test(billing): validate stripe customer id enforcement

backend/migrations/0001_init.sql

@@ -12,7 +12,7 @@ CREATE TABLE IF NOT EXISTS tenant (
   nwc_url TEXT NOT NULL DEFAULT '',
   nwc_error TEXT,
   created_at INTEGER NOT NULL,
-  stripe_customer_id TEXT NOT NULL DEFAULT '',
+  stripe_customer_id TEXT NOT NULL,
   stripe_subscription_id TEXT,
   past_due_at INTEGER
 );

backend/src/api.rs

@@ -122,7 +122,10 @@ impl Api {
             .route("/tenants/:pubkey/invoices", get(list_tenant_invoices))
             .route("/invoices/:id", get(get_invoice))
             .route("/invoices/:id/bolt11", get(get_invoice_bolt11))
-            .route("/tenants/:pubkey/stripe/session", get(create_stripe_session))
+            .route(
+                "/tenants/:pubkey/stripe/session",
+                get(create_stripe_session),
+            )
             .route("/stripe/webhook", post(stripe_webhook))
             .with_state(state)
     }
@@ -365,41 +368,53 @@ async fn get_identity(
     let pubkey = state.api.extract_auth_pubkey(&headers)?;
     let is_admin = state.api.admins.iter().any(|a| a == &pubkey);
 
-    // Only create if tenant doesn't exist yet
-    if let Ok(None) = state.api.query.get_tenant(&pubkey).await {
-        // TODO: Call Stripe API to create a new customer
-        let stripe_customer_id = String::new();
+    // Ensure tenant exists.
+    match state.api.query.get_tenant(&pubkey).await {
+        Ok(Some(_)) => {}
+        Ok(None) => {
+            let stripe_customer_id = match state.api.billing.stripe_create_customer(&pubkey).await {
+                Ok(id) => id,
+                Err(e) => {
+                    return Ok(err(
+                        StatusCode::INTERNAL_SERVER_ERROR,
+                        "stripe-customer-create-failed",
+                        &e.to_string(),
+                    ));
+                }
+            };
 
-        let tenant = Tenant {
-            pubkey: pubkey.clone(),
-            nwc_url: String::new(),
-            nwc_error: None,
-            created_at: now_ts(),
-            stripe_customer_id,
-            stripe_subscription_id: None,
-            past_due_at: None,
-        };
+            let tenant = Tenant {
+                pubkey: pubkey.clone(),
+                nwc_url: String::new(),
+                nwc_error: None,
+                created_at: now_ts(),
+                stripe_customer_id,
+                stripe_subscription_id: None,
+                past_due_at: None,
+            };
 
-        match state.api.command.create_tenant(&tenant).await {
-            Ok(()) => {}
-            Err(e) if matches!(map_unique_error(&e), Some("pubkey-exists")) => {}
-            Err(e) => {
-                return Ok(err(
-                    StatusCode::INTERNAL_SERVER_ERROR,
-                    "internal",
-                    &e.to_string(),
-                ));
-            }
-        };
+            match state.api.command.create_tenant(&tenant).await {
+                Ok(()) => {}
+                Err(e) if matches!(map_unique_error(&e), Some("pubkey-exists")) => {}
+                Err(e) => {
+                    return Ok(err(
+                        StatusCode::INTERNAL_SERVER_ERROR,
+                        "internal",
+                        &e.to_string(),
+                    ));
+                }
+            };
+        }
+        Err(e) => {
+            return Ok(err(
+                StatusCode::INTERNAL_SERVER_ERROR,
+                "internal",
+                &e.to_string(),
+            ));
+        }
     }
 
-    Ok(ok(
-        StatusCode::OK,
-        IdentityResponse {
-            pubkey,
-            is_admin,
-        },
-    ))
+    Ok(ok(StatusCode::OK, IdentityResponse { pubkey, is_admin }))
 }
 
 async fn get_plan(Path(id): Path<String>) -> Response {
@@ -489,14 +504,27 @@ async fn list_relay_activity(
     let relay = match state.api.query.get_relay(&id).await {
         Ok(Some(r)) => r,
         Ok(None) => return Ok(err(StatusCode::NOT_FOUND, "not-found", "relay not found")),
-        Err(e) => return Ok(err(StatusCode::INTERNAL_SERVER_ERROR, "internal", &e.to_string())),
+        Err(e) => {
+            return Ok(err(
+                StatusCode::INTERNAL_SERVER_ERROR,
+                "internal",
+                &e.to_string(),
+            ));
+        }
     };
 
     state.api.require_admin_or_tenant(&auth, &relay.tenant)?;
 
     match state.api.query.list_activity_for_relay(&id).await {
-        Ok(activity) => Ok(ok(StatusCode::OK, serde_json::json!({ "activity": activity }))),
-        Err(e) => Ok(err(StatusCode::INTERNAL_SERVER_ERROR, "internal", &e.to_string())),
+        Ok(activity) => Ok(ok(
+            StatusCode::OK,
+            serde_json::json!({ "activity": activity }),
+        )),
+        Err(e) => Ok(err(
+            StatusCode::INTERNAL_SERVER_ERROR,
+            "internal",
+            &e.to_string(),
+        )),
     }
 }
 
@@ -773,7 +801,11 @@ async fn get_invoice(
     Path(id): Path<String>,
 ) -> std::result::Result<Response, ApiError> {
     let auth = state.api.extract_auth_pubkey(&headers)?;
-    let (invoice, tenant) = state.api.billing.get_invoice_with_tenant(&id).await
+    let (invoice, tenant) = state
+        .api
+        .billing
+        .get_invoice_with_tenant(&id)
+        .await
         .map_err(|e| ApiError::Internal(e.to_string()))?;
     state.api.require_admin_or_tenant(&auth, &tenant.pubkey)?;
 
@@ -786,7 +818,11 @@ async fn get_invoice_bolt11(
     Path(id): Path<String>,
 ) -> std::result::Result<Response, ApiError> {
     let auth = state.api.extract_auth_pubkey(&headers)?;
-    let (invoice, tenant) = state.api.billing.get_invoice_with_tenant(&id).await
+    let (invoice, tenant) = state
+        .api
+        .billing
+        .get_invoice_with_tenant(&id)
+        .await
         .map_err(|e| ApiError::Internal(e.to_string()))?;
     state.api.require_admin_or_tenant(&auth, &tenant.pubkey)?;
 

backend/src/billing.rs

@@ -1,7 +1,7 @@
 use anyhow::{Result, anyhow};
 use hmac::{Hmac, Mac};
 use nwc::prelude::{
-    MakeInvoiceRequest, NostrWalletConnectURI, PayInvoiceRequest as NwcPayInvoiceRequest, NWC,
+    MakeInvoiceRequest, NWC, NostrWalletConnectURI, PayInvoiceRequest as NwcPayInvoiceRequest,
 };
 use sha2::Sha256;
 
@@ -75,8 +75,12 @@ impl Billing {
     async fn handle_activity(&self, activity: &Activity) -> Result<()> {
         let needs_billing_sync = matches!(
             activity.activity_type.as_str(),
-            "create_relay" | "update_relay" | "activate_relay" | "deactivate_relay"
-                | "fail_relay_sync" | "complete_relay_sync"
+            "create_relay"
+                | "update_relay"
+                | "activate_relay"
+                | "deactivate_relay"
+                | "fail_relay_sync"
+                | "complete_relay_sync"
         );
 
         if needs_billing_sync {
@@ -99,7 +103,9 @@ impl Billing {
         if relay.plan == "free" {
             if let Some(ref item_id) = relay.stripe_subscription_item_id {
                 self.stripe_delete_subscription_item(item_id).await?;
-                self.command.delete_relay_subscription_item(&relay.id).await?;
+                self.command
+                    .delete_relay_subscription_item(&relay.id)
+                    .await?;
             }
             self.cleanup_empty_subscription(&tenant.pubkey).await?;
             return Ok(());
@@ -109,16 +115,16 @@ impl Billing {
         if relay.status == "inactive" {
             if let Some(ref item_id) = relay.stripe_subscription_item_id {
                 self.stripe_delete_subscription_item(item_id).await?;
-                self.command.delete_relay_subscription_item(&relay.id).await?;
+                self.command
+                    .delete_relay_subscription_item(&relay.id)
+                    .await?;
             }
             self.cleanup_empty_subscription(&tenant.pubkey).await?;
             return Ok(());
         }
 
         // Active relay on a paid plan
-        let plan = Query::list_plans()
-            .into_iter()
-            .find(|p| p.id == relay.plan);
+        let plan = Query::list_plans().into_iter().find(|p| p.id == relay.plan);
 
         let Some(plan) = plan else {
             return Ok(());
@@ -128,6 +134,13 @@ impl Billing {
             return Ok(());
         };
 
+        if tenant.stripe_customer_id.trim().is_empty() {
+            return Err(anyhow!(
+                "tenant {} has no stripe_customer_id",
+                tenant.pubkey
+            ));
+        }
+
         // Ensure subscription exists
         if tenant.stripe_subscription_id.is_none() {
             let (subscription_id, item_id) = self
@@ -170,7 +183,9 @@ impl Billing {
 
         if let Some(ref subscription_id) = tenant.stripe_subscription_id {
             self.stripe_cancel_subscription(subscription_id).await?;
-            self.command.clear_tenant_subscription(tenant_pubkey).await?;
+            self.command
+                .clear_tenant_subscription(tenant_pubkey)
+                .await?;
         }
 
         Ok(())
@@ -240,7 +255,9 @@ impl Billing {
             return Err(anyhow!("webhook signature mismatch"));
         }
 
-        let ts: i64 = timestamp.parse().map_err(|_| anyhow!("bad webhook timestamp"))?;
+        let ts: i64 = timestamp
+            .parse()
+            .map_err(|_| anyhow!("bad webhook timestamp"))?;
         let now = chrono::Utc::now().timestamp();
         if (now - ts).abs() > WEBHOOK_TOLERANCE_SECS {
             return Err(anyhow!("webhook timestamp outside tolerance"));
@@ -272,9 +289,7 @@ impl Billing {
             match self.nwc_pay_invoice(amount_due, &tenant.nwc_url).await {
                 Ok(()) => {
                     self.stripe_pay_invoice_out_of_band(invoice_id).await?;
-                    self.command
-                        .clear_tenant_nwc_error(&tenant.pubkey)
-                        .await?;
+                    self.command.clear_tenant_nwc_error(&tenant.pubkey).await?;
                     return Ok(());
                 }
                 Err(e) => {
@@ -442,6 +457,37 @@ impl Billing {
         Ok((invoice, tenant))
     }
 
+    pub async fn stripe_create_customer(&self, tenant_pubkey: &str) -> Result<String> {
+        if self.stripe_secret_key.trim().is_empty() {
+            return Err(anyhow!("missing STRIPE_SECRET_KEY"));
+        }
+
+        let short_pubkey: String = tenant_pubkey.chars().take(12).collect();
+        let display_name = format!("Caravel tenant {short_pubkey}");
+
+        let resp = self
+            .http
+            .post(format!("{STRIPE_API}/customers"))
+            .bearer_auth(&self.stripe_secret_key)
+            .form(&[
+                ("name", display_name.as_str()),
+                ("metadata[tenant_pubkey]", tenant_pubkey),
+            ])
+            .send()
+            .await?;
+
+        let body: serde_json::Value = resp.error_for_status()?.json().await?;
+        let customer_id = body["id"]
+            .as_str()
+            .ok_or_else(|| anyhow!("missing customer id"))?;
+
+        if !customer_id.starts_with("cus_") {
+            return Err(anyhow!("unexpected customer id format"));
+        }
+
+        Ok(customer_id.to_string())
+    }
+
     pub async fn stripe_list_invoices(&self, customer_id: &str) -> Result<serde_json::Value> {
         let resp = self
             .http
@@ -470,7 +516,9 @@ impl Billing {
     pub async fn create_bolt11(&self, amount_due_cents: i64) -> Result<String> {
         let amount_msats = (amount_due_cents as u64) * 1000; // placeholder conversion
 
-        let system_uri: NostrWalletConnectURI = self.nwc_url.parse()
+        let system_uri: NostrWalletConnectURI = self
+            .nwc_url
+            .parse()
             .map_err(|_| anyhow!("invalid system NWC URL"))?;
         let system_nwc = NWC::new(system_uri);
 
@@ -550,10 +598,7 @@ impl Billing {
             .http
             .post(format!("{STRIPE_API}/subscription_items"))
             .bearer_auth(&self.stripe_secret_key)
-            .form(&[
-                ("subscription", subscription_id),
-                ("price", price_id),
-            ])
+            .form(&[("subscription", subscription_id), ("price", price_id)])
             .send()
             .await?;
 
@@ -649,7 +694,9 @@ impl Billing {
         let amount_msats = (amount_due_cents as u64) * 1000; // placeholder conversion, actual rate would come from exchange
 
         // Create a bolt11 invoice using the system wallet (self.nwc_url)
-        let system_uri: NostrWalletConnectURI = self.nwc_url.parse()
+        let system_uri: NostrWalletConnectURI = self
+            .nwc_url
+            .parse()
             .map_err(|_| anyhow!("invalid system NWC URL"))?;
         let system_nwc = NWC::new(system_uri);
 
@@ -668,7 +715,8 @@ impl Billing {
         system_nwc.shutdown().await;
 
         // Pay the bolt11 invoice using the tenant's wallet
-        let tenant_uri: NostrWalletConnectURI = tenant_nwc_url.parse()
+        let tenant_uri: NostrWalletConnectURI = tenant_nwc_url
+            .parse()
             .map_err(|_| anyhow!("invalid tenant NWC URL"))?;
         let tenant_nwc = NWC::new(tenant_uri);
 
@@ -684,3 +732,112 @@ impl Billing {
         Ok(())
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use sqlx::SqlitePool;
+    use sqlx::sqlite::{SqliteConnectOptions, SqlitePoolOptions};
+    use std::str::FromStr;
+
+    use crate::models::Activity;
+
+    async fn test_pool() -> SqlitePool {
+        let connect_options = SqliteConnectOptions::from_str("sqlite::memory:")
+            .expect("valid sqlite memory url")
+            .create_if_missing(true);
+
+        let pool = SqlitePoolOptions::new()
+            .max_connections(1)
+            .connect_with(connect_options)
+            .await
+            .expect("connect sqlite memory db");
+
+        sqlx::migrate!("./migrations")
+            .run(&pool)
+            .await
+            .expect("run migrations");
+
+        pool
+    }
+
+    fn test_billing(pool: SqlitePool, stripe_secret_key: &str) -> Billing {
+        Billing {
+            nwc_url: String::new(),
+            stripe_secret_key: stripe_secret_key.to_string(),
+            stripe_webhook_secret: String::new(),
+            http: reqwest::Client::new(),
+            query: Query::new(pool.clone()),
+            command: Command::new(pool),
+            robot: Robot::test_stub(),
+        }
+    }
+
+    #[tokio::test]
+    async fn stripe_create_customer_requires_secret_key() {
+        let pool = test_pool().await;
+        let billing = test_billing(pool, "");
+
+        let err = billing
+            .stripe_create_customer("tenant_pubkey")
+            .await
+            .expect_err("missing key should fail before HTTP call");
+
+        assert!(
+            err.to_string().contains("missing STRIPE_SECRET_KEY"),
+            "unexpected error: {err}"
+        );
+    }
+
+    #[tokio::test]
+    async fn sync_relay_subscription_fails_for_empty_tenant_customer_id() {
+        let pool = test_pool().await;
+
+        sqlx::query(
+            "INSERT INTO tenant (pubkey, nwc_url, created_at, stripe_customer_id)
+             VALUES (?, ?, ?, ?)",
+        )
+        .bind("tenant_pubkey")
+        .bind("")
+        .bind(0_i64)
+        .bind("")
+        .execute(&pool)
+        .await
+        .expect("insert tenant");
+
+        sqlx::query(
+            "INSERT INTO relay (id, tenant, schema, subdomain, plan, status)
+             VALUES (?, ?, ?, ?, ?, ?)",
+        )
+        .bind("relay_1")
+        .bind("tenant_pubkey")
+        .bind("relay_1")
+        .bind("relay-1")
+        .bind("basic")
+        .bind("active")
+        .execute(&pool)
+        .await
+        .expect("insert relay");
+
+        let billing = test_billing(pool, "sk_test_dummy");
+        let activity = Activity {
+            id: "activity_1".to_string(),
+            tenant: "tenant_pubkey".to_string(),
+            created_at: 0,
+            activity_type: "create_relay".to_string(),
+            resource_type: "relay".to_string(),
+            resource_id: "relay_1".to_string(),
+        };
+
+        let err = billing
+            .sync_relay_subscription(&activity)
+            .await
+            .expect_err("empty tenant customer id should fail clearly");
+
+        assert!(
+            err.to_string()
+                .contains("tenant tenant_pubkey has no stripe_customer_id"),
+            "unexpected error: {err}"
+        );
+    }
+}

backend/src/command.rs

@@ -64,6 +64,10 @@ impl Command {
     }
 
     pub async fn create_tenant(&self, tenant: &Tenant) -> Result<()> {
+        if tenant.stripe_customer_id.trim().is_empty() {
+            anyhow::bail!("stripe_customer_id is required");
+        }
+
         let mut tx = self.pool.begin().await?;
 
         sqlx::query(
@@ -77,7 +81,8 @@ impl Command {
         .execute(&mut *tx)
         .await?;
 
-        let activity = Self::insert_activity(&mut tx, "create_tenant", "tenant", &tenant.pubkey).await?;
+        let activity =
+            Self::insert_activity(&mut tx, "create_tenant", "tenant", &tenant.pubkey).await?;
 
         tx.commit().await?;
         self.emit(activity);
@@ -93,7 +98,8 @@ impl Command {
             .execute(&mut *tx)
             .await?;
 
-        let activity = Self::insert_activity(&mut tx, "update_tenant", "tenant", &tenant.pubkey).await?;
+        let activity =
+            Self::insert_activity(&mut tx, "update_tenant", "tenant", &tenant.pubkey).await?;
 
         tx.commit().await?;
         self.emit(activity);
@@ -185,7 +191,8 @@ impl Command {
             .execute(&mut *tx)
             .await?;
 
-        let activity = Self::insert_activity(&mut tx, "deactivate_relay", "relay", &relay.id).await?;
+        let activity =
+            Self::insert_activity(&mut tx, "deactivate_relay", "relay", &relay.id).await?;
 
         tx.commit().await?;
         self.emit(activity);
@@ -216,7 +223,8 @@ impl Command {
             .execute(&mut *tx)
             .await?;
 
-        let activity = Self::insert_activity(&mut tx, "fail_relay_sync", "relay", &relay.id).await?;
+        let activity =
+            Self::insert_activity(&mut tx, "fail_relay_sync", "relay", &relay.id).await?;
 
         tx.commit().await?;
         self.emit(activity);
@@ -231,7 +239,8 @@ impl Command {
             .execute(&mut *tx)
             .await?;
 
-        let activity = Self::insert_activity(&mut tx, "complete_relay_sync", "relay", relay_id).await?;
+        let activity =
+            Self::insert_activity(&mut tx, "complete_relay_sync", "relay", relay_id).await?;
 
         tx.commit().await?;
         self.emit(activity);
@@ -246,7 +255,11 @@ impl Command {
         Ok(())
     }
 
-    pub async fn set_relay_subscription_item(&self, relay_id: &str, stripe_subscription_item_id: &str) -> Result<()> {
+    pub async fn set_relay_subscription_item(
+        &self,
+        relay_id: &str,
+        stripe_subscription_item_id: &str,
+    ) -> Result<()> {
         sqlx::query("UPDATE relay SET stripe_subscription_item_id = ? WHERE id = ?")
             .bind(stripe_subscription_item_id)
             .bind(relay_id)
@@ -255,7 +268,11 @@ impl Command {
         Ok(())
     }
 
-    pub async fn set_tenant_subscription(&self, pubkey: &str, stripe_subscription_id: &str) -> Result<()> {
+    pub async fn set_tenant_subscription(
+        &self,
+        pubkey: &str,
+        stripe_subscription_id: &str,
+    ) -> Result<()> {
         sqlx::query("UPDATE tenant SET stripe_subscription_id = ? WHERE pubkey = ?")
             .bind(stripe_subscription_id)
             .bind(pubkey)
@@ -307,3 +324,56 @@ impl Command {
         Ok(())
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use sqlx::SqlitePool;
+    use sqlx::sqlite::{SqliteConnectOptions, SqlitePoolOptions};
+    use std::str::FromStr;
+
+    async fn test_pool() -> SqlitePool {
+        let connect_options = SqliteConnectOptions::from_str("sqlite::memory:")
+            .expect("valid sqlite memory url")
+            .create_if_missing(true);
+
+        let pool = SqlitePoolOptions::new()
+            .max_connections(1)
+            .connect_with(connect_options)
+            .await
+            .expect("connect sqlite memory db");
+
+        sqlx::migrate!("./migrations")
+            .run(&pool)
+            .await
+            .expect("run migrations");
+
+        pool
+    }
+
+    #[tokio::test]
+    async fn create_tenant_rejects_empty_stripe_customer_id() {
+        let pool = test_pool().await;
+        let command = Command::new(pool);
+
+        let tenant = Tenant {
+            pubkey: "tenant_pubkey".to_string(),
+            nwc_url: String::new(),
+            nwc_error: None,
+            created_at: 0,
+            stripe_customer_id: "   ".to_string(),
+            stripe_subscription_id: None,
+            past_due_at: None,
+        };
+
+        let err = command
+            .create_tenant(&tenant)
+            .await
+            .expect_err("empty customer id must be rejected");
+
+        assert!(
+            err.to_string().contains("stripe_customer_id is required"),
+            "unexpected error: {err}"
+        );
+    }
+}

backend/src/robot.rs

@@ -254,3 +254,23 @@ async fn set_cached(
         },
     );
 }
+
+#[cfg(test)]
+impl Robot {
+    pub fn test_stub() -> Self {
+        let keys = Keys::generate();
+        let client = Client::new(keys);
+
+        Self {
+            secret: String::new(),
+            name: String::new(),
+            description: String::new(),
+            picture: String::new(),
+            outbox_client: client.clone(),
+            indexer_client: client.clone(),
+            messaging_client: client,
+            outbox_cache: std::sync::Arc::new(Mutex::new(HashMap::new())),
+            dm_cache: std::sync::Arc::new(Mutex::new(HashMap::new())),
+        }
+    }
+}