feat: member invitation and activation (#535)

Co-authored-by: John Wang <takatost@gmail.com>

api/tasks/mail_invite_member_task.py

@@ -0,0 +1,52 @@
+import logging
+import time
+
+import click
+from celery import shared_task
+from flask import current_app
+
+from extensions.ext_mail import mail
+
+
+@shared_task
+def send_invite_member_mail_task(to: str, token: str, inviter_name: str, workspace_id: str, workspace_name: str):
+    """
+    Async Send invite member mail
+    :param to
+    :param token
+    :param inviter_name
+    :param workspace_id
+    :param workspace_name
+
+    Usage: send_invite_member_mail_task.delay(to, token, inviter_name, workspace_id, workspace_name)
+    """
+    if not mail.is_inited():
+        return
+
+    logging.info(click.style('Start send invite member mail to {} in workspace {}'.format(to, workspace_name),
+                             fg='green'))
+    start_at = time.perf_counter()
+
+    try:
+        mail.send(
+            to=to,
+            subject="{} invited you to join {}".format(inviter_name, workspace_name),
+            html="""<p>Hi there,</p>
+<p>{inviter_name} invited you to join {workspace_name}.</p>
+<p>Click <a href="{url}">here</a> to join.</p>
+<p>Thanks,</p>
+<p>Dify Team</p>""".format(inviter_name=inviter_name, workspace_name=workspace_name,
+                           url='{}/activate?workspace_id={}&email={}&token={}'.format(
+                               current_app.config.get("CONSOLE_WEB_URL"),
+                               workspace_id,
+                               to,
+                               token)
+                           )
+        )
+
+        end_at = time.perf_counter()
+        logging.info(
+            click.style('Send invite member mail to {} succeeded: latency: {}'.format(to, end_at - start_at),
+                        fg='green'))
+    except Exception:
+        logging.exception("Send invite member mail to {} failed".format(to))