dashboard/app: add similarity domains for namespaces

It does not make sense to show similar bugs across linux/openbsd/akaros.
Allow restricting similarity domains for namespaces.

Fixes #742

dashboard/app/config.go

@@ -47,6 +47,9 @@ type Config struct {
 	AccessLevel AccessLevel
 	// Name used in UI.
 	DisplayTitle string
+	// Unique string that allows to show "similar bugs" across different namespaces.
+	// Similar bugs are shown only across namespaces with the same value of SimilarityDomain.
+	SimilarityDomain string
 	// Per-namespace clients that act only on a particular namespace.
 	Clients map[string]string
 	// A unique key for hashing, can be anything.
@@ -197,6 +200,9 @@ func checkNamespace(ns string, cfg *Config, namespaces, clientNames map[string]b
 	if cfg.DisplayTitle == "" {
 		cfg.DisplayTitle = ns
 	}
+	if cfg.SimilarityDomain == "" {
+		cfg.SimilarityDomain = ns
+	}
 	checkClients(clientNames, cfg.Clients)
 	for name, mgr := range cfg.Managers {
 		checkManager(ns, name, mgr)

dashboard/app/main.go

@@ -504,6 +504,7 @@ func loadSimilarBugs(c context.Context, r *http.Request, bug *Bug, state *Report
 	managers := make(map[string][]string)
 	var results []*uiBug
 	accessLevel := accessLevel(c, r)
+	domain := config.Namespaces[bug.Namespace].SimilarityDomain
 	for _, similar := range similar {
 		if accessLevel < similar.sanitizeAccess(accessLevel) {
 			continue
@@ -511,6 +512,9 @@ func loadSimilarBugs(c context.Context, r *http.Request, bug *Bug, state *Report
 		if similar.Namespace == bug.Namespace && similar.Seq == bug.Seq {
 			continue
 		}
+		if config.Namespaces[similar.Namespace].SimilarityDomain != domain {
+			continue
+		}
 		if managers[similar.Namespace] == nil {
 			mgrs, err := managerList(c, similar.Namespace)
 			if err != nil {