Python agent release notesRSS

Notes

This release of the Python agent includes bug fixes for issues with agent registration and use of proxies which could result in no data being reported.

The agent can be installed using easy_install/pip/distribute via the Python Package Index or can be downloaded directly from our download site.

For a list of known issues with the Python agent, see Status of the Python agent.

Bug Fixes

• Agent not recovering when errors occur during registration

  If the agent initially registered with our data collector successfully, but subsequently failed to upload agent setting information due to a transient backend or network issue, the agent was not recovering from the error properly. The consequence of this was that the agent would not completely start up and no data would be collected or reported by that process. The operation of the web application as a whole would not have been affected. This issue, which was introduced in version 2.36.0.30 of the agent, is now fixed.

• Agent not able to connect via some proxy servers

  The Python agent was not able to connect to our data collector to register when certain proxy server installations or configurations were being used. We have updated the version of the internal HTTP client library used to resolve the issue.

• Identification of Python web server being used

  The Python agent was incorrectly reporting the Python web server being used as Tornado when both the 'gunicorn' and 'tornado' Python modules were being imported, even if the Tornado web server module wasn't actually being used. This did not affect the operation of the agent but could lead to confusion when trying to debug deployment issues.

Notes

This release of the Python agent enables the collection of transaction traces for synthetic requests by default, and adds the individual trip trace visualization for Cross Application Tracing.

The agent can be installed using easy_install/pip/distribute via the Python Package Index or can be downloaded directly from our download site.

For a list of known issues with the Python agent, see Status of the Python agent.

New Features

• Cross Application Tracing for individual transactions

  Version 2.38.0.31 of the Python agent introduced aggregated transaction maps. In this release, we have built on that feature to add the ability to view an end-to-end visualization of an individual transaction, in order to better understand what backend applications and external services were called during the course of a single transaction.

Features Changed

• Synthetic support enabled by default

  When the Python agent added support for the collection of transaction traces for synthetics requests in version 2.32.0.28, the feature had to be explicitly enabled in the agent configuration file. With this release, support for synthetics is enabled by default.

Bug Fixes

• Non ASCII characters in transaction names

  If a transaction name contained a Unicode character outside of the ASCII range, the generation of the cross application tracing attributes would result in a UnicodeEncodeError. This bug affected versions 2.38.0.31 through 2.38.2.33. The issue is fixed in the current release.

• Parsing SQL statements referencing the database schema

  Previously, SQL statements that referenced a table from a database schema namespace, such as “schema.table_name”, would not always be parsed correctly, resulting in the table being identified as just “schema”. The agent now handles this case correctly, and the table is reported as “schema.table_name”.

• Additional support for Tornado 1.X

  If Tornado 1.X was being used, the instrumentation would fail at run time causing all web requests to fail. Monitoring of Tornado 1.X applications should now work correctly.

Notes

This release of the Python agent fixes a memory leak which affects our Tornado instrumentation, and which was a factor in the recent issues we had with the Django template instrumentation.

The agent can be installed using easy_install/pip/distribute via the Python Package Index or can be downloaded directly from our download site.

For a list of known issues with the Python agent see Status of the Python agent.

Bug Fixes

• Due to an issue with the low level function wrappers we use to instrument third party Python modules, memory was being leaked and process memory usage could increase over time. This issue affects version 2.32.0 through 2.38.0 of the Python agent and has been impacting on our Tornado instrumentation.

  The memory leak has also been identified as the root cause for memory leaks in our Django template instrumentation, affecting versions 2.32.0.28 through 2.36.0.30. The Django template instrumentation was disabled in the prior 2.38.0.31 release while we investigated the cause. It remains disabled by default.

Notes

This release of the Python agent adds support for the mapping features of Cross Application Tracing, which provide a visualization of how requests flow through multiple applications within a distributed system.

The agent can be installed using easy_install/pip/distribute via the Python Package Index or can be downloaded directly from our download site.

For a list of known issues with the Python agent see Status of the Python agent.

New Features

• Cross Application Tracing

  The Cross Application Tracing feature is now enhanced with the aggregate transaction map visualizations. This new visualization will help users spot bottlenecks in external services and give them an end-to-end understanding of what other applications and services are called within a transaction. All agents involved in the cross application communication must be upgraded to see the complete graph.

Improvements

• Tornado 3.x Instrumentation

  The newly refactored Tornado instrumentation is turned on by default. This was introduced in the python agent version 2.32.0.28 under an optional feature flag. This change improves upon the stability of our Tornado instrumentation and accounts for the incremental changes introduced to the Tornado 3.x source tree. It also provides a more granular view of where the time is spent in a WebTransaction, by distinguishing the time spent doing work vs time spent waiting on a asynchronous call.

  Please be advised that we currently do not have instrumentation for Tornado 4.x, but we are working to add support for it.

• Capacity Analysis for mod_wsgi

  The capacity analysis report shows how many instances of your web application is running and how busy they are. For a web application, the measure of how busy the application is, is calculated by looking at how much of the time the total available set of request handler threads are busy.

  For the case of using Apache/mod_wsgi in daemon mode, the measure of how busy your application is, has been getting over reported due to the nature of how threads are managed by mod_wsgi. If you are using mod_wsgi version 4.1.0 or higher, this measure will now be more accurately reported as it will use information provided by mod_wsgi about the total number of request handler threads which are available, rather than trying to calculate it based on what threads have been seen to be handling requests.

Bug Fixes

• In version 2.28.0.26 and 2.32.0.28 of the agent, we added new features to track template includes and inclusion tags when using the Django template rendering system. We have had a few reports that indicate that for some users, but not everyone, that the instrumentation implementing these features may be causing an ongoing growth in memory usage for the web application processes over time. Right now, we don't understand the root cause for why this might be occurring in some instances, so to be on the safe side we have disabled these two features while we investigate further.

  The consequence of these features being disabled is that the web transaction performance breakdown and sample transaction traces will no longer show as a separate metric or entry where one template has been included in another. Further, if the tracking of special inclusion tags had been configured, they will also no longer be shown. We anticipate re-enabling the features once we have worked out what is occurring and made changes to ensure it does not occur again.

Notes

This release of the Python agent provides improvements to how we report agent configuration information. This enables us to better help you debug any issues you may experience with configuring the agent.

The agent can be installed using easy_install/pip/distribute via the Python Package Index or can be downloaded directly from our download site.

For a list of known issues with the Python agent see Status of the Python agent.

New Features

• Configuration Information

  Agent configuration information displayed in the New Relic UI will now reflect the final configuration used by the agent for an application. This includes the result of any server side configuration settings, which are applied on top of the agent defaults, agent configuration file or environment variables. Previously, the result of applying the server side configuration settings was not being displayed.

Bug Fixes

• If running a system with a Linux 3.X kernel, the agent could fail when attempting to register with our data collector. No data would subsequently be collected or reported. This would occur for versions of Python 2 prior to Python 2.7.3 and versions of Python 3 prior to Python 3.3, if they were built on a system with a Linux 3.X kernel.

Notes

This release of the Python agent provides support for Labels and Rollups, making it possible to organize your applications in the APM UI into meaningful categories.

The agent can be installed using easy_install/pip/distribute via the Python Package Index or can be downloaded directly from our download site.

For a list of known issues with the Python agent see Status of the Python agent.

New Features

• Labels and Rollups

  The Python agent now supports the ability to apply labels to applications, so that you can easily sort, filter, and page through all of the applications on your account's Applications list.

  Configuration can be done in the newrelic.ini file:

  labels = Server:One;Data Center:Primary

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  Labels can also be configured by setting a NEW_RELIC_LABELS environment variable:

  NEW_RELIC_LABELS=Server:One;Data Center:Primary

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  More information on using labels to categorize your applications can be found in the New Relic APM documentation.

• New CPU Reporting in Environment Snapshot

  Previously, the Python agent captured two CPU-related values to report to the Environment Snapshot: Logical Processors and Physical Processors. Now, it captures the following three values:

  • Logical Processors: The total number of hyper-threaded execution contexts available, including execution contexts that may exist on the same core. This value remains unchanged from previous agents.
  • Physical Cores: The total number of physical CPU cores available, counting hyper-threaded siblings as a single core. This value was previously reported as "Physical Processors."
  • Physical Processor Packages: The total number of processor packages or dies (each of which may contain multiple physical cores). This value is new with this agent release.

Bug Fixes

• A "Runtime Error: transaction already active" will no longer be seen in the case where the agent created nested transaction wrappers and newrelic.agent.ignore_transaction() was called within the outer wrapper but outside the inner wrapper. Previously, this error could have also been triggered when using the WSGI environment setting for newrelic.ignore_transaction set by SetEnv in mod_wsgi.
• Prior to this version, the HTTP_REFERER URL reported for a transaction contained query parameters, even if the capture_params setting was set to False. Now, the capture_params setting is respected when reporting the HTTP_REFERER URL.

Notes

This release of the Python agent provides a preview of a significant overhaul of our instrumentation for Tornado version 3.2 and earlier. Further improvements to our Django instrumentation are also included, allowing time spent in rendering Django sub templates to be viewed separately.

The agent can be installed using easy_install/pip/distribute via the Python Package Index or can be downloaded directly from our download site.

For a list of known issues with the Python agent see Status of the Python agent.

New Features

• Breakout of Django template rendering

  Previously when using Django templates, if the Django include tag was being used, the time spent rendering that sub template was shown under the generic Template/Render category. When the include tag is now used, a distinct metric is instead created corresponding to the rendering time for that sub template. This will appear in the transaction performance breakdown and also in sample transaction traces. In the case of sample transaction traces, as the name of the template will be included in the metric name, it now also provides additional context for understanding where any time is being spent when rendering that template.

Features Changed

• Preview of improved Tornado instrumentation

  Our instrumentation for Tornado version 3.2 and earlier has been experiencing a number of issues which could result in recording of data stopping and in some cases cause runtime exceptions which would affect the outcome of the executing web request. Upon investigation we found this has come about due to incremental changes in the internals of Tornado which were performed after we originally implemented the instrumentation for Tornado and which we didn't pick up as having being made. The Tornado developers have also recently released version 4.0 of Tornado. This version of Tornado has much more significant internal changes that result in our instrumentation failing completely.

  Before we could embark on trying to support version 4.0 of Tornado, we deemed it necessary to completely overhaul our existing instrumentation for older versions first in order to gives us good foundation on which to then implement support for version 4.0 of Tornado. This release of the agent provides a preview of the improved instrumentation for older versions of Tornado prior to version 4.0. The new instrumentation is not enabled by default and you will need to explicitly enable it. We have provided it as an opt in change at this point to allow you to properly test with the update first and provide us with any feedback on it and any remaining issues you may find.

  To enable the preview of the new Tornado instrumentation, you will need to add to the [newrelic]section of the agent configuration file the setting:

  feature_flag = tornado.instrumentation.r2

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  If you are running on Heroku and are not using an agent configuration file, you can instead set the NEW_RELIC_FEATURE_FLAG environment variable. You can do this by running the Heroku command:

  heroku config:set NEW_RELIC_FEATURE_FLAG=tornado.instrumentation.r2

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Bug Fixes

• When an exception was raised by a WSGI application during the yielding of response content via a generator, the recording of that web request by the agent may not be closed off properly. This would result in no further web requests handled by that thread being recorded and reported. If this occurred for all request handler threads, then no data would then be reported for the whole web process. This issue relates to behaviour of the Python garbage collector and when Python objects are destroyed. At this point in time we believe this only affects users of pypy and does not affect users of CPython as the reference counting model of CPython usually gives more deterministic behaviour around when Python objects are destroyed. We don't however rule out that it could affect CPython and may explain a situation matching this problem we have seen in a couple of cases where users were using uWSGI.

• When attempting to use Tornado as a worker for gunicorn, an exception could occur on startup which would result in gunicorn failing immediately and exiting. In order to use this combination it was previously necessary to disable the gunicorn specific instrumentation related to WSGI applications by adding to your agent configuration file:

  [import-hook:gunicorn.app.base] 
  enabled = false

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  If you were using the Tornado worker with gunicorn and using this workaround, the underlying problem has now been addressed and you should be able to remove that section from your agent configuration file.

• The mechanism we used for applying function wrappers for instrumentation was not being performed in the most optimal way for methods of classes. This could result in problems, including unexpected runtime exceptions, especially when trying to apply instrumentation to class methods, or methods of an existing instance of a type.

Notes

This release of the Python agent improves instrumentation for the Flask web framework and adds database monitoring support when using the pymssql client with a Microsoft SQL Server database.

The agent can be installed using easy_install/pip/distribute via the Python Package Index or can be downloaded directly from our download site.

For a list of known issues with the Python agent see Status of the Python agent.

New Features

• Improved instrumentation for Flask

  The Python agent now provides better web transaction naming and performance breakdown metrics when Flask style middleware are being used. This means that time spent in Flask @before_request and @after_request functions will now be broken out as their own metrics. If a @before_request function actually returns a response, the web transaction will be correctly named after that function rather than the Flask WSGI application entry point. These changes, in addition to being applied on middleware functions registered directly against the Flask application, will also work when Flask blueprints are used to encapsulate behavior.

• Browser monitoring auto-instrumentation when using Flask-Compress

  When the Flask-Compress package is used to perform response compression with Flask, insertion of browser monitoring tracking code into HTML responses is now automatically performed. Previously, if Flask-Compress was being used, manual instrumentation of HTML responses would have been required.

• Monitoring of MSSQL database

  Instrumentation is now provided for the pymssql database client module to monitor database calls made against a Microsoft SQL Server database.

Bug Fixes

• When using high-security mode, the use of newrelic.capture_request_params in the per request WSGI environ to enable capture of request parameters, possibly by setting it using the SetEnv directive when using Apache/mod_wsgi, was not being overridden and disabled as required.
• When using the DatabaseTrace context manager or associated wrappers explicitly to implement a custom monitoring mechanism for database calls, the instrumentation wrappers could fail with a TypeError exception when trying to internally derive the name of the database product being used.

Notes

This release of the Python agent improves data collection with the Django web framework. These improvements include better-targeted web transaction naming with the Django REST framework, better coverage of Django template inclusion tags, and better background task monitoring for Django management commands.

The agent can be installed using easy_install/pip/distribute via the Python Package Index or can be downloaded directly from our download site.

For a list of known issues with the Python agent see Status of the Python agent.

New Features

• Improved Django REST Framework naming

  Previously, when using the Django REST framework, web transactions were being named after the class based view that implemented the Django REST framework resources. Now, where such a view provides custom handler methods for different HTTP request method types or actions, the web transaction will be named after that custom handler method rather than the class as a whole. A new function breakdown metric will also be added for the custom handler method. This change will allow web requests using different HTTP request method types to be viewed separately.

• Django inclusion tag monitoring

  Usage of inclusion tags in Django templates can now be monitored and will appear in the transaction breakdown table, charts and sample transaction traces.

  Due to the possibility that a large range of custom inclusion tags might be used and that they may be invoked a large number of times in tight loops, tracking of all inclusion tags may not be practical or may not produce worthwhile results in the transaction breakdown or sample transaction traces. As a result, monitoring of inclusion tags is off by default, with the preferred approach being that specific inclusion tags of interest be individually enabled through the agent configuration file.

  To enable monitoring of specific inclusion tags, a new section called import-hook:django should be added to the agent configuration:

  [import-hook:django]
  instrumentation.templates.inclusion_tag = prepopulated_fields_js date_hierarchy

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  The instrumentation.templates.inclusion_tag setting within that section should then be set to a space separated list of the names of the inclusion tags to monitor. If there is any confusion over the identity of the inclusion tag, the full name of the inclusion tag function, with module name, can instead be listed. For example, data_hierarchy can also be identified using django.contrib.admin.templatetags.admin_list:date_hierarchy.

  In addition to specifying the names of the specific inclusion tags, it is also possible to specify * for instrumentation.templates.inclusion_tag in order to have usage of all inclusion tags be monitored:

  [import-hook:django]
  instrumentation.templates.inclusion_tag = *

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  Enabling monitoring of all inclusion tags in this way is only recommended in development or test environments so as to get an initial idea of what inclusion tags are worth tracking. Once identified, the specific inclusion tags of interest should thereafter be listed individually in a production environment.

• Better monitoring of Django management commands

  Previously, the Python agent required you to manually set up the instrumentation for each specific Django management command in the agent configuration file. We have now made that easier by integrating the functionality as part of the agent itself.

  Due to the limitations on what Django management commands can be monitored, you will still need to list explicitly the commands you want monitored, but it can now be done in a single location as a space separated list under the setting instrumentation.scripts.django_admin of the import-hook:django section:

  [import-hook:django] 
  instrumentation.scripts.django_admin = syncdb sqlflush

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  By default, we automatically specify the startup timeout to be 10.0 seconds when monitoring the Django management commands. If you need to override the startup timeout, you can set the instrumentation.background_task.startup_timeout setting within the same import-hook:django configuration section.