2X faster startup, defer galaxy-* imports to when needed

From 1.84user 0.18system 0:02.03elapsed to 0.71user 0.11system 0:00.83elapsed

Author: mr-c

cwltool/builder.py

@@ -23,7 +23,6 @@
 from .errors import WorkflowException
 from .loghandler import _logger
 from .mutation import MutationManager
-from .software_requirements import DependenciesConfiguration
 from .stdfsaccess import StdFsAccess
 from .utils import (
     CONTENT_LIMIT,
@@ -42,6 +41,7 @@
         ProvenanceProfile,  # pylint: disable=unused-import
     )
     from .pathmapper import PathMapper
+    from .software_requirements import DependenciesConfiguration
 
 INPUT_OBJ_VOCAB: dict[str, str] = {
     "Any": "https://w3id.org/cwl/salad#Any",
@@ -106,7 +106,7 @@ def __init__(
         formatgraph: Optional[Graph],
         make_fs_access: type[StdFsAccess],
         fs_access: StdFsAccess,
-        job_script_provider: Optional[DependenciesConfiguration],
+        job_script_provider: Optional["DependenciesConfiguration"],
         timeout: float,
         debug: bool,
         js_console: bool,

cwltool/main.py

@@ -84,10 +84,6 @@
 from .procgenerator import ProcessGenerator
 from .resolver import ga4gh_tool_registries, tool_resolver
 from .secrets import SecretStore
-from .software_requirements import (
-    DependenciesConfiguration,
-    get_container_from_software_requirements,
-)
 from .stdfsaccess import StdFsAccess
 from .subgraph import get_process, get_step, get_subgraph
 from .update import ALLUPDATES, UPDATES
@@ -1301,6 +1297,8 @@ def main(
             use_conda_dependencies = getattr(args, "beta_conda_dependencies", None)  # str
 
             if conf_file or use_conda_dependencies:
+                from .software_requirements import DependenciesConfiguration
+
                 runtimeContext.job_script_provider = DependenciesConfiguration(args)
             else:
                 runtimeContext.find_default_container = functools.partial(
@@ -1438,6 +1436,8 @@ def find_default_container(
 ) -> Optional[str]:
     """Find a container."""
     if not default_container and use_biocontainers:
+        from .software_requirements import get_container_from_software_requirements
+
         default_container = get_container_from_software_requirements(
             use_biocontainers, builder, container_image_cache_path
         )

cwltool/software_requirements.py

@@ -8,6 +8,7 @@
 """
 
 import argparse
+import importlib.metadata
 import os
 import string
 from collections.abc import MutableMapping, MutableSequence
@@ -16,18 +17,15 @@
 from .utils import HasReqsHints
 
 if TYPE_CHECKING:
+    from galaxy.tool_util.deps.requirements import ToolRequirements
+
     from .builder import Builder
 
 try:
-    from galaxy.tool_util import deps
-    from galaxy.tool_util.deps.requirements import ToolRequirement, ToolRequirements
-except ImportError:
-    ToolRequirement = None  # type: ignore
-    ToolRequirements = None  # type: ignore
-    deps = None  # type: ignore
-
-
-SOFTWARE_REQUIREMENTS_ENABLED = deps is not None
+    importlib.metadata.Distribution.from_name("galaxy-tool-util")
+    SOFTWARE_REQUIREMENTS_ENABLED = True
+except ModuleNotFoundError:
+    SOFTWARE_REQUIREMENTS_ENABLED = False
 
 COMMAND_WITH_DEPENDENCIES_TEMPLATE = string.Template(
     """#!/bin/bash
@@ -74,6 +72,8 @@ def __init__(self, args: argparse.Namespace) -> None:
 
     def build_job_script(self, builder: "Builder", command: list[str]) -> str:
         """Use the galaxy-tool-util library to construct a build script."""
+        from galaxy.tool_util import deps
+
         ensure_galaxy_lib_available()
         resolution_config_dict = {
             "use": self.use_tool_dependencies,
@@ -102,8 +102,12 @@ def build_job_script(self, builder: "Builder", command: list[str]) -> str:
         return job_script
 
 
-def get_dependencies(builder: HasReqsHints) -> ToolRequirements:
+def get_dependencies(
+    builder: HasReqsHints,
+) -> "ToolRequirements":
     (software_requirement, _) = builder.get_requirement("SoftwareRequirement")
+    from galaxy.tool_util.deps.requirements import ToolRequirement, ToolRequirements
+
     dependencies: list[Union["ToolRequirement", dict[str, Any]]] = []
     if software_requirement and software_requirement.get("packages"):
         packages = cast(