collab: Add billing thresholds to request overage subscription items (#29738)

Marshall Bowers created 7 months ago

This PR adds billing thresholds of the unit equivalent of $20 for model
request overages.

Release Notes:

- N/A

Change summary

crates/collab/src/api/billing.rs    | 10 +++++-----
crates/collab/src/stripe_billing.rs | 24 +++++++++++++++++++++---
2 files changed, 26 insertions(+), 8 deletions(-)

Detailed changes

crates/collab/src/api/billing.rs

@@ -1403,13 +1403,13 @@ async fn sync_model_request_usage_with_stripe(
         .await?;
 
     let claude_3_5_sonnet = stripe_billing
-        .find_price_id_by_lookup_key("claude-3-5-sonnet-requests")
+        .find_price_by_lookup_key("claude-3-5-sonnet-requests")
         .await?;
     let claude_3_7_sonnet = stripe_billing
-        .find_price_id_by_lookup_key("claude-3-7-sonnet-requests")
+        .find_price_by_lookup_key("claude-3-7-sonnet-requests")
         .await?;
     let claude_3_7_sonnet_max = stripe_billing
-        .find_price_id_by_lookup_key("claude-3-7-sonnet-requests-max")
+        .find_price_by_lookup_key("claude-3-7-sonnet-requests-max")
         .await?;
 
     for (usage_meter, usage) in usage_meters {
@@ -1434,7 +1434,7 @@ async fn sync_model_request_usage_with_stripe(
 
             let model = llm_db.model_by_id(usage_meter.model_id)?;
 
-            let (price_id, meter_event_name) = match model.name.as_str() {
+            let (price, meter_event_name) = match model.name.as_str() {
                 "claude-3-5-sonnet" => (&claude_3_5_sonnet, "claude_3_5_sonnet/requests"),
                 "claude-3-7-sonnet" => match usage_meter.mode {
                     CompletionMode::Normal => (&claude_3_7_sonnet, "claude_3_7_sonnet/requests"),
@@ -1448,7 +1448,7 @@ async fn sync_model_request_usage_with_stripe(
             };
 
             stripe_billing
-                .subscribe_to_price(&stripe_subscription_id, price_id)
+                .subscribe_to_price(&stripe_subscription_id, price)
                 .await?;
             stripe_billing
                 .bill_model_request_usage(

crates/collab/src/stripe_billing.rs

@@ -99,6 +99,16 @@ impl StripeBilling {
             .ok_or_else(|| crate::Error::Internal(anyhow!("no price ID found for {lookup_key:?}")))
     }
 
+    pub async fn find_price_by_lookup_key(&self, lookup_key: &str) -> Result<stripe::Price> {
+        self.state
+            .read()
+            .await
+            .prices_by_lookup_key
+            .get(lookup_key)
+            .cloned()
+            .ok_or_else(|| crate::Error::Internal(anyhow!("no price found for {lookup_key:?}")))
+    }
+
     pub async fn register_model_for_token_based_usage(
         &self,
         model: &llm::db::model::Model,
@@ -238,21 +248,29 @@ impl StripeBilling {
     pub async fn subscribe_to_price(
         &self,
         subscription_id: &stripe::SubscriptionId,
-        price_id: &stripe::PriceId,
+        price: &stripe::Price,
     ) -> Result<()> {
         let subscription =
             stripe::Subscription::retrieve(&self.client, &subscription_id, &[]).await?;
 
-        if subscription_contains_price(&subscription, price_id) {
+        if subscription_contains_price(&subscription, &price.id) {
             return Ok(());
         }
 
+        const BILLING_THRESHOLD_IN_CENTS: i64 = 20 * 100;
+
+        let price_per_unit = price.unit_amount.unwrap_or_default();
+        let units_for_billing_threshold = BILLING_THRESHOLD_IN_CENTS / price_per_unit;
+
         stripe::Subscription::update(
             &self.client,
             subscription_id,
             stripe::UpdateSubscription {
                 items: Some(vec![stripe::UpdateSubscriptionItems {
-                    price: Some(price_id.to_string()),
+                    price: Some(price.id.to_string()),
+                    billing_thresholds: Some(stripe::SubscriptionItemBillingThresholds {
+                        usage_gte: Some(units_for_billing_threshold),
+                    }),
                     ..Default::default()
                 }]),
                 trial_settings: Some(stripe::UpdateSubscriptionTrialSettings {