Structured Errors, Standard Errors, and Off Output Format

.changes/next-release/enhancement-ErrorMessages-78207.json

@@ -0,0 +1,5 @@
+{
+  "type": "enhancement",
+  "category": "Error Messages",
+  "description": "Standardize CLI error message format to use `aws: [ERROR]: <message>` prefix for consistency across all error types."
+}

.changes/next-release/enhancement-Output-51826.json

@@ -0,0 +1,5 @@
+{
+  "type": "enhancement",
+  "category": "Output",
+  "description": "Add support for ``--output off`` to suppress all stdout output while preserving stderr for errors and warnings."
+}

.changes/next-release/feature-Output-59989.json

@@ -0,0 +1,5 @@
+{
+  "type": "feature",
+  "category": "Output",
+  "description": "Add structured error output with configurable formats. CLI errors now display additional fields in the configured format (legacy, json, yaml, text, table, or enhanced). Configure via ``--cli-error-format``, ``cli_error_format`` config variable, or ``AWS_CLI_ERROR_FORMAT`` environment variable. The new enhanced format is the default. Set ``cli_error_format=legacy`` to preserve the original error format."
+}

awscli/argparser.py

@@ -113,8 +113,7 @@ def error(self, message):
         should raise an exception.
         """
         usage_message = self.format_usage()
-        error_message = f'{self.prog}: [ERROR]: {message}'
-        raise ArgParseException(f'{error_message}\n\n{usage_message}')
+        raise ArgParseException(f'{message}\n\n{usage_message}')
 
 
 class MainArgParser(CLIArgParser):

awscli/clidriver.py

@@ -119,7 +119,7 @@ def create_clidriver(args=None):
         session.full_config.get('plugins', {}),
         event_hooks=session.get_component('event_emitter'),
     )
-    error_handlers_chain = construct_cli_error_handlers_chain()
+    error_handlers_chain = construct_cli_error_handlers_chain(session)
     driver = CLIDriver(
         session=session, error_handler=error_handlers_chain, debug=debug
     )
@@ -246,7 +246,9 @@ def __init__(self, session=None, error_handler=None, debug=False):
             self.session = session
         self._error_handler = error_handler
         if self._error_handler is None:
-            self._error_handler = construct_cli_error_handlers_chain()
+            self._error_handler = construct_cli_error_handlers_chain(
+                self.session
+            )
         if debug:
             self._set_logging(debug)
         self._update_config_chain()
@@ -275,6 +277,9 @@ def _update_config_chain(self):
         config_store.set_config_provider(
             'cli_help_output', self._construct_cli_help_output_chain()
         )
+        config_store.set_config_provider(
+            'cli_error_format', self._construct_cli_error_format_chain()
+        )
 
     def _construct_cli_region_chain(self):
         providers = [
@@ -368,6 +373,20 @@ def _construct_cli_auto_prompt_chain(self):
         ]
         return ChainProvider(providers=providers)
 
+    def _construct_cli_error_format_chain(self):
+        providers = [
+            EnvironmentProvider(
+                name='AWS_CLI_ERROR_FORMAT',
+                env=os.environ,
+            ),
+            ScopedConfigProvider(
+                config_var_name='cli_error_format',
+                session=self.session,
+            ),
+            ConstantProvider(value='enhanced'),
+        ]
+        return ChainProvider(providers=providers)
+
     @property
     def subcommand_table(self):
         return self._get_command_table()
@@ -516,6 +535,7 @@ def main(self, args=None):
         command_table = self._get_command_table()
         parser = self.create_parser(command_table)
         self._add_aliases(command_table, parser)
+        parsed_args = None
         try:
             # Because _handle_top_level_args emits events, it's possible
             # that exceptions can be raised, which should have the same
@@ -538,6 +558,7 @@ def main(self, args=None):
                 e,
                 stdout=get_stdout_text_writer(),
                 stderr=get_stderr_text_writer(),
+                parsed_globals=parsed_args,
             )
 
     def _emit_session_event(self, parsed_args):
@@ -818,7 +839,10 @@ def _parse_potential_subcommand(self, args, subcommand_table):
     def __call__(self, args, parsed_globals):
         # Once we know we're trying to call a particular operation
         # of a service we can go ahead and load the parameters.
-        event = f'before-building-argument-table-parser.{self._parent_name}.{self._name}'
+        event = (
+            f'before-building-argument-table-parser.'
+            f'{self._parent_name}.{self._name}'
+        )
         self._emit(
             event,
             argument_table=self.arg_table,
@@ -1028,9 +1052,7 @@ def _make_client_call(
             paginator = client.get_paginator(py_operation_name)
             response = paginator.paginate(**parameters)
         else:
-            response = getattr(client, xform_name(operation_name))(
-                **parameters
-            )
+            response = getattr(client, py_operation_name)(**parameters)
         return response
 
     def _display_response(self, command_name, response, parsed_globals):

awscli/customizations/configure/mfalogin.py

@@ -24,6 +24,7 @@
 from awscli.customizations.commands import BasicCommand
 from awscli.customizations.configure import profile_to_section
 from awscli.customizations.configure.writer import ConfigFileWriter
+from awscli.errorformat import write_error
 
 LOG = logging.getLogger(__name__)
 
@@ -142,7 +143,7 @@ def _get_mfa_token(self):
             'None', 'mfa_token', 'MFA token code'
         )
         if not token_code:
-            sys.stderr.write("MFA token code is required\n")
+            write_error(sys.stderr, "MFA token code is required")
             return None
         return token_code
 
@@ -156,7 +157,7 @@ def _call_sts_get_session_token(self, sts_client, duration_seconds, mfa_serial,
             )
             return response
         except ClientError as e:
-            sys.stderr.write(f"An error occurred: {e}\n")
+            write_error(sys.stderr, f"An error occurred: {e}")
             return None
 
     def _resolve_mfa_serial(self, parsed_args, source_config):
@@ -167,7 +168,7 @@ def _resolve_mfa_serial(self, parsed_args, source_config):
                 'None', 'mfa_serial', 'MFA serial number or ARN'
             )
             if not mfa_serial:
-                sys.stderr.write("MFA serial number or MFA device ARN is required\n")
+                write_error(sys.stderr, "MFA serial number or MFA device ARN is required")
                 return None
         return mfa_serial
 
@@ -252,7 +253,7 @@ def _handle_interactive_prompting(self, parsed_args, duration_seconds):
                 'None', config_name, prompt_text
             )
             if not value or value == 'None':
-                sys.stderr.write(f"{prompt_text} is required\n")
+                write_error(sys.stderr, f"{prompt_text} is required")
                 return 1
             values[config_name] = value
 

awscli/customizations/ecs/exceptions.py

@@ -24,26 +24,26 @@ def __init__(self, **kwargs):
 
 
 class MissingPropertyError(ECSError):
-    fmt = "Error: Resource '{resource}' must include property '{prop_name}'"
+    fmt = "Resource '{resource}' must include property '{prop_name}'"
 
 
 class FileLoadError(ECSError):
-    fmt = "Error: Unable to load file at {file_path}: {error}"
+    fmt = "Unable to load file at {file_path}: {error}"
 
 
 class InvalidPlatformError(ECSError):
-    fmt = "Error: {resource} '{name}' must support 'ECS' compute platform"
+    fmt = "{resource} '{name}' must support 'ECS' compute platform"
 
 
 class InvalidProperyError(ECSError):
     fmt = (
-        "Error: deployment group '{dg_name}' does not target "
+        "deployment group '{dg_name}' does not target "
         "ECS {resource} '{resource_name}'"
     )
 
 
 class InvalidServiceError(ECSError):
-    fmt = "Error: Service '{service}' not found in cluster '{cluster}'"
+    fmt = "Service '{service}' not found in cluster '{cluster}'"
 
 
 class ServiceClientError(ECSError):

awscli/customizations/emr/applicationutils.py

@@ -62,7 +62,7 @@ def build_applications(region, parsed_applications, ami_version=None):
                 )
             else:
                 raise ParamValidationError(
-                    'aws: error: AMI version %s is not '
+                    'AMI version %s is not '
                     'compatible with HBase.' % ami_version
                 )
         elif app_name == constants.IMPALA:

awscli/customizations/emr/createcluster.py

@@ -298,7 +298,7 @@ def _run_main_command(self, parsed_args, parsed_globals):
                     )
                 except ValueError:
                     raise ParamValidationError(
-                        'aws: error: invalid json argument for '
+                        'invalid json argument for '
                         'option --configurations'
                     )
 
@@ -709,7 +709,7 @@ def _build_bootstrap_actions(self, cluster, parsed_boostrap_actions):
             > constants.MAX_BOOTSTRAP_ACTION_NUMBER
         ):
             raise ParamValidationError(
-                'aws: error: maximum number of '
+                'maximum number of '
                 'bootstrap actions for a cluster exceeded.'
             )
 

awscli/customizations/emr/emrutils.py

@@ -60,7 +60,7 @@ def apply_boolean_options(
 ):
     if true_option and false_option:
         error_message = (
-            'aws: error: cannot use both '
+            'cannot use both '
             + true_option_name
             + ' and '
             + false_option_name