[NOT READY] [v2] Lazily initialize built-in plugins to reduce command execution time

.changes/next-release/enhancement-Performance-9167.json

@@ -0,0 +1,5 @@
+{
+  "type": "enhancement",
+  "category": "Performance",
+  "description": "Defer loading of built-in plugins until they are actually needed to reduce initialization overhead."
+}

awscli/argprocess.py

@@ -270,6 +270,13 @@ def _is_complex_shape(model):
     return True
 
 
+def register_param_shorthand_parser(event_emitter):
+    event_emitter.register(
+        'process-cli-arg',
+        ParamShorthandParser(),
+    )
+
+
 class ParamShorthand:
     def _uses_old_list_case(self, command_name, operation_name, argument_name):
         """

awscli/botocore/hooks.py

@@ -196,7 +196,7 @@ def __init__(self):
         # read only access (we never modify self._handlers).
         # A cache of event name to handler list.
         self._lookup_cache = {}
-        self._handlers = _PrefixTrie()
+        self._handlers = PrefixTrie()
         # This is used to ensure that unique_id's are only
         # registered once.
         self._unique_id_handlers = {}
@@ -398,7 +398,7 @@ def __copy__(self):
         return new_instance
 
 
-class _PrefixTrie:
+class PrefixTrie:
     """Specialized prefix trie that handles wildcards.
 
     The prefixes in this case are based on dot separated

awscli/clidriver.py

@@ -64,11 +64,13 @@
     construct_entry_point_handlers_chain,
 )
 from awscli.formatter import get_formatter
+from awscli.handlers_registry import MAIN_COMMAND_TABLE_OPS
 from awscli.help import (
     OperationHelpCommand,
     ProviderHelpCommand,
     ServiceHelpCommand,
 )
+from awscli.lazy_emitter import LazyInitEmitter
 from awscli.logger import (
     disable_crt_logging,
     enable_crt_logging,
@@ -117,7 +119,10 @@ def create_clidriver(args=None):
         parser = FirstPassGlobalArgParser()
         args, _ = parser.parse_known_args(args)
         debug = args.debug
-    session = botocore.session.Session()
+    lazy_emitter = LazyInitEmitter(
+        main_command_table_ops=MAIN_COMMAND_TABLE_OPS
+    )
+    session = botocore.session.Session(event_hooks=lazy_emitter)
     _set_user_agent_for_session(session)
     load_plugins(
         session.full_config.get('plugins', {}),
@@ -214,6 +219,13 @@ def _set_user_agent_for_session(session):
     add_session_id_component_to_user_agent_extra(session)
 
 
+def register_no_pager_handler(event_emitter):
+    event_emitter.register(
+        'session-initialized',
+        no_pager_handler,
+    )
+
+
 def no_pager_handler(session, parsed_args, **kwargs):
     if parsed_args.no_cli_pager:
         config_store = session.get_component('config_store')

awscli/customizations/addexamples.py

@@ -33,6 +33,19 @@
 LOG = logging.getLogger(__name__)
 
 
+def register_docs_add_examples(event_emitter):
+    # The following will get fired for every option we are
+    # documenting.  It will attempt to add an example_fn on to
+    # the parameter object if the parameter supports shorthand
+    # syntax.  The documentation event handlers will then use
+    # the examplefn to generate the sample shorthand syntax
+    # in the docs.  Registering here should ensure that this
+    # handler gets called first, but it still feels a bit brittle.
+    # event_handlers.register('doc-option-example.*.*.*',
+    #                        param_shorthand.add_example_fn)
+    event_emitter.register('doc-examples.*.*', add_examples)
+
+
 def add_examples(help_command, **kwargs):
     doc_path = os.path.join(
         os.path.dirname(os.path.dirname(os.path.abspath(__file__))), 'examples'

awscli/customizations/binaryformat.py

@@ -18,6 +18,13 @@
 from awscli.shorthand import ModelVisitor
 
 
+def register_init_binary_formatter(event_emitter):
+    event_emitter.register(
+        'session-initialized',
+        add_binary_formatter,
+    )
+
+
 def add_binary_formatter(session, parsed_args, **kwargs):
     binary_format = parsed_args.cli_binary_format
     if binary_format is None:

awscli/customizations/codedeploy/codedeploy.py

@@ -22,11 +22,11 @@
 from awscli.customizations.codedeploy.uninstall import Uninstall
 
 
-def initialize(cli):
-    """
-    The entry point for CodeDeploy high level commands.
-    """
+def register_rename_codedeploy(cli):
     cli.register('building-command-table.main', change_name)
+
+
+def register_codedeploy(cli):
     cli.register('building-command-table.deploy', inject_commands)
     cli.register(
         'building-argument-table.deploy.get-application-revision',

awscli/customizations/ec2/decryptpassword.py

@@ -27,6 +27,13 @@
 password data sent from EC2 will be decrypted before display.</p>"""
 
 
+def register_ec2_add_priv_launch_key(event_emitter, **kwargs):
+    event_emitter.register(
+        'building-argument-table.ec2.get-password-data',
+        ec2_add_priv_launch_key,
+    )
+
+
 def ec2_add_priv_launch_key(
     argument_table, operation_model, session, **kwargs
 ):

awscli/customizations/iot.py

@@ -26,6 +26,20 @@
 from awscli.customizations.arguments import QueryOutFileArgument
 
 
+def register_iot_create_keys_from_csr(event_emitter):
+    event_emitter.register(
+        'building-argument-table.iot.create-certificate-from-csr',
+        register_create_keys_from_csr_arguments,
+    )
+
+
+def register_iot_create_keys_and_cert_args(event_emitter):
+    event_emitter.register(
+        'building-argument-table.iot.create-keys-and-certificate',
+        register_create_keys_and_cert_arguments,
+    )
+
+
 def register_create_keys_and_cert_arguments(session, argument_table, **kwargs):
     """Add outfile save arguments to create-keys-and-certificate
 

awscli/customizations/s3/s3.py

@@ -28,23 +28,14 @@
 )
 
 
-def awscli_initialize(cli):
-    """
-    This function is require to use the plugin.  It calls the functions
-    required to add all necessary commands and parameters to the CLI.
-    This function is necessary to install the plugin using a configuration
-    file
-    """
-    cli.register("building-command-table.main", add_s3)
-    cli.register('building-command-table.s3_sync', register_sync_strategies)
+def register_s3_main(event_handlers):
+    event_handlers.register('building-command-table.main', add_s3)
 
 
-def s3_plugin_initialize(event_handlers):
-    """
-    This is a wrapper to make the plugin built-in to the cli as opposed
-    to specifying it in the configuration file.
-    """
-    awscli_initialize(event_handlers)
+def register_s3_sync_strategies(event_handlers):
+    event_handlers.register(
+        'building-command-table.s3_sync', register_sync_strategies
+    )
 
 
 def add_s3(command_table, session, **kwargs):

awscli/customizations/streamingoutputarg.py

@@ -15,6 +15,13 @@
 from awscli.arguments import BaseCLIArgument
 
 
+def register_streaming_output_arg(event_emitter):
+    event_emitter.register(
+        'building-argument-table.*',
+        add_streaming_output_arg,
+    )
+
+
 def add_streaming_output_arg(
     argument_table, operation_model, session, **kwargs
 ):