server: send emails as a background tasks

server/polar/customer_portal/service/customer_session.py

@@ -10,7 +10,7 @@
 from polar.customer.service import customer as customer_service
 from polar.customer_session.service import customer_session as customer_session_service
 from polar.email.renderer import get_email_renderer
-from polar.email.sender import get_email_sender
+from polar.email.sender import enqueue_email
 from polar.exceptions import PolarError
 from polar.kit.crypto import get_token_hash
 from polar.kit.utils import utc_now
@@ -74,7 +74,6 @@ async def send(
         email_renderer = get_email_renderer(
             {"customer_portal": "polar.customer_portal"}
         )
-        email_sender = get_email_sender()
 
         customer = customer_session_code.customer
         organization = await organization_service.get(
@@ -99,9 +98,7 @@ async def send(
             },
         )
 
-        await email_sender.send_to_user(
-            to_email_addr=customer.email, subject=subject, html_content=body
-        )
+        enqueue_email(to_email_addr=customer.email, subject=subject, html_content=body)
 
     async def authenticate(
         self, session: AsyncSession, code: str

server/polar/email/sender.py

@@ -6,7 +6,9 @@
 
 from polar.config import EmailSender as EmailSenderType
 from polar.config import settings
+from polar.exceptions import PolarError
 from polar.logging import Logger
+from polar.worker import enqueue_job
 
 log: Logger = structlog.get_logger()
 
@@ -16,9 +18,17 @@
 DEFAULT_REPLY_TO_EMAIL_ADDRESS = "support@polar.sh"
 
 
+class EmailSenderError(PolarError): ...
+
+
+class SendEmailError(EmailSenderError):
+    def __init__(self, message: str) -> None:
+        super().__init__(message)
+
+
 class EmailSender(ABC):
     @abstractmethod
-    async def send_to_user(
+    async def send(
         self,
         *,
         to_email_addr: str,
@@ -34,7 +44,7 @@ async def send_to_user(
 
 
 class LoggingEmailSender(EmailSender):
-    async def send_to_user(
+    async def send(
         self,
         *,
         to_email_addr: str,
@@ -62,7 +72,7 @@ def __init__(self) -> None:
         super().__init__()
         self._api_key = settings.RESEND_API_KEY
 
-    async def send_to_user(
+    async def send(
         self,
         *,
         to_email_addr: str,
@@ -85,15 +95,24 @@ async def send_to_user(
             payload["reply_to"] = f"{reply_to_name} <{reply_to_email_addr}>"
 
         async with httpx.AsyncClient() as client:
-            response = await client.post(
-                "https://api.resend.com/emails",
-                headers={
-                    "Authorization": f"Bearer {self._api_key}",
-                },
-                json=payload,
-            )
-            response.raise_for_status()
-            email = response.json()
+            try:
+                response = await client.post(
+                    "https://api.resend.com/emails",
+                    headers={
+                        "Authorization": f"Bearer {self._api_key}",
+                    },
+                    json=payload,
+                )
+                response.raise_for_status()
+                email = response.json()
+            except httpx.HTTPError as e:
+                log.warning(
+                    "resend.send_error",
+                    to_email_addr=to_email_addr,
+                    subject=subject,
+                    error=e,
+                )
+                raise SendEmailError(str(e)) from e
 
         log.info(
             "resend.send",
@@ -109,3 +128,26 @@ def get_email_sender() -> EmailSender:
 
     # Logging in development
     return LoggingEmailSender()
+
+
+def enqueue_email(
+    to_email_addr: str,
+    subject: str,
+    html_content: str,
+    from_name: str = DEFAULT_FROM_NAME,
+    from_email_addr: str = DEFAULT_FROM_EMAIL_ADDRESS,
+    email_headers: dict[str, str] = {},
+    reply_to_name: str | None = DEFAULT_REPLY_TO_NAME,
+    reply_to_email_addr: str | None = DEFAULT_REPLY_TO_EMAIL_ADDRESS,
+) -> None:
+    enqueue_job(
+        "email.send",
+        to_email_addr=to_email_addr,
+        subject=subject,
+        html_content=html_content,
+        from_name=from_name,
+        from_email_addr=from_email_addr,
+        email_headers=email_headers,
+        reply_to_name=reply_to_name,
+        reply_to_email_addr=reply_to_email_addr,
+    )

server/polar/email/tasks.py

@@ -0,0 +1,35 @@
+from arq import Retry
+
+from polar.worker import JobContext, PolarWorkerContext, compute_backoff, task
+
+from .sender import SendEmailError, get_email_sender
+
+
+@task("email.send", max_tries=10)
+async def email_send(
+    ctx: JobContext,
+    to_email_addr: str,
+    subject: str,
+    html_content: str,
+    from_name: str,
+    from_email_addr: str,
+    email_headers: dict[str, str],
+    reply_to_name: str | None,
+    reply_to_email_addr: str | None,
+    polar_context: PolarWorkerContext,
+) -> None:
+    email_sender = get_email_sender()
+
+    try:
+        await email_sender.send(
+            to_email_addr=to_email_addr,
+            subject=subject,
+            html_content=html_content,
+            from_name=from_name,
+            from_email_addr=from_email_addr,
+            email_headers=email_headers,
+            reply_to_name=reply_to_name,
+            reply_to_email_addr=reply_to_email_addr,
+        )
+    except SendEmailError as e:
+        raise Retry(compute_backoff(ctx["job_try"])) from e

server/polar/email_update/service.py

@@ -8,7 +8,7 @@
 from polar.auth.models import AuthSubject
 from polar.config import settings
 from polar.email.renderer import get_email_renderer
-from polar.email.sender import get_email_sender
+from polar.email.sender import enqueue_email
 from polar.exceptions import PolarError, PolarRequestValidationError
 from polar.kit.crypto import generate_token_hash_pair, get_token_hash
 from polar.kit.extensions.sqlalchemy import sql
@@ -75,7 +75,6 @@ async def send_email(
         extra_url_params: dict[str, str] = {},
     ) -> None:
         email_renderer = get_email_renderer({"email_update": "polar.email_update"})
-        email_sender = get_email_sender()
 
         delta = email_update_record.expires_at - utc_now()
         token_lifetime_minutes = int(ceil(delta.seconds / 60))
@@ -91,7 +90,7 @@ async def send_email(
             },
         )
 
-        await email_sender.send_to_user(
+        enqueue_email(
             to_email_addr=email_update_record.email, subject=subject, html_content=body
         )
 

server/polar/magic_link/service.py

@@ -7,7 +7,7 @@
 
 from polar.config import settings
 from polar.email.renderer import get_email_renderer
-from polar.email.sender import get_email_sender
+from polar.email.sender import enqueue_email
 from polar.exceptions import PolarError
 from polar.kit.crypto import generate_token_hash_pair, get_token_hash
 from polar.kit.extensions.sqlalchemy import sql
@@ -69,7 +69,6 @@ async def send(
         extra_url_params: dict[str, str] = {},
     ) -> None:
         email_renderer = get_email_renderer({"magic_link": "polar.magic_link"})
-        email_sender = get_email_sender()
 
         delta = magic_link.expires_at - utc_now()
         token_lifetime_minutes = int(ceil(delta.seconds / 60))
@@ -85,7 +84,7 @@ async def send(
             },
         )
 
-        await email_sender.send_to_user(
+        enqueue_email(
             to_email_addr=magic_link.user_email, subject=subject, html_content=body
         )
 

server/polar/notifications/tasks/email.py

@@ -2,15 +2,13 @@
 
 import structlog
 
-from polar.email.sender import get_email_sender
+from polar.email.sender import enqueue_email
 from polar.notifications.service import notifications
 from polar.user.service.user import user as user_service
 from polar.worker import AsyncSessionMaker, JobContext, PolarWorkerContext, task
 
 log = structlog.get_logger()
 
-sender = get_email_sender()
-
 
 @task("notifications.send")
 async def notifications_send(
@@ -48,7 +46,7 @@ async def notifications_send(
                 )
                 return
 
-            await sender.send_to_user(
+            enqueue_email(
                 to_email_addr=user.email,
                 subject=f"[Polar] {subject}",
                 html_content=body,

server/polar/oauth2/service/oauth2_client.py

@@ -7,7 +7,7 @@
 
 from polar.auth.models import AuthSubject
 from polar.email.renderer import get_email_renderer
-from polar.email.sender import get_email_sender
+from polar.email.sender import enqueue_email
 from polar.enums import TokenType
 from polar.exceptions import PolarError
 from polar.kit.crypto import generate_token
@@ -93,7 +93,6 @@ async def revoke_leaked(
         session.add(client)
 
         email_renderer = get_email_renderer({"oauth2": "polar.oauth2"})
-        email_sender = get_email_sender()
 
         subject, body = email_renderer.render_from_template(
             subject,
@@ -107,7 +106,7 @@ async def revoke_leaked(
             },
         )
 
-        await email_sender.send_to_user(
+        enqueue_email(
             to_email_addr=client.user.email, subject=subject, html_content=body
         )
 

server/polar/oauth2/service/oauth2_token.py

@@ -8,7 +8,7 @@
 
 from polar.config import settings
 from polar.email.renderer import get_email_renderer
-from polar.email.sender import get_email_sender
+from polar.email.sender import enqueue_email
 from polar.enums import TokenType
 from polar.exceptions import PolarError
 from polar.kit.crypto import get_token_hash
@@ -85,7 +85,6 @@ async def revoke_leaked(
 
         # Notify
         email_renderer = get_email_renderer({"oauth2": "polar.oauth2"})
-        email_sender = get_email_sender()
 
         recipients: list[str]
         sub = oauth2_token.sub
@@ -113,7 +112,7 @@ async def revoke_leaked(
             )
 
             for recipient in recipients:
-                await email_sender.send_to_user(
+                enqueue_email(
                     to_email_addr=recipient, subject=subject, html_content=body
                 )
 

server/polar/order/service.py

@@ -17,7 +17,7 @@
 from polar.customer_session.service import customer_session as customer_session_service
 from polar.discount.service import discount as discount_service
 from polar.email.renderer import get_email_renderer
-from polar.email.sender import get_email_sender
+from polar.email.sender import enqueue_email
 from polar.exceptions import PolarError
 from polar.held_balance.service import held_balance as held_balance_service
 from polar.integrations.stripe.schemas import ProductType
@@ -501,7 +501,6 @@ async def send_confirmation_email(
         self, session: AsyncSession, organization: Organization, order: Order
     ) -> None:
         email_renderer = get_email_renderer({"order": "polar.order"})
-        email_sender = get_email_sender()
 
         product = order.product
         customer = order.customer
@@ -522,9 +521,7 @@ async def send_confirmation_email(
             },
         )
 
-        await email_sender.send_to_user(
-            to_email_addr=customer.email, subject=subject, html_content=body
-        )
+        enqueue_email(to_email_addr=customer.email, subject=subject, html_content=body)
 
     async def update_product_benefits_grants(
         self, session: AsyncSession, product: Product

server/polar/personal_access_token/service.py

@@ -9,7 +9,7 @@
 from polar.auth.models import AuthSubject
 from polar.config import settings
 from polar.email.renderer import get_email_renderer
-from polar.email.sender import get_email_sender
+from polar.email.sender import enqueue_email
 from polar.enums import TokenType
 from polar.integrations.loops.service import loops as loops_service
 from polar.kit.crypto import generate_token_hash_pair, get_token_hash
@@ -133,7 +133,6 @@ async def revoke_leaked(
         email_renderer = get_email_renderer(
             {"personal_access_token": "polar.personal_access_token"}
         )
-        email_sender = get_email_sender()
 
         subject, body = email_renderer.render_from_template(
             "Security Notice - Your Polar Personal Access Token has been leaked",
@@ -146,7 +145,7 @@ async def revoke_leaked(
             },
         )
 
-        await email_sender.send_to_user(
+        enqueue_email(
             to_email_addr=personal_access_token.user.email,
             subject=subject,
             html_content=body,

server/polar/subscription/service.py

@@ -21,7 +21,7 @@
 from polar.customer_session.service import customer_session as customer_session_service
 from polar.discount.service import discount as discount_service
 from polar.email.renderer import get_email_renderer
-from polar.email.sender import get_email_sender
+from polar.email.sender import enqueue_email, get_email_sender
 from polar.enums import SubscriptionRecurringInterval
 from polar.exceptions import PolarError
 from polar.integrations.stripe.service import stripe as stripe_service
@@ -715,7 +715,7 @@ async def send_confirmation_email(
             },
         )
 
-        await email_sender.send_to_user(
+        enqueue_email(
             to_email_addr=subscription.customer.email,
             subject=subject,
             html_content=body,
@@ -748,7 +748,7 @@ async def send_cancellation_email(
             },
         )
 
-        await email_sender.send_to_user(
+        enqueue_email(
             to_email_addr=subscription.customer.email,
             subject=subject,
             html_content=body,

server/polar/tasks.py

@@ -3,6 +3,7 @@
 from polar.benefit import tasks as benefit
 from polar.checkout import tasks as checkout
 from polar.customer_session import tasks as customer_session
+from polar.email import tasks as email
 from polar.email_update import tasks as email_update
 from polar.eventstream import tasks as eventstream
 from polar.integrations.github import tasks as github
@@ -24,6 +25,7 @@
     "benefit",
     "checkout",
     "customer_session",
+    "email",
     "email_update",
     "eventstream",
     "github",