From 40350600f8d8bf4a29957b3e77176031d25fd06d Mon Sep 17 00:00:00 2001
From: dtfiedler <dylan@ar.io>
Date: Thu, 26 Sep 2024 13:19:18 -0600
Subject: [PATCH] feat(arns): allow operator to override arns ttls and force
 refreshes based on env variable

Intrdocues `ARNS_RESOLVER_OVERRIDE_TTL_SECONDS` env variable which can be used to override when to refresh arns names. If set to `0` the resolver will always attempt to fetch the latest resolution data from the resolvers.
---
 src/config.ts                             |  9 +++++++++
 src/init/resolvers.ts                     |  5 +++++
 src/resolution/composite-arns-resolver.ts | 19 ++++++++++++++++---
 src/system.ts                             |  4 ++++
 4 files changed, 34 insertions(+), 3 deletions(-)

diff --git a/src/config.ts b/src/config.ts
index 10be111b..60ed3304 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -268,6 +268,15 @@ export const ARNS_CACHE_TTL_SECONDS = +env.varOrDefault(
   `${60 * 60}`, // 1 hour
 );
 
+export const ARNS_RESOLVER_OVERRIDE_TTL_SECONDS_STRING = env.varOrUndefined(
+  'ARNS_RESOLVER_OVERRIDE_TTL_SECONDS',
+);
+
+export const ARNS_RESOLVER_OVERRIDE_TTL_SECONDS =
+  ARNS_RESOLVER_OVERRIDE_TTL_SECONDS_STRING !== undefined
+    ? +ARNS_RESOLVER_OVERRIDE_TTL_SECONDS_STRING
+    : undefined;
+
 export const ARNS_CACHE_MAX_KEYS = +env.varOrDefault(
   'ARNS_CACHE_MAX_KEYS',
   '10000',
diff --git a/src/init/resolvers.ts b/src/init/resolvers.ts
index 778a5181..c13b15fb 100644
--- a/src/init/resolvers.ts
+++ b/src/init/resolvers.ts
@@ -70,12 +70,16 @@ export const createArNSResolver = ({
   resolutionOrder,
   trustedGatewayUrl,
   networkProcess,
+  overrides,
 }: {
   log: Logger;
   cache: KvArnsStore;
   resolutionOrder: (ArNSResolverType | string)[];
   trustedGatewayUrl?: string;
   networkProcess?: AoIORead;
+  overrides?: {
+    ttlSeconds?: number;
+  };
 }): NameResolver => {
   const resolverMap: Record<ArNSResolverType, NameResolver | undefined> = {
     'on-demand': new OnDemandArNSResolver({
@@ -113,5 +117,6 @@ export const createArNSResolver = ({
     log,
     resolvers,
     cache,
+    overrides,
   });
 };
diff --git a/src/resolution/composite-arns-resolver.ts b/src/resolution/composite-arns-resolver.ts
index 0bbe48ad..b09d65a1 100644
--- a/src/resolution/composite-arns-resolver.ts
+++ b/src/resolution/composite-arns-resolver.ts
@@ -24,23 +24,34 @@ export class CompositeArNSResolver implements NameResolver {
   private log: winston.Logger;
   private resolvers: NameResolver[];
   private cache: KvArnsStore;
+  private overrides:
+    | {
+        ttlSeconds?: number;
+        // TODO: other overrides like fallback txId if not found in resolution
+      }
+    | undefined;
 
   constructor({
     log,
     resolvers,
     cache,
+    overrides,
   }: {
     log: winston.Logger;
     resolvers: NameResolver[];
     cache: KvArnsStore;
+    overrides?: {
+      ttlSeconds?: number;
+    };
   }) {
     this.log = log.child({ class: this.constructor.name });
     this.resolvers = resolvers;
     this.cache = cache;
+    this.overrides = overrides;
   }
 
   async resolve(name: string): Promise<NameResolution> {
-    this.log.info('Resolving name...', { name });
+    this.log.info('Resolving name...', { name, overrides: this.overrides });
     let resolution: NameResolution | undefined;
 
     try {
@@ -50,11 +61,13 @@ export class CompositeArNSResolver implements NameResolver {
           cachedResolutionBuffer.toString(),
         );
         resolution = cachedResolution; // hold on to this in case we need it
+        // use the override ttl if it exists, otherwise use the cached resolution ttl
+        const ttlSeconds = this.overrides?.ttlSeconds ?? cachedResolution.ttl;
         if (
           cachedResolution !== undefined &&
           cachedResolution.resolvedAt !== undefined &&
-          cachedResolution.ttl !== undefined &&
-          cachedResolution.resolvedAt + cachedResolution.ttl * 1000 > Date.now()
+          ttlSeconds !== undefined &&
+          cachedResolution.resolvedAt + ttlSeconds * 1000 > Date.now()
         ) {
           metrics.arnsCacheHitCounter.inc();
           this.log.info('Cache hit for arns name', { name });
diff --git a/src/system.ts b/src/system.ts
index b06db503..157baed1 100644
--- a/src/system.ts
+++ b/src/system.ts
@@ -568,6 +568,10 @@ export const nameResolver = createArNSResolver({
   resolutionOrder: config.ARNS_RESOLVER_PRIORITY_ORDER,
   networkProcess: arIO,
   cache: arnsResolverCache,
+  overrides: {
+    ttlSeconds: config.ARNS_RESOLVER_OVERRIDE_TTL_SECONDS,
+    // TODO: other overrides like fallback txId if not found in resolution
+  },
 });
 
 const webhookEmitter = new WebhookEmitter({