# Tenzir Node v4.19.0 ## 馃殌 Features ### Add a package manager Jul 22, 2024 路 [@lava](https://github.com/lava) 路 [#4344](https://github.com/tenzir/tenzir/pull/4344) The new `package` operator allows for adding and removing packages, a combination of pipelines and contexts deployed to a node as a set. Nodes load packages installed to `/tenzir/package//package.yaml` on startup. ### Add the `buffer` operator for breaking back pressure Jul 19, 2024 路 [@dominiklohmann](https://github.com/dominiklohmann) 路 [#4404](https://github.com/tenzir/tenzir/pull/4404) The `buffer` operator buffers up to the specified number of events in an in-memory buffer. By default, operators in a pipeline run only when their downstream operators want to receive input. This mechanism is called back pressure. The `buffer` operator effectively breaks back pressure by storing up to the specified number of events in memory, always requesting more input, which allows upstream operators to run uninterruptedly even in case the downstream operators of the buffer are unable to keep up. This allows pipelines to handle data spikes more easily. ## 馃敡 Changes ### Refactor python operator setup Jul 23, 2024 路 [@tobim](https://github.com/tobim) 路 [#4336](https://github.com/tenzir/tenzir/pull/4336) The `python` operator now resolves dependencies with every fresh pipeline run. Just restart your pipeline to upgrade to the latest available versions of your Python modules. The `python` operator no longer uses `pip` but rather [`uv`](https://github.com/astral-sh/uv). In case you set custom environment variables for `pip` you need to exchange those with alternative settings that work with `uv`. ### Remove the `use_simple_format` option for `/serve` Jul 22, 2024 路 [@dominiklohmann](https://github.com/dominiklohmann) 路 [#4411](https://github.com/tenzir/tenzir/pull/4411) The `/serve` endpoint now always uses the simple output format for schema definitions. The option `use_simple_format` is now ignored. ## 馃悶 Bug Fixes ### Add the `buffer` operator for breaking back pressure Jul 19, 2024 路 [@dominiklohmann](https://github.com/dominiklohmann) 路 [#4404](https://github.com/tenzir/tenzir/pull/4404) Metrics emitted towards the end of an operator鈥檚 runtime were sometimes not recorded correctly. This now works reliably. [ Download on GitHub ](https://github.com/tenzir/tenzir/releases/tag/v4.19.0) [Get the release artifacts and source code.](https://github.com/tenzir/tenzir/releases/tag/v4.19.0)