feat: implement lazy loading for CLI groups

samcli/cli/lazy_group.py

@@ -0,0 +1,45 @@
+"""
+LazyGroup implementation for Click CLI performance optimization
+"""
+
+import importlib
+
+import click
+from click import ClickException
+
+
+class LazyGroup(click.Group):
+    def __init__(self, *args, lazy_subcommands=None, **kwargs):
+        super().__init__(*args, **kwargs)
+        # lazy_subcommands is a map of the form:
+        #   {command-name} -> {module-name}.{command-object-name}
+        self.lazy_subcommands = lazy_subcommands or {}
+
+    def list_commands(self, ctx):
+        base = super().list_commands(ctx)
+        lazy = sorted(self.lazy_subcommands.keys())
+        return base + lazy
+
+    def get_command(self, ctx, cmd_name):
+        if cmd_name in self.lazy_subcommands:
+            return self._lazy_load(cmd_name)
+        return super().get_command(ctx, cmd_name)
+
+    def _lazy_load(self, cmd_name):
+        # lazily loading a command, first get the module name and attribute name
+        import_path = self.lazy_subcommands[cmd_name]
+        modname, cmd_object_name = import_path.rsplit(".", 1)
+        # do the import
+        try:
+            mod = importlib.import_module(modname)
+        except ImportError as e:
+            raise ClickException(f"Failed to load command '{cmd_name}': {str(e)}")
+        # get the Command object from that module
+        try:
+            cmd_object = getattr(mod, cmd_object_name)
+        except AttributeError:
+            raise ClickException(f"Command '{cmd_name}' not found in module '{modname}'")
+        # check the result to make debugging easier
+        if not isinstance(cmd_object, click.Command):
+            raise ClickException(f"Lazy loading of {import_path} failed by returning a non-command object")
+        return cmd_object

samcli/commands/list/list.py

@@ -4,19 +4,18 @@
 
 import click
 
-from samcli.commands.list.endpoints.command import cli as testable_resources_cli
-from samcli.commands.list.resources.command import cli as resources_cli
-from samcli.commands.list.stack_outputs.command import cli as stack_outputs_cli
+from samcli.cli.lazy_group import LazyGroup
 
 
-@click.group()
+@click.group(
+    cls=LazyGroup,
+    lazy_subcommands={
+        "endpoints": "samcli.commands.list.endpoints.command.cli",
+        "resources": "samcli.commands.list.resources.command.cli",
+        "stack-outputs": "samcli.commands.list.stack_outputs.command.cli",
+    },
+)
 def cli():
     """
     Get local and deployed state of serverless application.
     """
-
-
-# Add individual commands under this group
-cli.add_command(resources_cli)
-cli.add_command(stack_outputs_cli)
-cli.add_command(testable_resources_cli)

samcli/commands/local/local.py

@@ -5,21 +5,19 @@
 
 import click
 
-from .generate_event.cli import cli as generate_event_cli
-from .invoke.cli import cli as invoke_cli
-from .start_api.cli import cli as start_api_cli
-from .start_lambda.cli import cli as start_lambda_cli
+from samcli.cli.lazy_group import LazyGroup
 
 
-@click.group()
+@click.group(
+    cls=LazyGroup,
+    lazy_subcommands={
+        "invoke": "samcli.commands.local.invoke.cli.cli",
+        "start-api": "samcli.commands.local.start_api.cli.cli",
+        "start-lambda": "samcli.commands.local.start_lambda.cli.cli",
+        "generate-event": "samcli.commands.local.generate_event.cli.cli",
+    },
+)
 def cli():
     """
     Run your Serverless application locally for quick development & testing
     """
-
-
-# Add individual commands under this group
-cli.add_command(invoke_cli)
-cli.add_command(start_api_cli)
-cli.add_command(generate_event_cli)
-cli.add_command(start_lambda_cli)

samcli/commands/pipeline/pipeline.py

@@ -5,17 +5,17 @@
 
 import click
 
-from .bootstrap.cli import cli as bootstrap_cli
-from .init.cli import cli as init_cli
+from samcli.cli.lazy_group import LazyGroup
 
 
-@click.group()
+@click.group(
+    cls=LazyGroup,
+    lazy_subcommands={
+        "bootstrap": "samcli.commands.pipeline.bootstrap.cli.cli",
+        "init": "samcli.commands.pipeline.init.cli.cli",
+    },
+)
 def cli() -> None:
     """
     Manage the continuous delivery of the application
     """
-
-
-# Add individual commands under this group
-cli.add_command(bootstrap_cli)
-cli.add_command(init_cli)

samcli/commands/remote/remote.py

@@ -5,17 +5,17 @@
 
 import click
 
-from samcli.commands.remote.invoke.cli import cli as invoke_cli
-from samcli.commands.remote.test_event.test_event import cli as event_cli
+from samcli.cli.lazy_group import LazyGroup
 
 
-@click.group()
+@click.group(
+    cls=LazyGroup,
+    lazy_subcommands={
+        "invoke": "samcli.commands.remote.invoke.cli.cli",
+        "test-event": "samcli.commands.remote.test_event.test_event.cli",
+    },
+)
 def cli():
     """
     Interact with your Serverless application in the cloud for quick development & testing
     """
-
-
-# Add individual commands under this group
-cli.add_command(invoke_cli)
-cli.add_command(event_cli)

samcli/commands/remote/test_event/test_event.py

@@ -2,20 +2,20 @@
 
 import click
 
-from samcli.commands.remote.test_event.delete.cli import cli as delete_cli
-from samcli.commands.remote.test_event.get.cli import cli as get_cli
-from samcli.commands.remote.test_event.list.cli import cli as list_cli
-from samcli.commands.remote.test_event.put.cli import cli as put_cli
+from samcli.cli.lazy_group import LazyGroup
 
 
-@click.group("test-event")
+@click.group(
+    "test-event",
+    cls=LazyGroup,
+    lazy_subcommands={
+        "delete": "samcli.commands.remote.test_event.delete.cli.cli",
+        "get": "samcli.commands.remote.test_event.get.cli.cli",
+        "put": "samcli.commands.remote.test_event.put.cli.cli",
+        "list": "samcli.commands.remote.test_event.list.cli.cli",
+    },
+)
 def cli():
     """
     Manage remote test events
     """
-
-
-cli.add_command(delete_cli)
-cli.add_command(get_cli)
-cli.add_command(put_cli)
-cli.add_command(list_cli)

schema/make_schema.py

@@ -186,18 +186,23 @@ def retrieve_command_structure(package_name: str) -> List[SamCliCommandSchema]:
         subcommands within the package.
     """
     module = importlib.import_module(package_name)
+
+    def create_command_schema(module, subcommand):
+        cmd_name = SamConfig.to_key([module.__name__.split(".")[-1], str(subcommand.name)])
+        return SamCliCommandSchema(
+            cmd_name,
+            clean_text(subcommand.help or subcommand.short_help or ""),
+            get_params_from_command(subcommand),
+        )
+
     command = []
 
     if isinstance(module.cli, click.core.Group):  # command has subcommands (e.g. local invoke)
-        for subcommand in module.cli.commands.values():
-            cmd_name = SamConfig.to_key([module.__name__.split(".")[-1], str(subcommand.name)])
-            command.append(
-                SamCliCommandSchema(
-                    cmd_name,
-                    clean_text(subcommand.help or subcommand.short_help or ""),
-                    get_params_from_command(subcommand),
-                )
-            )
+        ctx = click.Context(module.cli)
+        for subcommand_name in module.cli.list_commands(ctx):
+            subcommand = module.cli.get_command(ctx, subcommand_name)
+            if subcommand:
+                command.append(create_command_schema(module, subcommand))
     else:
         cmd_name = SamConfig.to_key([module.__name__.split(".")[-1]])
         command.append(

schema/samcli.json

@@ -408,6 +408,21 @@
             "parameters"
           ]
         },
+        "local_generate_event": {
+          "title": "Local Generate Event command",
+          "description": "Generate events for Lambda functions.",
+          "properties": {
+            "parameters": {
+              "title": "Parameters for the local generate event command",
+              "description": "Available parameters for the local generate event command:\n* ",
+              "type": "object",
+              "properties": {}
+            }
+          },
+          "required": [
+            "parameters"
+          ]
+        },
         "local_invoke": {
           "title": "Local Invoke command",
           "description": "Invoke AWS serverless functions locally.",
@@ -835,21 +850,6 @@
             "parameters"
           ]
         },
-        "local_generate_event": {
-          "title": "Local Generate Event command",
-          "description": "Generate events for Lambda functions.",
-          "properties": {
-            "parameters": {
-              "title": "Parameters for the local generate event command",
-              "description": "Available parameters for the local generate event command:\n* ",
-              "type": "object",
-              "properties": {}
-            }
-          },
-          "required": [
-            "parameters"
-          ]
-        },
         "local_start_lambda": {
           "title": "Local Start Lambda command",
           "description": "Emulate AWS serverless functions locally.",
@@ -2040,13 +2040,13 @@
             "parameters"
           ]
         },
-        "list_resources": {
-          "title": "List Resources command",
-          "description": "Get a list of resources that will be deployed to CloudFormation.\n\nIf a stack name is provided, the corresponding physical IDs of each\nresource will be mapped to the logical ID of each resource.",
+        "list_endpoints": {
+          "title": "List Endpoints command",
+          "description": "Get a summary of the cloud endpoints in the stack.\n\nThis command will show both the cloud and local endpoints that can\nbe used with sam local and sam sync. Currently the endpoint resources\nare Lambda functions and API Gateway API resources.",
           "properties": {
             "parameters": {
-              "title": "Parameters for the list resources command",
-              "description": "Available parameters for the list resources command:\n* parameter_overrides:\nString that contains AWS CloudFormation parameter overrides encoded as key=value pairs.\n* stack_name:\nName of corresponding deployed stack.(Not including a stack name will only show local resources defined in the template.)\n* output:\nOutput the results from the command in a given output format (json or table).\n* template_file:\nAWS SAM template file.\n* profile:\nSelect a specific profile from your credential file to get AWS credentials.\n* region:\nSet the AWS Region of the service. (e.g. us-east-1)\n* beta_features:\nEnable/Disable beta features.\n* debug:\nTurn on debug logging to print debug message generated by AWS SAM CLI and display timestamps.\n* save_params:\nSave the parameters provided via the command line to the configuration file.",
+              "title": "Parameters for the list endpoints command",
+              "description": "Available parameters for the list endpoints command:\n* parameter_overrides:\nString that contains AWS CloudFormation parameter overrides encoded as key=value pairs.\n* stack_name:\nName of corresponding deployed stack.(Not including a stack name will only show local resources defined in the template.)\n* output:\nOutput the results from the command in a given output format (json or table).\n* template_file:\nAWS SAM template file.\n* profile:\nSelect a specific profile from your credential file to get AWS credentials.\n* region:\nSet the AWS Region of the service. (e.g. us-east-1)\n* beta_features:\nEnable/Disable beta features.\n* debug:\nTurn on debug logging to print debug message generated by AWS SAM CLI and display timestamps.\n* save_params:\nSave the parameters provided via the command line to the configuration file.",
               "type": "object",
               "properties": {
                 "parameter_overrides": {
@@ -2113,19 +2113,30 @@
             "parameters"
           ]
         },
-        "list_stack_outputs": {
-          "title": "List Stack Outputs command",
-          "description": "Get the stack outputs as defined in the SAM/CloudFormation template.",
+        "list_resources": {
+          "title": "List Resources command",
+          "description": "Get a list of resources that will be deployed to CloudFormation.\n\nIf a stack name is provided, the corresponding physical IDs of each\nresource will be mapped to the logical ID of each resource.",
           "properties": {
             "parameters": {
-              "title": "Parameters for the list stack outputs command",
-              "description": "Available parameters for the list stack outputs command:\n* stack_name:\nName of corresponding deployed stack.\n* output:\nOutput the results from the command in a given output format (json or table).\n* profile:\nSelect a specific profile from your credential file to get AWS credentials.\n* region:\nSet the AWS Region of the service. (e.g. us-east-1)\n* beta_features:\nEnable/Disable beta features.\n* debug:\nTurn on debug logging to print debug message generated by AWS SAM CLI and display timestamps.\n* save_params:\nSave the parameters provided via the command line to the configuration file.",
+              "title": "Parameters for the list resources command",
+              "description": "Available parameters for the list resources command:\n* parameter_overrides:\nString that contains AWS CloudFormation parameter overrides encoded as key=value pairs.\n* stack_name:\nName of corresponding deployed stack.(Not including a stack name will only show local resources defined in the template.)\n* output:\nOutput the results from the command in a given output format (json or table).\n* template_file:\nAWS SAM template file.\n* profile:\nSelect a specific profile from your credential file to get AWS credentials.\n* region:\nSet the AWS Region of the service. (e.g. us-east-1)\n* beta_features:\nEnable/Disable beta features.\n* debug:\nTurn on debug logging to print debug message generated by AWS SAM CLI and display timestamps.\n* save_params:\nSave the parameters provided via the command line to the configuration file.",
               "type": "object",
               "properties": {
+                "parameter_overrides": {
+                  "title": "parameter_overrides",
+                  "type": [
+                    "array",
+                    "string"
+                  ],
+                  "description": "String that contains AWS CloudFormation parameter overrides encoded as key=value pairs.",
+                  "items": {
+                    "type": "string"
+                  }
+                },
                 "stack_name": {
                   "title": "stack_name",
                   "type": "string",
-                  "description": "Name of corresponding deployed stack."
+                  "description": "Name of corresponding deployed stack.(Not including a stack name will only show local resources defined in the template.)"
                 },
                 "output": {
                   "title": "output",
@@ -2137,6 +2148,12 @@
                     "table"
                   ]
                 },
+                "template_file": {
+                  "title": "template_file",
+                  "type": "string",
+                  "description": "AWS SAM template file.",
+                  "default": "template.[yaml|yml|json]"
+                },
                 "profile": {
                   "title": "profile",
                   "type": "string",
@@ -2169,30 +2186,19 @@
             "parameters"
           ]
         },
-        "list_endpoints": {
-          "title": "List Endpoints command",
-          "description": "Get a summary of the cloud endpoints in the stack.\n\nThis command will show both the cloud and local endpoints that can\nbe used with sam local and sam sync. Currently the endpoint resources\nare Lambda functions and API Gateway API resources.",
+        "list_stack_outputs": {
+          "title": "List Stack Outputs command",
+          "description": "Get the stack outputs as defined in the SAM/CloudFormation template.",
           "properties": {
             "parameters": {
-              "title": "Parameters for the list endpoints command",
-              "description": "Available parameters for the list endpoints command:\n* parameter_overrides:\nString that contains AWS CloudFormation parameter overrides encoded as key=value pairs.\n* stack_name:\nName of corresponding deployed stack.(Not including a stack name will only show local resources defined in the template.)\n* output:\nOutput the results from the command in a given output format (json or table).\n* template_file:\nAWS SAM template file.\n* profile:\nSelect a specific profile from your credential file to get AWS credentials.\n* region:\nSet the AWS Region of the service. (e.g. us-east-1)\n* beta_features:\nEnable/Disable beta features.\n* debug:\nTurn on debug logging to print debug message generated by AWS SAM CLI and display timestamps.\n* save_params:\nSave the parameters provided via the command line to the configuration file.",
+              "title": "Parameters for the list stack outputs command",
+              "description": "Available parameters for the list stack outputs command:\n* stack_name:\nName of corresponding deployed stack.\n* output:\nOutput the results from the command in a given output format (json or table).\n* profile:\nSelect a specific profile from your credential file to get AWS credentials.\n* region:\nSet the AWS Region of the service. (e.g. us-east-1)\n* beta_features:\nEnable/Disable beta features.\n* debug:\nTurn on debug logging to print debug message generated by AWS SAM CLI and display timestamps.\n* save_params:\nSave the parameters provided via the command line to the configuration file.",
               "type": "object",
               "properties": {
-                "parameter_overrides": {
-                  "title": "parameter_overrides",
-                  "type": [
-                    "array",
-                    "string"
-                  ],
-                  "description": "String that contains AWS CloudFormation parameter overrides encoded as key=value pairs.",
-                  "items": {
-                    "type": "string"
-                  }
-                },
                 "stack_name": {
                   "title": "stack_name",
                   "type": "string",
-                  "description": "Name of corresponding deployed stack.(Not including a stack name will only show local resources defined in the template.)"
+                  "description": "Name of corresponding deployed stack."
                 },
                 "output": {
                   "title": "output",
@@ -2204,12 +2210,6 @@
                     "table"
                   ]
                 },
-                "template_file": {
-                  "title": "template_file",
-                  "type": "string",
-                  "description": "AWS SAM template file.",
-                  "default": "template.[yaml|yml|json]"
-                },
                 "profile": {
                   "title": "profile",
                   "type": "string",