From 4aa58cf378a397e58dbdf0528adf9e5e914d348a Mon Sep 17 00:00:00 2001
From: achingbrain <alex@achingbrain.net>
Date: Thu, 14 Mar 2024 08:11:34 +0100
Subject: [PATCH] fix: add retries for dnslink

Hitting external services can be flaky as we see periodic failures
in CI for `ipfs.io` and friends so add a retry.
---
 packages/ipns/src/dnslink.ts               |  5 ++---
 packages/ipns/src/index.ts                 | 24 +++++++++++++++++++++-
 packages/ipns/test/resolve-dnslink.spec.ts | 17 +++++++++++++++
 3 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/packages/ipns/src/dnslink.ts b/packages/ipns/src/dnslink.ts
index 24d71a0aa..9be046054 100644
--- a/packages/ipns/src/dnslink.ts
+++ b/packages/ipns/src/dnslink.ts
@@ -12,7 +12,7 @@ async function recursiveResolveDnslink (domain: string, depth: number, dns: DNS,
     throw new Error('recursion limit exceeded')
   }
 
-  log('query %s for TXT and CNAME records', domain)
+  log('query %s for TXT records', domain)
   const txtRecordsResponse = await dns.query(domain, {
     ...options,
     types: [
@@ -76,9 +76,8 @@ async function recursiveResolveDnslink (domain: string, depth: number, dns: DNS,
     }
   }
 
-  // no dnslink records found, try CNAMEs
+  // see if there is a CNAME delegation
   log('no DNSLink records found for %s, falling back to CNAME', domain)
-
   const cnameRecordsResponse = await dns.query(domain, {
     ...options,
     types: [
diff --git a/packages/ipns/src/index.ts b/packages/ipns/src/index.ts
index 72f9013af..a689d893c 100644
--- a/packages/ipns/src/index.ts
+++ b/packages/ipns/src/index.ts
@@ -253,6 +253,7 @@ const HOUR = 60 * MINUTE
 
 const DEFAULT_LIFETIME_MS = 24 * HOUR
 const DEFAULT_REPUBLISH_INTERVAL_MS = 23 * HOUR
+const DEFAULT_DNSLINK_RETRIES = 3
 
 export type PublishProgressEvents =
   ProgressEvent<'ipns:publish:start'> |
@@ -321,6 +322,13 @@ export interface ResolveDNSLinkOptions extends AbortOptions, ProgressOptions<Res
    * @default 32
    */
   maxRecursiveDepth?: number
+
+  /**
+   * Retry in case of transport error
+   *
+   * @default 3
+   */
+  retries?: number
 }
 
 export interface RepublishOptions extends AbortOptions, ProgressOptions<RepublishProgressEvents | IPNSRoutingEvents> {
@@ -424,7 +432,21 @@ class DefaultIPNS implements IPNS {
   }
 
   async resolveDNSLink (domain: string, options: ResolveDNSLinkOptions = {}): Promise<ResolveResult> {
-    const dnslink = await resolveDNSLink(domain, this.dns, this.log, options)
+    let dnslink = ''
+    const retries = options.retries ?? DEFAULT_DNSLINK_RETRIES
+
+    for (let i = 0; i < retries; i++) {
+      try {
+        dnslink = await resolveDNSLink(domain, this.dns, this.log, options)
+        break
+      } catch (err) {
+        if (i === (retries - 1)) {
+          throw err
+        }
+
+        log.error('error resolving %s attempt %d of %d', domain, i + 1, retries, err)
+      }
+    }
 
     return this.#resolve(dnslink, options)
   }
diff --git a/packages/ipns/test/resolve-dnslink.spec.ts b/packages/ipns/test/resolve-dnslink.spec.ts
index 40c3ceb4a..9df6576e4 100644
--- a/packages/ipns/test/resolve-dnslink.spec.ts
+++ b/packages/ipns/test/resolve-dnslink.spec.ts
@@ -70,6 +70,23 @@ describe('resolveDNSLink', () => {
     expect(result.cid.toString()).to.equal('QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn')
   })
 
+  it('should retry on failure', async () => {
+    dns.query.withArgs('foobar.baz')
+      .rejects(new CodeError('Not found', 'ENODATA'))
+
+    dns.query.withArgs('_dnslink.foobar.baz')
+      .onFirstCall().rejects(new CodeError('Not found', 'ENODATA'))
+      .onSecondCall().resolves(dnsResponse([{
+        name: '_dnslink.foobar.baz.',
+        TTL: 60,
+        type: RecordType.TXT,
+        data: 'dnslink=/ipfs/QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn'
+      }]))
+
+    const result = await name.resolveDNSLink('foobar.baz', { nocache: true, offline: true })
+    expect(result.cid.toString()).to.equal('QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn')
+  })
+
   it('should handle bad records', async () => {
     dns.query.withArgs('_dnslink.foobar.baz').resolves(dnsResponse([{
       name: 'foobar.baz.',