Adding Line Items is really slow

[JanBlmr]

Hi there,

we are using async-stripe for creating invoices (FastAPI service)

import backoff
from async_stripe import stripe
from stripe.error import RateLimitError

from app import settings

class StripeClient:
    def __init__(self, api_key: str = settings.STRIPE_API_KEY) -> None:
        stripe.api_key = api_key
        stripe.api_version = settings.STRIPE_API_VERSION
        if settings.ENVIRONMENT not in ("dev", "prod") and settings.STRIPE_MOCK_API_BASE:
            stripe.api_base = settings.STRIPE_MOCK_API_BASE

    @backoff.on_exception(backoff.expo, RateLimitError, max_time=3, max_tries=4)
    async def draft_invoice(
        self,
        customer: str,
        statement_descriptor: str,
        description: str,
        metadata: dict,
        discounts: list[dict],
        currency: str,
        default_source: str | None = None,
    ) -> stripe.Invoice:
        return await stripe.Invoice.create(
            customer=customer,
            statement_descriptor=statement_descriptor,
            currency=currency.lower(),
            description=description,
            metadata=metadata,
            discounts=[discounts] or None,
            default_source=default_source,
        )

    @backoff.on_exception(backoff.expo, RateLimitError, max_time=3, max_tries=4)
    async def finalize_invoice(self, invoice_id: str) -> stripe.Invoice:
        return await stripe.Invoice.finalize_invoice(invoice_id)

    @backoff.on_exception(backoff.expo, RateLimitError, max_time=3, max_tries=4)
    async def pay_invoice(self, invoice_id: str, paid_out_of_band: bool = False) -> stripe.Invoice:
        pay_params = {}
        if paid_out_of_band:
            pay_params["paid_out_of_band"] = paid_out_of_band

        return await stripe.Invoice.pay(invoice_id, **pay_params)

    async def add_invoice_item(
        self,
        invoice_id: str,
        customer_id: str,
        quantity: int,
        metadata: dict,
        tax_rates: list[str],
        discountable: bool,
        unit_amount: int,
        product_id: str,
        currency: str,
    ) -> stripe.InvoiceItem:
        return await stripe.InvoiceItem.create(
            customer=customer_id,
            currency=currency,
            quantity=quantity,
            metadata=metadata,
            tax_rates=tax_rates,
            discountable=discountable,
            invoice=invoice_id,
            price_data=dict(
                unit_amount=unit_amount,
                currency=currency,
                product=product_id,
            ),
        )

Here is how the function looks like that we are using for creating the invoice:

async def process_invoice(self, invoice_request: InvoiceRequest) -> stripe.Invoice:
        invoice = await self.stripe_client.draft_invoice(
            customer=invoice_request.customer_id,
            description=invoice_request.description,
            metadata=invoice_request.metadata,
            statement_descriptor=invoice_request.statement_descriptor,
            currency=invoice_request.currency,
            discounts=invoice_request.discounts,
            default_source=invoice_request.default_source,
        )

        for invoice_line in invoice_request.lines:
            await self.stripe_client.add_invoice_item(
                invoice_id=invoice.id,
                customer_id=invoice_request.customer_id,
                product_id=invoice_line.product_id,
                quantity=invoice_line.quantity,
                unit_amount=invoice_line.unit_amount,
                tax_rates=invoice_line.tax_rates,
                discountable=invoice_line.discountable,
                metadata=invoice_line.metadata,
                currency=invoice_request.currency,
            )

        invoice = await self.stripe_client.finalize_invoice(invoice_id=invoice.id)

        await self.stripe_client.pay_invoice(invoice_id=invoice.id)

As you can see in the screenshot, adding the invoices takes a really long timer, much longer than when doing the same with the official stripe library (almost 12 seconds)

We also tried this, but same issue:

add_line_items_tasks = []

for invoice_line in invoice_request.lines:
    task = asyncio.ensure_future(
        self.stripe_client.add_invoice_item(
            invoice_id=invoice.id,
            customer_id=invoice_request.customer_id,
            product_id=invoice_line.product_id,
            quantity=invoice_line.quantity,
            unit_amount=invoice_line.unit_amount,
            tax_rates=invoice_line.tax_rates,
            discountable=invoice_line.discountable,
            metadata=invoice_line.metadata,
            currency=invoice_request.currency,
        )
    add_line_items_tasks.append(task)

await asyncio.gather(*add_line_items_tasks)