sdk: Improve console span exporter (open-telemetry#505)

The current version of the exporter prints everything in a single line, making
it difficult to read. It's also missing events, links and attributes.

This commit changes the console span exporter to use multiple lines and also
adds the missing information about attributes, events and links.

Author: mauriciovasquezbernal

Diff for: docs/examples/basic_tracer/tests/test_tracer.py

@@ -25,6 +25,6 @@ def test_basic_tracer(self):
             (sys.executable, test_script)
         ).decode()
 
-        self.assertIn('name="foo"', output)
-        self.assertIn('name="bar"', output)
-        self.assertIn('name="baz"', output)
+        self.assertIn('"name": "foo"', output)
+        self.assertIn('"name": "bar"', output)
+        self.assertIn('"name": "baz"', output)

Diff for: docs/examples/http/tests/test_http.py

@@ -32,7 +32,7 @@ def test_http(self):
         output = subprocess.check_output(
             (sys.executable, test_script)
         ).decode()
-        self.assertIn('name="/"', output)
+        self.assertIn('"name": "/"', output)
 
     @classmethod
     def teardown_class(cls):

Diff for: opentelemetry-sdk/src/opentelemetry/sdk/trace/__init__.py

@@ -15,9 +15,12 @@
 
 import abc
 import atexit
+import json
 import logging
+import os
 import random
 import threading
+from collections import OrderedDict
 from contextlib import contextmanager
 from types import TracebackType
 from typing import Iterator, MutableSequence, Optional, Sequence, Tuple, Type
@@ -276,19 +279,79 @@ def __repr__(self):
             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",
-        )
+    @staticmethod
+    def _format_context(context):
+        x_ctx = OrderedDict()
+        x_ctx["trace_id"] = trace_api.format_trace_id(context.trace_id)
+        x_ctx["span_id"] = trace_api.format_span_id(context.span_id)
+        x_ctx["trace_state"] = repr(context.trace_state)
+        return x_ctx
+
+    @staticmethod
+    def _format_attributes(attributes):
+        if isinstance(attributes, BoundedDict):
+            return attributes._dict  # pylint: disable=protected-access
+        return attributes
+
+    @staticmethod
+    def _format_events(events):
+        f_events = []
+        for event in events:
+            f_event = OrderedDict()
+            f_event["name"] = event.name
+            f_event["timestamp"] = util.ns_to_iso_str(event.timestamp)
+            f_event["attributes"] = Span._format_attributes(event.attributes)
+            f_events.append(f_event)
+        return f_events
+
+    @staticmethod
+    def _format_links(links):
+        f_links = []
+        for link in links:
+            f_link = OrderedDict()
+            f_link["context"] = Span._format_context(link.context)
+            f_link["attributes"] = Span._format_attributes(link.attributes)
+            f_links.append(f_link)
+        return f_links
+
+    def to_json(self):
+        parent_id = None
+        if self.parent is not None:
+            if isinstance(self.parent, Span):
+                ctx = self.parent.context
+                parent_id = trace_api.format_span_id(ctx.span_id)
+            elif isinstance(self.parent, SpanContext):
+                parent_id = trace_api.format_span_id(self.parent.span_id)
+
+        start_time = None
+        if self.start_time:
+            start_time = util.ns_to_iso_str(self.start_time)
+
+        end_time = None
+        if self.end_time:
+            end_time = util.ns_to_iso_str(self.end_time)
+
+        if self.status is not None:
+            status = OrderedDict()
+            status["canonical_code"] = str(self.status.canonical_code.name)
+            if self.status.description:
+                status["description"] = self.status.description
+
+        f_span = OrderedDict()
+
+        f_span["name"] = self.name
+        f_span["context"] = self._format_context(self.context)
+        f_span["kind"] = str(self.kind)
+        f_span["parent_id"] = parent_id
+        f_span["start_time"] = start_time
+        f_span["end_time"] = end_time
+        if self.status is not None:
+            f_span["status"] = status
+        f_span["attributes"] = self._format_attributes(self.attributes)
+        f_span["events"] = self._format_events(self.events)
+        f_span["links"] = self._format_links(self.links)
+
+        return json.dumps(f_span, indent=4)
 
     def get_context(self):
         return self.context

Diff for: opentelemetry-sdk/src/opentelemetry/sdk/trace/export/__init__.py

@@ -270,7 +270,7 @@ class ConsoleSpanExporter(SpanExporter):
     def __init__(
         self,
         out: typing.IO = sys.stdout,
-        formatter: typing.Callable[[Span], str] = lambda span: str(span)
+        formatter: typing.Callable[[Span], str] = lambda span: span.to_json()
         + os.linesep,
     ):
         self.out = out

Diff for: opentelemetry-sdk/tests/trace/export/test_export.py

@@ -286,10 +286,10 @@ def test_export(self):  # pylint: disable=no-self-use
 
         # Mocking stdout interferes with debugging and test reporting, mock on
         # the exporter instance instead.
-        span = trace.Span("span name", mock.Mock())
+        span = trace.Span("span name", trace_api.INVALID_SPAN_CONTEXT)
         with mock.patch.object(exporter, "out") as mock_stdout:
             exporter.export([span])
-        mock_stdout.write.assert_called_once_with(str(span) + os.linesep)
+        mock_stdout.write.assert_called_once_with(span.to_json() + os.linesep)
         self.assertEqual(mock_stdout.write.call_count, 1)
         self.assertEqual(mock_stdout.flush.call_count, 1)