[Tune] Add soft imports test (#16450)

.buildkite/pipeline.yml

@@ -261,16 +261,24 @@
   commands:
     - cleanup() { if [ "${BUILDKITE_PULL_REQUEST}" = "false" ]; then ./ci/travis/upload_build_info.sh; fi }; trap cleanup EXIT
     - TUNE_TESTING=1 ./ci/travis/install-dependencies.sh
-    - bazel test --config=ci $(./scripts/bazel_export_options) --test_tag_filters=-jenkins_only,-example,-flaky,-py37 python/ray/tune/...
-    - bazel test --config=ci $(./scripts/bazel_export_options) --build_tests_only --test_tag_filters=example,-tf,-pytorch,-py37,-flaky python/ray/tune/...
+    - bazel test --config=ci $(./scripts/bazel_export_options) --test_tag_filters=-jenkins_only,-example,-flaky,-py37,-soft_imports python/ray/tune/...
+    - bazel test --config=ci $(./scripts/bazel_export_options) --build_tests_only --test_tag_filters=example,-tf,-pytorch,-py37,-flaky,-soft_imports python/ray/tune/...
 
 - label: ":octopus: Tune tests and examples {2/2}"
   conditions: ["RAY_CI_TUNE_AFFECTED"]
   commands:
     - cleanup() { if [ "${BUILDKITE_PULL_REQUEST}" = "false" ]; then ./ci/travis/upload_build_info.sh; fi }; trap cleanup EXIT
     - TUNE_TESTING=1 ./ci/travis/install-dependencies.sh
-    - bazel test --config=ci $(./scripts/bazel_export_options) --build_tests_only --test_tag_filters=tf,-pytorch,-py37,-flaky python/ray/tune/...
-    - bazel test --config=ci $(./scripts/bazel_export_options) --build_tests_only --test_tag_filters=-tf,pytorch,-py37,-flaky python/ray/tune/...
+    - bazel test --config=ci $(./scripts/bazel_export_options) --build_tests_only --test_tag_filters=tf,-pytorch,-py37,-flaky,-soft_imports python/ray/tune/...
+    - bazel test --config=ci $(./scripts/bazel_export_options) --build_tests_only --test_tag_filters=-tf,pytorch,-py37,-flaky,-soft_imports python/ray/tune/...
+
+- label: ":octopus: Tune soft imports test"
+  conditions: ["RAY_CI_TUNE_AFFECTED"]
+  commands:
+    - cleanup() { if [ "${BUILDKITE_PULL_REQUEST}" = "false" ]; then ./ci/travis/upload_build_info.sh; fi }; trap cleanup EXIT
+    # no TUNE_TESTING=1 on purpose
+    - ./ci/travis/install-dependencies.sh
+    - bazel test --config=ci $(./scripts/bazel_export_options) --build_tests_only --test_tag_filters=soft_imports python/ray/tune/...
 
 - label: ":octopus: SGD tests and examples"
   conditions: ["RAY_CI_SGD_AFFECTED"]

python/ray/tune/BUILD

@@ -203,6 +203,14 @@ py_test(
     tags = ["exclusive"],
 )
 
+py_test(
+    name = "test_soft_imports",
+    size = "small",
+    srcs = ["tests/test_soft_imports.py"],
+    deps = [":tune_lib"],
+    tags = ["soft_imports"],
+)
+
 py_test(
     name = "test_sync",
     size = "medium",

python/ray/tune/suggest/__init__.py

@@ -7,6 +7,94 @@ from ray.tune.suggest.variant_generator import grid_search
 from ray.tune.suggest.repeater import Repeater
 
 
+def _import_variant_generator():
+    return BasicVariantGenerator
+
+
+def _import_ax_search():
+    from ray.tune.suggest.ax import AxSearch
+    return AxSearch
+
+
+def _import_blendsearch_search():
+    from ray.tune.suggest.flaml import BlendSearch
+    return BlendSearch
+
+
+def _import_cfo_search():
+    from ray.tune.suggest.flaml import CFO
+    return CFO
+
+
+def _import_dragonfly_search():
+    from ray.tune.suggest.dragonfly import DragonflySearch
+    return DragonflySearch
+
+
+def _import_skopt_search():
+    from ray.tune.suggest.skopt import SkOptSearch
+    return SkOptSearch
+
+
+def _import_hyperopt_search():
+    from ray.tune.suggest.hyperopt import HyperOptSearch
+    return HyperOptSearch
+
+
+def _import_bayesopt_search():
+    from ray.tune.suggest.bayesopt import BayesOptSearch
+    return BayesOptSearch
+
+
+def _import_bohb_search():
+    from ray.tune.suggest.bohb import TuneBOHB
+    return TuneBOHB
+
+
+def _import_nevergrad_search():
+    from ray.tune.suggest.nevergrad import NevergradSearch
+    return NevergradSearch
+
+
+def _import_optuna_search():
+    from ray.tune.suggest.optuna import OptunaSearch
+    return OptunaSearch
+
+
+def _import_zoopt_search():
+    from ray.tune.suggest.zoopt import ZOOptSearch
+    return ZOOptSearch
+
+
+def _import_sigopt_search():
+    from ray.tune.suggest.sigopt import SigOptSearch
+    return SigOptSearch
+
+
+def _import_hebo_search():
+    from ray.tune.suggest.hebo import HEBOSearch
+    return HEBOSearch
+
+
+SEARCH_ALG_IMPORT = {
+    "variant_generator": _import_variant_generator,
+    "random": _import_variant_generator,
+    "ax": _import_ax_search,
+    "dragonfly": _import_dragonfly_search,
+    "skopt": _import_skopt_search,
+    "hyperopt": _import_hyperopt_search,
+    "bayesopt": _import_bayesopt_search,
+    "bohb": _import_bohb_search,
+    "nevergrad": _import_nevergrad_search,
+    "optuna": _import_optuna_search,
+    "zoopt": _import_zoopt_search,
+    "sigopt": _import_sigopt_search,
+    "hebo": _import_hebo_search,
+    "blendsearch": _import_blendsearch_search,
+    "cfo": _import_cfo_search,
+}
+
+
 def create_searcher(
         search_alg,
         **kwargs,
@@ -30,78 +118,6 @@ def create_searcher(
         >>> search_alg = tune.create_searcher('ax')
     """
 
-    def _import_variant_generator():
-        return BasicVariantGenerator
-
-    def _import_ax_search():
-        from ray.tune.suggest.ax import AxSearch
-        return AxSearch
-
-    def _import_blendsearch_search():
-        from ray.tune.suggest.flaml import BlendSearch
-        return BlendSearch
-
-    def _import_cfo_search():
-        from ray.tune.suggest.flaml import CFO
-        return CFO
-
-    def _import_dragonfly_search():
-        from ray.tune.suggest.dragonfly import DragonflySearch
-        return DragonflySearch
-
-    def _import_skopt_search():
-        from ray.tune.suggest.skopt import SkOptSearch
-        return SkOptSearch
-
-    def _import_hyperopt_search():
-        from ray.tune.suggest.hyperopt import HyperOptSearch
-        return HyperOptSearch
-
-    def _import_bayesopt_search():
-        from ray.tune.suggest.bayesopt import BayesOptSearch
-        return BayesOptSearch
-
-    def _import_bohb_search():
-        from ray.tune.suggest.bohb import TuneBOHB
-        return TuneBOHB
-
-    def _import_nevergrad_search():
-        from ray.tune.suggest.nevergrad import NevergradSearch
-        return NevergradSearch
-
-    def _import_optuna_search():
-        from ray.tune.suggest.optuna import OptunaSearch
-        return OptunaSearch
-
-    def _import_zoopt_search():
-        from ray.tune.suggest.zoopt import ZOOptSearch
-        return ZOOptSearch
-
-    def _import_sigopt_search():
-        from ray.tune.suggest.sigopt import SigOptSearch
-        return SigOptSearch
-
-    def _import_hebo_search():
-        from ray.tune.suggest.hebo import HEBOSearch
-        return HEBOSearch
-
-    SEARCH_ALG_IMPORT = {
-        "variant_generator": _import_variant_generator,
-        "random": _import_variant_generator,
-        "ax": _import_ax_search,
-        "dragonfly": _import_dragonfly_search,
-        "skopt": _import_skopt_search,
-        "hyperopt": _import_hyperopt_search,
-        "bayesopt": _import_bayesopt_search,
-        "bohb": _import_bohb_search,
-        "nevergrad": _import_nevergrad_search,
-        "optuna": _import_optuna_search,
-        "zoopt": _import_zoopt_search,
-        "sigopt": _import_sigopt_search,
-        "hebo": _import_hebo_search,
-        "blendsearch": _import_blendsearch_search,
-        "cfo": _import_cfo_search,
-    }
     search_alg = search_alg.lower()
     if search_alg not in SEARCH_ALG_IMPORT:
         raise ValueError(

python/ray/tune/suggest/zoopt.py

@@ -11,12 +11,13 @@ from ray.tune.suggest.suggestion import UNRESOLVED_SEARCH_SPACE, \
     UNDEFINED_METRIC_MODE, UNDEFINED_SEARCH_SPACE
 from ray.tune.suggest.variant_generator import parse_spec_vars
 from ray.tune.utils.util import unflatten_dict
-from zoopt import Solution, ValueType
 
 try:
     import zoopt
+    from zoopt import Solution, ValueType
 except ImportError:
     zoopt = None
+    Solution = ValueType = None
 
 from ray.tune.suggest import Searcher
 

python/ray/tune/tests/test_soft_imports.py

@@ -0,0 +1,24 @@
+import sys
+import unittest
+
+
+class TestSoftImports(unittest.TestCase):
+    """Tests whether it's possible to use Ray Tune without soft dependencies
+    """
+
+    def testSoftImports(self):
+        import ray.tune.schedulers  # noqa: F401
+        from ray.tune.suggest import SEARCH_ALG_IMPORT
+        for name, import_func in SEARCH_ALG_IMPORT.items():
+            print(f"testing searcher {name}")
+            searcher = import_func()
+
+            # ensure that the dependencies aren't actually installed
+            if searcher and name not in ("variant_generator", "random"):
+                with self.assertRaises(AssertionError):
+                    searcher()
+
+
+if __name__ == "__main__":
+    import pytest
+    sys.exit(pytest.main(["-v", __file__]))