Send the billing interval with a custom VM price

API_CHANGELOG.md

@@ -26,6 +26,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ### Added
 
+- **Custom VM price states its billing period** (issue #302) — `POST /api/v1/vm/custom-template/price` gains `interval_amount` and `interval_type`, the same shape a standard template's cost plan already uses. Custom builds renew monthly, so the values are always `1` and `"month"`; the point is that a client no longer has to hard-code the period to render a recurring price. Additive: no existing field changed.
+
 - **Admin can create a custom-spec VM** (issue #335) — `POST /api/admin/v1/vms/custom` creates a VM from an arbitrary spec for any user, billed against a custom pricing plan, instead of only from the fixed template catalog. Body is the customer custom-order shape plus `user_id`/`reason`: `pricing_id` (also decides the region), `cpu`, `memory` and `disk` in bytes, `disk_type`, `disk_interface`, optional `cpu_mfg`/`cpu_arch`/`cpu_feature`, `image_id`, `ssh_key_id` (must belong to the target user), optional `ref_code`. Returns `{ "job_id": string }`; the VM is created unpaid like a customer order. Unknown enum spellings are `400` and are never defaulted. Additive: `POST /api/admin/v1/vms` (template path) is unchanged.
 
 - **A VM can hold more than one address per family** (issue #343) — every assignment is now placed on the VM's single NIC through a per-VM cloud-init network config (`cicustom network=`), instead of the built-in `ipconfig`, which carries only one IPv4 and one IPv6 per interface. A VM with one address per family is unaffected and keeps its existing `ipconfig`, so nothing already deployed is reconfigured. The interface is matched by MAC so the config does not depend on guest device naming; one default route per family is emitted (the first assignment's gateway wins, as before); a SLAAC range contributes router advertisement rather than a pinned address. No response shape changed — the offered maximum is now simply whatever an operator sets on the plan or template.

lnvps_api/src/api/model.rs

@@ -59,6 +59,10 @@ pub struct ApiCustomVmPrice {
     /// currencies. Use `GET /api/v1/exchange-rate` instead. Still populated for
     /// backward compatibility; will be removed in a future release.
     pub other_price: Vec<ApiPrice>,
+    /// Billing period the amount buys, same shape as a standard template's cost
+    /// plan. Custom builds renew monthly, so this is always 1 month.
+    pub interval_amount: u64,
+    pub interval_type: ApiIntervalType,
 }
 
 impl ApiCustomVmPrice {
@@ -80,6 +84,8 @@ impl ApiCustomVmPrice {
             currency: amount.currency().into(),
             amount: amount.value(),
             other_price,
+            interval_amount: CUSTOM_VM_INTERVAL_AMOUNT,
+            interval_type: CUSTOM_VM_INTERVAL_TYPE.into(),
         })
     }
 }

lnvps_api_common/src/pricing.rs

@@ -60,6 +60,15 @@ pub struct RemainingTimeInfo {
     pub prorated_cost: CurrencyAmount,
 }
 
+/// Billing period a custom VM price buys. Custom builds have no cost plan row,
+/// so the interval is fixed here and is what both the renewal and the quoted
+/// price report.
+pub const CUSTOM_VM_INTERVAL_AMOUNT: u64 = 1;
+pub const CUSTOM_VM_INTERVAL_TYPE: IntervalType = IntervalType::Month;
+// The renewal below advances by months, so a change of unit here has to be made
+// there too.
+const _: () = assert!(matches!(CUSTOM_VM_INTERVAL_TYPE, IntervalType::Month));
+
 /// ISO 3166-1 alpha-3 codes treated as inside the EU VAT area (27 member states).
 const EU_VAT_COUNTRIES: [&str; 27] = [
     "AUT", "BEL", "BGR", "HRV", "CYP", "CZE", "DNK", "EST", "FIN", "FRA", "DEU", "GRC", "HUN",
@@ -885,13 +894,14 @@ impl PricingEngine {
         let template = self.db.get_custom_vm_template(template_id).await?;
         let price = Self::get_custom_vm_cost_amount(&self.db, &template).await?;
 
-        // custom templates are always 1-month intervals; clamp base to now for expired VMs
+        // clamp base to now for expired VMs
         let base = self
             .vm_subscription_expires(vm)
             .await
             .unwrap_or_else(Utc::now)
             .max(Utc::now());
-        let time_value = (base.add(Months::new(1)) - base).num_seconds() as u64;
+        let time_value =
+            (base.add(Months::new(CUSTOM_VM_INTERVAL_AMOUNT as u32)) - base).num_seconds() as u64;
         let converted_amount = self
             .get_amount_and_rate(
                 CurrencyAmount::from_u64(price.currency, price.total()),
@@ -1396,7 +1406,10 @@ impl PricingEngine {
         } else if let Some(cid) = vm.custom_template_id {
             let template = self.db.get_custom_vm_template(cid).await?;
             let price = Self::get_custom_vm_cost_amount(&self.db, &template).await?;
-            let time_value = Self::cost_plan_interval_to_seconds(IntervalType::Month, 1);
+            let time_value = Self::cost_plan_interval_to_seconds(
+                CUSTOM_VM_INTERVAL_TYPE,
+                CUSTOM_VM_INTERVAL_AMOUNT,
+            );
             (
                 CurrencyAmount::from_u64(price.currency, price.total()),
                 time_value,
@@ -1557,7 +1570,8 @@ impl PricingEngine {
         let new_price = CurrencyAmount::from_u64(new_price.currency, new_price.total());
 
         // Get the time value for the custom template
-        let custom_plan_seconds = Self::cost_plan_interval_to_seconds(IntervalType::Month, 1);
+        let custom_plan_seconds =
+            Self::cost_plan_interval_to_seconds(CUSTOM_VM_INTERVAL_TYPE, CUSTOM_VM_INTERVAL_AMOUNT);
         let new_cost_per_second = new_price.value() as f64 / custom_plan_seconds as f64;
 
         // calculate the cost based on the time until the vm expires

lnvps_e2e/src/user_api.rs

@@ -295,6 +295,13 @@ mod tests {
                     "Custom template price calc should return 200, 400, or 500, got: {}",
                     resp.status()
                 );
+                if resp.status() == StatusCode::OK {
+                    // A recurring price with no period reads as a total, so the
+                    // interval has to be on the wire.
+                    let price: ApiData<Value> = parse_data(resp).await.unwrap();
+                    assert_eq!(price.data["interval_amount"], 1);
+                    assert_eq!(price.data["interval_type"], "month");
+                }
             }
         }
     }