From e1eb876c9bca0e0f06b5c5e23ed44a2e9578b083 Mon Sep 17 00:00:00 2001
From: Gusted <postmaster@gusted.xyz>
Date: Sat, 28 Jan 2023 13:29:54 +0100
Subject: [PATCH] Add re-try mechanism

---
 server/upstream/domains.go | 75 ++++++++++++++++++++++++--------------
 1 file changed, 48 insertions(+), 27 deletions(-)

diff --git a/server/upstream/domains.go b/server/upstream/domains.go
index 0e29673..a80429a 100644
--- a/server/upstream/domains.go
+++ b/server/upstream/domains.go
@@ -16,45 +16,66 @@ var canonicalDomainCacheTimeout = 15 * time.Minute
 const canonicalDomainConfig = ".domains"
 
 // CheckCanonicalDomain returns the canonical domain specified in the repo (using the `.domains` file).
-func (o *Options) CheckCanonicalDomain(giteaClient *gitea.Client, actualDomain, mainDomainSuffix string, canonicalDomainCache cache.SetGetKey) (string, bool) {
-	var (
-		domains []string
-		valid   bool
-	)
+func (o *Options) CheckCanonicalDomain(giteaClient *gitea.Client, actualDomain, mainDomainSuffix string, canonicalDomainCache cache.SetGetKey) (domain string, valid bool) {
+	// Check if this request is cached.
 	if cachedValue, ok := canonicalDomainCache.Get(o.TargetOwner + "/" + o.TargetRepo + "/" + o.TargetBranch); ok {
-		domains = cachedValue.([]string)
+		domains := cachedValue.([]string)
 		for _, domain := range domains {
 			if domain == actualDomain {
 				valid = true
 				break
 			}
 		}
-	} else {
-		body, err := giteaClient.GiteaRawContent(o.TargetOwner, o.TargetRepo, o.TargetBranch, canonicalDomainConfig)
+		return domains[0], valid
+	}
+
+	var body []byte
+	var err error
+
+	// Make a request to the Gitea instance.
+	// Do at least three attempts before bailing out.
+	for i := 0; i < 3; i++ {
+		body, err = giteaClient.GiteaRawContent(o.TargetOwner, o.TargetRepo, o.TargetBranch, canonicalDomainConfig)
 		if err == nil {
-			for _, domain := range strings.Split(string(body), "\n") {
-				domain = strings.ToLower(domain)
-				domain = strings.TrimSpace(domain)
-				domain = strings.TrimPrefix(domain, "http://")
-				domain = strings.TrimPrefix(domain, "https://")
-				if len(domain) > 0 && !strings.HasPrefix(domain, "#") && !strings.ContainsAny(domain, "\t /") && strings.ContainsRune(domain, '.') {
-					domains = append(domains, domain)
-				}
-				if domain == actualDomain {
-					valid = true
-				}
-			}
-		} else {
+			break
+		}
+
+		// Only log the error on the last iteration.
+		if i == 2 {
 			log.Info().Err(err).Msgf("could not read %s of %s/%s", canonicalDomainConfig, o.TargetOwner, o.TargetRepo)
 		}
-		domains = append(domains, o.TargetOwner+mainDomainSuffix)
-		if domains[len(domains)-1] == actualDomain {
+	}
+
+	var domains []string
+	for _, domain := range strings.Split(string(body), "\n") {
+		domain = strings.ToLower(domain)
+		domain = strings.TrimSpace(domain)
+		domain = strings.TrimPrefix(domain, "http://")
+		domain = strings.TrimPrefix(domain, "https://")
+		if len(domain) > 0 && !strings.HasPrefix(domain, "#") && !strings.ContainsAny(domain, "\t /") && strings.ContainsRune(domain, '.') {
+			domains = append(domains, domain)
+		}
+		if domain == actualDomain {
 			valid = true
 		}
-		if o.TargetRepo != "" && o.TargetRepo != "pages" {
-			domains[len(domains)-1] += "/" + o.TargetRepo
-		}
-		_ = canonicalDomainCache.Set(o.TargetOwner+"/"+o.TargetRepo+"/"+o.TargetBranch, domains, canonicalDomainCacheTimeout)
 	}
+
+	// Add [owner].[pages-domain] as valid domnain.
+	domains = append(domains, o.TargetOwner+mainDomainSuffix)
+	if domains[len(domains)-1] == actualDomain {
+		valid = true
+	}
+
+	// If the target repository isn't called pages, add `/[repository]` to the
+	// previous valid domain.
+	if o.TargetRepo != "" && o.TargetRepo != "pages" {
+		domains[len(domains)-1] += "/" + o.TargetRepo
+	}
+
+	// Add result to cache.
+	_ = canonicalDomainCache.Set(o.TargetOwner+"/"+o.TargetRepo+"/"+o.TargetBranch, domains, canonicalDomainCacheTimeout)
+
+	// Return the first domain from the list and return if any of the domains
+	// matched the requested domain.
 	return domains[0], valid
 }