remove stale opentelemetry_sdk packages

lib/charms/tempo_k8s/v1/charm_tracing.py

@@ -176,8 +176,10 @@ def my_tracing_endpoint(self) -> Optional[str]:
 import inspect
 import logging
 import os
+import shutil
 from contextlib import contextmanager
 from contextvars import Context, ContextVar, copy_context
+from importlib.metadata import distributions
 from pathlib import Path
 from typing import (
     Any,
@@ -217,7 +219,7 @@ def my_tracing_endpoint(self) -> Optional[str]:
 # Increment this PATCH version before using `charmcraft publish-lib` or reset
 # to 0 if you are raising the major API version
 
-LIBPATCH = 11
+LIBPATCH = 12
 
 PYDEPS = ["opentelemetry-exporter-otlp-proto-http==1.21.0"]
 
@@ -359,6 +361,28 @@ def _get_server_cert(
     return server_cert
 
 
+def _remove_stale_otel_sdk_packages():
+    """Hack to remove stale opentelemetry sdk packages from the environment.
+
+    See https://github.com/canonical/grafana-agent-operator/issues/146 and
+    https://bugs.launchpad.net/juju/+bug/2058335 for more context.  This patch can be removed after
+    this juju issue is resolved and sufficient time has passed to expect most users of this library
+    have migrated to the patched version of juju.
+
+    This only does something if executed on an upgrade-charm event.
+    """
+    if os.getenv("JUJU_DISPATCH_PATH") == "hooks/upgrade-charm":
+        # Find any opentelemetry_sdk distributions
+        otel_sdk_distributions = list(distributions(name="opentelemetry_sdk"))
+        # If there are more than 2, inspect them and infer that any with 0 entrypoints are stale
+        if len(otel_sdk_distributions) > 1:
+            for d in otel_sdk_distributions:
+                if len(d.entry_points) == 0:
+                    # Distribution appears to be empty.  Remove it
+                    logger.debug(f"Removing empty opentelemetry_sdk distribution at: {d._path}")  # type: ignore
+                    shutil.rmtree(d._path)  # type: ignore
+
+
 def _setup_root_span_initializer(
     charm_type: _CharmType,
     tracing_endpoint_attr: str,
@@ -391,6 +415,7 @@ def wrap_init(self: CharmBase, framework: Framework, *args, **kwargs):
         _service_name = service_name or f"{self.app.name}-charm"
 
         unit_name = self.unit.name
+        _remove_stale_otel_sdk_packages()
         resource = Resource.create(
             attributes={
                 "service.name": _service_name,