sdk: Span.resource will now default to an empty resource

[yashmehrotra]

Fixes #702

[yashmehrotra]

In Travis CI, the error I am getting is

sphinx.errors.SphinxWarning: /home/travis/build/open-telemetry/opentelemetry-python/opentelemetry-sdk/src/opentelemetry/sdk/trace/__init__.py:docstring of opentelemetry.sdk.trace.Span:17:py:class reference target not found: opentelemetry.sdk.resources.Resource

Warning, treated as error:

/home/travis/build/open-telemetry/opentelemetry-python/opentelemetry-sdk/src/opentelemetry/sdk/trace/__init__.py:docstring of opentelemetry.sdk.trace.Span:17:py:class reference target not found: opentelemetry.sdk.resources.Resource

ERROR: InvocationError for command /home/travis/build/open-telemetry/opentelemetry-python/.tox/docs/bin/sphinx-build -E -a -W -b html -T . _build/html (exited with code 2)

Do you know what could be the issue ?

[toumorokoshi]

Having some trouble pushing some fixes, but this is occurring because the sphinx document needs to resolve a reference to the Resource object in the docs itself, and no sphinx automodule sphinx.

Here's a patch that would fix it:

diff --git a/docs/sdk/resources.rst b/docs/sdk/resources.rst
new file mode 100644
index 0000000..08732ac
--- /dev/null
+++ b/docs/sdk/resources.rst
@@ -0,0 +1,7 @@
+opentelemetry.sdk.resources package
+==========================================
+
+.. automodule:: opentelemetry.sdk.resources
+    :members:
+    :undoc-members:
+    :show-inheritance:
diff --git a/docs/sdk/sdk.rst b/docs/sdk/sdk.rst
index 27e9d44..d6ca098 100644
--- a/docs/sdk/sdk.rst
+++ b/docs/sdk/sdk.rst
@@ -7,4 +7,5 @@ OpenTelemetry Python SDK
     :maxdepth: 1
 
     metrics
+    resources
     trace

[yashmehrotra]

Thanks @toumorokoshi , its all green now 😄

[yashmehrotra]

Should I also remove the None check in ext/opentelemetry-ext-jaeger/src/opentelemetry/ext/jaeger/__init__.py file ?

-        if span.resource:
-           tags.extend(_extract_tags(span.resource.labels))
+        tags.extend(_extract_tags(span.resource.labels))

[toumorokoshi]

Great, thank you! can you take a look around and see if there's any references that we should update? I believe the jaeger / zipkin integrations are defensively handling for a None resource object. That code should be cleaned up to reduce confusion.

[toumorokoshi]

Should I also remove the None check in ext/opentelemetry-ext-jaeger/src/opentelemetry/ext/jaeger/__init__.py file ?

-        if span.resource:
-           tags.extend(_extract_tags(span.resource.labels))
+        tags.extend(_extract_tags(span.resource.labels))

yes! that'd be great, along with any other places where this was handled defensively.

[yashmehrotra]

@toumorokoshi Could only find 1 instance where this was happening

[toumorokoshi]

Awesome, thank you!

[ocelotl]

👍