add option to require rate limit selection

src/adapter/basic.ts

@@ -315,7 +315,11 @@ export class Adapter<CustomSettingsDefinition extends SettingsDefinitionMap = Se
       )
     }
 
-    const rateLimitingTier = getRateLimitingTier(this.config.settings, this.rateLimiting?.tiers)
+    const rateLimitingTier = getRateLimitingTier(
+      this.config.settings,
+      this.rateLimiting?.tiers,
+      this.rateLimiting?.requireTierSelection,
+    )
 
     if (rateLimitingTier) {
       for (const limit of Object.values(rateLimitingTier)) {

src/adapter/types.ts

@@ -64,6 +64,7 @@ export interface EndpointContext<T extends EndpointGenerics> {
 export interface AdapterRateLimitingConfig {
   /** Adapter rate limits, gotten from the specific tier requested */
   tiers: Record<string, AdapterRateLimitTier>
+  requireTierSelection?: boolean
 }
 
 /**

src/rate-limiting/index.ts

@@ -94,6 +94,7 @@ export const lowestTierLimit = (limits?: AdapterRateLimitTier) => {
 export const getRateLimitingTier = (
   adapterSettings: AdapterSettings,
   tiers?: Record<string, AdapterRateLimitTier>,
+  requireTierSelection?: boolean,
 ): AdapterRateLimitTier | undefined => {
   if (
     adapterSettings.RATE_LIMIT_CAPACITY ||
@@ -124,6 +125,12 @@ export const getRateLimitingTier = (
   }
 
   if (!selectedTier) {
+    if (requireTierSelection) {
+      throw new Error(
+        `This adapter requires you to specify a rate limit tier via the RATE_LIMIT_API_TIER environment variable`,
+      )
+    }
+    // Default to the lowest tier if none is specified
     // Sort the tiers by most to least restrictive
     const sortedTiers = Object.entries(tiers).sort(
       ([_, t1], [__, t2]) => lowestTierLimit(t1) - lowestTierLimit(t2),

test/rate-limit-config.test.ts

@@ -187,6 +187,53 @@ test('throws error if explicit allocation exceeds 100%', async (t) => {
   )
 })
 
+test('throws error if requireTierSelection is true and no tier is specified in settings', async (t) => {
+  const adapter = new Adapter({
+    name: 'TEST',
+    endpoints: [
+      new AdapterEndpoint({
+        name: 'test',
+        transport: new (class extends NopTransport {
+          override async initialize(dependencies: AdapterDependencies): Promise<void> {
+            t.true(dependencies.rateLimiter instanceof BurstRateLimiter)
+            t.is(
+              (dependencies.rateLimiter as unknown as Record<string, number>)['perSecondLimit'],
+              123,
+            )
+          }
+        })(),
+      }),
+    ],
+    config: new AdapterConfig(
+      {},
+      {
+        envDefaultOverrides: {
+          RATE_LIMITING_STRATEGY: 'burst',
+        },
+      },
+    ),
+    rateLimiting: {
+      tiers: {
+        asd: {
+          rateLimit1s: 5234,
+        },
+        free: {
+          rateLimit1s: 123,
+        },
+        pro: {
+          rateLimit1m: 1234 * 60,
+        },
+      },
+      requireTierSelection: true,
+    },
+  })
+
+  await t.throwsAsync(async () => start(adapter), {
+    message:
+      'This adapter requires you to specify a rate limit tier via the RATE_LIMIT_API_TIER environment variable',
+  })
+})
+
 test('uses most restrictive tier if none is specified in settings', async (t) => {
   const adapter = new Adapter({
     name: 'TEST',