[feature] Create/update/remove domain permission subscriptions (#3623)

* [feature] Create/update/remove domain permission subscriptions

* lint

* envparsing

* remove errant fmt.Println

* create drafts, subs, exclude, from snapshot models

* name etag column correctly

* remove count column

* lint

internal/cache/db.go

@@ -70,6 +70,9 @@ type DBCaches struct {
 	// DomainPermissionDraft provides access to the domain permission draft database cache.
 	DomainPermissionDraft StructCache[*gtsmodel.DomainPermissionDraft]
 
+	// DomainPermissionSubscription provides access to the domain permission subscription database cache.
+	DomainPermissionSubscription StructCache[*gtsmodel.DomainPermissionSubscription]
+
 	// DomainPermissionExclude provides access to the domain permission exclude database cache.
 	DomainPermissionExclude *domain.Cache
 
@@ -589,6 +592,37 @@ func (c *Caches) initDomainPermissionDraft() {
 	})
 }
 
+func (c *Caches) initDomainPermissionSubscription() {
+	// Calculate maximum cache size.
+	cap := calculateResultCacheMax(
+		sizeofDomainPermissionSubscription(), // model in-mem size.
+		config.GetCacheDomainPermissionSubscriptionMemRation(),
+	)
+
+	log.Infof(nil, "cache size = %d", cap)
+
+	copyF := func(d1 *gtsmodel.DomainPermissionSubscription) *gtsmodel.DomainPermissionSubscription {
+		d2 := new(gtsmodel.DomainPermissionSubscription)
+		*d2 = *d1
+
+		// Don't include ptr fields that
+		// will be populated separately.
+		d2.CreatedByAccount = nil
+
+		return d2
+	}
+
+	c.DB.DomainPermissionSubscription.Init(structr.CacheConfig[*gtsmodel.DomainPermissionSubscription]{
+		Indices: []structr.IndexConfig{
+			{Fields: "ID"},
+			{Fields: "URI"},
+		},
+		MaxSize:   cap,
+		IgnoreErr: ignoreErrors,
+		Copy:      copyF,
+	})
+}
+
 func (c *Caches) initDomainPermissionExclude() {
 	c.DB.DomainPermissionExclude = new(domain.Cache)
 }