Remove viztracer support

Never seemed that useful compared to py-spy. Could have kept it around, but nice to not have to worry about maintaining it.

Author: gjoseph92

README.md

@@ -1,12 +1,12 @@
 # dask-profiling
 
-Profile dask [distributed](https://github.com/dask/distributed) clusters with [py-spy](https://github.com/benfred/py-spy) or [viztracer](https://github.com/gaogaotiantian/viztracer).
+Profile dask [distributed](https://github.com/dask/distributed) clusters with [py-spy](https://github.com/benfred/py-spy).
 
 ```python
 import dask
 import distributed
 
-from dask_profiling import pyspy_on_scheduler, viztrace_scheduler
+from dask_profiling import pyspy_on_scheduler
 
 client = distributed.Client()
 
@@ -20,19 +20,15 @@ df = dask.datasets.timeseries(
 with (
     pyspy_on_scheduler("pyspy.json"),
     # ^ Saves a speedscope profile to `pyspy.json` locally
-    viztrace_scheduler(
-        "viztracer.json", trace_sparse="distributed.Scheduler.update_graph_hlg"
-    ),
-    # ^ Saves a Chrome trace to `viztracer.json` locally
 ):
     df.set_index("id").mean().compute()
 ```
 
-Using `pyspy_on_scheduler` or `viztrace_scheduler` attaches a profiler to the scheduler process, records a profile, and sends the file back to the client.
+Using `pyspy_on_scheduler` attaches a profiler to the scheduler process, records a profile, and sends the file back to the client.
 
-By default, py-spy profiles are recorded in [speedscope](https://www.speedscope.app/) format. [Viztracer profiles](https://viztracer.readthedocs.io/en/latest/basic_usage.html#display-report) are recorded in Chrome trace format, viewable with [Perfetto](https://ui.perfetto.dev/) or <chrome://tracing>.
+By default, py-spy profiles are recorded in [speedscope](https://www.speedscope.app/) format.
 
-`dask-profiling` (and, transitively, `py-spy`/`viztracer`) must be installed in the environment where the scheduler is running.
+`dask-profiling` (and, transitively, `py-spy`) must be installed in the environment where the scheduler is running.
 
 ## Installation
 
@@ -56,19 +52,6 @@ In a Docker container, `dask-profiling` will "just work" for Docker/moby version
 
 On Ubuntu-based containers, ptrace system calls are [further blocked](https://www.kernel.org/doc/Documentation/admin-guide/LSM/Yama.rst): processes are prohibited from ptracing each other even within the same UID. To work around this, `dask-profiling` automatically uses [`prctl(2)`](https://man7.org/linux/man-pages/man2/prctl.2.html) to mark the scheduler process as ptrace-able by itself and any child processes, then launches py-spy as a child process.
 
-## Viztracer targeting with `trace_sparse`
-
-`viztrace_scheduler` adds a non-standard option to VizTracer: the `trace_sparse` parameter. With this, you basically give a passlist of names (as strings) of functions to trace. The tracer will only run while those functions are active; at all other times, it'll be paused. Names are given in the same way you would to `unittest.mock.patch`.
-
-`viztrace_scheduler` adds some magic so that if the function you want to trace happens to be registered as a comm handler on the Scheduler, everything will behave as you'd expect. (Since the handler functions are added into `scheduler.handlers` _before_ `viztrace_scheduler` has the chance to patch them, those dicts need to be explicitly updated to hold the patched handlers as well. `viztrace_scheduler` takes care of this for you.)
-
-Examples:
-
-* `trace_sparse="distributed.Scheduler.handle_task_finished"` - Trace only the `handle_task_finished` function, and everything it calls while running
-* `trace_sparse=["dask.highlevelgraph.HighLevelGraph.__dask_distributed_unpack__", "distributed.Scheduler.handle_task_finished"]` - Trace both high-level-graph unpacking and `handle_task_finished`
-
-Note that this doesn't work very well on async functions. `distributed.comm.tcp.TCP.read` doesn't work that well, for example.
-
 ## Development
 
 Install [Poetry](https://python-poetry.org/docs/#installation). To create a virtual environment, install dev dependencies, and install the package for local development:
@@ -83,5 +66,3 @@ There is one very very basic end-to-end test for py-spy. Running it requires Doc
 $ pytest tests
 ```
 and wait a long time for the image to build and run.
-
-There are currently no tests for viztracer.

dask_profiling/__init__.py

@@ -1,4 +1,3 @@
 from .pyspy import pyspy, pyspy_on_scheduler
-from .viztracer import viztrace_scheduler
 
-__all__ = ["pyspy", "pyspy_on_scheduler", "viztrace_scheduler"]
+__all__ = ["pyspy", "pyspy_on_scheduler"]