POC: support target dependencies for instrumentations

Author: owais

opentelemetry-instrumentation/src/opentelemetry/instrumentation/auto_instrumentation/sitecustomize.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 import sys
+import logging
 from logging import getLogger
 from os import environ, path
 from os.path import abspath, dirname, pathsep
@@ -23,7 +24,9 @@
 from opentelemetry.environment_variables import (
     OTEL_PYTHON_DISABLED_INSTRUMENTATIONS,
 )
+from opentelemetry.instrumentation.resources import get_target_dependency_conflict
 
+logging.basicConfig(level=logging.DEBUG)
 logger = getLogger(__file__)
 
 
@@ -53,6 +56,13 @@ def _load_instrumentors():
                     "Instrumentation skipped for library %s", entry_point.name
                 )
                 continue
+
+            # check if instrumentor has any missing or conflicting dependencies
+            conflict = get_target_dependency_conflict(entry_point.dist)
+            if conflict:
+                logger.debug(conflict)
+                continue
+
             entry_point.load()().instrument()  # type: ignore
             logger.debug("Instrumented %s", entry_point.name)
         except Exception as exc:  # pylint: disable=broad-except

opentelemetry-instrumentation/src/opentelemetry/instrumentation/resources.py

@@ -0,0 +1,32 @@
+from typing import Optional
+from pkg_resources import get_distribution, VersionConflict, DistributionNotFound
+
+
+class DependencyConflict:
+    required: str = None
+    found: Optional[str] = None
+
+    def __init__(self, required, found=None):
+        self.required = required
+        self.found = found
+
+    def __str__(self):
+        return 'DependencyConflict: requested: "{0}" but found: "{1}"'.format(self.required, self.found)
+
+
+def get_target_dependency_conflict(dist) -> Optional[DependencyConflict]:
+
+    # skip the check if the distribution has not specified any target dependencies
+    if 'target' not in dist.extras:
+        return
+
+    # figure out target dependencies
+    target_dependencies = [dep for dep in dist.requires(('target',)) if dep not in dist.requires()]
+    for dep in target_dependencies:
+        try:
+            get_distribution(str(dep))
+        except VersionConflict as exc:
+            return DependencyConflict(dep, exc.dist)
+        except DistributionNotFound as exc:
+            return DependencyConflict(dep)
+    return