Add Blueprint level cli command registration

Implements #1357.
Adds ability to register click cli commands onto blueprint.

flask/app.py

@@ -562,13 +562,14 @@ class Flask(_PackageBoundObject):
                 view_func=self.send_static_file
             )
 
-        #: The click command line context for this application.  Commands
+        #: Set the name of the cli context for this application.  Commands
         #: registered here show up in the :command:`flask` command once the
         #: application has been discovered.  The default commands are
         #: provided by Flask itself and can be overridden.
         #:
-        #: This is an instance of a :class:`click.Group` object.
-        self.cli = cli.AppGroup(self.name)
+        #: Set the name of the :class:``cli.AppGroup`` instance to allow
+        #: commands to be registered on the application.
+        self.cli.name = self.name
 
     @locked_cached_property
     def name(self):

flask/blueprints.py

@@ -118,7 +118,7 @@ class Blueprint(_PackageBoundObject):
     def __init__(self, name, import_name, static_folder=None,
                  static_url_path=None, template_folder=None,
                  url_prefix=None, subdomain=None, url_defaults=None,
-                 root_path=None):
+                 root_path=None, cli_group=-1):
         _PackageBoundObject.__init__(self, import_name, template_folder,
                                      root_path=root_path)
         self.name = name
@@ -130,6 +130,7 @@ class Blueprint(_PackageBoundObject):
         if url_defaults is None:
             url_defaults = {}
         self.url_values_defaults = url_defaults
+        self.cli_group = cli_group
 
     def record(self, func):
         """Registers a function that is called when the blueprint is
@@ -186,6 +187,16 @@ class Blueprint(_PackageBoundObject):
         for deferred in self.deferred_functions:
             deferred(state)
 
+        cli_resolved_group = options.get('cli_group', self.cli_group)
+        if cli_resolved_group is None:
+            app.cli.commands.update(self.cli.commands)
+        elif cli_resolved_group == -1:
+            self.cli.name = self.name
+            app.cli.add_command(self.cli)
+        else:
+            self.cli.name = cli_resolved_group
+            app.cli.add_command(self.cli)
+
     def route(self, rule, **options):
         """Like :meth:`Flask.route` but for a blueprint.  The endpoint for the
         :func:`url_for` function is prefixed with the name of the blueprint.

flask/helpers.py

@@ -15,6 +15,7 @@ import sys
 import pkgutil
 import posixpath
 import mimetypes
+from . import cli
 from time import time
 from zlib import adler32
 from threading import RLock
@@ -887,6 +888,14 @@ class _PackageBoundObject(object):
         self._static_folder = None
         self._static_url_path = None
 
+        #: The click command line context for registration of cli commands
+        #: on the application and associated blueprints, accessible via the
+        #: :command:`flask` command once the application has been discovered
+        #: and blueprints optionally registered.
+        #:
+        #: This is an instance of a :class:`click.Group` object.
+        self.cli = cli.AppGroup()
+
     def _get_static_folder(self):
         if self._static_folder is not None:
             return os.path.join(self.root_path, self._static_folder)

tests/test_cli.py

@@ -23,7 +23,7 @@ import pytest
 from _pytest.monkeypatch import notset
 from click.testing import CliRunner
 
-from flask import Flask, current_app
+from flask import Flask, current_app, Blueprint
 from flask.cli import (
     AppGroup, FlaskGroup, NoAppException, ScriptInfo, dotenv, find_best_app,
     get_version, load_dotenv, locate_app, prepare_import, run_command,
@@ -539,3 +539,47 @@ def test_run_cert_import(monkeypatch):
     with pytest.raises(click.BadParameter):
         run_command.make_context(
             'run', ['--cert', 'ssl_context', '--key', __file__])
+
+
+def test_cli_blueprints(app):
+    """Test blueprint commands register correctly to the application"""
+    custom = Blueprint('custom', __name__, cli_group='customized')
+    nested = Blueprint('nested', __name__)
+    merged = Blueprint('merged', __name__, cli_group=None)
+    late = Blueprint('late', __name__)
+
+    @custom.cli.command('custom')
+    def custom_command():
+        click.echo('custom_result')
+
+    @nested.cli.command('nested')
+    def nested_command():
+        click.echo('nested_result')
+
+    @merged.cli.command('merged')
+    def merged_command():
+        click.echo('merged_result')
+
+    @late.cli.command('late')
+    def late_command():
+        click.echo('late_result')
+
+    app.register_blueprint(custom)
+    app.register_blueprint(nested)
+    app.register_blueprint(merged)
+    app.register_blueprint(late, cli_group='late_registration')
+
+    app_runner = app.test_cli_runner()
+
+    result = app_runner.invoke(args=['customized', 'custom'])
+    assert 'custom_result' in result.output
+
+    result = app_runner.invoke(args=['nested', 'nested'])
+    assert 'nested_result' in result.output
+
+    result = app_runner.invoke(args=['merged'])
+    assert 'merged_result' in result.output
+
+    result = app_runner.invoke(args=['late_registration', 'late'])
+    assert 'late_result' in result.output
+