Console exporter (#156)

README.md

@@ -43,17 +43,18 @@ pip install -e ./ext/opentelemetry-ext-{integration}
 from opentelemetry import trace
 from opentelemetry.context import Context
 from opentelemetry.sdk.trace import Tracer
+from opentelemetry.sdk.trace.export import ConsoleSpanExporter
+from opentelemetry.sdk.trace.export import SimpleExportSpanProcessor
 
 trace.set_preferred_tracer_implementation(lambda T: Tracer())
 tracer = trace.tracer()
+tracer.add_span_processor(
+    SimpleExportSpanProcessor(ConsoleSpanExporter())
+)
 with tracer.start_span('foo'):
-    print(Context)
     with tracer.start_span('bar'):
-        print(Context)
         with tracer.start_span('baz'):
             print(Context)
-        print(Context)
-    print(Context)
 ```
 
 See [opentelemetry-example-app](./opentelemetry-example-app/README.rst) for a complete example.

opentelemetry-sdk/src/opentelemetry/sdk/trace/__init__.py

@@ -280,7 +280,20 @@ def __init__(
         self.start_time = None
 
     def __repr__(self):
-        return '{}(name="{}")'.format(type(self).__name__, self.name)
+        return '{}(name="{}", context={})'.format(
+            type(self).__name__, self.name, self.context
+        )
+
+    def __str__(self):
+        return '{}(name="{}", context={}, kind={}, parent={}, start_time={}, end_time={})'.format(
+            type(self).__name__,
+            self.name,
+            self.context,
+            self.kind,
+            repr(self.parent),
+            util.ns_to_iso_str(self.start_time) if self.start_time else "None",
+            util.ns_to_iso_str(self.end_time) if self.end_time else "None",
+        )
 
     def get_context(self):
         return self.context

opentelemetry-sdk/src/opentelemetry/sdk/trace/export/__init__.py

@@ -76,3 +76,17 @@ def on_end(self, span: Span) -> None:
 
     def shutdown(self) -> None:
         self.span_exporter.shutdown()
+
+
+class ConsoleSpanExporter(SpanExporter):
+    """Implementation of :class:`SpanExporter` that prints spans to the
+    console.
+
+    This class can be used for diagnostic purposes. It prints the exported
+    spans to the console STDOUT.
+    """
+
+    def export(self, spans: typing.Sequence[Span]) -> SpanExportResult:
+        for span in spans:
+            print(span)
+        return SpanExportResult.SUCCESS

opentelemetry-sdk/src/opentelemetry/sdk/trace/export/in_memory_span_exporter.py

@@ -20,7 +20,7 @@
 
 
 class InMemorySpanExporter(SpanExporter):
-    """Implementation of :class:`.Exporter` that stores spans in memory.
+    """Implementation of :class:`.SpanExporter` that stores spans in memory.
 
     This class can be used for testing purposes. It stores the exported spans
     in a list in memory that can be retrieved using the

opentelemetry-sdk/src/opentelemetry/sdk/util.py

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import datetime
 import time
 
 try:
@@ -21,3 +22,9 @@
 
     def time_ns():
         return int(time.time() * 1e9)
+
+
+def ns_to_iso_str(nanoseconds):
+    """Get an ISO 8601 string from time_ns value."""
+    ts = datetime.datetime.fromtimestamp(nanoseconds / 1e9)
+    return ts.strftime("%Y-%m-%dT%H:%M:%S.%fZ")