bazel: Add implementation of ABazelQuery

tools/base/BUILD

@@ -1,3 +1,4 @@
+load("@rules_python//python:defs.bzl", "py_binary")
 load("@base_pip3//:requirements.bzl", "requirement")
 load("//bazel:envoy_build_system.bzl", "envoy_package")
 load("//tools/base:envoy_python.bzl", "envoy_py_library")
@@ -37,3 +38,13 @@ envoy_py_library(
         requirement("setuptools"),
     ],
 )
+
+py_binary(
+    name = "bazel_query",
+    srcs = ["bazel_query.py"],
+    main = "bazel_query.py",
+    deps = [
+        "@envoy_repo",
+        requirement("envoy.base.utils"),
+    ],
+)

tools/base/bazel_query.py

@@ -0,0 +1,63 @@
+#!/usr/bin/env python3
+"""Envoy Bazel query implementation.
+
+This module can be used either as a `py_binary` or a `py_library`.
+
+cli usage (outputs to json):
+
+```console
+$ bazel run //tools/base:bazel_query "deps(source/...)" | jq "."
+```
+
+python usage:
+
+```python
+from tools.base.bazel_query import query
+
+result = query("deps(source/...)")
+```
+
+NB: This allows running queries that do not define scope and cannot be
+run as genqueries. **It should not therefore be used in build rules**.
+"""
+
+# The upstream lib is maintained here:
+#
+#    https://github.com/envoyproxy/pytooling/tree/main/envoy.base.utils
+#
+# Please submit issues/PRs to the pytooling repo:
+#
+#    https://github.com/envoyproxy/pytooling
+#
+
+import json
+import pathlib
+import sys
+from functools import cached_property
+
+import abstracts
+
+from envoy.base.utils import ABazelQuery
+
+import envoy_repo
+
+
+@abstracts.implementer(ABazelQuery)
+class EnvoyBazelQuery:
+
+    @cached_property
+    def path(self) -> pathlib.Path:
+        return pathlib.Path(envoy_repo.PATH)
+
+
+query = EnvoyBazelQuery().query
+
+
+def main(*args):
+    print(json.dumps(query(*args[0:1])))
+
+
+if __name__ == "__main__":
+    sys.exit(main(*sys.argv[1:]))
+
+__all__ = ("query",)