating Spans and propagating context as appropriate.
-    opentelemetry.ext.http_requests.enable(trace.tracer_provider())
+    opentelemetry.ext.http_requests.enable(trace.get_tracer_provider())
     instrument_app(flask_app)