Custom routes + Further notification cleanup (#309)

* Further notification cleanup

* Catch any errors getting the user for metrics + add doc for INIT_CUSTOM_ROUTES

* Revert change to _build_metrics

amundsen_application/__init__.py

@@ -56,4 +56,8 @@ def create_app(config_module_class: str, template_folder: str = None) -> Flask:
     app.register_blueprint(search_blueprint)
     init_routes(app)
 
+    init_custom_routes = app.config.get('INIT_CUSTOM_ROUTES')
+    if init_custom_routes:
+        init_custom_routes(app)
+
     return app

amundsen_application/api/utils/notification_utils.py

 import logging
 
 from http import HTTPStatus
+from enum import Enum
 
 from flask import current_app as app
 from flask import jsonify, make_response, Response
@@ -9,8 +10,27 @@ from typing import Dict, List
 from amundsen_application.api.exceptions import MailClientNotImplemented
 from amundsen_application.log.action_log import action_logging
 
+
+class NotificationType(str, Enum):
+    """
+    Enum to describe supported notification types. Must match NotificationType interface defined in:
+    https://github.com/lyft/amundsenfrontendlibrary/blob/master/amundsen_application/static/js/interfaces/Notifications.ts
+    """
+    OWNER_ADDED = 'owner_added'
+    OWNER_REMOVED = 'owner_removed'
+    METADATA_EDITED = 'metadata_edited'
+    METADATA_REQUESTED = 'metadata_requested'
+
+    @classmethod
+    def has_value(cls, value: str) -> bool:
+        for key in cls:
+            if key.value == value:
+                return True
+        return False
+
+
 NOTIFICATION_STRINGS = {
-    'added': {
+    NotificationType.OWNER_ADDED.value: {
         'comment': ('<br/>What is expected of you?<br/>As an owner, you take an important part in making '
                     'sure that the datasets you own can be used as swiftly as possible across the company.<br/>'
                     'Make sure the metadata is correct and up to date.<br/>'),
@@ -20,14 +40,14 @@ NOTIFICATION_STRINGS = {
         'notification': ('<br/>You have been added to the owners list of the <a href="{resource_url}">'
                          '{resource_name}</a> dataset by {sender}.<br/>'),
     },
-    'removed': {
+    NotificationType.OWNER_REMOVED.value: {
         'comment': '',
         'end_note': ('<br/>If you think you have been incorrectly removed as an owner, '
                      'add yourself back to the owners list.<br/>'),
         'notification': ('<br/>You have been removed from the owners list of the <a href="{resource_url}">'
                          '{resource_name}</a> dataset by {sender}.<br/>'),
     },
-    'requested': {
+    NotificationType.METADATA_REQUESTED.value: {
         'comment': '',
         'end_note': '<br/>Please visit the provided link and improve descriptions on that resource.<br/>',
         'notification': '<br/>{sender} is trying to use <a href="{resource_url}">{resource_name}</a>, ',
@@ -84,7 +104,7 @@ def get_notification_html(*, notification_type: str, options: Dict, sender: str)
     end_note = notification_strings.get('end_note', '')
     salutation = '<br/>Thanks,<br/>Amundsen Team'
 
-    if notification_type == 'requested':
+    if notification_type == NotificationType.METADATA_REQUESTED:
         options_comment = options.get('comment')
         need_resource_description = options.get('description_requested')
         need_fields_descriptions = options.get('fields_requested')
@@ -118,12 +138,15 @@ def get_notification_subject(*, notification_type: str, options: Dict) -> str:
     """
     resource_name = options.get('resource_name')
     notification_subject_dict = {
-        'added': 'You are now an owner of {}'.format(resource_name),
-        'removed': 'You have been removed as an owner of {}'.format(resource_name),
-        'edited': 'Your dataset {}\'s metadata has been edited'.format(resource_name),
-        'requested': 'Request for metadata on {}'.format(resource_name),
+        NotificationType.OWNER_ADDED.value: 'You are now an owner of {}'.format(resource_name),
+        NotificationType.OWNER_REMOVED.value: 'You have been removed as an owner of {}'.format(resource_name),
+        NotificationType.METADATA_EDITED.value: 'Your dataset {}\'s metadata has been edited'.format(resource_name),
+        NotificationType.METADATA_REQUESTED.value: 'Request for metadata on {}'.format(resource_name),
     }
-    return notification_subject_dict.get(notification_type, '')
+    subject = notification_subject_dict.get(notification_type)
+    if subject is None:
+        raise Exception('Unsupported notification_type')
+    return subject
 
 
 def send_notification(*, notification_type: str, options: Dict, recipients: List, sender: str) -> Response:
@@ -174,7 +197,7 @@ def send_notification(*, notification_type: str, options: Dict, recipients: List
             subject=subject,
             html=html,
             optional_data={
-                'email_type': 'notification'
+                'email_type': notification_type,
             },
         )
         status_code = response.status_code

amundsen_application/config.py

 import os
-from typing import Dict, Optional, Set  # noqa: F401
+from typing import Callable, Dict, Optional, Set  # noqa: F401
+
+from flask import Flask  # noqa: F401
+
 from amundsen_application.tests.test_utils import get_test_user
 
 
@@ -22,6 +25,9 @@ class Config:
     MAIL_CLIENT = None
     NOTIFICATIONS_ENABLED = False
 
+    # Initialize custom routes
+    INIT_CUSTOM_ROUTES = None  # type: Callable[[Flask], None]
+
 
 class LocalConfig(Config):
     DEBUG = False

amundsen_application/static/js/interfaces/Notifications.ts

-// TODO: Remove notification types that can be triggered in flask layer if necessary
 export enum NotificationType {
-  OWNER_ADDED = 'added',
-  OWNER_REMOVED = 'removed',
-  METADATA_EDITED = 'edited',
-  METADATA_REQUESTED = 'requested',
+  OWNER_ADDED = 'owner_added',
+  OWNER_REMOVED = 'owner_removed',
+  METADATA_EDITED = 'metadata_edited',
+  METADATA_REQUESTED = 'metadata_requested',
 }
 
 export enum RequestMetadataType {

docs/flask_config.md

@@ -4,6 +4,18 @@ After modifying any variable in [config.py](https://github.com/lyft/amundsenfron
 
 **NOTE: This document is a work in progress and does not include 100% of features. We welcome PRs to complete this document**
 
+## Custom Routes
+In order to add any custom Flask endpoints to Amundsen's frontend application, configure a function on the `INIT_CUSTOM_ROUTES` variable. This function takes the created Flask application and can leverage Flask's [add_url_rule](https://flask.palletsprojects.com/en/1.1.x/api/#flask.Flask.add_url_rule) method to add custom routes.
+
+Example: Setting `INIT_CUSTOM_ROUTES` to the `init_custom_routes` method below will expose a `/custom_route` endpoint on the frontend application.
+```bash
+def init_custom_routes(app: Flask) -> None:
+  app.add_url_rule('/custom_route', 'custom_route', custom_route)
+
+def custom_route():
+  pass
+```
+
 ## Mail Client Features
 Amundsen has two features that leverage the custom mail client -- the feedback tool and notifications. For these features a custom implementation of [base_mail_client](https://github.com/lyft/amundsenfrontendlibrary/blob/master/amundsen_application/base/base_mail_client.py) must be mapped to the `MAIL_CLIENT` configuration variable.