feat: Added --skip-prepare-infra to skip the prepare hook stage

samcli/commands/_utils/custom_options/hook_name_option.py

@@ -73,10 +73,15 @@ def _call_prepare_hook(self, iac_hook_wrapper, opts):
             output_dir_path = os.path.join(iac_project_path, ".aws-sam-iacs", "iacs_metadata")
             if not os.path.exists(output_dir_path):
                 os.makedirs(output_dir_path, exist_ok=True)
+
             debug = opts.get("debug", False)
             aws_profile = opts.get("profile")
             aws_region = opts.get("region")
-            metadata_file = iac_hook_wrapper.prepare(output_dir_path, iac_project_path, debug, aws_profile, aws_region)
+            skip_prepare_infra = opts.get("skip_prepare_infra", False)
+
+            metadata_file = iac_hook_wrapper.prepare(
+                output_dir_path, iac_project_path, debug, aws_profile, aws_region, skip_prepare_infra
+            )
 
             LOG.info("Prepare hook completed and metadata file generated at: %s", metadata_file)
             opts["template_file"] = metadata_file

samcli/commands/_utils/options.py

@@ -200,6 +200,26 @@ def resolve_s3_callback(ctx, param, provided_value, artifact, exc_set, exc_not_s
     return provided_value
 
 
+def skip_prepare_infra_callback(ctx, param, provided_value):
+    """
+    Callback for --skip-prepare-infra to check if --hook-name is also specified
+
+    Parameters
+    ----------
+    ctx: click.core.Context
+        Click context
+    param: click.Option
+        Parameter properties
+    provided_value: bool
+        True if option was provided
+    """
+    is_option_provided = provided_value or ctx.default_map.get("skip_prepare_infra")
+    is_hook_provided = ctx.params.get("hook_name") or ctx.default_map.get("hook_name")
+
+    if is_option_provided and not is_hook_provided:
+        raise click.BadOptionUsage(option_name=param.name, ctx=ctx, message="Missing option --hook-name")
+
+
 def template_common_option(f):
     """
     Common ClI option for template
@@ -693,6 +713,25 @@ def decorator(f):
     return composed_decorator(decorator_list)
 
 
+def skip_prepare_infra_click_option():
+    """
+    Click option to skip the hook preparation stage
+    """
+    return click.option(
+        "--skip-prepare-infra",
+        is_flag=True,
+        required=False,
+        callback=skip_prepare_infra_callback,
+        help="This option should be used to skip the preparation stage if there "
+        "have not been any infrastructure changes. The --hook-name option should "
+        "also be specified when using this option.",
+    )
+
+
+def skip_prepare_infra_option(f):
+    return skip_prepare_infra_click_option()(f)
+
+
 @parameterized_option
 def resolve_s3_option(f, guided=False):
     return resolve_s3_click_option(guided)(f)

samcli/commands/build/command.py

@@ -10,6 +10,7 @@
 from samcli.cli.context import Context
 from samcli.commands._utils.experimental import experimental, ExperimentalFlag, is_experimental_enabled
 from samcli.commands._utils.options import (
+    skip_prepare_infra_option,
     template_option_without_build,
     docker_common_options,
     parameter_override_option,
@@ -85,6 +86,7 @@
     force_prepare=True,
     invalid_coexist_options=["t", "template-file", "template", "parameter-overrides"],
 )
+@skip_prepare_infra_option
 @use_container_build_option
 @click.option(
     "--container-env-var",
@@ -172,6 +174,7 @@ def cli(
     config_file: str,
     config_env: str,
     hook_name: Optional[str],
+    skip_prepare_infra: bool,
 ) -> None:
     """
     `sam build` command entry point

samcli/commands/local/invoke/cli.py

@@ -7,7 +7,7 @@
 
 from samcli.cli.main import pass_context, common_options as cli_framework_options, aws_creds_options, print_cmdline_args
 from samcli.commands._utils.experimental import experimental, is_experimental_enabled, ExperimentalFlag
-from samcli.commands._utils.options import hook_name_click_option
+from samcli.commands._utils.options import hook_name_click_option, skip_prepare_infra_option
 from samcli.commands.local.cli_common.options import invoke_common_options, local_common_options
 from samcli.commands.local.lib.exceptions import InvalidIntermediateImageError
 from samcli.lib.telemetry.metric import track_command
@@ -40,6 +40,7 @@
 @hook_name_click_option(
     force_prepare=False, invalid_coexist_options=["t", "template-file", "template", "parameter-overrides"]
 )
+@skip_prepare_infra_option
 @click.option(
     "--event",
     "-e",
@@ -83,6 +84,7 @@ def cli(
     container_host_interface,
     invoke_image,
     hook_name,
+    skip_prepare_infra,
 ):
     """
     `sam local invoke` command entry point

samcli/commands/local/start_lambda/cli.py

@@ -7,7 +7,7 @@
 
 from samcli.cli.main import pass_context, common_options as cli_framework_options, aws_creds_options, print_cmdline_args
 from samcli.commands._utils.experimental import experimental, is_experimental_enabled, ExperimentalFlag
-from samcli.commands._utils.options import hook_name_click_option
+from samcli.commands._utils.options import hook_name_click_option, skip_prepare_infra_option
 from samcli.commands.local.cli_common.options import (
     invoke_common_options,
     service_common_options,
@@ -64,6 +64,7 @@
 @hook_name_click_option(
     force_prepare=False, invalid_coexist_options=["t", "template-file", "template", "parameter-overrides"]
 )
+@skip_prepare_infra_option
 @service_common_options(3001)
 @invoke_common_options
 @experimental
@@ -103,6 +104,7 @@ def cli(
     container_host_interface,
     invoke_image,
     hook_name,
+    skip_prepare_infra,
 ):
     """
     `sam local start-lambda` command entry point

samcli/hook_packages/terraform/hooks/prepare/hook.py

@@ -75,6 +75,7 @@
 PropertyBuilder = Callable[[dict, TFResource], Any]
 PropertyBuilderMapping = Dict[str, PropertyBuilder]
 
+TERRAFORM_METADATA_FILE = "template.json"
 TERRAFORM_BUILD_SCRIPT = "copy_terraform_built_artifacts.py"
 TF_BACKEND_OVERRIDE_FILENAME = "z_samcli_backend_override"
 
@@ -132,78 +133,89 @@ def prepare(params: dict) -> dict:
         output_dir_path = os.path.normpath(os.path.join(terraform_application_dir, output_dir_path))
         LOG.debug("The normalized OutputDirPath value is %s", output_dir_path)
 
-    try:
-        # initialize terraform application
-        LOG.info("Initializing Terraform application")
-        invoke_subprocess_with_loading_pattern(
-            command_args={
-                "args": ["terraform", "init", "-input=false"],
-                "cwd": terraform_application_dir,
-            }
-        )
+    skip_prepare_infra = params.get("SkipPrepareInfra")
+    metadata_file_path = os.path.join(output_dir_path, TERRAFORM_METADATA_FILE)
+
+    if skip_prepare_infra and os.path.exists(metadata_file_path):
+        LOG.info("Skipping preparation stage, the metadata file already exists at %s", metadata_file_path)
+    else:
+        if skip_prepare_infra:
+            LOG.info(
+                "The option to skip infrastructure preparation was provided, but we could not find "
+                "the metadata file. Preparing anyways."
+            )
 
-        # get json output of terraform plan
-        LOG.info("Creating terraform plan and getting JSON output")
-        with osutils.tempfile_platform_independent() as temp_file:
+        try:
+            # initialize terraform application
+            LOG.info("Initializing Terraform application")
             invoke_subprocess_with_loading_pattern(
-                # input false to avoid SAM CLI to stuck in case if the
-                # Terraform project expects input, and customer does not provide it.
                 command_args={
-                    "args": ["terraform", "plan", "-out", temp_file.name, "-input=false"],
+                    "args": ["terraform", "init", "-input=false"],
                     "cwd": terraform_application_dir,
                 }
             )
 
-            result = run(
-                ["terraform", "show", "-json", temp_file.name],
-                check=True,
-                capture_output=True,
-                cwd=terraform_application_dir,
-            )
-        tf_json = json.loads(result.stdout)
-
-        # convert terraform to cloudformation
-        LOG.info("Generating metadata file")
-        cfn_dict = _translate_to_cfn(tf_json, output_dir_path, terraform_application_dir)
-
-        if cfn_dict.get("Resources"):
-            _update_resources_paths(cfn_dict.get("Resources"), terraform_application_dir)  # type: ignore
-
-        # Add hook metadata
-        cfn_dict["Metadata"][HOOK_METADATA_KEY] = TERRAFORM_HOOK_METADATA
-
-        # store in supplied output dir
-        if not os.path.exists(output_dir_path):
-            os.makedirs(output_dir_path, exist_ok=True)
-        metadataFilePath = os.path.join(output_dir_path, "template.json")
-        LOG.info("Finished generating metadata file. Storing in %s", metadataFilePath)
-        with open(metadataFilePath, "w+") as metadata_file:
-            json.dump(cfn_dict, metadata_file)
-
-        return {"iac_applications": {"MainApplication": {"metadata_file": metadataFilePath}}}
-
-    except CalledProcessError as e:
-        stderr_output = str(e.stderr)
+            # get json output of terraform plan
+            LOG.info("Creating terraform plan and getting JSON output")
+            with osutils.tempfile_platform_independent() as temp_file:
+                invoke_subprocess_with_loading_pattern(
+                    # input false to avoid SAM CLI to stuck in case if the
+                    # Terraform project expects input, and customer does not provide it.
+                    command_args={
+                        "args": ["terraform", "plan", "-out", temp_file.name, "-input=false"],
+                        "cwd": terraform_application_dir,
+                    }
+                )
 
-        # stderr can take on bytes or just be a plain string depending on terminal
-        if isinstance(e.stderr, bytes):
-            stderr_output = e.stderr.decode("utf-8")
+                result = run(
+                    ["terraform", "show", "-json", temp_file.name],
+                    check=True,
+                    capture_output=True,
+                    cwd=terraform_application_dir,
+                )
+            tf_json = json.loads(result.stdout)
+
+            # convert terraform to cloudformation
+            LOG.info("Generating metadata file")
+            cfn_dict = _translate_to_cfn(tf_json, output_dir_path, terraform_application_dir)
+
+            if cfn_dict.get("Resources"):
+                _update_resources_paths(cfn_dict.get("Resources"), terraform_application_dir)  # type: ignore
+
+            # Add hook metadata
+            cfn_dict["Metadata"][HOOK_METADATA_KEY] = TERRAFORM_HOOK_METADATA
+
+            # store in supplied output dir
+            if not os.path.exists(output_dir_path):
+                os.makedirs(output_dir_path, exist_ok=True)
+
+            LOG.info("Finished generating metadata file. Storing in %s", metadata_file_path)
+            with open(metadata_file_path, "w+") as metadata_file:
+                json.dump(cfn_dict, metadata_file)
+        except CalledProcessError as e:
+            stderr_output = str(e.stderr)
+
+            # stderr can take on bytes or just be a plain string depending on terminal
+            if isinstance(e.stderr, bytes):
+                stderr_output = e.stderr.decode("utf-8")
+
+            # one of the subprocess.run calls resulted in non-zero exit code or some OS error
+            LOG.debug(
+                "Error running terraform command: \n" "cmd: %s \n" "stdout: %s \n" "stderr: %s \n",
+                e.cmd,
+                e.stdout,
+                stderr_output,
+            )
 
-        # one of the subprocess.run calls resulted in non-zero exit code or some OS error
-        LOG.debug(
-            "Error running terraform command: \n" "cmd: %s \n" "stdout: %s \n" "stderr: %s \n",
-            e.cmd,
-            e.stdout,
-            stderr_output,
-        )
+            raise PrepareHookException(
+                f"There was an error while preparing the Terraform application.\n{stderr_output}"
+            ) from e
+        except LoadingPatternError as e:
+            raise PrepareHookException(f"Error occurred when invoking a process: {e}") from e
+        except OSError as e:
+            raise PrepareHookException(f"OSError: {e}") from e
 
-        raise PrepareHookException(
-            f"There was an error while preparing the Terraform application.\n{stderr_output}"
-        ) from e
-    except LoadingPatternError as e:
-        raise PrepareHookException(f"Error occurred when invoking a process: {e}") from e
-    except OSError as e:
-        raise PrepareHookException(f"OSError: {e}") from e
+    return {"iac_applications": {"MainApplication": {"metadata_file": metadata_file_path}}}
 
 
 def _update_resources_paths(cfn_resources: Dict[str, Any], terraform_application_dir: str) -> None:

samcli/lib/hook/hook_wrapper.py

@@ -51,6 +51,7 @@ def prepare(
         debug: bool = False,
         aws_profile: Optional[str] = None,
         aws_region: Optional[str] = None,
+        skip_prepare_infra: bool = False,
     ) -> str:
         """
         Run the prepare hook to generate the IaC Metadata file.
@@ -67,6 +68,8 @@ def prepare(
             AWS profile to use. Default is None (use default profile)
         aws_region: str
             AWS region to use. Default is None (use default region)
+        skip_prepare_infra: bool
+            Flag to skip skip prepare hook if we already have the metadata file. Default is False.
 
         Returns
         -------
@@ -78,6 +81,7 @@ def prepare(
             "IACProjectPath": iac_project_path if iac_project_path else str(Path.cwd()),
             "OutputDirPath": output_dir_path,
             "Debug": debug,
+            "SkipPrepareInfra": skip_prepare_infra,
         }
         if aws_profile:
             params["Profile"] = aws_profile