Add management command to send api move announcement email (#4229)

* Add management command to send api move announcement email

* Add final text for email, with placeholder for make post URL

* Apply suggestions from code review

Co-authored-by: Dhruv Bhanushali <hi@dhruvkb.dev>

* Add link to make post

* Confirm command does not send duplicates

---------

Co-authored-by: Dhruv Bhanushali <hi@dhruvkb.dev>

api/api/management/commands/sendapimoveannouncement.py

@@ -0,0 +1,118 @@
+import argparse
+
+from django.conf import settings
+from django.core.mail import send_mail
+
+import django_redis
+from django_tqdm import BaseCommand
+
+from api.models.oauth import OAuth2Verification
+
+
+message = """
+On 3 June 2024, the Openverse API’s domain will be changed to api.openverse.org and api.openverse.engineering will start
+redirecting to api.openverse.org. Existing API credentials and all other aspects of integrations with the
+Openverse API will continue to work without changes, provided requests follow redirects.
+
+For the best experience, and to avoid redirects, please update code referencing api.openverse.engineering to use api.openverse.org.
+
+To read more about this change, including opportunities to ask questions or give feedback, please read the Make Openverse blog post announcing it:
+
+https://make.wordpress.org/openverse/2024/05/06/the-openverse-api-is-moving-to-api-openverse-org/
+
+You are receiving this email because you’ve registered and verified with the Openverse API.
+
+Openverse only sends emails for critical operational notifications.
+"""
+
+
+class Command(BaseCommand):
+    help = "Resends verification emails for unverified Oauth applications."
+    """
+    This command sends a corrected oauth verification email to users who have
+    not yet verified their Openverse oauth applications. A previous version sent
+    an email with an incorrectly formatted link.
+
+    It stores a cache of successfully sent emails in Redis, so running it multiple
+    times (in case of failure) should not be an issue.
+    """
+
+    processed_key = "apimoveannouncement:processed"
+
+    def add_arguments(self, parser):
+        parser.add_argument(
+            "--dry_run",
+            help="Count the emails to send, and don't do anything else.",
+            type=bool,
+            default=True,
+            action=argparse.BooleanOptionalAction,
+        )
+
+    def handle(self, *args, **options):
+        dry = options["dry_run"]
+
+        redis = django_redis.get_redis_connection("default")
+
+        sent_emails = [
+            email.decode("utf-8") for email in redis.smembers(self.processed_key)
+        ]
+
+        # Join from verification because it has a reference to both the application and the email
+        unsent_email_addresses = (
+            OAuth2Verification.objects.filter(
+                # Only send to verified email addresses to avoid bounce rate increase
+                associated_application__verified=True
+            )
+            .exclude(
+                email__in=sent_emails,
+            )
+            .distinct("email")
+            .values_list("email", flat=True)
+        )
+
+        count_to_process = unsent_email_addresses.count()
+        errored_emails = []
+
+        if dry:
+            self.info(
+                f"{count_to_process} announcement emails to send. This is a dry run, exiting without making changes."
+            )
+            return
+
+        if not count_to_process:
+            self.info("No emails to send.")
+            return
+
+        with self.tqdm(total=count_to_process) as progress:
+            while chunk := unsent_email_addresses.exclude(
+                email__in=sent_emails + errored_emails
+            )[:100]:
+                for email in chunk:
+                    try:
+                        send_mail(
+                            subject="Openverse API is moving to api.openverse.org",
+                            message=message,
+                            from_email=settings.DEFAULT_FROM_EMAIL,
+                            recipient_list=[email],
+                            fail_silently=False,
+                        )
+                        sent_emails.append(email)
+                        redis.sadd(self.processed_key, email)
+                    except BaseException as err:
+                        errored_emails.append(email)
+                        self.error(f"Unable to process {email}: " f"{err}")
+
+                    progress.update(1)
+
+        if errored_emails:
+            joined = "\n".join(errored_emails)
+            self.info(
+                self.style.WARNING(
+                    f"The following emails were unable to be processed.\n\n"
+                    f"{joined}"
+                    "\n\nPlease check the output above for the error related"
+                    "to each email."
+                )
+            )
+
+        self.info(self.style.SUCCESS("Sent API move notifications."))

api/test/unit/management/commands/test_sendapimoveannouncement.py

@@ -0,0 +1,102 @@
+import smtplib
+from io import StringIO
+
+from django.core.management import call_command
+
+import pytest
+
+from test.factory.models.oauth2 import (
+    OAuth2VerificationFactory,
+)
+
+
+command_module_path = "api.management.commands.sendapimoveannouncement"
+
+
+@pytest.fixture
+def captured_emails(monkeypatch) -> list[str]:
+    captured = []
+
+    def send_mail(*args, **kwargs):
+        captured.extend(kwargs["recipient_list"])
+
+    monkeypatch.setattr(f"{command_module_path}.send_mail", send_mail)
+
+    yield captured
+
+
+@pytest.fixture
+def failed_emails(monkeypatch) -> list[str]:
+    failed = []
+
+    def send_mail(*args, **kwargs):
+        failed.extend(
+            kwargs["recipient_list"],
+        )
+        raise smtplib.SMTPAuthenticationError(1, "beep boop bad password")
+
+    monkeypatch.setattr(f"{command_module_path}.send_mail", send_mail)
+
+    yield failed
+
+
+def call_cmd(**options):
+    out = StringIO()
+    err = StringIO()
+    options.update(stdout=out, stderr=err)
+    call_command("sendapimoveannouncement", **options)
+
+    res = out.getvalue(), err.getvalue()
+    print(res)
+
+    return res
+
+
+def make_emails(count: int, *, verified: bool):
+    verifications = OAuth2VerificationFactory.create_batch(
+        count, associated_application__verified=verified
+    )
+    return [v.email for v in verifications]
+
+
+@pytest.mark.django_db
+def test_should_not_resend_for_already_sent(redis, captured_emails):
+    emails = make_emails(10, verified=True)
+    for email in emails:
+        redis.sadd("apimoveannouncement:processed", email)
+
+    call_cmd(dry_run=False)
+    assert captured_emails == []
+
+
+@pytest.mark.django_db
+def test_should_not_count_email_as_sent_if_failed(failed_emails, redis):
+    emails = make_emails(1, verified=True)
+    call_cmd(dry_run=False)
+    assert failed_emails == emails
+
+    for email in emails:
+        assert not (redis.sismember("apimoveannouncement:processed", email))
+
+
+@pytest.mark.django_db
+def test_should_not_send_to_unverified_emails(captured_emails):
+    make_emails(10, verified=False)
+
+    call_cmd(dry_run=False)
+    assert len(captured_emails) == 0
+
+
+@pytest.mark.django_db
+def test_should_not_send_to_email_twice(captured_emails):
+    emails = make_emails(10, verified=True)
+    OAuth2VerificationFactory.create(
+        email=emails[0],
+    )
+
+    call_cmd(dry_run=False)
+    # Not 11
+    assert len(captured_emails) == 10
+
+    # Only appears once
+    assert len([email for email in emails if email == emails[0]]) == 1