feat(cli): add autocomplete module

lean/commands/__init__.py

@@ -11,7 +11,15 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from os import environ
+from copy import copy
+
+if environ.get("_LEAN_COMPLETE", "").startswith("powershell_"):
+    from lean.components.util.click_shell_autocomplete import register_shell_autocomplete
+    register_shell_autocomplete()
+
 from lean.commands.lean import lean
+from lean.commands.autocomplete import autocomplete
 from lean.commands.backtest import backtest
 from lean.commands.build import build
 from lean.commands.cloud import cloud
@@ -36,6 +44,11 @@
 from lean.commands.private_cloud import private_cloud
 
 lean.add_command(config)
+lean.add_command(autocomplete)
+completion = copy(autocomplete)
+completion.name = "completion"
+completion.hidden = True
+lean.add_command(completion)
 lean.add_command(cloud)
 lean.add_command(data)
 lean.add_command(decrypt)

lean/commands/autocomplete.py

@@ -0,0 +1,100 @@
+# QUANTCONNECT.COM - Democratizing Finance, Empowering Individuals.
+# Lean CLI v1.0. Copyright 2021 QuantConnect Corporation.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from typing import Optional
+
+from click import Choice, ClickException, Context, echo, group, option, pass_context
+
+from lean.components.util.click_aliased_command_group import AliasedCommandGroup
+
+
+SHELL_OPTION = option("--shell",
+                      "-s",
+                      type=Choice(["powershell", "bash", "zsh", "fish"], case_sensitive=False),
+                      default=None,
+                      help="Target shell. Auto-detected if not specified.")
+
+
+def _profile_permission_error(exception: PermissionError) -> ClickException:
+    path = exception.filename or "the shell profile"
+    return ClickException(
+        f"Unable to update {path}. "
+        "The current PowerShell session is still disabled if Lean autocomplete was loaded there. "
+        "To remove it permanently, close any editor or terminal using that profile, or remove the Lean autocomplete block manually."
+    )
+
+
+@group(cls=AliasedCommandGroup, invoke_without_command=True)
+@SHELL_OPTION
+@pass_context
+def autocomplete(ctx: Context, shell: Optional[str]) -> None:
+    """Print the native shell autocomplete script for your shell.
+
+    \b
+    PowerShell (current session):
+        lean autocomplete --shell powershell | Out-String | Invoke-Expression
+
+    \b
+    Bash or Zsh (current session):
+        eval "$(lean autocomplete --shell bash)"
+
+    \b
+    Fish (current session):
+        lean autocomplete --shell fish | source
+    """
+    if ctx.invoked_subcommand is None:
+        from lean.components.util.click_shell_autocomplete import get_autocomplete_script
+        echo(get_autocomplete_script(shell))
+
+
+@autocomplete.command(name="show", help="Print the native shell autocomplete script for your shell")
+@SHELL_OPTION
+def show(shell: Optional[str]) -> None:
+    from lean.components.util.click_shell_autocomplete import get_autocomplete_script
+    echo(get_autocomplete_script(shell))
+
+
+@autocomplete.command(name="on", help="Enable shell autocomplete in your shell profile")
+@SHELL_OPTION
+def on(shell: Optional[str]) -> None:
+    from lean.components.util.click_shell_autocomplete import install_autocomplete
+    try:
+        profile_path = install_autocomplete(shell)
+    except PermissionError as exception:
+        raise _profile_permission_error(exception)
+
+    echo(f"Enabled shell autocomplete in {profile_path}")
+    echo("Open a new terminal session for the change to take effect.")
+
+
+@autocomplete.command(name="off", help="Disable shell autocomplete in your shell profile")
+@option("--current-session", is_flag=True, help="Print a script that disables autocomplete in the current shell session.")
+@SHELL_OPTION
+def off(shell: Optional[str], current_session: bool) -> None:
+    from lean.components.util.click_shell_autocomplete import get_autocomplete_cleanup_script, uninstall_autocomplete
+
+    if current_session:
+        echo(get_autocomplete_cleanup_script(shell))
+        return
+
+    try:
+        profile_path, removed = uninstall_autocomplete(shell)
+    except PermissionError as exception:
+        raise _profile_permission_error(exception)
+
+    if removed:
+        echo(f"Disabled shell autocomplete in {profile_path}")
+        echo("Open a new terminal session for the change to take effect.")
+        echo("To disable it in this PowerShell session, run `lean autocomplete off` again after reloading the updated script.")
+    else:
+        echo(f"Shell autocomplete was not enabled in {profile_path}")

lean/commands/cloud/__init__.py

@@ -12,6 +12,7 @@
 # limitations under the License.
 
 from click import group
+from lean.components.util.click_aliased_command_group import AliasedCommandGroup
 
 from lean.commands.cloud.backtest import backtest
 from lean.commands.cloud.live.live import live
@@ -21,7 +22,7 @@
 from lean.commands.cloud.status import status
 from lean.commands.cloud.object_store import object_store
 
-@group()
+@group(cls=AliasedCommandGroup)
 def cloud() -> None:
     """Interact with the QuantConnect cloud."""
     # This method is intentionally empty

lean/commands/config/__init__.py

@@ -12,14 +12,15 @@
 # limitations under the License.
 
 from click import group
+from lean.components.util.click_aliased_command_group import AliasedCommandGroup
 
 from lean.commands.config.get import get
 from lean.commands.config.list import list
 from lean.commands.config.set import set
 from lean.commands.config.unset import unset
 
 
-@group()
+@group(cls=AliasedCommandGroup)
 def config() -> None:
     """Configure Lean CLI options."""
     # This method is intentionally empty

lean/commands/data/__init__.py

@@ -12,12 +12,13 @@
 # limitations under the License.
 
 from click import group
+from lean.components.util.click_aliased_command_group import AliasedCommandGroup
 
 from lean.commands.data.download import download
 from lean.commands.data.generate import generate
 
 
-@group()
+@group(cls=AliasedCommandGroup)
 def data() -> None:
     """Download or generate data for local use."""
     # This method is intentionally empty

lean/commands/init.py

@@ -207,6 +207,7 @@ def init(organization: Optional[str], language: Optional[str]) -> None:
 - Synchronizing projects with the cloud: https://www.lean.io/docs/v2/lean-cli/projects/cloud-synchronization
 
 Here are some commands to get you going:
+- Run `lean autocomplete --shell powershell | Out-String | Invoke-Expression` to enable PowerShell autocomplete in the current session
 - Run `lean create-project "My Project"` to create a new project with starter code
 - Run `lean cloud pull` to download all your QuantConnect projects to your local drive
 - Run `lean backtest "My Project"` to backtest a project locally with the data in {DEFAULT_DATA_DIRECTORY_NAME}/

lean/commands/library/__init__.py

@@ -12,12 +12,13 @@
 # limitations under the License.
 
 from click import group
+from lean.components.util.click_aliased_command_group import AliasedCommandGroup
 
 from lean.commands.library.add import add
 from lean.commands.library.remove import remove
 
 
-@group()
+@group(cls=AliasedCommandGroup)
 def library() -> None:
     """Manage custom libraries in a project."""
     # This method is intentionally empty

lean/commands/private_cloud/__init__.py

@@ -12,13 +12,14 @@
 # limitations under the License.
 
 from click import group
+from lean.components.util.click_aliased_command_group import AliasedCommandGroup
 
 from lean.commands.private_cloud.start import start
 from lean.commands.private_cloud.stop import stop
 from lean.commands.private_cloud.add_compute import add_compute
 
 
-@group()
+@group(cls=AliasedCommandGroup)
 def private_cloud() -> None:
     """Interact with a QuantConnect private cloud."""
     # This method is intentionally empty

lean/components/util/click_aliased_command_group.py

@@ -11,35 +11,86 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from click import Group
+from typing import Any, Callable, Optional, Union, overload
+
+from click import Command, Context, Group
+
+
+CommandCallback = Callable[..., Any]
+CommandDecorator = Callable[[CommandCallback], Command]
 
 
 class AliasedCommandGroup(Group):
-    """A click.Group wrapper that implements command aliasing."""
+    """A click.Group wrapper that implements command aliasing and autocomplete prefix matching."""
+
+    def get_command(self, ctx: Context, cmd_name: str) -> Optional[Command]:
+        rv = super().get_command(ctx, cmd_name)
+        if rv is not None:
+            return rv
+
+        matches = []
+        for name in self.list_commands(ctx):
+            command = super().get_command(ctx, name)
+            if command is not None and not command.hidden and name.startswith(cmd_name):
+                matches.append(name)
+
+        if not matches:
+            return None
+        elif len(matches) == 1:
+            return super().get_command(ctx, matches[0])
+
+        ctx.fail(f"Too many matches: {', '.join(sorted(matches))}")
 
-    def command(self, *args, **kwargs):
+    @overload
+    def command(self, __func: CommandCallback) -> Command:
+        ...
+
+    @overload
+    def command(self, *args: Any, **kwargs: Any) -> CommandDecorator:
+        ...
+
+    def command(self, *args: Any, **kwargs: Any) -> Union[CommandDecorator, Command]:
         aliases = kwargs.pop('aliases', [])
 
-        if not args:
-            cmd_name = kwargs.pop("name", "")
-        else:
-            cmd_name = args[0]
-            args = args[1:]
+        if not aliases:
+            return super().command(*args, **kwargs)
+
+        func = None
+        if args and callable(args[0]):
+            assert len(args) == 1, "Use 'command(**kwargs)(callable)' to provide arguments."
+            func = args[0]
+            args = ()
 
-        alias_help = f"Alias for '{cmd_name}'"
+        def _decorator(f: CommandCallback) -> Command:
+            cmd_kwargs = dict(kwargs)
+            cmd_name = cmd_kwargs.pop("name", None)
+
+            if args:
+                if cmd_name is None:
+                    cmd_name = args[0]
+                    cmd_args = args[1:]
+                else:
+                    cmd_args = args
+            else:
+                cmd_name = cmd_name or f.__name__.lower().replace("_", "-")
+                cmd_args = ()
+
+            alias_help = f"Alias for '{cmd_name}'"
 
-        def _decorator(f):
             # Add the main command
-            cmd = super(AliasedCommandGroup, self).command(name=cmd_name, *args, **kwargs)(f)
+            cmd = super(AliasedCommandGroup, self).command(*cmd_args, name=cmd_name, **cmd_kwargs)(f)
 
             # Add a command to the group for each alias with the same callback but using the alias as name
             for alias in aliases:
                 alias_cmd = super(AliasedCommandGroup, self).command(name=alias,
                                                                      short_help=alias_help,
-                                                                     *args,
-                                                                     **kwargs)(f)
+                                                                     *cmd_args,
+                                                                     **cmd_kwargs)(f)
                 alias_cmd.params = cmd.params
 
             return cmd
 
+        if func is not None:
+            return _decorator(func)
+
         return _decorator

lean/components/util/click_group_default_command.py

@@ -11,9 +11,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from click import Group
+from lean.components.util.click_aliased_command_group import AliasedCommandGroup
 
-class DefaultCommandGroup(Group):
+class DefaultCommandGroup(AliasedCommandGroup):
     """allow a default command for a group"""
 
     def command(self, *args, **kwargs):