Upgrading to 0.38.0

Integrations

Celery

• Support for distributed tracing was added in #1194. It is default disabled but is easily enabled via DD_CELERY_DISTRIBUTED_TRACING=true or via the config API ddtrace.config.celery['distributed_tracing'] = True. Thanks @thieman!
• Analyzed span configuration was added to easily configure Celery spans to be analyzed. This can be done via the environment variable DD_CELERY_ANALYTICS_ENABLED=true or with the config API ddtrace.config.celery['analytics_enabled'] = True.

Django

• A config option was added to allow enabling/disabling instrumenting middleware. It can be set with the environment variable DD_DJANGO_INSTRUMENT_MIDDLEWARE=true|false or via the config API ddtrace.config.django['instrument_middleware'] = False # default is True.

Core

• Runtime ID tag support for traces and profiles. This will allow us to correlate traces and profiles generated by applications.

OpenTracing

• Support for active_span() was added to our OpenTracing tracer.

Profiling

• Storing of span id in profiling events which will enable linking between a trace and a profile in the product.

Tracer

• DD_TAGS environment variable added to replace DD_TRACE_GLOBAL_TAGS.

Changes

New features

• opentracer: implement active_span (#1395)
• django: add config for instrumenting middleware (#1384)
• celery: Add analyzed span configuration option (#1383)
• Add runtime id tag support for traces & profiles (#1379)
• profiling: retry on upload error (#1376)
• tracer: Add DD_TAGS environment variable support (#1315)
• celery: Add distributed tracing (#1194 -- thanks @thieman)
• profiling: Store span ids in profiling events (#1043)

Improvements

• monkey: add better error messages (#1430)
• Make hooks settings generic (#1428)
• internal: Change trace too large message to debug (#1403 -- thanks @ZStriker19)
• internal: Ensure queue is at or over max size before dropping (#1399)
• performance: improve span id generation (#1378)

Bug fixes

• hooks: use log.error to log hook exceptions (#1436)
• writer: raise RuntimeError("threads can only be started once") (#1425 -- thanks @YasuoSasaki)
• settings: pass the memodict argument to subcall to deepcopy (#1401)
• profiling: correct the scheduler sleep time based on exporter time (#1386)
• integration config: copy and deepcopy implementations (#1381)
• utils: do not expose deepmerge function (#1375)

Documentation

• Updated to pypi advance usage docs (#1402)

Testing

• update tests to latest versions of libraries (#1434, #1433, #1432, #1424, #1423, #1422, #1421, #1420, #1419, #1418, #1417, #1416, #1412, #1411, #1410, #1409, #1408, #1407, #1406, #1405)
• circleci: remove unused busybox (#1426)